Saturday, January 2, 2016

Long-term Outlook


With the past few days of computer model runs, forecasts are coming into agreement that colder, and potentially snowier weather is on the way. While colder temperatures and snow showers are likely this weekend and early in the week, this will only be brief, as temperatures will moderate once again above normal by the mid to late portion of next week. However, this appears to be only transient.

Models are now beginning to show much colder weather infiltrating into the United States beginning in the 8 to 10 day period. [January 10th through the 12th]. Interaction with a disturbance in the southern stream will likely result in some sort of storm system moving from the Deep South off the coast and developing as a potential coastal low. After this disturbance, the northern stream [polar jet] will begin to dominate again as blocking begins to develop across high latitudes. A lot remains to be seen with this storm system [the Deep South/potential coastal storm], as it is only one possible solution, but even if this storm system does not develop, a fresh wave of Arctic air should move southward out of Canada and engulf the area soon after. And given past scenarios where this has occurred, there's at least a decent chance some areas will get accumulating snow out of this, whether it is from the southern low or from the weak clipper system that brings the cold air out of Canada.

At the same time, however, it is uncertain as to how long this wave of Arctic air will last. Given the depiction of the event on ensembles and operational model runs, it looks as if it as the potential to last for at least a several day period if not longer. Even when the coldest of the air leaves the region, it is still very likely that temperatures remain near or below normal for the remainder of January, with only a few days of above normal temperatures to end the month [it is possible that we see another transient warm up ahead of another Arctic wave as we head towards the end of the month].

Hopefully I'll be able to post a more detailed discussion of the situation later tonight or tomorrow. Until then, I'll just end the post with the 06z GFS solution for ten days from now [shown above]. This image is depicting a massive Arctic high pressure system sliding southward out of Canada, bringing a round of snow to the Central Plains with the associated clipper [which very well may give a good portion of the Ohio Valley a snow event].

Wednesday, December 30, 2015

Top Four Misconceptions About Weather Forecasting

Whenever I tell someone that I aspire to be a meteorologist as my future career goal, I'm usually faced with a lot of the same questions and statements, ranging from the rather insulting to the more curious inquiries:

Weather forecasting is the only job where you can be wrong 50% of the time and still keep your job.

Meteorologists are never right.

It must be easy having their job.

Do meteorologists predict meteor showers (or earthquakes, tsunamis, eclipses, and other physical phenomena)?

How can anyone predict the future?
 

And there are many more statements that I have had asked to me [and about other meteorologists] over the past several years. In order to help remedy this situation, I thought it would be nice to write an article explaining what forecasting is and isn't, as well as clearing up some common misconceptions. While I won't necessarily address all of the concerns listed above, I will be addressing more common [and reasonable] sentiments about the field of weather forecasting.

1. Meteorologists are hardly ever accurate.

This is the common profile of the meteorologist as known and expressed by the general public. Meteorologists are generally the punchline of many a joke, especially those that make light of our inaccurate forecasts.

However, this is not necessarily true. Yes, it is true that there are many forecasts that we screw up and there are many times when we fail to admit that we've screwed up. But for the average operational forecaster, either working for a private firm, a broadcast station, or for the U.S. Department of Commerce, there is generally a lot more forecast skill and accuracy than one would expect (as a side note, I would like to point out that there is a major distinction between 'skill' and 'accuracy' which won't be addressed here, but it is possible for a forecaster to have high accuracy, but low skill in their forecasting, just as it is possible to have high skill, but lower accuracy). What many do not often account for is the fact that forecasters do a lot more than just tell us when the next storm will hit or how much snowfall we will get from a winter weather event, but also make daily forecasts. Daily forecasts generally consist of the high temperature, the low temperature, wind speeds/direction, cloud cover, and the chance of precipitation. For the vast majority of situations, forecasters are generally fairly accurate. It is only when abnormal weather shows up that forecast skill and accuracy begins to vary.

Even then, however, forecast accuracy has strongly improved over the past several decades. Studies and assessments from the last ten years ultimately show that forecast skill and accuracy has markedly improved, especially in forecasting events that occur in the short term, ranging from six hours in the future to as much as two days. This is especially true for rapidly developing severe weather situations and mesoscale winter weather features. In all likelihood, this is due to the development of high-resolution short-range numerical weather models that are specifically designed to forecast small-scale phenomena which 'larger' global models cannot handle. Computer models will be addressed below.

In all, forecasts are generally not as inaccurate as everyone supposes. Most only remember 'that one time' when the forecaster screwed up on a major weather event. The general public usually doesn't remember when the forecaster actually got the forecast right, which is probably a majority of the time.

Note: There is still some debate about whether forecast accuracy has actually improved over the last ten years [from 2005-2015], but I can't find any sources on the issue. What I do know, however, is that the National Weather Service has come under heavy criticism from various meteorologists about their training process and their accuracy.


2. Forecasters just make up numbers from nothing. Anyone can do what they do.
 

Although I haven't heard this one from anyone in particular, I think there is a general confusion from a lot of people about what exactly forecasters do and how the forecasts are even made. I will address this issue here and in the next section.

Here's the problem: A lot of time and effort often goes into the making of a forecast [or at least it should for any good forecaster] and is really more complicated than what one imagines. There are times when it certainly feels like forecasters are simply making up numbers just for the sake of getting a forecast out. There are even times when this is all a forecaster can do. When the weather pattern is relatively stable and nothing much is changing, this is really all the forecaster can do.

When a particularly dangerous and abnormal situation comes up, this is when forecasting skills are best tested for their accuracy. A forecaster must learn to draw upon not only his conceptual and scientific knowledge of the atmosphere. They must also be able to learn from their experience and apply what they learn to new situations. Finally, the forecaster must rely upon his or her intuition in order to make the final decision in the forecast. When dealing with intense situations, like major winter storms or imminent severe weather, these decisions have to be made regardless of what the actual data shows. The data only shows a part of the whole story; the forecaster has to be able to connect the data with their own experience and make a quick decision.

This goes along with general forecast accuracy; sometimes the forecast is inaccurate because of the precautions that the forecaster personally took when publishing the forecast. It is always better to remain on the safe side during a dangerous situation than to not say anything at all.

3. There's no way you can predict the future! 

While this is technically true, I think the objection misunderstands the nature of the practice of weather forecasting. Weather forecasting isn't so much about 'foretelling the future' as it is simulating the future state of the atmosphere based upon known data from the present. It isn't so much predicting what will happen as it is trying to establish connections between weather phenomena.

As mentioned above, the main reason why modern forecasting has made great strides in forecasting is due to the advent and use of computer technology in forecasting. Because of the impressive advances in computer power, calculation, and storage, meteorologists have used these computers to simulate the future state of the atmosphere.

How is this possible? In the early 1900's, scientists, who became the pioneers for the modern field of meteorology and atmospheric science [this is one of the newer sciences], derived a series of equations dependent upon Newton's laws of motion and thermodynamics that were able to 'describe' (in a sense) certain scalar and vector quantities in the atmosphere. These included, but are not limited to, variables such as temperature, moisture, wind, pressure, etc. Some of these scientists proposed that, in theory, if one could solve these equations and then duplicate this process, one could forecast the state of the atmosphere at a given future time period. One particular scientist attempted this process by hand, trying to forecast the weather for a location in France for 48 hours out; it took this particular scientist nearly two years before he could finally come up with a forecast! This might seem like a huge failure, but in reality, it was one of the biggest breakthroughs in modern scientific thought. This precipitated action by other scientists to try to solve this dilemma by using different methods for solving these equations.

Finally, with the advent of computers, they were utilized to attempt to address this issue. The first model 'forecasts' were run in the early 1950's on some of the first supercomputers. The forecast was crude and very inaccurate, but it was a breakthrough in modern forecasting. Over the next decade, forecast accuracy improved remarkably with these primitive equation models (as they were called). While they were not used to forecast variables such as surface temperature and wind directly, they were used to forecast the general upper level weather pattern, which allowed forecasters to make more reasonable predictions about imminent weather.

Now, forecast models are run on the world's fastest supercomputers, making billions upon billions of calculations in a very short period of time. These model forecasts, in the United States at least, are produced every 6 hours [at 00, 06, 12, and 18 GMT], and can span either the entire world [as in the infamous Global Forecasting System] or simply North America [as in the North American Model or the NAM]. Forecasters then take this data and integrate them into their own decision making process for the final forecast product.

Unfortunately, numerical weather prediction doesn't solve all the troubles of the forecaster. Model forecasts are limited by the data they ingest, their own physical parameters and methods of solving the equations (which differ from model to model). Plus, there is simply too much chaotic motion in the atmosphere for any model simulator to deal with. This is why human forecasters will always be needed. Unlike computers, humans possess the necessary memory and intuition needed for the final forecast to be successful.

4. Meteorology is an easy career path

 
Unfortunately, it isn't very easy at all. For those who become meteorologists by going the traditional route, by attending college and acquiring a B.S., the road isn't easy. Meteorology is a field of science that draws upon many other different fields. In a way, it is very interdisciplinary in comparison to other fields of science. Because of this, meteorology majors are required to be rigorous in mathematics and must be able to have computer and programming skills. They must also have additional advanced knowledge in fields like physics and chemistry, both very important fields for understanding atmospheric processes. Meteorologists must also have a working knowledge of geography and topography. They must be familiar with social media, have writing and communication skills, and should be familiar with broadcast journalism.

Even for the meteorologist that does not take the traditional college route, they must have a working knowledge of all the fields mentioned above. Furthermore, a meteorologist who is not college educated has to pass the American Meteorological Society test that allows one to become a certified meteorologist. Thus, they must be able to demonstrate that they have working experience and knowledge in operational forecasting [which is the most practical application of the field].

Even after all the educational requirements are completed, it's often very difficult for students to find jobs in the field of meteorology. In years past, the federal government has been the largest employer of meteorologists, but with freezes in spending and the cutting of funds to branches like the National Weather Service, there isn't as much hiring anymore. "Tenured' or experienced meteorologists generally remain with the weather service for long periods of time which doesn't allow for a lot of flexibility for incoming meteorologists.

Fortunately, the private forecasting field is expanding for incoming meteorology students. Energy corporations, private firms, insurance companies, and others are now looking for more meteorologists to hire. These companies benefit from both the short term and long-term forecasts that meteorologists can give, allowing them to make better and wiser decisions.

Conclusion

 
With how difficult forecasting and the career field can be, why does anyone bother becoming a meteorologist in the first place? Mainly because most of us enjoy what we do. I have talked to many meteorologists and nearly every single one that I have talked to have always had a passion for the weather. One thing that characterizes many meteorologists is the 'in-born' passion that many of us had as children. This is one field that if you don't truly love it you shouldn't go into it. It isn't for the light-hearted and it certainly isn't for those who only give lip service to the passion. But for anyone who truly loves nature and the outdoors, meteorology is certainly a field that is both practical and awe-inspiring to study and admire.

Tuesday, December 29, 2015

Winter is Arriving... Finally

After waiting anxiously for well over a month, snow lovers are gasping a sigh of relief as forecast models are finally depicting a better and improved winter weather pattern across much of the United States.

While I don't have too many details at this time, it appears that we will likely see progressively colder weather affect the area over the next two weeks. The first wave of colder weather will hit the area later this week, as highs struggle to make it above 30 degrees by the opening days of 2016.  Fortunately [or unfortunately, depending upon your perspective], temperatures will once again moderate as upper-level ridging across Canada allows warmer air to filter into the region. There are, however, consistent long-range signals from forecast models and ongoing observations/trends that suggest a far more substantial pattern shift is ongoing. In fact, in the January 10-15th time period, we could finally see an active winter pattern across the East, with cold Arctic air and the potential for snow coming into the picture. I will have more updates on this possibility in the next few days.

Sunday, May 3, 2015

Thunderstorms and Warm Summer-like Weather On the Way

After several consecutive months of below normal temperatures, wet, snowy conditions, and overall dismal weather, things are finally turning around for the month of May. And it looks to stick around for a good portion of the next two to three weeks, if not longer.

Over the past two or three days, the area has experienced temperatures in the mid to upper 70's, which is above to well above normal for this time of year. With sunny skies and light winds, this has allowed for nearly optimal conditions for prom weekend across the region. However, this nice weather doesn't look to stick around. Thunderstorms are moving back into the forecast and they look to impact the area on more than a few days this week and the following weekend.

A surge of modest moisture from the Gulf of Mexico, a shifting frontal boundary and relatively warm conditions will allow for the development of scattered numerous thunderstorms on Monday afternoon and evening. While instability is not expected to be all that incredible, it will be enough for thunderstorm development and even a small chance for isolated severe weather. Thunderstorms will become more widespread Monday night into Tuesday before ending Tuesday afternoon. Rainfall amounts could be up to a half inch or more across the area.

By Wednesday, drier, warmer conditions will move into the region, with highs approaching the lower 80's under partly sunny skies. By Thursday and Friday, temperatures may approach the mid-80's with slightly higher humidity. By Saturday and Sunday, thunderstorms look to be a threat once again, especially as humidity levels increase. That being said, temperatures should remain relatively warm in the 80's, which is well above normal for this time of year. This type of pattern is expected to continue well into next week as weak upper-level ridging remains across the eastern United States.

I will have more updates later.

Monday, February 2, 2015

Post Storm Overview


This is a revised version of an article I wrote that will be published in the West Bend News this coming Wednesday. I will be posting a more detailed analysis of the storm later this week.

After a winter that has been relatively cold and snowy across the area, I think many of us are ready for the nice, warm, and even wet weather of March and April. This is especially true after the area was recently hit by a strong blast of winter weather, blasting the area with heavy snow, ice, and gusty winds. Now we’re all hoping that winter ends soon, even if Punxatawney Phil disagrees.


On January 31st through February 2nd, the lower Great Lakes region, including northwest Ohio, northeast Indiana, and southern Michigan, was hit by a crippling winter-storm. Stretching from Omaha, Nebraska to Albany, New York, heavy snowfall and freezing rain shut down major highways and cities, with up to 20” of snow observed in some locations. The I-80/I-90 turnpike had travel restrictions due to the dangerous conditions. Hundreds of flights were cancelled at Chicago O’Hare and Midway airports, as well as at Fort Wayne, Detroit, and Cleveland. Many schools were closed on February 2nd due to snow-covered and in some cases, impassable roads.

Freshly-fallen snow outside of my house in the early morning February 2nd.
The storm was just as significant across northeast Indiana and northwest Ohio. Reported total snowfall across the area ranged from as little as 6” in Putnam county to as much as 13” in Allen and Whitley County, Indiana. In Antwerp, 10.6” of snow was measured, while in Fort Wayne and Defiance, as much as a foot of snow was reported. Across far northern Indiana, snow totals ranged from 15-20”, making it the most significant snowstorm since the Groundhog’s Day blizzard of 2011 and the New Year’s blizzard of 1999. The storm also produced strong, gusty winds across the area, leading to significant blowing and drifting snow well after snowfall had ended on the night of February 1st and into the morning of February 2nd. Drifts as high as three to five feet were reported in some locations, especially in northern Indiana. Blowing and drifting lead to travel emergencies and restrictions area wide, with many roads becoming impossible to drive on or even impassable.

Across Northern Illinois and lower Michigan, snowfall amounts as much as 20" were reported. Chicago reported a snow total of 19.3", making it its fourth largest snowstorm on record. Detroit reported over 16" of snow, making the storm its third largest snowstorm on record. Many other locations reported similar totals.

Where did this storm come from? Why did it form? And can we expect more to come for the rest of the winter?

It began with an upper-level disturbance that moved onshore British Columbia Thursday night, January 29th. Forecast model guidance had suggested that the disturbance would dive southeast into the United States and produce a swath of light to moderate snow from the Central Plains to the East Coast. At most, snowfall of 4-6” was expected across parts of the Midwest, southern Indiana, Ohio, and into Maryland and Virginia. However, by early Thursday morning, forecast guidance began to shift the track northward, foreshadowing the development of a much more powerful storm system.

By January 30th, the development of the storm was fairly certain. The upper-level disturbance across British Columbia would still dive southeast, but it would also interact with a weak upper-level low across the American Southwest. This interaction would strengthen the disturbance, fueling it with abundant moisture from the Pacific Ocean and the Gulf of Mexico. Forecast models were then showing a significant snowstorm stretching from Chicago eastward into Pennsylvania. Snowfall totals of 16-20” of snow were indicated by forecast models, especially from Chicago to the Fort Wayne area. National Weather Service forecasters indicated that if 16-20” of snow were to fall, it would be one of the area’s heaviest snowstorms to ever impact the area. However, the NWS was not going to predict such high totals due to the uncertainty involved.

By Saturday, January 31st, forecast models were making some uneasy. While they had retained the record-breaking snowfall amounts, models were showing differing placement of the heaviest snow. They were now indicating that the heaviest snow would fall just to the north of our area. For this reason, the National Weather Service kept snowfall amounts in the 10-15” range when they issued the Winter Storm Warning. Not only this, but there was also the possibility that blizzard conditions would be present across the area. The National Weather Service refrained from issuing a blizzard warning due to the fact that the strongest winds were not expected to impact the area until after the snow had ended, but they did note that near blizzard conditions would be possible during the heaviest snowfall.

Widespread precipitation developed across the Central Plains by the afternoon and evening hours Saturday. By nightfall, light to moderate snowfall mixed with rain was impacting the Chicago area.

Snow began falling across our area by 11 p.m. that night. Light to moderate snow fell through most of the night, with most locations reporting 2-4” by Sunday morning. As the low-pressure system developed, however, a break in the snow was observed in many locations, especially east of I-69. Very light snow fell for most of the morning across Paulding and Defiance counties, with heavier snow just off to the west. At the same time, moderate to heavy snowfall continued across northern Indiana, extreme northwest Ohio, and southern Michigan, with snowfall totals quickly approaching a foot by early afternoon.

By noon, moderate to heavy snow had shifted back into the region, dropping visibilities and making roads hazardous.


Snow continued through most of the afternoon, mainly north of U.S. 30. With the strengthening low-pressure system, warmer air was drawn northward into the Lima and Van Wert areas, causing some of the snow to mix with or change over to rain. Surface temperatures rose into the mid and even upper 30’s across these locations. This was something that surprised forecasters, as the warm air was not expected to reach this far north. By late afternoon, cold, Arctic air seeped southward into the area, changing all precipitation to snow, and allowing another period of moderate to heavy snow to blast the area. By 9 p.m., only light snow was being reported across the area, with storm total accumulations approaching a foot in many locations. This was especially true north and west of U.S. 24.

This winter-storm will not likely be forgotten. Although we didn’t see nearly as much snowfall as areas north and west of us did, the 8-14” of snow that many of us did see was enough to shutdown schools and businesses across the area. This certainly reminded us that we are still in winter, and still in an area that is prone to major winter storms.

Thursday, January 29, 2015

Winter-Weather and Potential Storm

As I said in an earlier post this month, I won't be posting as much because I'm working on a new Wordpress site, and I'm still trying to transfer articles from this page onto that one. But for now, I'll occasionally post on this blog and on my FB page. I am also a blogger on another significant weather page, so you can follow me at www.wildaboutweather.com.

I have a few concerns this morning.

First, the area had some light freezing rain last night, leading to icy surfaces just about everywhere. At this time, most schools across the area have closed and nearly all have delayed. Be careful out there! Temperatures should rise throughout the morning hours, so by noon, icy roads should be gone. The potential for snow, sleet and rain will continue into the afternoon, before tapering off later this evening.

After this, a weak cold-front will move through, dropping temperatures back into the 20's. This is when yet another system will begin to impact the area.

At this time, however, not much is known, and any rumor that you have heard about a "major snowstorm" is probably wrong. No forecast scenario shows a "major snowstorm" and many of the forecast solutions show only a short period of light-moderate snow on Sunday. However, there is a LOT of disagreement between forecast models at this point, and so we really can't rule anything out.

Going against the grain of the European and the American model, I believe there is enough evidence to support my growing confidence that a strengthening system will track through the Ohio Valley, and then transfer to the coast. This means that many areas from the Central Plains through the lower Great Lakes and Northeast could see some sort of winter-weather event. Whether it will be a "significant snowstorm" or a period of light snow has yet to be determined.

Model guidance such as the long-range NAM is showing the potential for a much more significant storm. So are the Canadian and British guidance [CMC and UKMET]. The GFS is taking the middle ground with only a moderate snow-event for areas from Chicago to Indianapolis, Detroit, and Cleveland [and everywhere in between]. However, given that there is very little confidence at this point, we really don't know what's going to happen. The only thing I can say is that I will be monitoring the potential for a winter-storm and it *COULD* be significant.

I will have more details over the next few days.

Saturday, January 3, 2015

Icy Roads, Rain, Bitter Cold, Snow and More!


I apologize for not having posted in the last two months. I've mainly been posting updates on the FB page for the time being, as I plan on transitioning the blog to a Wordpress site [which is quite a bit more user-friendly than blogger].

Here's what I had posted on Facebook page earlier today:

After a rather messy set-up this morning [I had a lot of trouble just getting to work this morning!], all precipitation has transitioned over to rain with the exception of counties further north. Counties along the Indiana/Michigan/Ohio border COULD continue to see freezing rain for a little while longer before temperatures get warm enough to allow any remaining ice to melt. Even in areas where temperatures have warmed into the mid-30's, roads are still rather icy and dangerous, so exercise caution.

Rain will continue through the evening hours before tapering off overnight. A few showers will persist but nothing substantial until Sunday morning when sleet/freezing rain/snow should redevelop, with a complete transition over to snow for the afternoon, mainly west of I-69. Areas farther east will likely see some snow, but not before it tapers off. Snow accumulations will not be substantial, with the only real chance of accumulation being in the lake-effect zones.

By Sunday night, all precipitation will taper-off, leaving behind breezy conditions and falling temperatures. Temperatures will likely fall into the lower 10's and single digits Monday morning as the Arctic front sweeps into the region. Wind-chills will likely be below zero as well.

Temperatures will remain rather steady on Monday, with a very real possibility that some areas DO NOT make it above 10 degrees for a high. With slightly breezy conditions, bitterly cold wind-chills will be in place.

However, by Monday night, a clipper-system will approach the region rather quickly, bringing periods of light to moderate snow by the very early morning hours. Snowfall should be at its heaviest by the Tuesday morning commute. Based upon current model indications most of the snowfall should end by noon or early afternoon, but could linger a little while longer in areas east of I-69.

At this time, snowfall amounts are uncertain, as there is too much uncertainty regarding the intensity of the system and the amount of moisture involved. If more moisture is involved and the system actually develops a closed surface low, we might see more substantial snowfall. However, this does not appear likely. The National Weather Service has said that they are expecting rough amounts in between 3-6". I will keep you updated on this system!


Monday, November 10, 2014

Winter is Coming... And Not in a Good Way.

Winter is coming! But probably not in the way that you want it to. I guess this year it decided to come three weeks early and it looks like it's here to stay.

As many of you have probably heard by now, the "polar vortex" is coming and we're all going to freeze to death!

No, just kidding.

But this is how many media outlets are presenting the latest outlook for the period of mid-late November.

And it's a myth. It's a sensationalist fabrication of the journalist attempting to make a "newsworthy" story.

First, the "polar vortex" is not coming down from the Arctic. It didn't even technically come down "last winter" either. In reality, intense warming in the lower stratosphere, aided by a meridional polar jet stream caused the polar vortex to split, forcing the cold air southward on both sides of the hemisphere. It was a "piece" of the polar vortex, but it wasn't the "polar vortex" itself.

What's happening right now is the same thing.

Second, it isn't "comparable" to Hurricane Sandy or any other extreme event. The only thing "extreme" about it is that temperatures in the core of the Arctic air mass associated with it will be nearly three standard deviations below the mean temperature for this time of year. In other words, temperatures will be colder than approximately 99% of all recorded Novembers for many locations. It will definitely be cold and definitely close to historic in terms of longevity and intensity.

So, let me give a brief synopsis of what's happening, and what we expect to happen over the next few weeks.

Let's begin with looking at today's weather map. Right now, we have a sprawling low-pressure system centered in the Central Plains and quickly developing to the northeast. By late tonight, the surface low will become closed and quickly move eastward. By Tuesday night, the storm system will swing a polar front through the region, dropping temperatures into the upper 20's by early morning.

WPC North American surface analysis

By Wednesday, a vast Canadian vortex will be centered to our north, pivoting multiple minor waves across the area at the same time. The vortex will keep the cold-air mass in place through the weekend. By Sunday, the general model consensus is that a slight moderation in temperatures will occur, as another wave of low pressure approaches from the west. While nothing major is anticipated, we could see a few snow showers and/or light snow during the day. Temperatures will likely be in the mid-upper 30's.

This is when major model discrepancies come into play. There are numerous variations between model solutions right now in terms of the strength, placement, and timing of another wave of Arctic air into the region. The only thing that is somewhat certain at this point is that temperatures will likely be colder than what they will be with the first wave of Arctic air. Models continue to contradict each other in terms of when this cold wave will make it to the area, how long it will last, and ultimately, how cold it will get. At this point, there's nothing much else I can say.

However, given current observations and trends in long-term indicators, it appears to me that a more prolonged period of Arctic air is likely. This is due to two significant factors:

1. Intense ridging across Alaska and far northwestern Canada will be nearly three standard deviations above normal, which indicates an incredibly strong ridge of high-pressure. This will likely cause an omega block to form, which will trap cold, Arctic air in most of the United States, especially east of the Continental Divide. Blocking across Greenland could become a major factor as well, depending upon the strength of the Scandinavian ridge that is expected to develop in response to the polar-vortex breakdown.

2. Snow-cover build up has accelerated once again across Canada and now across the Northern Plains and Upper Midwest [especially after the current snowstorm]. This will lessen any air mass modification that might occur over the next few weeks and help to lock the cold-air in. This will especially be the case if we see several more winter weather events in the next two weeks or so. Right now, I am monitoring the possibility for a possible snow-accumulation event occurring sometime next week, but the details are too uncertain to say much else.

http://www.hpc.ncep.noaa.gov/medr/d7500wbg.gif

While I do not expect this wave of cold-air to last much longer than a week or two at the current time, it is possible that this colder-than-normal weather sticks around for Thanksgiving time. Given the fact that long-range meteorologists are even surprised at the magnitude of this event, it would not even surprise me if we see a significant winter weather event around the time of Thanksgiving.

Tuesday, November 4, 2014

Comparisons Between November 1976 and the Present Pattern




Differences and comparisons between Nov. 1976 pattern and current predicted pattern for the 8-14 day period:

As I was doing research today during school on the ensemble forecasts for the next few weeks, as well as the analogues that the Climate Prediction Center puts out on a daily basis, I found an interesting trend. Nov. 1976 keeps appearing as one of the analog years.

So, I decided to do a comparison between the two.

First, the overall pattern for Nov. 1976 was one in which there was an enormous trough stretching from western Siberia to just south of the Aleutian islands. This is the type of trough that is currently being forecasted by ensemble guidance due to the influence of the incredible remnants of the super typhoon. Due to this influence on the global longwave pattern, I don't expect that this longwave trough will break down very quickly. And as long as this trough remains in place, the pattern will remain blocked and stuck, meaning that a mean trough will continue over Canada and the Central/Eastern United States.

THIS DOES NOT MEAN THAT THERE WON'T BE ANY PERIODS OF ABOVE NORMAL TEMPERATURES. It just means that the pattern will be dominated by bouts of Arctic air, and occasional waves of Pacific air [due to the fact that blocking won't be as prevalent as we would like it until the effects of the SSW become more prevalent].

Given that the longwave won't necessarily be locked in place across North America, I still expect quite a bit of volatility, meaning the potential for large temperature swings and major storm-systems [mainly cutters and possibly a Nor'easter].

As for other comparisons, the Western North American ridge is pretty much in the same location that it was in Nov. 1976. Given this, and holding other factors constant, I would not doubt that this will become a more permanent feature of the winter. But this is still rather uncertain [as there always with comparisons to past analogue years]. Blocking should also be slightly farther west than what occurred in 1976-1977, which may mean that the colder air may be positioned farther west than what one would normally expect in an El Nino-like pattern.

The only main difference is that the Canadian-vortex in Nov. 1976 seems to have been much stronger, but I don't doubt that the Canadian vortex that is forecast to drop into the United States sometime next week could be just as intense. I just don't expect the Canadian vortex to be as consistently strong as it was in '76.

Another difference is perhaps the fact that there was a lack of strong blocking across the poles. Based upon the mean 500 MB pattern from Nov. 1976, it appears that the PV was stronger across the poles, but this is more likely due to the fact that the Arctic regions were well below the 1981-2010 normal [average column temperatures] in comparison to today. I don't know if this will have any impact on the going forecast for late Nov. to early Dec. but it could be significant in terms of potential winter-storms, and Arctic outbreaks.



Thursday, October 16, 2014

NOAA's Winter Outlook and My Criticisms

Okay, I would like to begin by saying that I am not a "degreed" meteorologist. I am not paid by the government. I am not even in college *yet. I don't have much experience either. I've been attempting to forecasting the weather for about three or four years now, based upon my limited knowledge of atmospheric science and the countless hours I've spent reading books and participating in internet discussions. I'm certainly not a professional by any definition of the word.

With that being said, I would like to share a few of my thoughts on the National Oceanic and Atmospheric Administration's latest released winter-outlook.

Today, the Climate Prediction Center released its forecast outlook for the months of December 2014 through February 2015, which is generally considered the winter-outlook period by NOAA. Keeping consistent with CPC "tradition", they have released both the temperature outlook and the precipitation outlook.

For one thing, you'll notice that the CPC's outlooks are relatively similar to most other winter-outlooks; they both show expected precipitation and temperature anomalies.

However, the difference between the CPC's outlook and most other outlooks is that the CPC relies upon probabilities for the map. If you'll notice the maps [see above], the defining feature of the shaded regions is that of probabilities. The probabilities indicate the amount of certainty that climate forecasters at the Climate Prediction Center have for that particular forecast. For instance, in the case of the precipitation map, the "wetter" regions are actually regions where the CPC is MORE confident that higher-than-normal precipitation will occur during the winter months. In the case of the temperature maps, the "warmer" regions denote regions where the CPC is more confident that higher-than-normal temperatures will occur.

There is also a large region of "equal chances" on both maps. This is a category that the CPC uses when it is most uncertain about a specific forecast. In reality, it just means that the outlook for these regions is highly uncertain and could swing either way.

But I have a major criticism of this type of forecasting.

And take them for what they are-- opinions. That's it.

My problem with the CPC's forecast is two-fold. In the first place, the forecast is too general and vague for anyone in the general public to take seriously. The CPC would be better off not releasing a public forecast such as this and keeping quiet about press-releases. Of course, it is the job of the CPC to release long-range outlooks such as this. But it is all too easy for the general public to misunderstand what is actually being said. Most will take a first glance at the maps and then conclude that the Great Lakes will be dry and normal for the winter [probably good news for anyone who hates snowy, cold weather!]. Yet, that is precisely what the CPC is NOT saying! In other words, the CPC is about as bad at communicating statistical information to the public as USAToday is.

My second criticism has more to do with my own personal thoughts on the winter.

First, I think the forecast is too reliant upon the fact that an El Nino is developing in the Equatorial Pacific. While it is not certain how strong the El Nino will become in the next few months, recent strengthening of warm SST anomalies along the Equator has lead many forecasters to believe that a long-term El Nino is finally developing [having been forecast to do so two years ago].

According to what the "textbooks" say about a general El Nino pattern, a general rule of thumb for the winter-outlook is that the winter will feature above normal temperatures across the northern United States, Canada, and Western North America. Also included in this "rule of thumb" is that the Ohio Valley and Great Lakes will generally see below normal precipitation, along with equal chances of being warm or cold for the winter-months. Most importantly, an El Nino usually correlates with a cold, wet Southern winter.

As you can see, this "textbook" definition almost exactly matches the forecast released by the CPC today.

I agree that an El Nino is developing in the Pacific. A more dominant +PDO, along with warmer waters in the Western Pacific will definitely allow it to develop further.

However, given the weak state of the El Nino currently [in fact, it isn't even officially classified as an "El Nino" until SST anomalies have been consistently above +0.5 C for three months or longer], there is no reason to believe that it will be the main factor driving the winter-time pattern, as it was with last winter season. Generally, the stronger the El Nino, the stronger the response farther north. However, in this case, the response probably won't even develop in time for the early winter season.

From what I have seen, there are much greater factors that must be taken into account.

First, I think that we will see an active Pacific jet, with a stronger southern jet towards the end of the winter. Why? Because a strong Aleutian low will likely dominate off the West Coast of North America, likely leading to a stormy pattern along the coast and farther inland. With an active Pacific jet, snow-cover across Canada will likely have a much longer chance to build southward, allowing for the long-term development of a stronger Arctic air mass.

Secondly, I believe that a lack of blocking will characterize at least part of December. Unless we see a return to an overall blocking pattern soon, I see no reason why it should rebuild before December. Of course, it's very likely that blocking will redevelop by later in the winter [for several reasons], but December will likely feature near normal temperatures for most of the United States, with a general stormy trend.

Lastly, I believe that blocking will return by the latter portion of the winter. Stratospheric warming events have a much higher likelihood this winter, and when they do happen, they generally lead to an increase in blocking over the Arctic regions. If this is the case, I expect a downtick in storminess towards January and February, but with overall colder conditions. While storminess may increase along the East Coast and South, drier and colder conditions will likely prevail in the Northern Plains and Midwest.

Even though I have a lot of respect for the CPC and their forecasts, I do not believe that their winter outlooks are overly helpful, and in many cases, I strongly disagree with their conclusions.

*I am going to be going to college soon however. I will probably be going into the field of meteorology or some related mathematics/physical science.

Tuesday, September 9, 2014

SEVERE WEATHER OUTLOOK

After a seemingly long period of rather warm, humid weather to end the summer, the pattern is finally transitioning to something that is far more recognizable as fall weather. Along with this cooler weather, however, comes the possibility for more organized storm systems, as well as severe weather. In this instance, we have a strong potential for severe weather that could be fairly widespread across the Great Lakes and Ohio Valley regions.

Here's what's going on: A strong trough in west central Canada is digging southward into the United States right now. A shortwave is expected to eject from the trough within the next few hours, causing a developing frontal zone to drop southward and allow rapid cyclogenesis to commence.

Here's the position of the surface low pressure system right now:





Today, this low pressure system will continue to organize along the front, and eventually move to the northeast. By tomorrow, the low-pressure system will likely be in Wisconsin, traveling northeast into Canada at a rather rapid pace.

At the same time that this cyclogenesis occurs, a strong cold-front will develop alongside the low-pressure system, drawing colder, drier air out of Canada and into the United States. Warm and moist "return-flow" from the Gulf of Mexico will also be drawn into the "battleground", setting the stage for an unstable and volatile atmosphere in the lower Great Lakes and Ohio Valley region. At the same time, strong winds in the upper atmosphere will allow the system to continue to organize and will also provide the support that tomorrow's thunderstorms will need in order to become severe.

All of this is expected to come together to allow for a decent severe weather outbreak to unfold across the area. However, there are still a few uncertainties as to what  will happen.

1.) Cloud-cover/early morning rainfall- Many forecasters are concerned that early morning cloud-cover across the region will remain through the afternoon, suppressing rising temperatures from making it into the 80's. This will lead to a significant reduction in instability for the afternoon hours. While it won't rule out severe weather, it will definitely limit the impact of the severe thunderstorms later in the afternoon and early evening.

At the same time, however, some models, such as the NAM and SREF, are predicting moderate instability to develop across the area, in response to rising boundary-layer moisture and some breaks in the cloud-cover. If this occurs, the severe weather threat will be much more imminent.

2.) Stronger low-level jet winds may shift to the east of the area before the actual cold-front arrives, possibly limiting some of the severe potential. Although I do not see this as a potential problem as of yet, it is something that I will continue to monitor.

Given the above considerations and the factors going into this outbreak, it appears that our main threat will be widespread damaging winds. Even if we don't see enough instability tomorrow, damaging winds will still be a major threat with these thunderstorms. It is also possible that some areas see significant winds above 65 kts [75 mph] in some thunderstorms. If conditions are more unstable than currently forecast, we may in fact see a few isolated tornadoes as well.


Damaging wind threat for the area is at the forty-fifth percentile

I will keep you updated on our FB page.

Monday, August 11, 2014

Rain and Thunderstorms Today

Today's forecast is rather gloomy for the late summer months. Showers and thunderstorms are expected to development and move repeatedly over the area late this morning and early afternoon. The incredibly humid air mass, in combination with weak-moderate instability will lead to heavy, slow-moving thunderstorms which could lead to localized flooding in some areas.

Showers and thunderstorms should end across the area by the late evening, giving way to cloudy skies and drier conditions by the morning.




Sunday, June 29, 2014

In Remembrance of the Great "Land Hurricane"

The massive storm that swept through the area on Friday, June 29th, 2012, will not soon be forgotten by many folks around the northwest Ohio and northeast Indiana region. Packing winds of over 80 mph, the derecho [pronounced "day-RAY-cho"] raced through, uprooting trees, tearing off roofs, and knocking down hundreds of power-lines across the region. But it wasn't just our area that was impacted by this record-setting storm. The monster caused widespread and intense damage from northwest Indiana all the way to the East Coast, making it one of longest and most intense derechoes to ever impact the United States east of the Mississippi River. In total, the storm caused billions of dollars in damage and cut-off electricity to more than three million people.

In any given year, northwest Ohio and northeast Indiana are usually impacted by one or two derechoes in the summer. However, derechoes as violent as the one we experienced in late June 2012 are rare across the area. Derechoes, by the Storm Prediction Center definition, most produce significant wind damage [winds of 60 mph or greater] over a distance of 200 miles. However, this derecho produced winds in excess of 70 mph over a distance of over 800 miles. The Storm Prediction Center received around 900+ wind reports from the system that day. This made the event unique, rare and not likely to occur again for many years. So what factors lead up to this impressive event?

One of the major factors in the production and the sustenance of the system over a long distance was the fact that a weak, Canadian cold-front had settled across the area. North of the front, temperatures had dropped into the lower 90's, with dew points in the low-mid 60's. South of the front [the front was basically along the U.S. 30 corridor], temperatures were in the mid-upper 90's and dew points were in the low-mid 70's [Fort Wayne had reached the mid-90's with a dew point in the low-mid 70's by noon]. The incredibly hot and humid air mass present south of the front caused instability levels to sky-rocket. One of the parameters used to measure instability is known as CAPE [or Convective Available Potential Energy]; normal values of CAPE range from 1000-3000 J/kg on any given summer day. On this particular summer day, values were as high as 5000-6000 J/kg, especially in Southern Ohio. When instability levels are this high, thunderstorm formation can be explosive and deadly, which is exactly what happened.

At the same time, the intense levels of instability in the atmosphere allowed the thunderstorms to force the dry-air downward into the lower-atmosphere, which is what contributed to the very strong wind gusts that were observed at the surface. Because of the hot, humid atmosphere south of the front, the storm system was able to maintained all the way to the East Coast. This was unusual because most storm systems of this magnitude require a great deal of wind-shear throughout the atmosphere, and on this particular day, there was little or no shear.

The most damaging aspect of this storm system was the fact that it hit with little or no warning. Early in the morning on Friday, June 29, Storm Prediction Center forecasters noted that thunderstorms were possible across the area, but they were not originally expecting severe weather. They believed that the cap, a warm-layer in the mid-levels of the atmosphere, would inhibit widespread thunderstorm formation. However, by the mid-morning hours, the SPC realized that storms were already breaking through the cap and becoming organized over northeast Illinois and northwest Indiana, which lead them to include the threat of severe weather.

By this time, the thunderstorms had already organized and were racing eastward at speeds of up to 70 mph, giving little or no advanced warning time to those in the path of the storm. That is why severe thunderstorm and tornado warnings were only issued minutes in advance of the strongest wind gusts impacting areas. The local NWS did not realize that the storm system was developing so rapidly and had to race to issue warnings in advance to protect lives and property.

The problem was made worse by the fact that people were also caught off-guard. The storms were not forecasted in advance and were only able to be tracked after it had already done considerable damage. The damage it caused was further compounded, especially when hundreds of thousands of people were without power during one of the worst heat waves that has ever hit the eastern United States. The record heat and humidity contributed to several deaths after the storm was over with.

The good news is that this system isn't one that we will likely see again for several years, if not decades. The aftermath of this massive storm has caused us to realize how important it is to remain prepared and protected during forecasted severe weather events, and hopefully a re-analysis of the event by forecasters around the nation will help to improve forecasts of similar events and save lives in the future.

Monday, June 16, 2014

WPC 500 MB FORECAST; MEDIUM-RANGE OUTLOOK

Based upon the latest ensemble and global model forecasts, it appears that a relatively active weather pattern will continue through at least the end of June. The jet-stream will remain relatively zonal and progressive, allowing for fast moving systems to move through occasionally. On the flip-side, temperatures will likely remain near or above normal, especially with every surge of heat from the Desert Southwest. No major heat waves or ridging is expected over the next few weeks [outside of tomorrow, Wednesday and Thursday], but there is the possibility of the Southeast ridge building into the United States by the end of June and early July which could contribute to the first heat wave we've had all summer. An active thunderstorm pattern will also remain in place, continuing the possibility of periodic heavy rain and even severe weather.

Friday, May 30, 2014

Warm, Pleasant Weather to Continue; Storms Next Week


Has everyone enjoyed the gorgeous weather we've had over the past few days? Because I certainly have! Looking back through the archives of the weather from the past year or so, it appears that this has been the longest stretch of pleasant warm weather that we've seen since the beginning of 2014! It certainly is nice after the terribly harsh winter we had this year.

As of now, it looks as if this stretch of nice, warm weather will continue through the weekend before a humid, tropical air mass moves into the region, allowing for several days of high humidity and the possibility of thunderstorms. Each day will feature isolated to scattered thunderstorms with intervals of partly cloudy skies and sometimes even sunny conditions. This will make the afternoons feel uncomfortable, with nighttime conditions not feeling much better [lows will likely be in the mid-upper 60's]. By mid-week, a cold front out of Canada will likely side-sweep the area, bringing drier and cooler air to the region. This cooler period does not look to last too long with the return of warmer weather and humid conditions in the long-term period for the second-week of June.

Synopsis:
Here's the general synopsis of what's going on: a weak, upper-level circulation across the South is contributing to the very slow and weak development of an overarching ridge which stretches into Canada over the next few days. Once this weak upper level low breaks down, strong moist flow from the Gulf of Mexico will surge into the area, setting up the potential for several rounds of thunderstorms. For the first two days, likely Sunday and Monday, thunderstorms will be sparse and isolated. However, as the upper-level trough descending out of Canada approaches the area, there is the potential for more organized severe weather activity along the cold front.




The upper-level trough will approach the area, driving the cold front into the region by Tuesday and Wednesday. Thunderstorms will become numerous on Tuesday, with the possibility of severe weather given moderate instability and increasing deep-layer shear. At this time, however, severe weather does not appear to be a strong threat, but I will continue to monitor the possibility. The cold front will sideswipe the area by mid-late next week, bringing temperatures down to normal levels [after a few days in the mid-80's] and much drier conditions. However, the upper-level ridge will begin to quickly re-build into the region after this, bringing warmer and drier weather once again. This appears to be the general pattern that will continue to face the region through at least early-mid June.


More details on this later.

Monday, May 26, 2014

Summer Weather's Arrival; Upcoming Blogposts

Now that school is about ready to get out, I'll be able to blog more often than I have been able to over the past few months. I realize that my last blog post on here was way back in early February, and I do apologize for that. There were plenty of winter storms that I had been following since then and other inclement weather events, but I never had the time to post on here. However, if you have been following my FB page @ Northwest Ohio Storm Prediction Center, you'll know that I've been making periodic updates over the past few months.

That being said, I have established a more regular schedule of blog posts this summer, which will deal with various topics. Depending upon how busy I am with getting ready for college, my work, etc. I will likely post at least two times a week, hopefully three times a week. Blog-posts will generally feature updates on the weather forecast, various weather topics, and even some issues that might currently be featured in the media. I will keep you updated on the various topics that I will be posting about!

Now, let's get down to business. After a long struggle for spring and summer to actually arrive, it finally has. The weather has finally settled down, and I do not expect the strong variations in temperatures that we've been seeing over the past few weeks. In fact, this entire week is expected to be at least 80 degrees or warmer, with the highest temperatures occurring today in the upper 80's to possibly lower 90's. By next week, things get sketchier with the possibility of a lingering SE Canadian trough developing and pushing a "backdoor" cold front through. Even so, I do not expect temperatures to drop much below normal; high temperatures will likely remain in the upper 70's to lower 80's. However, by early-mid June, the possibility of a much warmer period  of weather is possible, so we will have to keep an eye on that.

And given the dominance of warmth over the area for the next two weeks or so, be on the lookout for severe weather. I will keep you updated on that as well.

Sunday, February 2, 2014

Winter-Storm Potential and Model Disagreement


If you haven't heard by now, you will soon, but there is yet ANOTHER winter-storm expected to affect the area this week [and this isn't the only winter-weather event that will affect us this week; there is another system that will develop along the leading edge of the Arctic boundary by next weekend, which could bring more wintry weather to the area, but right now, we will be focusing on the more imminent threat]. Another winter-storm in the middle of an already record-breaking snowy and cold season will just add salt to the wound, the wound that could become disastrous for the area by Spring [more on that later]. At this point, the winter-storm looks to be fairly significant and it looks to produce enough snowfall to rival several of the snowstorms we've seen this year already, most notably the December 14th storm [which produced 6-10" of snow area-wide] and quite possibly even the January 5th snowstorm that we had. However, there are a few vital differences between this upcoming event and past events that we have seen. Not only this, but I want to discuss one possible analogue that could have strong implications for a major-winter storm across the area.

First, model agreement on the track of the storm is not ideal at this point. There are some differences between the global model solutions [the GFS and the GGEM being the furthest southeast, and the ECMWF being the furthest northwest of the global guidance], but nearly as severe as the differences between the global solutions and the mesoscale-model solutions, most notably with the NAM. While the GFS is indicating a weaker primary low tracking into C. Pennsylvania, the NAM is indicating that the low-pressure system will track from S. Indiana and into SW Ohio, with the low tracking just to the south of Toledo. As you can see, there is still some relative uncertainty as to the track of the storm. If the GFS's rather progressive solution verifies [which is possible, but unlikely], we will likely see a longer period of light-moderate snow, with some heavier snowfall rates in the deformation zone behind the storm. Snow-ratios would be rather high, and in combination with QPF totals of 0.3-0.5 inches [according to the GFS; not a forecast], we would see snow-totals in the range of 5-9". That is still rather impressive with how far east the GFS solution is. If the NAM's more-amped and western solution verifies, most of the area will see a long duration of heavy snow, with sleet and freezing rain mixing in for those who are near Lima and southeast. QPF totals, if this solution were to verify, would be in between 0.6-1", yielding snow totals around 8-12". At this point, it is hard to say which model is correct. The shortwave itself has not made it onshore yet to be sampled by the upper-air data. However, where the current wave is located is not in a data sparse region and just offshore of the West-Coast. Tonight will then be the night when we should see the final model trends coming into play.



At this point, I am favoring a compromise between the NAM and the global models. The NAM is likely too far northwest. Even though these types of events tend to lean "left-of-track", the NAM probably isn't handling the offshore energy all too well just yet. By tonight and early tomorrow morning, the NAM should have a better handle on the storm, and will most likely shift southeast. On the other-hand, the global models are likely too progressive. With the presence of a strong Hudson Bay vortex in a farther west position, it puts the storm in a prime position to take a shift west. Not only this, but it appears that the global models are too flat with the initial shortwave ejecting out of the SW. Even though a strong shortwave will flatten the SE ridge slightly today and tomorrow, rebuilding heights behind the system should cause the next storm-system to go much farther northwest, hence my preference towards a compromise. Given this, I expect that the storm will track from the lower Mississippi Valley [Arkansas, Louisiana, Mississippi, etc.] into Kentucky and then into Eastern Ohio. Until I have seen other-wise, I do not expect a track farther west than that. And given the above reasons, I do not believe the storm has as significant chance of taking the further south and east route. Either way, the storm will be weakened and shoved eastward by the development of a secondary low by late Tuesday night into Wednesday morning. Whether this has a significant impact on snow totals or not is too difficult to pinpoint at this time.

And as for the overall event, given the uncertainty above, I cannot give any details with any exactness or uncertainty, but at this point, I am expecting an all-snow event for most of the area. If the farther north track verifies, some portions of the area, especially near Lima and southeast could see periods of sleet and freezing rain, but that's about all of the mixing that we will have to worry about. Snow totals should range around 6-10", with the possibility of 8-12" if a stronger and slower system verifies. As for timing, there is still too much uncertainty to say anything for certain at this point.

Friday, January 24, 2014

Two Clipper Systems and the Arctic "Hounds" Awaken Once Again

After a "brief" hiatus from extremely cold, snowy and blustery weather, our exceptional winter has brought another round of weather that only seems to be suitable for regions north of the Arctic circle [not literally, but you get my point]. After seeing a full weak with temperatures slightly above normal along with rainfall, temperatures have drastically fallen with temperatures below freezing for nearly a week now [discounting Sunday-night into Monday when temperatures rose above freezing for a brief time]. Not only this, but temperatures have fallen below zero for the past several nights, and along with strong, gusty winds at times has lead to wind-chills far below zero on all three nights. Today, breezy conditions have caused another problem; intense blowing and drifting snow. This has lead to near "ground-blizzard" conditions across the region, mainly in the rural areas and has made some roads nearly impassable.

After all this crazy weather, you'd think that Mother Nature would be done by now. I'm here to bring you the solemn news that this is not so. At least two more rounds of light-moderate snowfall is expected over the next three days, followed by a longer period of bitterly cold temperatures and biting Arctic winds. The first round of snow begins tonight, with the potential for 2-4" likely across most of the area [potentially more depending upon if lift/dynamics is focused more in the dendritic-snow growth layer] through Saturday morning. Although I am not expecting heavy snowfall rates [it is possible that snowfall rates could become moderate to heavy in some areas, but it is unlikely at this time, and if it does, it will be brief, small periods of it], I do expect that extremely windy conditions will lead to incredibly low visibilities, with possible whiteout conditions at times. At the same time, the good news is that temperatures will be rising all night, to a peak of 22 or 23 by the early morning hours. However, this will not be enough to affect road conditions until windy conditions subside.

There are several potential factors that could affect snowfall amounts tonight, including:

1.) Moisture- an unusual surge of moisture will affect regions along the front, which will aid in precipitation/snowfall development. Depending upon how much moisture interacts with the DGZ layer [-10 to -18 C temperature range in the mid-levels of the atmosphere], this could enhance snowfall amounts in some parts of the area.

2.) Dynamics- Upper-level forcing could be rather significant tonight, especially as the main wave dives southward towards the region. This in combination with some jet-streak dynamics and WAA will allow light-moderate snow to develop across the area. If dynamics become more focused in the DGZ region of the atmosphere, we could see more efficient snowfall production and thus higher snowfall amounts.

While there are a few other minor issues, they won't have near the effect on snowfall tonight. For instance, if we see less WAA, but colder mid-level temperatures, we will see higher snow ratios, but less overall moisture/forcing. However, if we see slightly warmer mid-level temperatures, we will see more moisture/forcing but lesser snow ratios. At this point, I'm leaning towards slightly higher mid-level temperatures, which could aid in heavier snow totals, even though snow ratios could be a bit lower [around 15:1 or 16:1]. Also, given the fact that clipper systems tend to over-perform on many occasions, I'm willing to bet on 3-4" of snow occurring in some areas.

After the snowfall begins to wane on Saturday, gusty winds behind the front will lead to more blowing and drifting snowfall, as well as falling temperatures. By the end of the day, temperatures will be below 10 degrees again, with lows around 0 Saturday night.

By Sunday, there is still some disagreement between models on precip. amount and heaviest snowfall placement, but at this point it appears that it will be a similar event to what is happening tonight, but perhaps with stronger dynamics and slightly more moisture. For this reason, I believe Sunday's event will be more along the lines of 2-4"/3-5" instead of 1-3"/2-4". This is especially the case if the mid-level instability that is expected can overspread parts of the area, causing mesoscale-banding. However, there is still some uncertainty, especially given the fact that snow-ratios will likely be lower than tonight [around 13:1 or 14:1]. Even so, gusty winds are still expected, leading to more blowing and drifting snowfall. Temperatures will fall throughout the night Sunday into the lower single-digits. Highs on Monday behind the cold front will barely make it above this low, with temperatures falling well below-zero Monday night. By Tuesday and Wednesday, temperatures could be even colder. Tuesday it doesn't look like the area will make it above 0 [some models are indicating highs around -5 to -10 below], with Tuesday-night lows around -10 to -15 [some models are indicating that temperatures could drop below -20, which isn't out of the realm of possibility]. By Wednesday and Thursday, temperatures begin warming up again, with only a slow moderation likely. Given model discrepancy at this point, it appears that the warmest temperatures will get by Thursday is about 19 degrees.

I'll have more updates later. 

Monday, January 13, 2014

The Myth of the Polar Vortex and the "Mega-storm".

This post isn't going to be so much of a forecast as it is going to be a clarifier, but I will add in some medium-long range forecast details about what I expect to occur across the region during the next few weeks.

With that being said, however, there seems to be this persistent "hype" going about the media over the past few weeks about the so-called "polar vortex". So many people have been "fooled" into believing that it should be something to be concerned about when it really isn't. So, I'm here to clarify what is meant when meteorologists and atmospheric scientists use the term "polar vortex".

Unlike what the media has made it seem to be, the "polar vortex" is not something that can be seen with the eyes. It is not a rare or unusual phenomena, and its certainly nothing to panic about either. The "polar vortex" is actually a semi-permanent feature of the Arctic region, which is occasionally displaced when periods of anomalous warming occurs over the poles [known as "blocking" in "weather slang"] and can then break-off and slide southward into the temperate regions. This is the reason why we occasionally see exceptionally strong blasts of Arctic air into the region. It is not because the polar vortex itself has actually moved into the area, but it originates from the polar vortex. In more "scientific" terms, the polar vortex is actually a climatological pattern of the Arctic which results in upper-level troughing and the formation of a cold-dome. As a result, a large cyclonic circulation develops, which contributes to the development of long-wave troughs across the temperate zones, and hence the formation of the main jet-stream pattern. It is not a rare occurrence, and its not something that can be seen, or something to be afraid of.

Secondly, I've been having people ask me all day if there's going to be a "big storm" coming soon. I can emphatically say that this is false as well. It IS true that we will be going into a pattern more conducive to winter-weather for the area, including the establishment of a mean long-wave trough across the East, which will lead to below-normal temperatures for the second-half of January. It IS true that at times, this pattern will become conducive to strong clipper-systems moving into the region, and the potential for a Colorado low to bring us some decent snowfall. HOWEVER, as of this point, there is no indication of any major storm hitting the area. Zilch. None. I don't know where these rumors began, but we have a very low chance of seeing another "big storm" this winter. We will definitely see several 4-6"+ events through February, but I think its going to be very difficult for the area to see another 10"+ storm like we had just last week. However, I will not rule out the potential, given how volatile this winter has been so far. I will keep you updated. For now, however, there is no major storm coming, and all I'm expecting is several clipper systems, and temperatures dropping into the 10's and 20's.

Friday, January 3, 2014

Major Update and Analysis.


After looking at the 12z data [and some of the 18z data], I will give you my latest thoughts on the system, as well as certain, specific details in the evolution of the system, and how I expect the system to impact us over the next several days.

Short Technical Discussion:

The 12z model suite came in rather well at a modest consensus among guidance. Nearly all guidance was tracking the storm-system from the lower Mississippi Valley and into Kentucky and South Central Ohio before rapidly deepening across the Northeast. There were still model differences, especially in the track and intensity of the system, but all in all it was nearly similar across the board. And because of this, I do think it is safe to conclude that parts of our area [N. Indiana and NW Ohio] will at least get clipped by the heaviest snow, if not rest in the axis of heaviest snowfall. Again, this is all dependent upon the actual development of the system. However, there is still evidence that the storm might shift paths ever so slightly and affect snowfall amounts. Today's 18z guidance [particularly the GFS and NAM] did not present such a "good" snowfall solution for us. In fact, the NAM trended much drier across the forecast area and moves the system out of the area much quicker than other guidance. For now, the NAM is seen as an outlier given its flat, progressive bias in amplified patterns [as evidenced by what happened with the last storm-system]. The bad news is that the GFS also followed suite, even though it kept the intensifying low and heavier precipitation back west [and we still got a decently heavy snow event]. At this point, I'm favoring the 12z guidance for two major reasons:

1.) The way the shortwave trough is amplifying currently, as well as short-range extrapolations of the shortwave indicate much more digging at the base of the trough AS WELL AS much more interaction of the primary shortwave [seen here over Montana and North Dakota] with a piece of the Polar Vortex farther north [which is ultimately going to be the factor which draws the intense Siberian air mass south into the United States behind the Arctic front]. All of this rules out the NAM solution as of now. We should be expecting a more amplified solution and it appears that models have not caught on quite yet [even the more amplified models]. On this point, the WPC and NWS IWX agree, and in this afternoon's AFD, the NWS did say that they were concerned that the entire storm-system could be stronger and farther northwest than currently predicted [as in the SREF solutions].

2.) The interaction of the strong clipper-system along the U.S./Canadian border currently and the cold-front which will be shifting through our area Saturday night will also allow a further west solution; the reason I say this is because of the fact that the cold front will rapidly slow down as the mean-flow above surface-frontal boundary becomes parallel to it. By this time, the shortwave will interact with the frontal boundary and produce another surface-trough, which, if the shortwave is oriented correctly, will rapidly develop into a 1004 MB low-pressure system by the time it reaches Central and Eastern Ohio. Due to the strong nature of the high-pressure system behind the front, a strong pressure gradient will also set-up. Regardless, I do not see this scenario reflected in the weaker guidance such as the 18z NAM, and hence why I do not believe it will come to fruition. However, better judgements can be made after the 00z guidance comes in tonight.

Now that I've cleared that up, I think we can quite confidently say that the 18z NAM [and possibly the 18z GFS] are both outliers. My own solution is in line with the ECMWF and CMC forecasts, although I believe a slight shift east or west is possible. A more substantial eastward shift is altogether unlikely but it is quite possible and not something to be dismissed at this time.




Now to the actual precipitation.

While snow-totals across the region will largely be dependent upon the track, speed and intensity of the low, another major factor which could affect snow-amounts is the moisture input into the area. Right now, we have too extremes/outliers in the guidance. On the one hand, the ensemble SREF mean is indicative of a very wet system over the area. Although it has a difficult time accurately printing out mean snow-totals that are realistic across the area, the amount of moisture that gets involved in the system [in the mean] is incredible and likely overdone. On the other-hand, we have the NAM and the high-res NAM which appear to be the "driest" solutions on the board. And the very reason why they are drier is for the very same reason that I described above; they do not amplify the shortwave aloft enough, and thus under-develops the surface-low, which in turn limits Gulf-return flow aloft. Even though moisture profiles will be less than ideal [mixing ratios only near 4 g/kg], I do believe we will see plentiful moisture from the Gulf of Mexico, and due to the anafrontal nature of the original wave, most of the precipitation will be behind the front [hence why we are seeing a major snowstorm].

Because of this, I believe QPF [Quantitative Precipitation Forecast] totals will exceed 0.5-0.6 inches across the entire area for the total event [Saturday night through Sunday evening], with localized higher amounts of 0.8-1 inches, especially along and southeast of the U.S. 24 corridor. Given that average snow-ratios will be around 16:1 or 17:1, snowfall totals should easily reach the 8-12" snowfall range especially along and southeast of the U.S. 24 corridor. However, if the cold-front does end up moving faster across the region and we see colder air, ratios could be as high as 20:1, which will enhance snowfall amounts.

Any other details regarding precipitation will have to be refined in now-casting and the use of mesoscale models, because right now it is extremely uncertain as to where heavier bands of snow will set up across the area, when and for how long. However, it is certainly possible that bands of 1"/hr could set up around the area and to our southeast, which could easily enhance snow totals.

NON-TECHNICAL DISCUSSION
In brief, here is what I expect from this winter storm across the area:

Snowfall totals will range from six inches in the northwest [especially in N. Central Indiana and SW Michigan] to as much as 12 inches along and southeast of the U.S. 24 corridor. However, this is subject to change [given what I discussed above], and especially if we see a stronger storm-system. If we see a weaker storm, snowfall amounts across the area will range from four inches in the NW to nearly eight inches in the east/southeast.

Blowing and drifting snow will be a major concern, especially after the snowfall ends as the storm "bombs" out to our east. However, as I discussed above, if we can get the storm to strengthen faster, we will likely see near blizzard conditions DURING the storm. Again, its very contingent upon a few seemingly minor details in the current upper-air analysis.

And because of this, we will have to also remain cautious about wind-chills, given that temperatures will fall down to about -11 Sunday-night after the storm passes through. Wind-chills with winds of 25 mph produces wind-chills of -30 to -40, which isn't pleasant for the human-body. Similar conditions will continue Monday into Tuesday and early Wednesday.

I will have more details tomorrow on this potentially crippling winter-storm.