Winter Storm **UPDATE**

I normally don’t post and evening update, but there has been so much concern over what the models are showing today in regards to the system for early next week, that I felt compelled to post some thoughts.

First off, and this needs to really be stressed and understood, the energy in the atmosphere that is going to be the catalyst for this storm hasn’t even made it to the lower 48 yet. It is still out over the data-void Pacific. So, until this energy makes it over the U.S. and can be sampled, the models are not going to be all that reliable. I am seeing people embracing various model runs like they are the be all, end all models for this storm that hasn’t even formed yet. I am perplexed and somewhat amused by this.

I am certainly not saying that the models should be ignored until the energy makes it to U.S. atmosphere. There are definitely some trends that can be noted and used as possible predictors of the future of this system. The most notable trend today has been for a weaker, non-phased system that tracks farther south than models were indicating yesterday. Given the current look of the mid and upper levels and what is happening upstream and downstream of the Southeast in the atmosphere, I’d say a weaker, non-phased system looks reasonable at this point. I am, however, having difficulty buying into the extreme southerly track shift indicated by the NAM, and especially the 18z GFS. Track is difficult enough to be forecasted by the models 24 hours in advance, let alone 72 hours prior. And track is something that really cannot be determined very accurately without the benefit of sound, real-time data, which this system does not have yet since it is still out over the Pacific ocean. So, a weaker system that is not phased takes the storm out of the major winter storm category and places it in the normal winter storm category. Still a winter storm that is sure to cause some problems across parts of the Southeast, but not one that goes down in the history books as a really memorable or historic event.

Until the system gets better sampled and a true and substantiated track forecast begins to emerge on the models later tomorrow into Sunday, I will not change my thinking on where the most significant snow will fall. I will still say that significant snow of 3 inches is possible across central and southern AR, northern MS, much of TN, northern AL, northern GA. South of that to the I-20/85 corridor, I will continue to go with a possible accumulation of a trace to as much as 3 inches. I am not so sure about the certainty of a major snowfall in the mountains of NC and TN, so right now I’ll revise my thinking downward on that into the 4 to 8 inch range, instead of the foot or more that had been my previous thinking.

Something else that has emerged on today’s models is the chance for a fast moving upper impulse zipping across the Southeast Tuesday afternoon through Wednesday morning. If this happens it would bring a burst of snow lasting about 6 hours. Given the air mass in place it would fall as all snow, and the ground would be cold, so there would be no initial melting. Also, ratios as high as 15 to 20 inches of snow to one inch of water equivalent could yield an inch or two or maybe even three of fluffy powder for those under the fast-moving area of snow. Definitely something to watch.

All in all I would just advise the snow hounds of the Southeast to remain calm and patient and wait until Saturday night or even Sunday before buying lock, stock and barrel into a forecast model solution, especially in regards to track of the storm.

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7 Responses to “Winter Storm **UPDATE**”

  1. Mike Stinneford Says:

    Mike, nice summary. Snow hounds are starting to howl, and it’s way, way too early for that. We’ve been watching for possible effects here in DC…as you mentioned, it’s all depending on the track and the strength of the storm.

    I think I’ll go buy some bread and milk and beat the rush! LOL

    • stormstream Says:

      Thanks Mike. Hey, do my blogs bring back memories of the summaries I used to write for you guys at The Weather Channel? lol

      The 0z NAM absolutely blows chunks. I fear this southward trend depicted by it all day could be legit. If things have not changed by the 0z runs tomorrow, then this thing is going to end up being a whole lot of nothing. What a frustrating winter this has been to forecast.

  2. Mike Stinneford Says:

    Mike, forgot all about those summaries! They were a great tool. Believe me, I’ve tried to blot out those getting up at 230 am mornings!

    Kinda fun just doing weather one evening a week. No pressure, and I have a good time kidding around with the anchors on WTOP

  3. It seems that all of the models are now depicting that the low in the Gulf will be way south than first thought- meaning no likely snowstorm for S.E. states.

    What’s your take?

    • stormstream Says:

      It’s not looking good Calvin. Keeping hope alive that the clipper might bring us a burst of light to moderate snow Tuesday night.

  4. Accuweather Meteorologist Henry Margusity posted his theory on why the models experienced a sudden shift of the upcoming storm system:

    http://www.accuweather.com/mt-news-blogs.asp?partner=accuweather&blog=Meteomadness&pgurl=/mtweb/content/Meteomadness/archives/2009/01/theory_on_why_models_made_big_shift_in_storm.asp

    Read it and give your input..

    • stormstream Says:

      Teacking the wave back into the Pacific it seems to me that it was well south of the area where flights would have been diverted, and in fact, may have actually been in an area that saw more air traffic yesterday due to re-routing. So, it is an interesting theory, but I’m not so sure it holds much weight. Now if the models today suddenly shift west again with a stronger solution, just as fast as they did in the other direction yesterday, then I may believe in his theory a little more. If they do not, however, then it’s just yet another case of the models being terribly wrong 5 days or more out, then finally coming around some in the shorter range. It has happened like that all winter.

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