Tuesday, November 24, 2009

Not Stormy for Thanksgiving Travels

Tuesday, 11:30 A.M. http://www.accuweather.com/mt-news-blogs.asp?partner=accuweather&blog=Lundberg&pgurl=/mtweb/content/Lundberg/archives/2009/11/not_stormy_for.asp

Anyway, the main message for today and tomorrow is one of no major storms coast to coast, and border to border. Oh, there will be some places where the travel will be a little dicey tomorrow, but in terms of large-scale storms that will have a significant disruptive impact on travelers, there won't be any.

Let's look at the problem spots one by one, starting first in the Northwest. A storm heading across the northeast Pacific will head for northern British Columbia tomorrow, dragging a cold front, weak at that, toward western Washington and northwest Oregon in the afternoon. The result will be some rain, with some locations getting an inch or two of rain, mainly over the Olympics. There won't be the wind with this storm that we've seen in recent events, either. Snow levels will be high, so I suspect getting over the passes shouldn't be too difficult tomorrow afternoon. Once east of the Cascades, it will be dry, and very little moisture will even reach northwest Oregon until Thanksgiving afternoon when a second system will break off from the main flow of the jet stream and take direct aim at the state.

Another area of potentially bad weather will be the Midwest tomorrow, as a slow-moving storm coming out of southern Iowa this afternoon will send some rain out of Wisconsin into Michigan, though the rain won't be all that heavy. If there's any real travel problems, it would be in the colder air on the back side of the storm. A second upper level disturbance digging southeastward from Montana this afternoon and tonight will invigorate this whole storm and cool the column to the point where snow can make it to the ground across parts of western Wisconsin, eastern Minnesota, northeastern Iowa, and northwest Illinois, especially tomorrow afternoon and early tomorrow night. Even here, though, it would be a sloppy, wet snow that at best would amount to a few inches. In most cases, it would be a coating to an inch or two, enough to cause some headaches and make for great snowmen. Otherwise, it's not going to affect a very big area.

Farther downstream, the weather from the eastern Lakes and across the Appalachians into New England and the mid-Atlantic states will just be gloomy, as in little to no sun. The low level moisture that has invaded the region will have no escape hatch without much wind and a fresh air mass to replace it. Look for some drizzle and fog to be your biggest weather adversary in these areas, with a little rain in some areas thrown in for good measure. Bleak and boring, but it could be much, much worse.

The final area will be Florida, especially the central and southern counties of the state. There's a ton of activity right now bursting across the Gulf of Mexico, and an upper level disturbance will help drive this all across the sunshine state tonight and tomorrow in conjunction with a developing surface storm. Some of this will also graze the coast of Georgia and the coastal Carolinas.

Aside from that, the weather will be benign across most of the country, and that's good for those who are planning trips of any distance, especially from the nations' major airports.

This Gulf storm development will not be done once crossing Florida tomorrow afternoon. As it develops further Wednesday night and Thursday off the Southeast coast, it will threaten parts of the Northeast with a more significant precipitation event sometime later on Thanksgiving into Friday, though I suspect that most will be disappointed at the outcome.

More upstream energy digging in from Midwest into the Great Lakes Wednesday and Thursday will help to deepen the storm as it heads by Cape Cod and heads for the Gulf of Maine. In the absence of any real overrunning surface, it will be tough to throw Atlantic moisture back over a non-existent cold dome over New England. Therefore, I'd have to believe most of New England will be too warm on the front side of this storm to get anything other than rain. About the only way it can snow as I see it is as the cold air collapses into the back side of the storm that you get fitful bursts of precipitation across western New England into the Adirondacks that could easily change to wet snow late Thursday night and Friday morning before going away in the afternoon.

There will be some lake effect snow around the Lakes Thursday into Friday, even though the air really won't be arctic in nature. It'll simply be cold enough so that some of the preferred areas pick up several inches of snow. And in most cases, this will be the first meaningful snow event of the season around the lakes!

A quick check of the longer range forecast suggests this cold that comes through the pattern with this developing trough will come and go. In other words, the moderating process will begin on the Plains Friday, spread across the Mississippi into the Midwest Saturday, and then filter into the Northeast in reduced fashion for Sunday and the early part of next week.

Still another storm will come out of the southern branch of the jet to open up next week, but it really looks as if the upper level trough to accompany this will be a little farther west, thanks in large part to blocking downstream that isn't over Greenland, but rather WEST of Greenland. In turn, that is likely to turn that storm toward the Great Lakes over time, and keep any snow associated with it to the north and west of the storm track, none of which should impact the northern Rockies and northern Plains, or maybe even much of the Midwest.

The cold that follows this trough will be more destined for the southern tier of states, not the Northeast, where it just may stay warmer than normal through most of next week. After that, THEN maybe some arctic air will truly get involved in the picture, but in deference to the NAEFS and the European Weekly Climate Forecasts from last Thursday night, my hunch is this will be centered on the Rockies and Plains, not the East, at least initially. Now, if the block were farther east over Greenland, then the cold might be centered along or east of the Mississippi, but that doesn't appear to be the case. More on that line of thinking tomorrow. For now, my son is already waiting - time to run!

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