1) My main focus has always been weather in the Shenandoah Valley. While I do try to at least give a brief overview of what I think will happen everywhere across the state, my most time certainly goes into the forecasts for northwestern Virginia and eastern West Virginia.
2) Growing up right outside Harrisonburg surrounded by mountains, I really came to learn how important topographic factors such as elevation and slope direction are when it comes to forecasting the weather. So while my maps may look a bit funky or drawn by a 6 year old, there's method behind the madness. I could just draw very general areas and say to expect 1-2" with 2-4" expected above 2,000 feet, but I feel like actually dividing this up in map form is a much better representation for people traveling or are unsure of their elevation.
Now onto the important storm stuff and my first call for the Friday-Saturday system:
Synoptic Setup:We have a piece of energy which shot out of the 4-Corners Region and is currently trekking across the Gulf of Mexico. This will help spawn a low pressure system that will strengthen as it works up the east coast. Although we are on the northwest or cold side of this system, we lack a strong high to our north. For this reason, earlier this week I mentioned that this wouldn't be the most favorable setup and that we would need our coastal storm to be quite strong in order to generate its own cold air. For a time the past few days, there were signs that this would end up being the case. Well, low and behold we have since seen a trend for a weaker, more strung out system. This will likely lead to more issues regarding p-type (or precipitation type) which I'll discuss below.
What's it Gonna Do?: Well I'm really expecting a little bit of everything across the Valley. I think we likely begin as some light rain or wet snow during the evening hours on Friday. As precipitation becomes steadier..we'll go over to snow mixed with sleet at times. Easterly winds (as opposed to northerly if we had a high pressure sitting over New England) will try to bring in warmer air off the Atlantic aloft...known as a warm nose in meteorology. So even overnight, without the presence of daytime heating, we will be in the battle zone between rain to our east and all snow to our west.
How Much?: This million dollar question depends on how long we stay snow vs how long we see sleet or even plain rain. One obvious point to make is that elevation will play a huge role here. The higher up you are, the more snow you see. With all the data I've looked at today, I'm expecting a general coating to 2" along most of the Valley floor with 2-4" along the higher elevations of the Blue Ridge. The even higher elevations of the Allegheny Mountains in western VA and eastern WV could end up somewhere in the 4-8" range.
Uncertainty?: Yes, quite a bit of it actually. A few degrees one way or another will greatly effect these totals. A lot of that will depend on how strong out coastal system gets...a stronger coastal system could very well mean more snow. Another huge caveat of this forecast is the possibility of a pretty potent deformation band on Saturday. As our coastal storm starts to spin away up the coast, some upper level energy on the backside may try to fire up a band that could bring additional accumulations. Right now, I do think this forms and contributes to my snow totals for far southwest VA and eastern WV...but I'm not sure how this band will behave once it reaches the mountains. If dynamic enough, it could provide a burst of snow from western Virginia all the way to I95. If not, well we could see a few light rain or snow showers and it won't be much of a deal at all. Just something additional to watch for now.
A few other notes:
- This map only accounts for snow and sleet accumulations...watch out for some freezing rain especially across western NC and the Roanoke and New River Valleys
- This is a very fluid situation...and will likely need updated
- My final call for this system will be out Friday evening, so be on the lookout for that
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| First Call: Created 1/22 5pm |
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