Winter Storm Watches Expand

December 14, 2024 7:00am

Winter Storm Watches have expanded for Sunday, we’ll go to that in a moment. First out the door conditions this morning

A very cold start this morning across the area valleys, and “less cold” on the ridgetops.

▪︎Temps mainly teens to upper 20s and low 30s on the high Wv ridges out there on this Saturday morning.

Views on the morning:

• A fairly tranquil Saturday in place. Temps remaining cold across the high ground and east. Milder west. That theme continues Sunday with the incoming weather event. That weather event had watches and advisories out across the region. I strongly expect these to expand east in some form or fashion. A bit shocked that they are not already as THATS the prime zone. Some of the area under watches may see limited impact, and areas currently without a much more significant impact.

• Surface Map Sunday Morning

-afternoon

That cold dry High, clockwise winds funneling in cold dry air at the surface.

All the while the encroaching Low with counter clockwise winds pushing milder, moist air up and over the surface cold.

• 5000′ winds and temps below

• A visual of the Wedge

The wedge gets more shallow and eventually dissappear as you go west under the entire column is above freezing. Eventually the mild air takes over the highest areas of the Allegheny Front, leaving the 2800-3000 sector north the coldest. Then the final step will see all the high ground rise to 35-40 while the low protected valleys east, while above freezing remain chilled the longest.

• Lets do a side by side. The surface temps left, 5000′ temps right. Look at that. At 5000′ winds from the low pressure out of the SW. Look at the temps at 5000′ . Now compare to the left, winds at the surface out of the ESE undercutting and riding up the Allegheny Front and wedging west. That wedge gets narrower and narrower as you go west.
• The areas you see surface to 5000′ above freezing would be rain. Areas you see 5000′ above freezing and the surface below, you’d see sleet or freezing rain depending the depth of the warm and cold layer. Areas you see both layers cold, the column would support snow. That’s mainly eastern Alleghenies and east of the Allegheny Front. I really like that Cumberland to Bedford to Altoona thump.

• A look at the soundings displays the above visual

-Garrett County Airport. Mild surge aloft. Cold at the surface. Again the surface here can run 28 with sleet or freezing rain while Cumberland is 32,33 and snow. Thats not uncommon. That’s how Cumberland can mostly escape ice as you have the column cold enough for snow, and as the upper air warms enough, the surface is just above freezing when the snow transitions over.

Garrett County Airport below

-Cumberland, the column holding below freezing.

• The visual off the 6z Euro

• Snowfall off the 6z Euro

• Sleet zone off the 6z Euro

• Freezing Rain zone off the Euro and likely the western edge of this is brief before the flip to straight rain. Amounts are generally over done on models.

Again, using the Euro as it looks most like the climatology of these setups as far as precip type boundaries. Other modeling is veering that way. The HRRR is a bit colder and if that played out, the snow would work a bit further west. Adjustments are likely.