Wednesday, October 19, 2011

Low pressure progressing northward over the Ohio & Tennessee River Valleys allows for a strong front to sweep across our area today & tonight. A steep pressure gradient and strong convergence at the surface triggers strong, damaging winds this afternoon & evening. According to the Storm Prediction Center, there is a slight risk for severe thunderstorms across much of the forecast area into tonight. Further east, isolated supercells & possibly a tornado may form this evening into tonight. Stay tuned to local TV/radio for latest weather updates!

Warm air mixing finally shuts down behind the front and much cooler air will begin to filter in overnight. As a result we'll keep elevated risk for potentially damaging winds tonight & Thursday. Wrap around moisture will also trigger light rain showers, especially along our western slopes into tonight. Enough cold air will be mixing in to allow for a changeover to snow in the higher terrain tonight. But we are only expecting a light dusting of snow for those locations above 3300 feet into Thursday morning. Elsewhere lows will fall into the low/mid 40s and winds will stay breezy enough to prevent widespread fog development.

The storyline for Thursday will definitely be the strong winds and cold air advection. Gusts are expected to reach 35 MPH across much of the forecast area & up to 45 MPH in the higher terrain. Our area's NWS forecast office may need to hoist the wind advisory Thursday. Still expecting limited snowfall to occur Thursday morning and again by Friday morning. But by then, the departing system will not have much available moisture to work with...so accumulations will be in the order of 1 inch above 3300 feet. Rainfall totals are also expected to reach 1 inch before things start drying out late Friday... 

Mainly cloudy skies & lots of cold air will linger over much of the eastern US Friday. Highs are expected to only reach the low/mid 50s Thursday, Friday and Saturday. And with the breezy conditions, the wind chill will feel much, much colder. With clearing skies expected Friday & Saturday, lows Friday night & Saturday night will be closing in on freezing both nights.

The good news is that high pressure will have a strong foothold over the Mid Atlantic states by the weekend. So we can expect drier air, clearing skies & some sunshine for the weekend. Warmer air will gradually mix into the region by Sunday/Monday.


Click here for regional radar http://weather.unisys.com/radar/rcm_rad.php?image=rad&inv=0&t=cur&region=at

Images courtesy of SPC & HPC depict tornado threat into this evening & rainfall totals through Thursday...Click to enlarge!