... High pressure will remain across our area through Thursday. Aside for some scattered cloud cover at times, expecting mainly dry conditions. Next chance of rain is Friday associated with a cold front.
NEAR TERM /THROUGH TUESDAY/... As of 800 PM EDT Monday...
For the evening update: Added isolated shower potential for Allegheny Highlands until midnight.
Key Message: Locally dense mountain/river valley fog late tonight.
High pressure will keep us mainly dry though Tuesday with seasonable lows and slightly warmer daytime highs. Pattern fairly unchanged so expect a repeat of fog in the valleys again late tonight/Tue morning, dense near the rivers from the Greenbrier Valley through the New River Valley.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... As of 105 PM EDT Monday...
1. Above normal temperatures and dry.
The upper ridge will remain across the eastern US into Wednesday night. Thursday into Thursday night, the center of the ridge will shift offshore with the approach of a long wave trough. This weather pattern supports the continuations of dry conditions with above normal temperatures. With light winds and low level moisture expect late night and early morning river valley fog.
Moisture and cloud cover should increase Thursday into Thursday night ahead of the approaching upper trough. The model solutions looked a little slower with the timing of the cold front. Most of the operational models keep us dry through Thursday night.
High confidence in the Short Term Period.
LONG TERM /FRIDAY THROUGH MONDAY/... As of 105 PM EDT Monday...
1. Scattered showers Friday into early Saturday with a few storms possible.
2. Trending colder into the weekend.
The NCEP Ensemble 500 mb Mean Geopotential height animation showed a broad and highly amplified long wave trough crossing our region. At the surface, a cold front crossing the area Friday evening into early Saturday morning, with high pressure on its heels arriving by Sunday night into Monday. The mean 1000-500mb thickness pattern will decrease to around 5520 to 5580m by Monday.
It is time to get out your fall gear for cold weather. Temperatures will trend notably colder, especially by Monday. The 850mb temperatures start around +12C on Friday, then quickly fall off behind the cold front to values around +6C on Saturday +4 early next week.
The best chance for showers is primarily on Friday into Friday night, with perhaps some lingering showers in the mountains on Saturday. Drier weather prevails early next week with some moisture return from the north Tuesday night into Wednesday.
Moderate to high confidence in the Long Term Forecast.