Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 211413 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 1013 AM EDT Wed Sep 21 2016 .SYNOPSIS... High pressure will build over the region through Thursday. A cold front will move through the area Saturday. High pressure builds again over the region early next week. && .NEAR TERM /THROUGH TONIGHT/... GFS not doing particularly well with extent of high clouds this morning. ECMWF and HRRR simulated cloud imagery doing much better and have followed their output closely. Expect current extent of high clouds to remain pretty much as is through midday with thining of high clouds in the afternoon and clouds shifting south and east by evening. Adjusted temps a bit based on model trends from ECMWF indicating a 2-3 deg rise from yesterday in the east with temps west of the Blue Ridge not showing any trend at all from yesterday. Showers to graze southern St. Marys county through the day with precip shifting south tonight. && .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Onshore NEly flow persists Thursday with above normal temperatures, mid 80s, under mostly sunny skies as cloud shield looks to be along southern periphery of the CWA. Surface high pressure settles south over the area Friday with sunny skies and light/variable winds. Maxima mid to upper 80s. && .LONG TERM /SATURDAY THROUGH TUESDAY/... A transition to autumn weather will occur over the weekend after a cold front tracks down from the north Saturday afternoon. This is a dry trajectory...so don`t expect much if any rainfall with this system. After reaching 80 degrees Saturday it does not appear the area will be seeing that for the next several days. Sunday highs will likely only reach the mid 70s but the real story will be Sunday night/Monday morning when lows east of the mountains will drop into the lower 50s...and likely 40s in the Highlands. By Tuesday some warming to the atmosphere should take place ahead of a cold front. This will likely provide the next chance for rain to the Mid Atlantic. In somewhat of a coincidence..at IAD both since Sep 1 and Jan 1 the precipitation departure from normal is -2.21". && .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/... High cloud shield persists over the area from low pressure lingering along the NC coast. This is limiting fog development across the DC metros. Best fog chance through sunrise is at MRB though high clouds are currently over that area too. VFR conds prevail through Friday high pressure slowly settles south over the area. VFR conditions expected this weekend. && .MARINE... NEly flow 10-15kt down the main portion of the Bay through Thursday as low pressure lingers along the Carolina coast. Weak Nly flow Thursday night through Friday as high pressure settles south over the area. Winds could increase to near SCA values near/behind a cold front Saturday into Sunday. && .TIDES/COASTAL FLOODING... Elevated water levels persist through the rest of the week due to low pressure off the Carolina coast. Coastal flooding threat is low through Friday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ PRODUCTS...BAJ/WOODY!/LFR

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