Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 150130 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 930 PM EDT Mon Aug 14 2017 .SYNOPSIS... A frontal boundary will remain offshore through Tuesday. Weak high pressure will build over the area mid week. A frontal boundary will approach the area at the end of the week. && .NEAR TERM /THROUGH TUESDAY/... Model guidance and Blended TPW product show moisture increasing tonight especially over eastern areas on deep layered SSW flow. Forcing, however, appears to weaken overnight with more showers moving into southwest areas toward daybreak. Expect current showers over northeast MD to lift to the northeast in the next couple of hrs with not much happening overnight other than developing stratus/lowering ceilings ovr southern MD into DC metro. Otherwise, plenty of mid-high level clouds over the area overnight. Lowered POPs to chance this evening, but increased them overnight for southwest areas as activity over ern KY moves northeast. && .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/... Showers will end from northwest to southeast Tue evening with a dry period Tue night into Wed night as high pressure builds to the north. && .LONG TERM /THURSDAY THROUGH MONDAY/... A weak upper level ridge will be moving over the region Thursday, while at the surface, a warm front will be advancing back north across the region. The end result will be a significant warm up, with temperatures possibly reaching 90 for the first time in quite a while (since August 4th at DCA, August 2nd at BWI, and July 24th at IAD). With the frontal passage, however, we will have a returning risk of showers and t-storms. We will be solidly in the warm sector on Friday as well, so if we don`t make it Thursday, we could definitely still get there Friday. By then however, a shortwave and cold front will be approaching, which will result in an increased risk of showers and t-storms, perhaps with a severe threat. The timing of the next cold front crossing the region is still a bit uncertain, with various models depicting a range from Friday night to Saturday. However, by Sunday, we should be solidly behind the front with cooler and drier weather taking hold, and likely remaining through Monday. && .AVIATION /01Z TUESDAY THROUGH SATURDAY/... Developing stratus overnight with cigs dropping to IFR even possibly LIFR. Chance of very light rain overnight, but rain will probably hold off until tomorrow for most places. Main concern Thursday and Friday will be possible intervals of sub- VFR cigs and vis due to thunderstorms. Risk is mainly afternoon/evening hours both days, as is typical with convection. && .MARINE... Light winds through Thu night. Winds mainly sub SCA Thursday and Friday, but will need to watch for potential southerly channeling as a warm front moves through and the next cold front approaches. Other concern will be potential gusty winds with thunderstorms, which will be possible both Thursday and Friday. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...RCM AVIATION...RCM/LFR MARINE...RCM/LFR is the U.S. government's official web portal to all federal, state and local government web resources and services.