Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 271413 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 1013 AM EDT FRI MAY 27 2016 .SYNOPSIS...
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High pressure will remain over the area through early Sunday. Low pressure may affect the region Memorial Day through Tuesday. Weak high pressure builds for the middle of next week. A cold front may push through the region at the end of next week.
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Blended TPW product shows a pool of 1.5 inch PWAT over the area while GOES WV channel shows dry air aloft. All of these indicate the best moisture is found in the low levels today. Additional height rises forecast for today may inhibit t-storm coverage although NSSL WRF-ARW shows sct to possibly numerous showers and t-storms this afternoon with best coverage west of Blue Ridge. Hard to argue against this model given its good performance yesterday. With better moisture today than yesterday and more inclined to believe that there will be more activity today despite building mid- upper level ridge. Temperatures in the upper 80s to near 90F combined with sfc dewpoints in the mid 60s would bring heat indices into the low 90s.
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&& .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Upper level ridge builds into the area from the east north of a developing low off the SC coast Saturday. Associated height rises create a subsidence inversion and greatly limit convective development. Exception is chance PoPs for thunderstorms that were maintained in the Allegheny Mountains where terrain and less influence from the high combine to allow scattered activity. Maxima mid 80s again with dewpoints down into the mid 60s with mid to upper 80s heat indices. The warm core low is expected to be near the SC coast Sunday. Associated inverted trough extends north into the area with likely showers and thunderstorms for north-central VA and southern MD. Maxima mid to upper 80s in northern and northwestern portions of the CWA where rain/clouds arrive last. Expect low to mid 80s south of there. && .LONG TERM /MONDAY THROUGH THURSDAY/... Low pressure slowly moving northward up the southeast coast Monday will provide extensive cloud cover and chances of rain for Memorial Day. Highs will be around 80. Euro is implying an upper level short wave will be tracking along the US-Canada border late Monday. Question is whether this will be able to lift the low pressure area across the Mid Atlantic away from the area - MEX/GFS is giving area clear skies Tuesday. I`m a bit skeptical of this happening and would prefer to keep a chance of showers/thunderstorms over the region. I`ve written for the past few nights that the Superblend are trending cold in the first part of next week. This still seems to be the case. GFS and Euro are forecasting mid 80s Tuesday-Wednesday while Sblend is going mid 70s. This may turn out to be cloud-dependent but believe the odds are higher towards at least reaching 80. The next thing to talk about is a possible cold frontal passage late next week. This would lead to a return to the western ridge/eastern trough that N America saw for a decent portion of the winter. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Light southerly flow and patchy valley fog through sunrise. Diurnal thunderstorms are expected to form again with first storms west of the DC metros in the terrain. IFR conditions expected in heaviest activity. Southerly flow continues through Saturday. However, upper level high pressure limits thunderstorms Saturday. Showers and thunderstorms spread north from a low along the South Carolina coast Sunday. Showers and thunderstorms spread north from a low along the South Carolina coast Sunday...continuing Monday. && .MARINE... Light southerly flow persists through Saturday as high pressure lingers near Bermuda. SCA for southerly channeling late this afternoon through midnight for southern MD Bay waters. Isolated thunderstorms possible again across the waters. Southerly channeling possible again Saturday evening. Rain and thunderstorms spread north across the waters Sunday into Sunday night from low pressure along the South Carolina coast. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 5 PM this afternoon to 2 AM EDT Saturday for ANZ533-534-537-543. && $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...BAJ LONG TERM...ABW AVIATION...LFR/ABW MARINE...LFR/ABW is the U.S. government's official web portal to all federal, state and local government web resources and services.