Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 131302 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 902 AM EDT Wed Sep 13 2017 .SYNOPSIS...
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The remnants of Irma will move across the Ohio Valley today and into Pennsylvania Thursday. High pressure will return to our region during the weekend.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Rain showers over northeast MD will continue to track northeast, but visible satellite shows extensive cloud cover remains across all except southern VA, so it won`t be until the afternoon that we encounter a few peeks of sunshine. High temperatures near 80. This evening will be predominantly dry with weak high pressure in control ahead of the last stage of the remnants of Irma. Models are indicating increasing clouds and chances of showers after midnight in the Potomac Highlands. Chances will proceed eastward to the I-81 corridor and the Shenandoah Valley by daybreak Thursday. Rain amounts would be generally between one tenth to one quarter of an inch and would be mainly in the northern Potomac Highlands, along the Mason-Dixon region.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
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The chance for rain showers persists from west to east Thursday with a few thunderstorms along the Mason-Dixon region from around central Maryland east to the northern Chesapeake Bay and south to around the I-66 corridor. Thunderstorms should be isolated Thursday afternoon due to daytime heating underneath a remnant low of Irma. Once evening approaches, any thunderstorms will lose their punch. High temperatures Thursday will be lower 80s mainly east of I-95, near 80 along and just east of the Blue Ridge, and mid to upper 70s west. The chance for lingering rain showers exist Thursday evening before a quiet period Thursday overnight arrives as the low slides to the east. Low temps Thursday night will be cooler than Wednesday night. Models are indicating that a small piece of energy could wrap around the departing remnant low Friday and approach us from the north before departing to the east as well. For this reason, as well as our high temperatures reaching around 80 once again, we will allow for a chance of a few rain showers in parts of the region. Dry conditions should arrive once again Friday night as this final piece of energy slides to the south and east. Lows will be in mid 60s.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/... Extended forecast hinges on the fate of Jose. There is limited skill at track/intensity forecasts at this timeframe, which is only magnified by lack of run-to-run forecast consistency amongst model guidance. Latest official NHC forecast calls for this cyclone to loop toward coast but stay offshore through Sunday, which is what the local extended forecast will be based upon. That still wouldn`t preclude occasional 20-30% PoPs this weekend into early next week due to onshore flow, vort lobes and/or an approaching cold front. && .AVIATION /13Z WEDNESDAY THROUGH SUNDAY/...
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IFR at all TAF sites expected to continue through late morning. VFR expected at all terminals this afternoon into Thursday morning. MVFR or brief IFR conditions possible at all sites except CHO Thursday afternoon due to isolated thunderstorms that could develop due to daytime heating under the remnant low of Irma. VFR conditions at all terminals Thursday night. Winds shifting northwest 5 to 10 knots Thursday, becoming light and variable Thursday night. VFR conditions for the most part Friday at all terminals.VFR conditions Friday night. Winds northwest around 5 knots Friday into Friday night.
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&& .MARINE...
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No marine hazards expected today through Friday night. Winds should be mainly 10 kt or less this weekend due to a ridge of high pressure located near the waters.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ UPDATE...WOODY! PREVIOUS...KLW/HTS

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