Area Forecast Discussion
Issued by NWS Sterling, VA

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628 FXUS61 KLWX 231342 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 942 AM EDT MON MAY 23 2016 .SYNOPSIS... Low pressure east of Norfolk this morning will move north towards New England today and tonight, then move into the Canadian Maritimes on Tuesday. High pressure over the Midwest will slide southeastward into the western Atlantic by Tuesday night, where it will remain through next weekend. && .NEAR TERM /THROUGH TONIGHT/...
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Closed upper level low remains stationed near Norfolk VA this morning and will slowly lift northeastward through today. Band of steady rain from earlier this morning across portions of eastern VA and southern MD will continue to shrink and pull south and east of the region through the rest of the morning. Breaks of sun have formed across northern VA, eastern WV, and into MD, and this will allow for temperatures to rise into the upper 60s and lower 70s. The warming, coupled with lingering low level moisture, and cold temperatures aloft under the upper low will lead to the development of instability this afternoon (BL CAPE values 300-800 J/KG this afternoon), and in turn convective showers and a few thunderstorms. Severe weather not expected, but with low freezing heights (7000-8000 feet AGL), could see some gusty winds and small hail in any thunderstorms that do form. Previous Discussion... Tonight the low aloft and at the surface both head northeastward away from us and their influence should wane. We will likely still have some showers and even a thunderstorm or two to deal with in the early evening...but precip and then clouds should wane as the night progresses. Lows will remain near normal with limited advection behind the system so far and the moist atmosphere may result in fog development.
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&& .SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
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Ridge continues moving east towards us on Tuesday as the low pressure system pushes further northeast away from us. Some clouds or even a stray shower may linger early Tuesday but we should end up with a much nicer day. As already mentioned...some patchy fog could also impair conditions early but it should not persist as northwest downslope winds should bring sun back to the region. Temps should also rebound considerably as temps warm quickly aloft and the sun does its job. Unlike today...with the warming aloft we should not see much if any attempt at convection in the afternoon. Highs will reach the high 70s to even some low 80s. Continued improvement with ridging moving in Tuesday night through Wednesday night. Warmth will also increase as westerly to southwesterly flow develops aloft and at the surface. Will need to watch a shortwave with attendant weak frontal boundary later Wednesday and Wednesday night which may try to spark off a shower or storm but overall think period is dry. Highs into the 80s most spots Wednesday.
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&& .LONG TERM /THURSDAY THROUGH SUNDAY/... Bermuda high pressure sets up Wednesday night and persists at least through the Memorial Day weekend. Moisture influx from SLY flow around the high should enable afternoon/evening thunderstorms Thursday through Monday per typical diurnal trends in this pattern. General thunderstorms expected with low bulk shear. Warmest stretch of the year so far. Mid to upr 80s max temps expected Thursday through Monday. Only caveat is how quickly clouds develop and where rain falls before the diurnal maximum in temperatures. Areas sunniest longest may hit 90F any of the days. && .AVIATION /14Z MONDAY THROUGH FRIDAY/...
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VFR at most sites at most times through today and into this evening. Will see the development of additional showers and a few thunderstorms this afternoon which may lead to brief reductions to MVFR/IFR at times this afternoon. Later tonight, as showers end and skies begin to clear, may see the development of some patchy fog and Sub-VFR conditions. VFR returns Tuesday and should persist thru Wednesday night. Winds will be light (less than 10 knots) and generally west/northwesterly. Bermuda high sets up Wednesday night with diurnal thunderstorms and light SLY flow starting Thursday. IFR conds expected in heaviest activity.
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&& .MARINE...
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No marine headlines in effect. Winds light northwesterly today with showers and few thunderstorms this afternoon. Near-SCA gusts may develop Tuesday afternoon on west/northwest flow around departing low. Southwest winds then develop Wednesday, but should remain sub-SCA. Light SLY flow continues Wednesday night as a Bermuda high sets up. Localized SMWs likely any day. Will need to watch for SLY channeling.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...None.
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&& $$ SYNOPSIS...RCM NEAR TERM...MM/RCM SHORT TERM...RCM LONG TERM...BAJ AVIATION...BAJ/MM/RCM MARINE...BAJ/MM/RCM

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