Area Forecast Discussion
Issued by NWS Sterling, VA

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022 FXUS61 KLWX 010055 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 855 PM EDT Tue Apr 30 2024 .SYNOPSIS... A cold front will slowly push through the region this afternoon and evening bringing scattered showers and thunderstorms. A few showers linger Wednesday morning with dry high pressure settling back in for the afternoon. Warm and dry conditions continue Thursday before shower and thunderstorm chances return with another front Friday into the start of the weekend. && .NEAR TERM /THROUGH WEDNESDAY/...
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As of 0830 PM, a broken line of showers and thunderstorms extends from north-central Maryland southwestward to just west of Charlottesville. These showers and storms have formed along a pre-frontal trough, and will slowly progress eastward and weaken through the remainder of the evening. Dry conditions are expected during the second half of the night, with temperatures dropping back into the upper 50s to mid 60s. Some patchy fog may be possible late tonight in some of the more sheltered valley locations to the west of the Blue Ridge that received rain this evening.
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&& .SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
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Upper troughing will progress off to our south and east tomorrow. Subsidence in the wake of the departing trough will lead to dry conditions and mostly sunny skies. Temperatures will reach highs in he upper 70s and lower 80s, and winds will be out of the northwest at around 10 mph. Upper level ridging firmly builds over the area Thursday leading to a continuation of warm and dry conditions. 850 mb temperatures will be back up around +13 to +17 degrees C with PWAT values around 1". Meanwhile, a moisture starved cold front will sit across western portions of the forecast area acting as a catalyst for perhaps an isolated mountain shower or thunderstorm. Elsewhere across the region expect dry conditions with passing fairly weather strato- cumulus during the peak heating of the day. High temperatures will remain above average in the low to mid 80s with 70s over the mountains. Metro areas will be a tad warmer with highs closer to 90 degrees. Lows Thursday night will fall back into the mid to upper 50s.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/... A mostly dry period on Friday will soon be met with increasing moisture ahead of the next front system early Saturday and through much of the weekend. The front will slowly move through the Mid- Atlantic region during the weekend, with QPF totals reaching nearly an inch in localized areas. Some isolated instances of flooding will be possible with increase precipitation and the drier antecedent conditions across the area. Convection should be fairly weak if it were to occur this weekend given the lack of instability parameters. More afternoon, summertime precipitation will likely spawn Monday and Tuesday with a lingering boundary nearby off to the south of the area. Temperatures will fluctuate late this week into early next weekend with the cold front passage. Highs in the upper 70s to low 80s on Friday will be followed by low to mid 60s by Saturday. A progressive warmup will follow Sunday into early next week with highs in the low to mid 80s by Tuesday. && .AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
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As of 0830 PM a broken line of showers and a few thunderstorms extends from east of HGR to just west of CHO. This line of showers and a few embedded thunderstorms will continue to press slowly eastward and gradually weaken through the first half of the night. Some brief MVFR to IFR conditions will be possible with the any showers or storms, but prevailing VFR conditions are expected. Some fog also can`t be ruled out at MRB or CHO closer to daybreak. VFR conditions are expected to continue Wednesday despite a few lingering morning showers and perhaps an isolated thunderstorm for terminals south and east of KDCA and KCHO. 12z model guidance has trended drier as strong upper level ridging/high pressure build back into the region. Southwesterly winds today will shift to northwesterly winds on Wednesday. Winds gust between 10-15 knots this afternoon with winds gusting up to 20 knots at DCA. Winds diminish overnight before remaining light on Wednesday, blowing between 5-10 knots. VFR conditions are expected through Friday, with sub-VFR ceilings possible Saturday as increasing showers approach the terminals.
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&& .MARINE...
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SCAs continue through midnight for southwest winds 10 to 15 knots with gusts up to 20 kts at times. A line of showers and a few storms is approaching from the west this evening. This activity is expected to slowly weaken as it moves toward the waters, but gusts to around 30 knots along with lightning may be possible in any storm that moves over the waters this evening. A few showers will linger near the waters Wednesday morning as an additional piece of upper level energy swings through. Winds will shift to the northwest in the wake of the front and will likely stay below SCA criteria. Marginal SCA conditions could occur in channeling on the bay Thursday and Friday afternoon/evening. Otherwise no marine hazards are expected with south winds Thursday switching to the southeast Friday. Marginal SCA winds will be possible through the weekend. SCAs may be needed during this period as another front passes through.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until midnight EDT tonight for ANZ530>543. && $$ SYNOPSIS...EST NEAR TERM...KJP SHORT TERM...KJP/EST LONG TERM...ADM AVIATION...KJP/ADM/EST MARINE...KJP/ADM/EST