827 FXUS61 KLWX 080105 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 905 PM EDT Sat Jun 7 2025 .SYNOPSIS... A cold front will slowly settle southward toward the area through today, then meander across the Mid-Atlantic through Monday. A stronger cold front will cross the area on Tuesday night, followed by high pressure Wednesday and Thursday. && .NEAR TERM /UNTIL MIDNIGHT TONIGHT/... Earlier showers and storms located along a cold front dropping southward into the area from Pennsylvania have dissipated, resulting in dry conditions across the vast majority of the forecast area this evening. The lone exception is across the Shenandoah Valley, where a few light showers remain. The aforementioned frontal boundary will continue to slowly drop southward through the area tonight. Showers and storms may begin to reignite just to the north of the front later tonight across Central Virginia as 850 hPa flow turns out of the east to southeast, leading to upslope flow impinging on the Blue Ridge. The majority of the forecast area should experience dry conditions through the bulk of the night, with lows generally in the 60s. && .SHORT TERM /MIDNIGHT TONIGHT THROUGH MONDAY NIGHT/... Evening update: The main forecast change this evening was the issuance of a Flood Watch for flash flooding for portions of the Alleghenies, Potomac Highlands, Shenandoah Valley and Central Virginia from 7 AM to 10 PM tomorrow. Within this corridor, flash flood guidance is very low due to saturated soils and high background streamflow levels following recent rains. East to southeasterly 850 hPa flow to the north of the surface front will also intersect the Blue Ridge and Alleghenies, potentially leading to orographic enhancement of rainfall. A widespread 1 to 2 inches of rainfall is expected across this area, with localized totals up to 5 inches possible. This rain will likely be spread across multiple rounds of showers and thunderstorms late tonight through tomorrow evening. For now, the Watch is in effect where wet antecedent conditions and potential terrain enhancements resulted in greater confidence regarding flash flooding potential. The Watch may possibly need to be expanded along the edges at a later time, but decisions for those surrounding areas were deferred to subsequent shifts due to uncertainty in the northeastward extent of the heavier rains and/or higher flash flood guidance values. Previous discussion follows... The main front dips south through the area tonight, though it is expected to stall somewhere over central to southern VA. As this happens, winds turn north to northeast and low clouds build in from the east over our area. Showers begin increasing in coverage from west to east late tonight into Sunday morning in response to increased forcing for ascent from another shortwave trough aloft. This first round of showers and possible a few embedded thunderstorms moves across the area through late Sunday morning. The stalled front could lift slightly north as a warm front, though it is not expected to make much progress. There is a lot of uncertainty where the front is located come Sunday afternoon, and that will be critical to where heavy rainfall and/or strong to severe thunderstorms develop. A wave of low pressure is expected to develop and move across the frontal boundary Sunday afternoon to Sunday evening. Where the low crosses it will scour out the clouds along/east of its path, with a couple of hours of sunshine leading to additional instability. Model soundings indicate deep-layer westerly shear around 40 knots and increasing SRH along the warm front. There will be plentiful moisture to work with as dew points in the upper 60s to low 70s are in place, and afternoon temps reach the upper 70s. In terms of the severe threat, SPC has a Slight Risk (level 2 of 5) of severe weather from along the Blue Ridge up to the DC Metro, stretching to Annapolis and the Eastern Shore. Elsewhere, there is a Marginal Risk (level 1 of 5). Damaging wind gusts are likely to be the main threat from any severe storms that develops. Depending on where the surface low/front area, there will be a tornado threat along the warm front where SRH is maximized. However, must stress that this is a conditional threat until we know where the front and low are going to be. The upper trough and surface low pull east of the area Sunday night. Much lower rain chances for Monday morning/afternoon as the area remains in light south to southwest flow in a modified warm sector. Sources of lift will be minimal, so not expecting a high coverage of showers and thunderstorms until Monday night when another strong trough approaches from the west. Highs Monday reach the upper 70s to mid 80s as humid conditions persist. && .LONG TERM /TUESDAY THROUGH SATURDAY/... An area of low pressure will develop along a slow-moving cold front over central Virginia Tuesday. Additional showers and thunderstorms will evolve along and east of the Blue Ridge Tuesday into early Tuesday evening. High temperatures will be close to average and reach the 80 degree mark in most places. As the low, front, and associated humidity moves to the east overnight Tuesday into Wednesday, high pressure will build in and remain in control Wednesday through Thursday night. High temperatures each day will be about 5 degrees higher than the previous day. The high is expected to shift to the east on Friday; thus, bringing back another chance for showers and thunderstorms late Friday into Friday night. && .AVIATION /01Z SUNDAY THROUGH THURSDAY/... Conditions remain VFR this evening, but low clouds will build in from the east late tonight into Sunday morning. MVFR to IFR conditions prevail through Sunday afternoon, and likely into Sunday night. There is uncertainty regarding when the strongest showers and thunderstorms develop, but there will likely be several hours of impacts at all terminals. VFR conditions are expected on Monday as low pressure moves offshore. MVFR conditions possible at the MTN, BWI, DCA, and IAD terminals with shower and thunderstorm activity Tuesday into early Tuesday evening. VFR conditions overnight Tuesday for all terminals through Wednesday night. Winds southwest around 5 knots with exception to gusts over 35 knots in thunderstorms Tuesday into Tuesday evening. Winds becoming northwest 5 to 10 knots overnight Tuesday through Wednesday night. && .MARINE... Several cold fronts and waves of low pressure are set to move across the area through Monday. Winds are forecast to remain below SCA levels through the start of the week, however near SCA gusts are possible Sunday afternoon/evening due to a wave of low pressure crossing near the waters. Additionally, heavy showers and thunderstorms will pose a threat to mariners from strong gusty winds and lighting strikes. A waterspout or two will be possible Sunday afternoon to evening. Special Marine Warnings may occur in stronger thunderstorms Tuesday afternoon and evening. Otherwise, no marine hazards expected Tuesday through Wednesday night. Winds southwest 5 to 10 knots, except for gusts over 35 knots in thunderstorms Tuesday and Tuesday evening; otherwise, winds becoming northwest 5 to 10 knots through Wednesday night. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Flood Watch from 7 AM EDT Sunday through Sunday evening for MDZ501-509-510. VA...Flood Watch from 7 AM EDT Sunday through Sunday evening for VAZ026>030-037>040-507. WV...Flood Watch from 7 AM EDT Sunday through Sunday evening for WVZ050-055-501>506. MARINE...None. && $$ SYNOPSIS...KRR NEAR TERM...KJP SHORT TERM...KJP/KRR LONG TERM...KLW AVIATION...KLW/KJP/KRR MARINE...KLW/KRR