Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
350 FXUS61 KLWX 292330 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 730 PM EDT Sat Aug 29 2026 .WHAT HAS CHANGED... Updated the Aviation section. && .KEY MESSAGES... - 1) Warmer and more humid Sunday with isolated afternoon thunderstorms. - 2) Late summer heat, thunderstorm chances return next week. && .DISCUSSION... KEY MESSAGE 1...Warmer and more humid Sunday with isolated afternoon thunderstorms. High pressure to the northeast will move offshore tonight into Sunday. A stray shower or rumble of thunder could develop over parts of the Appalachians early this evening; otherwise, conditions will be dry. Dry and seasonable conditions will become more humid with warmer temperatures on Sunday. A southerly return flow will bring in this more humid airmass; thus, setting the moisture ingredient in the development of a few thunderstorms Sunday afternoon and evening. A weak disturbance arriving from the west-northwest on Sunday could be the trigger needed for such convection Sunday afternoon and evening. KEY MESSAGE 2...Late summer heat, thunderstorm chances return next week. Confidence remains high that summertime heat returns to the region for most of next week as a strong mid-level ridge builds across the southern CONUS. Uncertainty remains on exactly where the ridge is positioned come the middle of next week, but it certainly looks like we will have highs in the 90s Monday through Thursday and heat indices between 95-105. Wednesday looks to be hottest day at this time, with potential for heat advisories across portions of the Shenandoah Valley and across the DC and Baltimore metro areas into Southern MD. The main caveat for heat impacts is timing of expected rounds of convection as MCSs move through/near the region, and any potential backdoor fronts that could slide in late in the week. Disturbances rounding a ridge will steadily move from the Great Lakes to Mid-Atlantic for most of next week. The timing and amplitude of these waves have very low predictability beyond a couple days in advance (at best). However, the general theme will be enhanced lift and shear clashing with an increasingly hot and unstable airmass over or near the Mid-Atlantic. AI/ML guidance has broad elevated probabilities of severe weather much of next week, though focus appears to be shifting to Wednesday and Thursday. Again, timing is going to be a big determining factor in whether any severe weather occurs in the forecast area. It should be noted that there is a conditional potential for one or more organized clusters of strong to severe storms at some point next week. The most likely time currently appears to be around mid week, but changes are to be expected at this time range. && .AVIATION /00Z SUNDAY THROUGH THURSDAY/... Some guidance is hinting at sct to bkn low clouds (500-1000 ft) and BR mainly east of the Blue Ridge tonight, possibly briefly LIFR just after daybreak Sunday. Highest probs would appear to be at CHO closer to more low-level moisture near a front stalled to the south. Low confidence, but any L/IFR conditions would develop 06Z-09Z, then lift between 12Z-15Z. Otherwise, VFR conditions through Sunday night. Isolated t-storms possible Sunday afternoon and early evening. VFR conditions are likely to prevail across the area for most of next week. The main impacts to the terminals will come from any organized clusters of thunderstorms that move across the region. These systems have little predictability this far out. && .MARINE... SCA conditions possible again Sunday night into Monday morning in southerly channeling. Favorable marine conditions expected through most of next week. Southerly channeling at times during the week could result in SCA conditions for parts of the waters. Expect clusters of thunderstorms to move across the waters at times during the week, but predictability of exactly when this will occur is low at this time. Special Marine Warnings are certainly going to be needed for any strong to severe thunderstorm that crosses the waters. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ DISCUSSION...LFR/KLW/DHOF/KRR AVIATION...LFR/KLW/DHOF/KRR MARINE...LFR/KLW/DHOF/KRR