Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
828 FXUS61 KLWX 061846 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 246 PM EDT Sun Sep 6 2026 .WHAT HAS CHANGED... No significant changes to the forecast from what was issued this morning, just added details in Key Message 2 regarding potential storms on Thursday. Uncertainty remains high at this point, but given the right timing of the frontal passage, a severe threat could unfold. && .KEY MESSAGES... - 1) Drier conditions with seasonable temperatures and lower humidity today into early parts of the week. - 2) Shower and thunderstorm chances return by mid week. && .DISCUSSION... KEY MESSAGE 1...Drier conditions with seasonable temperatures and lower humidity Sunday into early next week. Broad high pressure over the Great Lakes will track over the Mid-Atlantic through Monday. This will bring a change in airmass with notably lower dew points. Highs in the low 80s for most today and Monday. Overnight lows in the 50s and low 60s. Surface high pressure begins to transition south of the Mid- Atlantic on Tuesday as upper level ridging builds over the southeast CONUS. Temperatures likely begin to creep up again during this time, accompanied by increasing humidity as mid- level dry air tracks south of the region with more humid air coming in from the north. KEY MESSAGE 2...Shower and thunderstorm chances return by mid week. Upper-level ridging over the Appalachians starts to flatten into zonal flow beginning Wednesday. As this occurs, a trough forming over Quebec will begin to track east across the northeast CONUS, with a stemming cold front moving across the East Coast by Thursday. Temperatures gradually increase during this time, along with increasing humidity ahead of the front. By Thursday, temps potentially reach the upper 80s to low 90s. As this frontal boundary tracks through the Mid-Atlantic, showers & thunderstorms are possible across the region, beginning Wednesday evening and into Thursday. The 12z guidance remains unclear in terms of timing and the exact evolution of this system, so a lot of uncertainties remain. There is general agreement in trough digging south into the region, but the exact strength and timing of that trough is still being ironed out. Temperatures Thursday are expected to be in the 80s to near 90, with dew point in the 60s to perhaps low 70s. This should yield plenty of CAPE south of the front itself and allow for at least some thunderstorm development if the forcing arrives near peak heating. The severe threat is still in question, but remains non-zero. If the trough tracks far enough south, there could be a fair amount of wind shear to work with as well, which would increase that severe threat. Some of the AI guidance (particularly the WxNext) do highlight our region, so it is certainly something to keep a close eye on. Will continue to monitor latest guidance in hopes of honing in on a more confident solution. As this cold front transitions offshore towards the end of next week, temps drop again & conditions become much drier heading into the weekend as high pressure moves in overhead. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Light showers and drizzle linger near CHO this morning, and will likely continue to do so over the next couple hours. This should taper off into the early afternoon. Thereafter, VFR conditions should persist through Wednesday evening. Showers & thunderstorms associated with an incoming cold front could temporarily bring sub-VFR conditions to terminals by Thursday afternoon. Ahead of the front on Thursday, winds could gust between 20-25 knots before diminishing overnight. && .MARINE... No marine hazards are expected through the holiday weekend. Generally light flow is expected, though onshore gusts could approach marginal SCA levels late this afternoon. Currently favoring a Marine Weather Statement given brief duration. Northeasterly winds Monday shift southerly on Tuesday, remaining below SCA levels. SCAs are possible across the Bay by Wednesday evening ahead of an incoming cold front. Winds could remain elevated throughout Thursday as this frontal boundary tracks east across the coast. && .TIDES/COASTAL FLOODING... Tidal anomalies remain elevated over the next several days due to an onshore flow. Minor tidal flooding is becoming increasingly likely at Annapolis, and could also be possible in the other sensitive tidal locations in the northern Chesapeake Bay. Will continue to monitor as the current high tide ends and transitions to low tide. If the forecast holds, may need to issue an advisory later this evening. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ DISCUSSION...CJL/CPB AVIATION...CJL/CPB MARINE...CJL/CPB