


Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
033 FXUS61 KLWX 301926 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 326 PM EDT Sat Aug 30 2025 .SYNOPSIS... High pressure will slowly drift north and northeast of the area through the middle of next week. An upper-level disturbance may bring a few showers to the Potomac Highlands Sunday, but most of the area will remain dry with below normal temperatures through Wednesday. The next frontal system may bring higher rain chances toward the end of next week. Cooler tempeatures are likely in the wake of this front. && .NEAR TERM /THROUGH TONIGHT/... Anomalous troughing anchoring much of northeastern North America has largely maintained an autumnal like air mass over the area. Characterized by mid-level height anomalies around 2 standard deviations below average, the core of lower heights extend from southeastern Quebec and points southward. The post-frontal environment is comprised of dew points more representative of late September into early October. As of 18Z/2 PM, current temperatures are in the low/mid 70s, with 60s across the mountains. Meanwhile, dew points are holding steady in the low/mid 40s. Per local aircraft thermodynamic profiles, some additional dry air at the inversion top (~850 mb) could contribute to a bit more low-level drying. Wind fields within the deep mixed layer are running around 10 to 15 knots. This is ultimately contributing to occasional gusts to near 15 mph which should persist through the afternoon hours. Expect temperatures to rise another couple of degrees underneath sunny skies. Aside from shallow cumulus fields across higher elevations west of I-81 and high cirrus in far southern Maryland, skies remain free of much cloud cover. A strong anticyclone currently across the Ohio Valley and Great Lakes will approach from the west this evening into the overnight hours. This eventually sets up an optimal period for nocturnal radiational cooling. Models have recently been underdoing the amount of cooling within these favorable conditions. Consequently, have favored the colder solutions which supports overnight lows in the low/mid 50s (mid/upper 40s across the higher terrain). Relative to late August climatology, this is around 10 degrees below average. Skies should remain clear overnight along with calm winds. Some patchy fog development is possible across the more sheltered river and mountain valleys. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Benign weather prevails through the remainder of the holiday weekend. As a brunt of the upper trough translates offshore into the Canadian Maritimes, additional longwave energy begins to close off over the Mid-Atlantic region. While mainly centered over the local area, this closed low configuration begins to extend back toward the Upper Great Lakes. However, this does not contribute to any meaningful shower chances given a dearth of moisture. A brief uptick across the Potomac Highlands could introduce a short lived shower, but this would be the exception more than the rule. Otherwise, modified Canadian high pressure remains in charge with the primary moisture axis tied to an inverted trough near the Carolinas. Forecast highs generally remain on repeat given the fairly persistent pattern. The current package calls for high temperatures in the upper 70s to near 80 degrees (60s to low 70s for mountain locales). Surface high pressure gradually weakens in time, but this will still support seasonably cool overnight temperatures. Forecast lows fall into the 50s, with mid/upper 40s in the mountains. Overall wind fields generally stay out of the east to northeast through the second half of the Labor Day holiday weekend. Some minor shifts are possible at times as the anticyclone shifts its position. However, weak pressure gradients will keep gusts mainly at 10 mph or less. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Surface high pressure shifts offshore over the Atlantic Tuesday and Wednesday. Winds shift southerly on Wednesday, ushering in warm and moist air. This will result in increased moisture, cloud cover, and gradually warming temps. Precipitation chances increase beginning Wednesday afternoon from west to east as a cold front approaches from the Great Lakes region. Precipitation chances increase on Thursday as the front pushes through the forecast area. Given high temperatures in the 80s, instability will be limited although isolated thunderstorms cannot be ruled out. In the wake of the cold front, surface high pressure returns on Friday. High temperatures Tuesday through Thursday will be in the 70s to low 80s with higher elevations staying in the 60s. On Friday, temperatures will be slightly cooler in the wake of the cold front. Expect high temperatures in the 60s to 70s. && .AVIATION /18Z SATURDAY THROUGH THURSDAY/... With the dominance of surface high pressure over the region, VFR conditions are looking likely through the remainder of the holiday weekend. Winds will largely be out of the north this afternoon, with occasional gusts to 10 to 15 knots. Some patchy fog is possible, but this should stay west of all TAF sites. As high pressure shifts position in time, expected winds on Sunday and Monday will turn more northeast to easterly. VFR conditions are expected Tuesday and Wednesday as high pressure shifts offshore. Cloud cover increases on Wednesday, with VFR conditions expected both days. Northeast winds on Tuesday shift to southerly Wednesday, blowing 5 to 10 knots each day. && .MARINE... In the wake of yesterday`s frontal passage, any gusty winds have finally abated. Northerly winds may gust to 10 to 15 knots this afternoon before diminishing in strength into the night. Winds turn more east to northeasterly for Sunday and Monday with gusts staying below advisory criteria. Northeast winds on Tuesday shift to southerly Wednesday. Winds remain below SCA criteria on Tuesday before increasing to just under SCA criteria on Wednesday. Advisories may be needed in the central portions of the Chesapeake Bay Wednesday afternoon. && .TIDES/COASTAL FLOODING... A surge of northerly winds have resulted in decreasing anomalies today, generally averaging between -0.25 to 0.25 feet. As winds slacken this evening, some of the water may slosh back up the bay, but flooding is not expected. The combination of low pressure passing offshore and easterly winds will allow water to build starting Monday. Winds then remain easterly then southerly through at least Thursday. This could result in some minor flooding during the higher high tides along sensitive shoreline (such as Annapolis). && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BRO NEAR TERM...BRO SHORT TERM...BRO LONG TERM...AVS AVIATION...AVS/BRO MARINE...AVS/BRO TIDES/COASTAL FLOODING...ADS/BRO