


Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
344 FXUS61 KLWX 230130 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 930 PM EDT Fri Aug 22 2025 .SYNOPSIS... Weak high pressure will continue to build in from the north through Saturday bringing mostly sunny skies, near normal temperatures, and lower humidity. Shower and thunderstorm chances return with a cold front that is set to cross the area Sunday into Monday. A strong dome of Canadian high pressure builds thereafter with near to below normal temperatures for much of next week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... High pressure is centered near the Delmarva peninsula this evening. Higher moisture remains pooled along the Appalachians on its southwestern flank and earlier cumulus have flattened into a stratocumulus deck. With deeper moisture convergence along the Appalachian crest, a very light shower or sprinkle could occur over the next few hours (most radar returns have been farther west in West Virginia, but it`s possible the beam will overshoot any shallow precipitation). The expanse of these clouds won`t change much through the night, though they may tend to thin out toward dawn. To the northeast, skies should remain mostly clear. Outlying areas with calm winds will dip into the upper 50s, with lower to mid 60s elsewhere. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... High pressure will shift further offshore Sat allowing winds to to turn southerly allowing moisture to return into western areas. Scattered showers and thunderstorms are possible across the spine of the Appalachians Saturday afternoon and early evening before dissipating overnight Saturday night. A cold front will approach the area Sunday associated a digging upper level trough/closed low across the Great Lks and northern Mid- Atlantic. The best low-level forcing/sfc convergence along the front will be located well north of the area over nrn PA and western NY and the best moisture is expected to arrive late Sunday night prior to frontal passage when instability should be waning. Not sure how much thunderstorm coverage there will be and also severity as instability looks marginal. The cold front will exit the area early Monday after 06Z with showers ending shortly thereafter. && .LONG TERM /MONDAY THROUGH FRIDAY/... A few lingering showers and perhaps a thunderstorm are possible mainly east of the Blue Ridge Monday as the cold front slowly exits the region. A large dome of Canadian high pressure will dominate the forecast thereafter for much of the new work/school week. This high pressure system will deliver an early tease to fall with unseasonably cool temperatures (below normal) for late August into early September. Dry conditions will also prevail outside of Monday furthering the return or expansion of abnormally dry conditions across portions of the area (mainly north of I-66/US-50 (see latest drought monitor)). Expect a slight bump in winds Monday as the front exits east and high pressure builds from the Ohio River Valley. Gusts of 15 to 20 mph are possible out of the north and northwest before a quick decrease Tuesday into midweek as the high settles overhead. Skies will trend mostly sunny to partly cloudy throughout the week as several weak mid level disturbances pivot through the longwave trough nearby. The bigger story in the extended will be the temperatures and humidity. Dewpoint values will hang out in the 40s and 50s throughout much of the week with air temperatures running 5 to 10 degrees below average making for an early Fall feel. High temperatures Tuesday and Wednesday will hang out in the mid to upper 70s with low to mid 60s across the mountains. Overnight lows will sit in the upper 40s and low to mid 50s. The colder high valleys of the Alleghenies could see a touch of fronts on Tuesday, Wednesday, and Thursday mornings with lows in the 30s. High pressure will gradually move out of the area by Friday with another front approaching next weekend. This will bring the next chance of showers and thunderstorms to the region. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR conditions will likely continue into Saturday as high pressure pushes east of the region. Convective chances return for terminals mainly west of MRB and SHD Saturday afternoon and evening as another front/trough approach the region. Winds will turn back to the south gusting between 10 to 15 kts. Additional showers are possible for areas east of the MRB and southeast of DCA Saturday night although confidence is low. This is in association with some added moisture from an area of low pressure moving up along the southeast U.S coast. Prevailing VFR conditions are expected on Sunday and Monday, although temporary drops to sub-VFR may be possible on Sunday afternoon as scattered thunderstorms move through. Winds will be out of the south on Sunday, and then out of the west to northwest on Monday. VFR conditions are expected thereafter for much of next week (Tuesday through Friday) as Canadian high pressure settles over the region. && .MARINE... Weak high pressure will settle overhead tonight. High pressure eventually weakens further while shifting offshore Saturday. This will allow the winds to switch back to the south and for channeling to occur. Southerly winds will gusts to around 15 to 20 kts Saturday afternoon and evening. This may lead to a brief period of SCA conditions over the middle and lower waters Saturday evening. Sub-SCA level winds are expected on both Sunday and Monday. Winds will be out of the south on Sunday, and then out of the west to northwest on Monday. SMWs may potentially be needed as thunderstorms pass over the waters Sunday afternoon into Sunday evening. No marine hazards are expected for next week (Tuesday through Friday) as high pressure settles over the waters. && .TIDES/COASTAL FLOODING... Tidal anomalies will remain elevated through the weekend ahead of the next cold front. Water levels will remain high as water will have no place to go under light winds and then under southerly channeling Sat afternoon-Sat night until strong cold front crosses the area early Monday. For this reason, Coastal Flood Advisories have been extended through the weekend. The worst flooding will occur at Annapolis with the high tide at 610 AM Saturday when the tide will be the highest of the next few days. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Coastal Flood Advisory until 11 AM EDT Saturday for DCZ001. MD...Coastal Flood Advisory until 6 AM EDT Monday for MDZ011-018- 508. Coastal Flood Warning until 10 AM EDT Sunday for MDZ014. Coastal Flood Advisory until 7 PM EDT Sunday for MDZ016. Coastal Flood Advisory until 6 PM EDT Saturday for MDZ017. VA...Coastal Flood Advisory until 7 PM EDT Sunday for VAZ054-057. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...ADS SHORT TERM...LFR LONG TERM...EST AVIATION...LFR/EST MARINE...LFR/EST TIDES/COASTAL FLOODING...LFR