Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
505 FXUS61 KLWX 240736 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 336 AM EDT Mon Aug 24 2026 .WHAT HAS CHANGED... Expanded on the mid-week thunderstorm threat in Key Message 2. Severe threat is low, but not zero Thursday afternoon/evening. && .KEY MESSAGES... - 1) Dry conditions anticipated through early portions of the week. - 2) Warmer and more humid conditions return mid-week, with thunderstorm chances returning by Thursday. && .DISCUSSION... KEY MESSAGE 1...Dry conditions anticipated through early portions of the week. High pressure will continue to slowly build toward the area on Monday and Tuesday, resulting in dry conditions and lower humidity levels. High temperatures will generally be in the upper 70s to mid 80s, with overnight lows in the 50s to lower 60s. KEY MESSAGE 2...Warmer and more humid conditions return mid- week, with thunderstorm chances returning by Thursday. Heading into Wednesday, dry, pleasant conditions continue into much of the day and afternoon. As an upper level ridge over the midwest begins to flatten in amplitude, southwesterly mid-level winds advect tropical moisture northward into our region. As this tropical air mass moves through our region, humid conditions return through the end of the week. A weak piece of shortwave energy is also expected to approach the region Wednesday evening, which could spark a few storms in the evening/overnight hours. As the upper trough over the northeast CONUS starts to push more offshore on Wednesday, we will see some subtle rises in 500 hPa heights. This, paired with a developing southerly surface wind pattern will yield more typical August warmth and increased humidity. Expect high temperatures in the upper 80s to near 90, along with dew points increasing into the low to mid 60s. The ridge doesn`t will only be overhead during the day though, as another piece of shortwave energy rotates through late in the evening into the overnight. There won`t be a lot of instability left over when this rotates through, but there may be enough to pop off a few overnight showers. By Thursday, after a day of southerly flow ahead of an approaching cold front from the west, humidity will jump markedly. Temperatures remain in the mid 80s to low 90s, but dew points jump into the upper 60s and perhaps even into the low 70s. The aforementioned cold front will come through during the day Thursday. If timed during peak heating, there could be around 1000 to 1500 J/kg of MLCAPE to work with. The shortwave is subtle, with only about 20 kts of deep layer shear showing up in most guidance. So, the threat for organized severe weather is rather low. Additionally, this is not one of the extreme heat/humidity setups, so thinking is a more isolated wind threat at this point. Latest AI medium-range guidance generally agrees, painting anywhere from 5 to 15 percent severe probs over the region depending on which one you use. By Friday, the front should be mostly offshore. However, there is still the slight chance that it lingers somewhere near/east of I-95, which could bring renewed afternoon storm chances. && .AVIATION /06Z MONDAY THROUGH FRIDAY/... Prevailing VFR conditions and westerly winds are expected at the terminals through Tuesday. Winds today will be around 5 to 10 knots, with gusts up to 18 knots. Wind Tuesday will be a little lighter. Light to gentle winds turn southerly Wednesday afternoon. Initial VFR conditions could deteriorate as showers and thunderstorms potentially move in Wednesday night. Additional showers and storms may be possible on Thursday with continued southerly winds. && .MARINE... West to northwesterly winds are forecast over the waters through Tuesday as high pressure gradually approaches from the Ohio Valley. Winds shift southerly by Wednesday, with winds gusting above SCA thresholds later that evening in a classic southerly channeling event ahead of an approaching cold front. Southerly winds nearing SCA criteria continue into Thursday afternoon as well. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ DISCUSSION...CJL/SRT AVIATION...CJL/SRT MARINE...CJL/SRT