Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
450 FXUS61 KLWX 040757 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 357 AM EDT Fri Jul 4 2025 .SYNOPSIS... High pressure will build across the area this weekend, while low pressure develops off the southeast coast. A cold front will approach from the northwest Monday, before potentially stalling near the area during the middle of the week. && .NEAR TERM /THROUGH TONIGHT/... A dry front is pushing south through the area this morning, ushering in a drier and slightly cooler airmass. North to northwest trajectories remain in place through the day, as surface high pressure spreads eastward from the Great Lakes and mid/upper troughing moves east from New England. There will be plenty of sunshine with temperatures topping out in the mid 80s for most areas. Dew points in the 50s are already apparent behind the boundary, which will result in a much more comfortable feeling compared to the past few weeks. While not currently mentioned in the forecast database, multiple models show the potential for a pop up shower or thunderstorm over the Alleghenies this afternoon and evening, particularly Highland and Pendleton Counties. There will be a combination of surface convergence, terrain circulations, and higher dew points in this area on the southwest flank of the high. However, subsidence aloft should keep updrafts weak and may ultimately prevent development. The high will move to the Mid Atlantic coast by Saturday morning. Clear skies and light winds may result in some patchy river valley fog late tonight. Lows will be in the 60s, with potentially some upper 50s where radiational cooling is maximized. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... The surface high will progress off the coast through the weekend as upper level ridging builds overhead. This ridge should largely keep a low suppressed along the southeast coast (which NHC has highlighted for possible tropical cyclone development). Saturday should remain mostly sunny and dry with temperatures and dew points a few degrees higher than Friday. Sunday will continue that trend, as more areas potentially reach 90 degrees and some locations fail to drop below 70 Sunday night. One wild card will be moisture associated with the southeast low. This moisture could result in a little additional cloud cover on Sunday. However, there is a low chance a few showers could even sneak into southern parts of the forecast area. && .LONG TERM /MONDAY THROUGH THURSDAY/... A an approaching cold front will bring the return of precipitation chances on Monday with showers and thunderstorms possible in the afternoon. Precipitation chances increase on Tuesday as the cold front pushes through the forecast area. As the boundary stalls over the southern portions of the forecast area, shower and thunderstorm chances linger Wednesday and Thursday. Each day, warm temperatures and humidity will lead to plenty of instability (CAPE) although convection will be limited by the lack of shear. This will inhibit widespread strong to severe thunderstorms. Temperatures Monday and Tuesday will be in the the 80s to low 90s with higher elevations staying in the upper 70s. Overnight low temperatures will dip into the 60s and 70s. High temperatures cool slightly on Wednesday in the wake of the cold front. Highs will be in the 80s for most with only isolated locations reaching the 90s both Wednesday and Thursday. Higher elevations will stay in the 70s both days. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... High pressure will build across the area through the weekend, resulting in VFR conditions. Light northerly winds today will start veering toward evening, becoming south to southeast by Saturday morning (and continuing through Sunday). Depending on the effects of low pressure off the southeast coast, some sub- VFR ceilings may develop over portions of the area Sunday night. Sub-VFR conditions are possible Monday and Tuesday afternoon as showers and thunderstorms impact the terminals due to an approaching cold front. Winds will be light and variable on Monday and Tuesday before shifting to northwesterly in the wake of the front Tuesday evening. && .MARINE... A front pushing south of the area early this morning has brought northerly winds. A brief period of postfrontal gusts approaching 20 kt should depart the local waters by sunrise. Light winds prevail through the weekend with dry conditions as high pressure pushes off the coast. Winds will turn south/southeast by Saturday morning. The greatest chance for advisory conditions (albeit marginal) will come Sunday evening/night due to a slightly enhanced wind field between the departing high and nearly stationary low pressure along the southeast coast. Showers and thunderstorms are possible over the waters as a cold front approaches the forecast area next week. Winds are expected to stay below SCA criteria both Monday and Tuesday, although SMWs are possible during afternoon showers and thunderstorms. && .TIDES/COASTAL FLOODING... Southerly winds will return this weekend, driving slight increases in water level anomalies. While flooding is unlikely for most areas, a push of slightly stronger winds could result in Annapolis nearing the minor threshold early Monday morning. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...ADS NEAR TERM...ADS SHORT TERM...ADS LONG TERM...AVS AVIATION...ADS/AVS MARINE...ADS/AVS TIDES/COASTAL FLOODING...ADS