Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 161508 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1108 AM EDT Sat Jul 16 2016 .SYNOPSIS... A surface trough will remain overhead through the weekend. The boundary will dissipate Monday before a cold front moves into the area Monday night into Tuesday. The boundary will stall just to the south during the middle portion of next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Weak remnant of a frontal boundary settles near the area and stalls out this afternoon. This combined with an impulse of energy aloft will be enough to trigger some scattered showers and thunderstorms this afternoon. While not expecting much in the way of a widespread severe threat, could see an isolated stronger storm or two with the development of 1000-1500 J/KG of MLCAPE and around 30 knots of 0-6KM shear. It should be noted that if convection can build tall enough, there is significantly more shear available above 6KM AGL. Another very warm near-seasonal summer day expected with highs in the mid 80s to around 90F. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... Convection ongoing this evening will weaken and dissipate heading into tonight. Also expecting gradual clearing, which may lead to the development of some patchy fog, especially in areas that see rain this afternoon/evening. Lows 60s to mid 70s. Sunday will be the best day of the weekend with mostly sunny skies as high pressure moves in overhead. Temperatures similar to today, but likely a degree or two warmer, mid 80s to low 90s. Temperatures increase further Monday, the hottest of the next several days, out ahead of an approaching frontal system. Highs expected to reach the low to mid 90s, but with higher dew point values slow to return, should not be overly oppressive, with heat indices currently forecast to remain below 100F. Some showers and thunderstorms may approach from the northwest late in the day. Cold front moves towards the region for Monday night. Mid level lapse rates increase, and some MLCAPE modeled to remain over the region, so will have to watch to see if some of the showers/thunderstorms likely ongoing Monday evening upstream over the Ohio Valley can make it into the region Monday night. && .LONG TERM /TUESDAY THROUGH FRIDAY/... A cold front will will pass through the area Tuesday into Tuesday night and it will stall out just to the south Wednesday and Thursday. Showers and thunderstorms are possible...especially along and ahead of the boundary Tuesday. The best chance for thunderstorms will be across central Virginia into southern Maryland where heat and humidity will be a bit higher. Weak high pressure will build in the area behind the front for Wednesday and Thursday. Seasonably hot conditions are expected during this time...but humidity will be a bit lower. The high will shift offshore and weaken late in the week while a cold front moves through the central Conus. A southwest flow will likely allow for the return of more hot and humid conditions for Friday and Saturday. Much of the time should turn out dry for Wednesday and Thursday due to lower humidity...but also for Friday and Saturday too due to a westerly component to the low-level wind field. && .AVIATION /15Z SATURDAY THROUGH WEDNESDAY/... Generally VFR through the TAF period. Mostly clear skies expected for the remainder of the early morning hours. Some patchy fog possible at CHO for a few hours, so have maintained some MVFR in the TAF. Scattered showers and thunderstorms expected to develop this afternoon, so have shown a VCTS. Activity too scattered to warrant TSRA yet. VFR Sunday aside from any patchy early fog potential. VFR conditions expected to prevail through much of Monday. The next chance for some showers/thunderstorms will be late Monday/Monday night. VFR conditions are expected most of Tuesday through Wednesday. A couple showers and thunderstorms are possible Tuesday...with the best chance toward KCHO. && .MARINE... Winds are 18 knots this morning, but may again briefly approach criteria later this afternoon and evening. Will leave gusts below 18 knots for now. Risk of gusty thunderstorms later this afternoon and evening as well, with potential for Marine Weather Statements/Special Marine Warnings. Sunday expected to be tranquil with sub-SCA winds, but southerly channeling ahead of next front will bring potential for SCA winds Sunday night, and more likely late Monday/Monday night. A cold front will pass through the area Tuesday into Tuesday night. A few showers and thunderstorms are possible. The best chance for thunderstorms will be across the lower Tidal Potomac River and middle portions of the Bay. Any thunderstorms that do develop may contain gusty winds. High pressure will settle overhead for Wednesday and Thursday. A pressure surge behind the cold front may cause gusts around SCA criteria Tuesday night. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BJL NEAR TERM...MM/RCM SHORT TERM...MM LONG TERM...BJL AVIATION...BJL/MM/RCM MARINE...BJL/MM/RCM

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