


Area Forecast Discussion
Issued by NWS Sterling, VA
Issued by NWS Sterling, VA
696 FXUS61 KLWX 151430 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1030 AM EDT Tue Jul 15 2025 .SYNOPSIS... A frontal boundary will remain nearly stationary today before lifting northward as a warm front on Wednesday. Another cold front moves through the region late Friday before stalling nearby through the weekend and into early next week. && .NEAR TERM /THROUGH TONIGHT/... *10:30 AM UPDATE* Relative to 24 hours ago, the IAD sounding indicated a decrease in precipitable water (PWAT) values over the area. The July 14 (12Z) PWAT was 2.14", with a drop to 1.83" this morning. While the low levels remain moist as evidenced by the high dew point air mass, the biggest change is the drying of the 500-250 mb layer. Given the southward shift in the tropical air mass, expect the better chance for organized heavy rainfall closer to the I-64 corridor. With that in mind, have added a Flood Watch (for flash flooding) across Augusta, Nelson, and Albemarle counties, which includes the central Virginia Blue Ridge. This is in effect from 2 PM until midnight with rainfall rates up to 1.50 to 2.50 inches per hour possible in the heavier cores. Most notably, the biggest concern would be across the higher terrain which have recently seen heavy rainfall. *PREVIOUS DISCUSSION* A frontal system slowly moves through the forecast area this morning before stalling across the northern portions of the area this afternoon. Warm and humid conditions continue today with high temperatures in the mid to upper 80s. Heat indices will rise into the low to mid 90s across much of the area. Diurnally driven showers and thunderstorms are expected this afternoon and will be less organized compared to yesterday. Given the lack of forcing and lack of steering flow, pulse convection will lack movement and will be capable of producing heavy rainfall. With PWATS nearing or exceeding 2" combined with previous rainfall in days prior, there is a risk of flash flooding. WPC has a slight risk for excessive rainfall across portions of the area. Patchy fog is possible again overnight as humid conditions continue with light winds. Overnight low temperatures will be in the mid to upper 60s for those west of the Blue Ridge and in the 70s for those east of the Blue Ridge. && .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/... The aforementioned boundary is forecast to slowly lift northward as a warm front on Wednesday before dissipating. While showers and thunderstorms are expected each day, Wednesday looks to be the more active of the two days as the front remains nearby. High temperatures on Wednesday will be in the 80s to low 90s with heat indices rising into the upper 90s to 100. Overnight low temperatures will be in the 70s for most. Precipitation linger on Thursday, with diurnally driven showers and thunderstorms remaining possible. Temperatures warm under a tropical airmass with highs in the upper 80s to mid 90s. With humid conditions expected, heat indices near Heat Advisory Criteria along the I-95 corridor. Overnight lows will stay in the 70s for most. && .LONG TERM /FRIDAY THROUGH MONDAY/... Some shower and thunderstorm activity could develop in the western and parts of the central zones midday Friday and Friday afternoon as a cold front slides southeast across the region. Otherwise, convection should fade some and slide southward by Friday evening and night. High temperatures should be in the lower 90s. A couple of showers and a thunderstorm could linger or pop up on Saturday with the heating of the day, mainly across the southern half of the region. A weak area of high pressure could push into the region and bring some slightly drier air into the region late Saturday into Saturday night. High temperatures should reach the middle to upper 80s. Dry conditions could linger through midday Sunday with high pressure still holding on. A slight upslope component to the wind in the mountains in the west, followed by a developing warm front, could spawn a few showers or a thunderstorm during the warmest time of the day on Sunday and into Sunday evening. Highs in the upper 80s. Showers and thunderstorms, once again, could become more widespread Monday afternoon and evening with a low pressure system moving across Pennsylvania and a trailing cold front pushing southeast toward our region. Highs in the upper 80s to lower 90s. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... A cold front remains stalled overhead today before lifting northward as a warm front tomorrow. This will lead to daily shower and thunderstorm chances with Wednesday expected to be the more active day. Flight restrictions are expected during showers and thunderstorms. Light winds out of the south are forecast across all terminals today before becoming light and variable overnight. Winds increase on Wednesday, gusting 15 knots out of the south in the afternoon. Winds shift to southwesterly on Thursday, gusting 15 knots or less. VFR conditions should start the day Friday, but MVFR to IFR conditions may develop Friday midday through Friday afternoon at any of the terminals. Once convection clears Friday evening and at night, VFR conditions should redevelop. Winds southwest to west 5 to 10 knots. VFR conditions expected for the most part at all terminals as a weak area of high pressure influences slightly drier conditions. A few showers or a thunderstorm could move over CHO Saturday afternoon and evening, but shouldn`t be too overbearing. Winds becoming northwesterly 5 to 10 knots with light and variable winds across the southern areas && .MARINE... Showers and thunderstorm chances continue over the waters each afternoon and evening with SMWs possible today and Wednesday. Precipitation chances decrease slightly on Thursday, though the risk lingers for storms over the waters. Winds increase to near SCA criteria Wednesday evening due to southerly channeling. A Small Craft Advisory may be needed. Southerly winds continue through Thursday with Small Craft Advisories possible again on Thursday. The only marine hazards that could occur Friday into Friday evening would be Special Marine Warnings for thunderstorms that could develop and move out over the Potomac River and Chesapeake Bay waters Friday afternoon and evening. Winds generally southwest to west 10 knots with exception to higher gusts in thunderstorms. No marine hazards expected Saturday and Saturday night. Winds becoming more northeast 10 knots. && .TIDES/COASTAL FLOODING... After a brief lull in the warm advection flow regime, expect a return to the prolonged period of southeasterly winds. This will lead to elevated tidal anomalies through midweek, particularly across Annapolis. This location will see Action stage at times, particularly during the higher of the two astronomical high tide cycles. However, outside of freshwater influences from heavy rainfall, the threat for tidal flooding appears low. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...Flood Watch from 2 PM EDT this afternoon through this evening for VAZ025-036-037-508. WV...None. MARINE...None. && $$ SYNOPSIS...AVS NEAR TERM...AVS/BRO SHORT TERM...AVS LONG TERM...KLW AVIATION...AVS/KLW MARINE...AVS/KLW TIDES/COASTAL FLOODING...BRO