


Area Forecast Discussion
Issued by NWS Sterling, VA
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Issued by NWS Sterling, VA
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-- Discussion containing changed information from previous version are highlighted. --232 FXUS61 KLWX 140106 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 906 PM EDT Sun Jul 13 2025 .SYNOPSIS... High pressure will remain in place offshore over the course of the week. A weakening cold front will approach from the northwest tomorrow, before ultimately stalling out and dissipating overhead by mid-week. && .NEAR TERM /THROUGH MONDAY/...-- Changed Discussion --Most of the organized convection earlier this afternoon has now dissipated, with remnant heavy showers and a few thunderstorms lingering. Will watch that complex across south-central PA, though it also looks to be weakening this evening. The Flood Watch has been dropped for the southern half of the area, and kept up along the Alleghenies, northern Shenandoah Valley, and northern Maryland until 1 AM. It is possible we can cancel the watch before that as convection continues to dissipate. Given the soupy tropical environment, popup showers and a few thunderstorms will be possible across the area tonight. Some of these will produce heavy downpours, though the flood threat looks to be minimal. Overnight low temperatures settle in the upper 60s to low 70s.-- End Changed Discussion --&& .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/... Another active day is expected tomorrow as a shortwave and associated cold front approach from the northwest. Differential cyclonic vorticity advection ahead of the aforementioned shortwave will provide synoptic scale forcing that has been lacking on previous days, within what will be a very similar thermodynamic environment. A much higher areal coverage of storms is expected as a result. With the increased organization and slightly stronger mid-level flow (around 15 knots), storms may be be slightly more progressive compared to preceding days, but will likely pose an even greater threat for flash flooding, given the higher areal coverage and a thermodynamic environment that will still be very favorable for producing heavy rainfall. Forecast soundings still show 2000-3000 J/kg of MLCAPE, deep saturated profiles, PWATs near or in excess of 2 inches, and high freezing levels. A Flood Watch for flash flooding will likely be needed for much of the area once again. Storms may fire over the higher elevations of western MD and the WV Panhandle, as well as along the Bay Breeze further east. Much like today, outflows from these areas of storms may eventually meet up. The aforementioned cold front will stall out overhead on Tuesday, with slightly drier air filtering in behind the front, especially in the mid-upper levels. The drier air moving in aloft and lack of large scale forcing may limit thunderstorm development across northwestern portions of the forecast area on Tuesday. Better chances for showers and thunderstorms will reside further southeast, where they`ll hang on to deeper moisture. && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... On Wednesday, a southeastern U.S. upper ridge will continue to bulge northward into the Mid-Atlantic region. Eventually the northern extent of this ridge axis erodes in response to amplification in the northern branch of the jet. As this occurs, shortwave intrusions over subsequent days will augment convective chances, particularly in light of the continued warm and humid conditions in place. Although these impulses should only offer a grazing blow to the region, even subtle height falls can still have notable effects on the quality of the forcing. Given the unpredictability of such shortwaves, plus any storm-scale features which are unknown at this time, will contribute to a low confidence convective forecast. By late next weekend into the following week, a few deterministic solutions attempt to show a deeper trough on the horizon. However, as expected, global ensembles favor a more conservative elongated longwave trough over much of eastern North America. The aforementioned cold front will stall out overhead on Tuesday Looking at the surface pattern, the early week boundary which stalls nearby is expected to return northward as a warm front on Wednesday. This returns the area into the broadening warm/moist sector and more 90 degree temperatures. The next frontal system of interest enters the picture by Friday into Saturday. While daily afternoon/evening thunderstorm chances are possible through the period, they will likely further increase with the approach of this cold front. At this point, like typical summertime boundaries, this system may stall nearby toward the end of next weekend. Daily high temperatures through the period will mainly rise into the upper 80s to low 90s (70s to mid 80s across the mountains). For low temperatures, expect readings in the upper 60s to mid 70s (low/mid 60s for mountain locations). Global ensembles are fairly consistent in this signal with some downtick next weekend as the trough/front moves through. && .AVIATION /01Z MONDAY THROUGH FRIDAY/...-- Changed Discussion --Most of the convection from this afternoon has now dissipate, with isolated showers/storms through the night. While VFR conditions are likely to prevail, will have to monitor for the possibility of low stratus developing late tonight into Monday morning. Additional thunderstorms are expected tomorrow afternoon as a cold front approaches from the north and west. Coverage of the storms should be higher tomorrow afternoon into tomorrow evening. Storms may be possible again on Tuesday afternoon, but the highest coverage will likely be further south (in the vicinity of CHO). With convection perpetually in the forecast, restrictions are possible each afternoon/evening from Wednesday through Friday. Each day carries a 50 to 70 percent chance of showers and thunderstorms. Thus, it is difficult to say which day will be more active than the other. However, outside of these thunderstorms, VFR conditions should be anticipated. Given the warm/moist conditions in place, patchy fog cannot be ruled out at night, particularly for areas which see appreciable rainfall. Winds through the period meander between south to southwesterly before turning more westerly in nature by Friday. Afternoon gusts could push into the 10 to 15 knot range.-- End Changed Discussion --&& .MARINE...-- Changed Discussion --Sub-SCA level winds are expected over the waters through Tuesday. Winds shift to the south late tonight through Tuesday. SMWs are likely to be needed at times Monday and Tuesday afternoon to evening as thunderstorms move across the waters. A stalled frontal zone is expected to lift north of the waters on Wednesday. As this occurs, south to southwesterly winds pick up in strength Wednesday evening into much of Thursday. Wind gusts across the southernmost waters could near 20 knots at times which would warrant Small Craft Advisories. Elsewhere, gusts of 10 to 15 knots are expected. The threat for convection increases through the period with a 40 to 60 percent chance of showers and thunderstorms on both Wednesday and Thursday afternoon/evening. Special Marine Warnings may be needed for some of the stronger storms.-- End Changed Discussion --&& .TIDES/COASTAL FLOODING... A prolonged period of southeasterly winds will lead to elevated tidal anomalies today and into early next week. This carries most of the tidal locations into Action stage, particularly during the higher of the two astronomical high tide cycles. Sensitive locations, such as Annapolis, are forecast to stay just below Minor stage during the high tide cycles Sunday and Monday morning. && .LWX WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --DC...Flood Watch from 1 AM to 2 AM EDT Monday for DCZ001. MD...Flood Watch from 1 AM to 2 AM EDT Monday for MDZ011-013-014- 016-503>506. Flood Watch until 2 AM EDT Monday for MDZ003>006-501-502- 507>510. VA...Flood Watch from 1 AM to 2 AM EDT Monday for VAZ025>027- 029>031-036>040-050-051-053>057-501>508-526-527. Flood Watch until 2 AM EDT Monday for VAZ028. WV...Flood Watch until 2 AM EDT Monday for WVZ050>053-055-501>506. MARINE...None.-- End Changed Discussion --&& $$ SYNOPSIS... NEAR TERM...KRR SHORT TERM...KJP LONG TERM...BRO AVIATION...KRR/KJP/BRO MARINE...KRR/KJP/BRO TIDES/COASTAL FLOODING...LWX