Area Forecast Discussion
Issued by NWS Sterling, VA

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682 FXUS61 KLWX 031405 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1005 AM EDT Thu Jul 3 2025 .SYNOPSIS... A weak cold front will move through tonight. High pressure will build into the area in its wake, before progressing offshore by early next week. && .NEAR TERM /THROUGH TONIGHT/...
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Current water vapor imagery depicts a shortwave trough diving southeast through the Ohio Valley this morning. Mid-level moisture ahead of this trough has allowed for some wavy altocumulus to develop off of the higher terrain across central/northern VA. Not expecting any precipitation to develop out of this, but just resulting in a bit more cloudcover than originally anticipated. Do expect drier air to move in throughout the day, but could see this altocu field to continue for much of the day. Temperatures will be seasonable, with highs in the upper 80s to around 90. Dewpoints will drop back into the upper 50s and lower 60s, which will make it feel less humid than preceding days. As we move through the afternoon hours, a shortwave trough will dive southeastward across the Great Lakes toward Upstate NY, driving a cold front southward across NY/PA. Model guidance hints that a few showers and storms will likely develop to our north across NY/PA this afternoon. Most guidance weakens or completely dissipates this activity as it works southeastward into drier mid-level air, but a few solutions show those showers/storms dropping into northern MD and northern portions of the WV Panhandle late this afternoon into this evening. Model soundings show around 1000 J/kg of MLCAPE and 30-40 knots of effective bulk shear in northeast MD, so there could be a conditional threat for a damaging wind gust or instance of large hail if storms were to make it this far south. As a result, SPC currently has northeast and north-central Maryland outlooked in a Marginal Risk for severe thunderstorms. Any storms will wind down as they drift southeastward during the evening hours. Dry conditions are forecast overnight, with lows in the 60s for most.
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&& .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Upper troughing will progress off the New England coast on Friday, with high pressure building within the zone of subsidence in its wake across the Eastern Great Lakes/Upstate NY. Mostly sunny skies are forecast with high pressure in control. High temperatures will be in the mid-upper 80s for most. Humidity values will be lower than normal, with dewpoints holding in the upper 50s to lower 60s. Clear skies are expected 4th of July evening, with temperatures in the upper 70s and low humidity levels. Dry conditions will continue through the remainder of the night, with lows in the 60s. Upper ridging will build in from the west on Saturday as high pressure at the surface starts to move offshore. Mostly sunny skies and seasonable temperatures are forecast, with highs in the upper 80s for most. && .LONG TERM /SUNDAY THROUGH WEDNESDAY/... Heights aloft are expected to slowly build through the weekend and into early next week. The net result is a gradual warming/moistening trend which carries high temperatures to around 90 degrees by Sunday and Monday. Based on the latest global ensemble guidance, the peak in this increase in summertime heat comes on Monday. A few solutions carry high temperatures into the low to perhaps even mid 90s. However, this will largely depend on cloud cover and the timing/coverage of any shower and thunderstorm development. The return of storm chances comes with the uptick in humidity as southerly flow increases. In response to a slow moving trough back across the Midwest and Great Lakes region, the opportunities for showers and thunderstorms will increase on Tuesday, Wednesday, and Thursday. Given how far this is into the forecast period, any severe component to these storms is uncertain at this time. Additionally, precipitable water values increase given the continued deep southerly flow. By the middle of next week, the parent frontal system is forecast to be just off to the north and west of the local area. Depending on when this boundary passes through, a decrease in humidity would be expected once this front exits. && .AVIATION /14Z THURSDAY THROUGH MONDAY/...
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Prevailing VFR conditions are expected at all TAF sites through Saturday. However, there is a very small chance for a brief shower or storm late this afternoon or evening as a cold front drops towards the region from the north. MRB would have the greatest chance, followed by MTN and BWI, but chances are still too low to mention in the TAFs. Northwesterly winds early today will turn westerly toward the middle of the day, and then north to northwest just prior to midnight as the aforementioned cold front moves through. Light northerly winds are expected tomorrow, with light southerly winds on Saturday. High pressure remains over the region over the weekend which will favor VFR conditions across the area terminals. Thunderstorm chances (20-30 percent) return by Monday which could lead to brief restrictions during the afternoon/evening hours. Winds should be out of the south through Monday with gusts increasing to around 10 knots each afternoon.
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&& .MARINE... Sub-SCA level winds are expected over the waters through Saturday. Winds will be out of the west to northwest today, north tomorrow, and south on Saturday. There`s a very small chance that there could be an SMW across far northern portions of the Bay late this afternoon into this evening, but most solutions have storms staying off to our north. Southerly winds prevail through the weekend with wind gusts largely topping out between 10 and 15 knots. By Sunday night, some southerly channeling effects are possible which could near Small Craft Advisory levels across the more southern waters. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...KJP NEAR TERM...CJL/KJP SHORT TERM...KJP LONG TERM...BRO/CPB AVIATION...CJL/KJP/CPB MARINE...KJP/CPB