Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 281903 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 303 PM EDT SAT MAY 28 2016 .SYNOPSIS... High pressure will remain over the area through the first part of the coming week with low pressure impacting the area from the south. A cold front may push through the region at the end of the week. && .NEAR TERM /THROUGH TONIGHT/... Surface high combined with ridging aloft over the eastern portions of the US keeping warm conditions in place. Temps this afternoon reaching the 80s across the board except for isolated spots right along the shoreline. Isolated thunderstorms popping up on radar this afternoon, mainly impacting right along the Mason- Dixon and northward. The warm temps leading to marginal instability but with lack of any real forcing mechanism both at the surface and aloft along with minimal shear, not anticipating anything severe, only brief heavy rainfall. Any activity drops off after sunset with the loss of diurnal heating. Thinking dry conditions for most of the area most of the night. Increasing moisture in the low levels could result in patchy valley fog as we saw last night. The 12Z guidance has slowed the precip down a bit for tomorrow, but cannot rule out showers reaching the southern fringes of the CWA by daybreak Sun morning. && .SHORT TERM /SUNDAY THROUGH MONDAY NIGHT/... Increasing coverage in rain and thunderstorms Sunday. As previously mentioned, latest guidance showing that the rain will reach the area slightly slower than previous runs indicated. TD 2 nearing the SC coast this afternoon is expected to be right along the coast by Sun morning, then slowly progressing nearly parallel to the coast into the first part of the coming week. Please refer to NHC products for the official forecast. Also to monitor during this time is an approaching trough across the northern US. As energy from the low to the south swings around the western side of the ridge aloft, it becomes sandwiched between the ridge to the east and this approaching trough from the west. There remains some question exactly where this energy becomes trapped, but the latest guidance shows to be right across the Mid- Atlantic. This will aid in enhancing further shower and thunderstorm development across the CWA. Moisture advection will increase Sun from the low to the south and combined with the aforementioned features, the potential exists for moderate to periods of heavy rain. With the overall flow on the lighter side and the potential of training activity, will continue to highlight flooding potential in the HWO. At the moment can not pinpoint exactly where, but the latest thinking is that the heaviest band sets up between the Blue Ridge and Chesapeake Bay. The rain will continue into Monday, especially over eastern areas. Subsidence builds in later in the day with the next ridge nudging in from the west so should see precip cutting off over western areas with a possible dry period over the east before the remnants of the low finally move north mid week. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Upper level ridging starts building up on Tuesday and a low pressure system stalls over the North Carolina coast through Thursday. Moisture advection from this system will depend on its location... but guidance is showing that showers and thunderstorms are possible over our CWA from Tuesday into Thursday. A cold front approaches from the west on Friday and moves across Friday night into Saturday, continuing with the chance of showers and thunderstorms during this period. Upper trough approaches the eastern CONUS during the weekend. High temperatures will be in the upper 70s and low 80s before the cold front... in the 70s for Saturday. Low temperatures will be in the 50s and 60s. && .AVIATION /19Z SATURDAY THROUGH THURSDAY/... VFR conditions through at least the first half of tonight. Possible patchy fog dropping vis to 4-5SM late tonight, around daybreak. Rain moves in generally late tomorrow morning into Sun afternoon. With the heavier rain later in the day comes sub-VFR conditions in both the cigs and vis, lasting into Sun night. Improvement back to VFR returns on Monday. Winds less than 10 knots through the period, southerly becoming easterly. VFR conditions expected for Tuesday through Thursday...with some showers and thunderstorms possible bringing brief periods of sub- VFR conditions due to a low pressure system to our southeast. && .MARINE... SCA gusts on the open waters of the Chesapeake Bay this afternoon on southerly flow. Sub-SCA on the remaining waters. Any stronger gusts will diminish after sunset, with sub-SCA conditions on the waters through the first part of the coming week. Sub-SCA conditions expected as winds will be below SCA criteria. Showers and thunderstorms possible during the waters during this period with low pressure system to our southeast. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 7 PM EDT this evening for ANZ532>534. && $$ SYNOPSIS...Sears NEAR TERM...Sears SHORT TERM...Sears LONG TERM...IMR AVIATION...Sears/IMR MARINE...Sears/IMR is the U.S. government's official web portal to all federal, state and local government web resources and services.