Area Forecast Discussion
Issued by NWS Sterling, VA

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097 FXUS61 KLWX 231851 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 251 PM EDT Thu Mar 23 2017 .SYNOPSIS... High pressure overhead this afternoon will shift offshore tonight. A warm front will cross the region Friday. A low pressure system will then approach the region on Sunday, and cross the area Sunday night into Monday. && .NEAR TERM /THROUGH TONIGHT/... High pressure overhead is providing for mostly sunny skies and light winds across the region this afternoon. Temperatures remain quite chilly with highs about 10 degrees below climatological normals, generally in the mid 40s to low 50s. Tonight, the high pressure will shift offshore, promoting developing southerly flow. A warm front will approach from the west, so clouds will be on the increase after midnight. However, before this occurs, should see radiational cooling allow temperatures to drop off back into the low 30s for most locations, with even a few upper 20s. Towards morning, with the strong warm air advection, a band of light precipitation may near the northwestern reaches of our region across eastern West Virginia and western Maryland. While the bulk of the precipitation should remain north across Pennsylvania, there may be some light rain, and perhaps patchy light freezing rain. && .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Aforementioned band of light precipitation will be moving from west to east near the northern extent of our forecast area Friday morning. Again while the bulk of the precipitation will remain across Pennsylvania, some light rain and patches of freezing rain are possible, especially across eastern West Virginia and northern Maryland. After warm frontal passage, the afternoon should warm significantly with breaks of sun and highs reaching the upper 50s to mid 60s. Dry and mild conditions expected Friday night with lows only in the 40s to around 50F. Frontal boundary will remain north of the region on Saturday with mainly dry conditions and warm southerly flow. Despite high clouds, should see temperatures rise to near or above 70F pretty much area-wide. Closed low pressure system will be moving towards the Great Lakes region Saturday night with high pressure building into the Canadian Maritimes. This will strengthen the frontal boundary over the Northeastern United States, and may push it back southwestward towards the region overnight as a backdoor front. However, even so, we should still remain mild, with lows near 50F. Dry conditions expected for most of the area. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Unsettled weather expected for parts of the long term as frontal boundaries stall nearby and southerly flow brings Gulf moisture over our area. Sunday into Monday, a low pressure system moves east over the southern Great Lakes and into the NE US as a frontal boundary stalls north of us. A brief dry period is possible Monday night before another low pressure and its front affects our area Tuesday into Wednesday. Conditions start drying on Wednesday and into Thursday as high pressure builds into the area. Temperatures will be above normal, with high temperatures in the 50s and 60s, with some 70s on Monday and Tuesday. Low temperatures will be in the 40s and 50s, with 30s Wednesday night. && .AVIATION /18Z THURSDAY THROUGH TUESDAY/... Expecting mainly VFR through Saturday night. There may be a band of light precipitation that crosses the northern terminals late tonight into Friday morning, but no significant reductions to ceilings or visibilities are expected. There is the threat of some patches of light freezing rain, with highest risk at MRB. Winds will become southerly and a bit gusty, up to 20 knots or so, on Friday, slackening somewhat on Saturday. Unsettled weather Sunday into Monday as frontal boundaries stall near our area. Brief period of dry conditions Monday night before another front approaches on Tuesday. Sub-VFR conditions possible most of this period. && .MARINE... Southerly flow will increase tonight as a warm front approaches, with SCA threat spreading up the bay and portions of the tidal Potomac overnight and then to the adjacent waters during the day Friday. Winds should diminish somewhat for Friday night and Saturday. Gusts may be near SCA criteria Friday night but with the water likely remaining cooler than the surrounding air mass, the lack of mixing will reduce gusts over the waters for Friday night through Saturday night. Unsettled weather Sunday into Monday as frontal boundaries stall near our area. Brief period of dry conditions Monday night before another front approaches on Tuesday. Small Craft Advisories may be needed for portions of the waters Sunday into Sunday night ahead of the front. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from midnight tonight to 6 PM EDT Friday for ANZ531>534-537-539>541-543. Small Craft Advisory from noon to 6 PM EDT Friday for ANZ535- 536-538. Small Craft Advisory from 6 AM to 6 PM EDT Friday for ANZ530- 542. && $$ SYNOPSIS...MM NEAR TERM...MM SHORT TERM...MM LONG TERM...IMR AVIATION...MM/IMR MARINE...MM/IMR is the U.S. government's official web portal to all federal, state and local government web resources and services.