Area Forecast Discussion
Issued by NWS Sterling, VA

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938 FXUS61 KLWX 240037 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 837 PM EDT Thu Mar 23 2017 .SYNOPSIS...
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High pressure 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.
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&& .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
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High pressure will move offshore tonight and a warm front will approach the area from the west overnight. A southerly flow will allow for milder conditions compared to Wednesday night. However...radiational cooling will still cause min temps to drop into the upper 20s to the middle 30s across most areas. Clouds will increase overnight as the warm front approaches. A period of rain is possible toward morning...especially across northern Maryland...eastern West Virginia and northern Virginia. Confidence in precipitation remains low since most of the lift associated with the warm front will be over Pennsylvania. However...a period of light rain cannot be ruled out. Temps will be near freezing across northern Maryland...eastern West Virginia and extreme northern Virginia. Pockets of freezing rain cannot be ruled out. Confidence is too low for an advisory at this time.
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&& .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/...
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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. Any pockets of freezing rain will be over by 9 am as temperatures rise above freezing across all locations. 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.
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&& .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 /01Z FRIDAY THROUGH TUESDAY/...
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Expecting mainly VFR through Saturday night. There may be a band of light precipitation that crosses the northern terminals late 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 but even across this area confidence is low. 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.
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&& .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...BJL/MM SHORT TERM...MM LONG TERM...BJL/IMR AVIATION...BJL/MM/IMR MARINE...BJL/MM/IMR

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