Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 180201 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 901 PM EST Fri Feb 17 2017 .SYNOPSIS... High pressure will linger over the area through Saturday. A weakening low crosses the area Saturday night. A backdoor cold front will enter the area Monday into Tuesday, followed by another disturbance Tuesday night into Wednesday. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/... As of 9pm, a 1001mb low is over Lubbock and a 981mb low is on the NW side of Newfoundland. A weak surface ridge is in between. Just scattered cirrus with light flow and decoupled locations. Air mass above the surface will be warming rapidly overnight, but with mainly clear skies and light winds, radiational cooling should still allow surface/2-meter temperatures to fall into the 30s. && .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... Significantly warmer weather is expected for the weekend. Mostly sunny skies for the first half of Saturday will give way to increasing clouds in the afternoon ahead of a weakening disturbance moving into the southeastern US. Temperatures will soar to 20-25 degrees above normal, with highs well into the 60s with low 70s south of DC. The disturbance will pass south of the region Saturday night. There may be some light rain showers overnight as the system passes nearby, but any precipitation will be very light. Lows generally in the 40s. Dry weather and mostly sunny skies return for Sunday with another day of highs in the 60s to around 70F. A system will pass through New England Sunday night, and while not directly affecting our region, it may set up a backdoor cold front that will be near the area for Monday. Lows Sunday night around 40F. && .LONG TERM /MONDAY THROUGH FRIDAY/... Main concern in the long term to start out is the growing potential for a northeasterly flow behind a backdoor cold front Monday and Tuesday, and potentially Wednesday as well. This will be due to a high pressure centered over southeastern Canada allowing cooler maritime air to surge south and west around the bottom of the high into our region. While no precipitation is expected Monday and Tuesday thanks to ridging aloft, low clouds are possible, especially Tuesday, and temperatures will be cooler than what otherwise might be expected given warm air present aloft and a ridge overhead. Wednesday a weakening cold front is expected to move in from the west. Some showers are possible but significant precipitation is not anticipated, so our very dry February will continue with little improvement. As this front moves through, the wedge of cooler air may be displaced briefly, but may return quickly as high pressure returns to its favorable location for wedging - southeastern Canada. Otherwise, late week looks dry. && .AVIATION /02Z SATURDAY THROUGH WEDNESDAY/... VFR conditions prevail through Saturday under high pressure. Weakening low moves across the area Saturday night...with a chance for light rain showers. Light rainfall rates should keep flight restrictions rather marginal/brief...with perhaps a brief period of MVFR. VFR returns after daybreak Sunday. Sub-VFR will be possible early next week, especially BWI/MTN, as a back door cold front could bring some low clouds into the region. Best chance of this is Tuesday. A little drizzle is even possible though significant rain is not expected through Tuesday. A few showers are expected on Wednesday as a weak front passes with continued chance for sub-VFR. Winds through the period look mostly below 20 knots. && .MARINE... Light south flow with high pressure centered to the south. Sub- SCA winds expected through Sunday night...with the typical increases/decreases during the day/night due to diurnal mixing trends. Backdoor cold front may bring a risk of marginal SCA conditions Monday and Tuesday with another cold front bringing the same small risk on Wednesday. Winds may briefly reach 20 knots in gusts Monday through Wednesday, but should not get stronger than that. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BAJ/MM NEAR TERM...BAJ/MM SHORT TERM...MM LONG TERM...RCM AVIATION...BAJ/MM/RCM MARINE...BAJ/MM/RCM is the U.S. government's official web portal to all federal, state and local government web resources and services.