Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 171943 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 243 PM EST Fri Feb 17 2017 .SYNOPSIS... A warm front will cross through the area this afternoon. A weak system then passes nearby Saturday night into Sunday morning. A backdoor cold front will be near the region Monday into Tuesday, followed by another disturbance Tuesday night into Wednesday. && .NEAR TERM /THROUGH TONIGHT/... A warm front is crossing through the area this afternoon with temperatures still in the 40s as of 2PM northeast of the DC Metro to around 60F across central VA and parts of West Virginia. This will continue pushing northeastward through the remainder of the day. Mid-cloud deck from earlier today has dissipated with only some high clouds streaming overhead. For tonight, aside from scattered high clouds, we`ll be looking at mostly clear skies. 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 /SATURDAY 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 to even some low 70s southward towards Charlottesville and Fredericksburg. 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 /19Z FRIDAY THROUGH WEDNESDAY/... VFR conditions expected to prevail through Saturday as high pressure remains in control of the weather. Weak disturbance moves near the area Saturday night into Sunday morning...with a chance for light showers. Light rainfall rates should keep flight restrictions rather marginal/brief...with perhaps a brief period of sub-VFR (best chance at KCHO). 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... Relatively light and 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...MM NEAR TERM...MM SHORT TERM...MM LONG TERM...RCM AVIATION...MM/RCM MARINE...MM/RCM

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