Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 230734 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 334 AM EDT Fri Sep 23 2016 .SYNOPSIS... Low pressure remains off the Carolina coast while high pressure is centered over New England. A backdoor cold front will move through the area Saturday. High pressure returns to the region Sunday before moving off the coast Monday. A cold front will slowly pass through Tuesday into Wednesday. High pressure will return for late next week. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... Mostly sunny and very warm to hot day in store for the region. Dry northwest flow aloft will be in place, and only clouds will be some high cirrus drifting overhead and a few afternoon cumulus. Highs well into the 80s to around 90F. && .SHORT TERM /6 PM THIS EVENING THROUGH SUNDAY NIGHT/... Cold front will approach from the north late tonight and pass through the region Saturday morning. For the most part, this will be a dry frontal passage with only an increase in clouds, although a few isolated showers are possible across the terrain on Saturday. Lows tonight in the low to mid 60s for most. Highs Saturday in the 70s to low 80s. High pressure will nose into the area behind the front Saturday night with generally clearing and drying conditions. Exception will be across the terrain in western areas where northeasterly flow behind the front may produce some low stratus and possibly an isolated shower or two in some light upslope flow. Lows Saturday night in the 50s to low 60s. High pressure will settle across the Northeastern US for Sunday and Sunday night, keeping the area mostly dry, but promote the development of onshore easterly flow. At the same time, will see warming aloft beginning Sunday night. Sunday likely to be partly- mostly sunny for central/eastern areas, with more clouds west along the terrain. Clouds then increase Sunday night, and onshore flow may lead to the development of some low clouds, patchy fog, and some drizzle, especially west towards the terrain. Highs Sunday in the 70s with lows Sunday night in the 50s to around 60F. && .LONG TERM /MONDAY THROUGH THURSDAY/... A cold front will approach the area Monday before slowly passing through Tuesday into Wednesday. A southerly flow ahead of the front along with isentropic lift will likely bring plenty of clouds along with a few showers Monday into Monday night. Exact timing of the frontal passage is uncertain...with some guidance bringing it through early Tuesday and other guidance holding off on the frontal passage until Wednesday. This will have a significant impact on the forecast during this time. Will allow for the chance of showers Tuesday and Wednesday...but confidence is low. High pressure will build in behind the boundary late next week...bringing dry and seasonable conditions. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... Some patchy fog early this morning may bring a period of sub-VFR conditions, mainly CHO/MRB, although possibly at IAD/BWI for a brief time. Otherwise, will see VFR area-wide after 12z with a few cirrus and fair weather cumulus through the day. Winds variable, turning generally westerly this afternoon, but light, mainly 5-7 knots. A cold front will cross Saturday morning with a shift to northerly winds and an increase in clouds, although likely remaining mainly VFR. Primarily VFR conditions continue into Sunday, with the possibility for the development of some sub-VFR conditions Sunday night in low stratus, mainly CHO/MRB. A cold front will approach the terminals Monday. Subvfr cigs along with a few showers are possible Monday into Tuesday. Subvfr cigs may persist through Tuesday depending on the timing of the frontal passage. Uncertainty with timing of the frontal passage remains high at this time. && .MARINE... Sub-SCA conditions expected today with mainly sea-breeze flow, less than 15 knots. Cold front crosses late tonight and Saturday morning, with a surge of wind gusts up to about 20 knots. Thus, a Small Craft Advisory has been issued from 2 am to 2 pm on Saturday. Winds taper off Saturday afternoon. An additional wind surge is possible Saturday night into Sunday morning with near-SCA conditions once again. Sub-SCA conditions then return by Sunday afternoon and Sunday night. A cold front will approach the waters Monday through Monday night. A southerly flow may gust past SCA criteria late Monday through Monday night. The cold front will slowly pass through Tuesday into Wednesday. Timing of the frontal passage remains uncertain so Small Craft conditions are possible during this time. High pressure will approach for late next week. && .TIDES/COASTAL FLOODING... Tidal anomalies remain around one-half foot above normal. Minor flooding is not expected during the next high tide cycle this morning into this afternoon. The next high tide late this afternoon into tonight will be the higher of the two astronomical norms. Water levels will likely be closer to minor flooding levels...but with the lack of an onshore flow the latest forecast keeps levels below minor flooding thresholds. && .CLIMATE... Unusually warm weather has persisted over the area for quite some time. Autumn-like temperatures will finally make an appearance over the weekend likely bringing low temperatures at DCA below 60 degrees for the first time since June 9th, or 105 days ago. The record most consecutive days at or above 60 degrees in the Washington DC area is 112 set in 2012. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 2 AM to 2 PM EDT Saturday for ANZ530>534-537>543. && $$ SYNOPSIS...BJL NEAR TERM...MM SHORT TERM...MM LONG TERM...BJL AVIATION...BJL/MM MARINE...BJL/MM TIDES/COASTAL FLOODING...BJL CLIMATE...BJL is the U.S. government's official web portal to all federal, state and local government web resources and services.