Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 171455 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1055 AM EDT Mon Oct 17 2016 .SYNOPSIS... High pressure over the Mid-Atlantic will shift southward Monday and remain to our south through midweek. A cold front will cross the Thursday night into Friday. High pressure will return for the weekend. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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Surface high pressure has shifted south of the region and this will allow for the development of southerly flow and warming temperatures today. The area also lies on the northeastern extent of a building upper level ridge with several pieces of energy moving around the ridge. Thus, some mid/high clouds as well as some cumulus will be around today. With warming both in the low levels and aloft, will see temperatures significantly warmer than yesterday, with highs in the low 80s for most locations. This will be near-record warmth today for IAD (Dulles), see climate section below.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/... Sprawling upper level ridge will build further northeastward tonight and Tuesday, with a continued warming trend expected. Near-record or record highs and high-mins are possible. Lows tonight in the 50s and 60s with highs Tuesday in the mid to upper 80s. These high temperatures will be 15 to 20 degrees above the climatological normals. A weak boundary will try to push southeastward towards the region Wednesday before lifting back northward Wednesday night. There are some discrepancies as to the southern extent of its progression. Will lean towards the ECMWF solution which keeps it mainly north of the area. Could see a few isolated showers near the boundary, mainly northern areas, although dependent on actual location of the boundary. Very warm temperatures continue with record or near- record warmth. Lows Tuesday night and Wednesday night in the 50s and 60s, with highs Wednesday well into the 80s again. && .LONG TERM /THURSDAY THROUGH SUNDAY/... A cold front will pass through the Ohio Valley Thursday while high pressure remains over the Atlantic. A southerly flow will continue to usher in unusually warm conditions for this time of year. The cold front will pass through late Thursday night into Friday...bringing some showers with it. High pressure will build overhead late Friday through the weekend...ushering more seasonably cool conditions. && .AVIATION /15Z MONDAY THROUGH FRIDAY/...
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VFR expected area-wide with some mid/high clouds as well as some cumulus this afternoon. Winds light and variable this morning will become light south/southwest this afternoon. Mainly VFR expected tonight through Wednesday night, however there may be intervals of patchy fog each night/early morning with reductions to MVFR/IFR. MRB/CHO will be most susceptible. Winds generally south/southwesterly less than 10 knots. Patchy low clouds and fog may impact the terminals Thursday morning. A cold front will pass through late Thursday night into Friday...bringing the chance for showers and subvfr conditions.
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&& .MARINE... Winds will be primarily out of the south and sub-SCA through Wednesday night. With high pressure located south of the region, a nocturnal low level jet is likely each night, however mixing will be limited and a SCA is not currently expected to be needed. High pressure will remain off the coast for Thursday and a southerly flow will continue over the waters. A cold front will pass through Friday and high pressure will build toward the waters during the weekend. A small craft advisory may be needed for portions of the waters Friday and Saturday. && .TIDES/COASTAL FLOODING... A southwest flow will continue over the waters through Tuesday. Elevated water levels are expected during this time. Some thresholds may be threatened...but only by an inch or so at times. Elevated water levels will likely continue through Thursday into early Friday before an offshore flow develops behind a cold front. && .CLIMATE... Below is a list of record daily warm temperatures for October 17th through 20th. Record daily high temperatures Site 10/17 10/18 10/19 10/20 DCA 86 (1938)* 85 (1938)* 88 (1938) 86 (1969) BWI 90 (1938) 82 (1945)* 82 (1947)* 87 (1969) IAD 83 (1963) 82 (2007)* 83 (1991)* 83 (1969) *also occurred in previous years Record daily warm low temperatures Site 10/17 10/18 10/19 10/20 DCA 68 (1928) 68 (1947)* 65 (1905) 64 (1885)* BWI 67 (1928) 69 (1928) 67 (1905) 65 (1910) IAD 62 (1989) 60 (1968) 60 (2011) 59 (1993) *also occurred in previous years && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...BJL/RCM NEAR TERM...MM/RCM SHORT TERM...MM LONG TERM...BJL/MM AVIATION...BJL/MM/RCM MARINE...BJL/MM/RCM TIDES/COASTAL FLOODING...BJL CLIMATE...DFH is the U.S. government's official web portal to all federal, state and local government web resources and services.