Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 220853 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 353 AM EST Wed Feb 22 2017 .SYNOPSIS...
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A weak disturbance will cross the area today. A cold front will pass through the area on Saturday. High pressure builds over the area during the early part of next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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High pressure is stretched along the Mid-Atlantic and New England coastlines this morning. A closed upper level low is located over the Gulf coast states while a weak shortwave trough moves across the Mid-Atlantic region. Most of the moisture is located south and west of the region however enough is present to produce showers across the VA Highlands, Shenandoah Valley and Central Foothills this morning. Light showers will likely stretch eastward into northern VA and the southern suburbs of DC this morning however most of the showers will stay confined to the south... across Central VA. Mid-high level clouds will persist today however warm air advection will lead to temps rising into the mid 60s. Breaks in the clouds are possible this afternoon mainly north of I-66/MD Route 50. Moisture will continue to advect into the Mid-Atlantic region from the southern stream system through tonight. Low clouds and fog are expected by Thursday morning as dewpts remain elevated. Temps will drop into the U40s/L50s tonight.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
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The southern stream system will persist off the SE coast Thursday and Thursday night. Due to the southwesterly flow aloft...moisture advection and above normal temperatures will persist. A cold front will approach the Mid-Atlantic region Thursday and showers are possible Thursday afternoon mainly west of the metros. Showers may move east across the metros Thursday evening however the cold front will stay north of the region and amts will be light. A mix of sun and clouds will allow temperatures to reach the mid 70s and 60s near the waters. Showers move east and dissipate across the region by Friday morning. Dry conditions expected Friday. Another warm day expected with temperatures reaching the mid to upper 70s. A strong system will approach the Mid-Atlantic region Friday night and showers are possible as southerly flow increases.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/...
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Cdfnt will move through the fcst area Sat afternoon with showers and possible t-storms. Simulated satellite imagery from both ECMWF and GFS shows strong convection over Ohio Fri night weakening as it approaches the Appalachians Sat morning with a narrow frontal rain band developing east of the Blue Ridge Sat afternoon. The simulated imagery shows convection deep enough to produce lightning north of I-70 with shallow convection south of there. H85 winds peak between 35-45kt and CAPE values rise between 100-350 J/kg. A few severe t-storms may develop along the PA border. Cdfnt clears the Chesapeake Bay by 00Z Sun. High pressure then builds over the area Sunday night and early Mon. Developing waa pattern on Monday will result in increasing chances of precip Mon afternoon. Warm and unsettled conditions will then prevail through Wed before a cdfnt clears the area by next Thu. Guidance also suggest another chance at reaching 80F on Wed with h85 temps as high as 17.5C and 1000-850 mb thicknesses of near 1400 meters under a strong SW flow.
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&& .AVIATION /08Z WEDNESDAY THROUGH SUNDAY/...
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VFR conditions expected today as light southerly winds persist. Low clouds and/or fog are expected Thursday morning. MVFR/IFR restrictions are expected at all terminals. Clouds will dissipate by mid morning Thursday and VFR conditions are expected. S winds continue through Friday night. Cdfnt to move through terminals around 18Z Sat with showers and possible t-storms with gusty winds.
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&& .MARINE...
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High pressure will remain off the coast through Thursday night. A southerly flow is expected during this time...but wind speeds should remain below SCA criteria. Dry conditions expected for Friday before a cold front moves across the Mid-Atlantic on Saturday. Strong cold front will move through the waters Sat afternoon with showers and possible t-storms some of which could produce strong winds and require SMWs particularly across northern portions of the waters.
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&& .CLIMATE...
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Warmest Februaries DCA BWI IAD 1. 46.9 (1976) 44.0 (1976) 42.1 (1990) 2. 45.2 (1990) 43.9 (1949) 41.1 (1976) 3. 44.7 (1997) 43.3 (1890) 41.0 (1998) 4. 44.3 (2012) 42.7 (1932) 40.9 (2012) 5. 43.9 (1949) 42.6 (1909) 40.5 (1997) Feb 2017 (through the 20th) DCA: 44.9 BWI: 41.5 IAD: 41.9 Warmest Winters (Dec 1-Feb 28) DCA BWI IAD 1. 44.7 (1931-32) 45.3 (1931-32) 40.0 (2011-12) 2. 44.3 (1889-90) 44.4 (1889-90) 39.7 (2001-02) 3. 43.3 (2011-12) 42.4 (1948-49) 39.4 (1997-98) 4. 43.2 (2001-02) 41.9 (1949-50) 39.0 (2015-16) 5. 42.8 (1949-50) 41.3 (1879-80) 38.3 (1990-91) Winter 2016-17 (through Feb 20) DCA: 42.9 BWI: 39.6 IAD: 39.8 Temperature records for the Washington DC area have been kept at Ronald Reagan National Airport (DCA) since 1941. Additional temperature records for the Washington DC area date back to 1872. Temperature records for the Baltimore MD area have been kept at Baltimore-Washington International Thurgood Marshall Airport (BWI) since 1950. Additional temperature records for the Baltimore MD area date back to 1872. Temperature records in the Dulles VA area have been kept at Washington Dulles International Airport (IAD) since 1962. All records are considered preliminary until reviewed by the National Center for Environmental Information (NCEI).
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...HSK SHORT TERM...HSK LONG TERM...LFR AVIATION...HSK/LFR MARINE...HSK/LFR CLIMATE...DFH

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