Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 281949 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 249 PM EST Mon Nov 28 2016 .SYNOPSIS...
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A warm front will lift north through the area Tuesday. An area of low pressure will move across the area Wednesday with a cold frontal passage Wednesday night. High pressure will return to the region during the weekend.
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&& .NEAR TERM /THROUGH TUESDAY/...
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Strengthening warm air advection pattern on a 50+kt low-level jet will lead to thickening clouds and showers tonight mainly after midnight. Temperatures will remain mainly steady tonight with a warm front lifting through the area Tue morning. It will be breezy to windy especially at higher elevations and over the waters, but speeds should remain below advisory/gale warning criteria due to stable low-levels. Showers should begin to exit the area during the mid-afternoon hrs as warm front lifts north and mid-levels dry out. About half inch of rain is expected on Tuesday.
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&& .SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
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Shortwave- ridge aloft and associated subsidence should be conducive to widespread low clouds and fog Tue night. MOS guidance is showing strong signal for development of dense fog. On Wed, upper low over the upper midwest moves across the western Great Lks. Models indicate significant height falls in the order of 200 meters will occur over the area between 12Z Wed and 12Z Thu promoting large scale forcing for upward vertical motion. A new sfc low develops over the OH valley Wed with showers and perhaps a few thunderstorms developing over the area Wed and continuing into Wed evening along/ahead of a cdfnt. There could be strong gusty winds Wed afternoon and evening given strong environmental flow and marginal instability (200-400 J/kg of CAPE). Another quarter to half inch of rain is expected. Frontal zone clears the area by 06Z Thu with showers ending.
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&& .LONG TERM /THURSDAY THROUGH MONDAY/...
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High pressure builds in behind cold front on Monday and remains into Sunday... therefore another period of dry conditions is expected Thursday into Sunday. Sunday into Monday guidance is in disagreement... GFS shows an upper level shortwave trough late on Sunday into Monday... while the Euro shows a warm front lifting from the Gulf states. Either scenario, there will be an increase in chance of precipitation sometime on Sunday and into Monday. Temperatures will be near or slightly above normal, with high temperatures in the 40s and 50s, and low temperatures mainly in the 30s, and some 40s... higher elevations could see some 20s.
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&& .AVIATION /19Z MONDAY THROUGH SATURDAY/...
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Showers moving in late tonight with low-level wind shear and developing IFR conditions. Widespread LIFR/VLIFR conditions Tue night under shortwave-ridge aloft and weak pressure gradient. Another round of showers Wed with gusty winds and MVFR/IFR conditions. Cdfnt pushes through the area Wed night with drying conditions and shifting winds. Dry conditions expected for Thursday into Saturday with high pressure dominating weather conditions. So, mainly VFR conditions expected.
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&& .MARINE...
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Solid SCA conditions expected tonight and especially Tue. Kept winds below gale conditions for now given stable low- levels. Best chance for gales would be over the lower Chesapeake Bay. Dry conditions expected for Thursday into Saturday with high pressure dominating weather conditions. So, mainly VFR conditions expected. Gusty winds possible Friday into Friday night, so small craft advisory may be needed.
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&& .TIDES/COASTAL FLOODING...
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Elevated water levels are expected Tue and Wed due to strong srly flow. At this time, no coastal flooding is expected, but this will need to be monitored closely.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 6 AM EST Wednesday for ANZ531>534- 536>543. Small Craft Advisory from 3 AM to 6 PM EST Tuesday for ANZ530- 535.
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&& $$ SYNOPSIS...LFR NEAR TERM...LFR SHORT TERM...LFR LONG TERM...IMR AVIATION...IMR/LFR MARINE...IMR/LFR TIDES/COASTAL FLOODING...LFR

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