Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 140155 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 855 PM EST Mon Nov 13 2017 .SYNOPSIS... High pressure will return tonight through Wednesday. A weak cold front will cross the area Wednesday night into Thursday morning with high pressure moving back in for Friday. A stronger cold front will cross the area Saturday. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... High pressure will build over the area tonight. A northerly flow around the building high will cause seasonably chilly conditions...but it will remain dry. A thin deck of stratus clouds are expected...especially west of the Blue Ridge Mountains through late this evening. Breaks in the clouds and low temp/dewpoint depressions may lead to patchy fog late this evening and overnight. Fog may be locally dense...but a light northerly flow should prevent widespread fog from developing. A light upslope flow will cause areas of drizzle along and west of the Allegheny Front this evening. Temps will drop below freezing overnight across these areas. Somewhat drier air may cause drizzle to dissipate or become less widespread overnight...but any wet areas will have the potential to freeze late tonight with temps dropping below freezing. Lows tonight will range from the upper 20s and lower 30s along the Allegheny Front...to the mid and upper 30s across most other locations...to near 40 in downtown Washington and Baltimore. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... High pressure will hold over the area Tue into Wed. A weak cold front will cross the area late Wed night into Thu morning bringing sct showers as far east as the Rt 15 corridor. Temperatures will continue to warm a bit more into the mid 50s Tue and Wed. && .LONG TERM /THURSDAY THROUGH MONDAY/... Relatively active pattern expected for the latter part of this week and into the weekend with the most impactful weather likely to be Saturday. Weak cold front anticipated to be passing through the area early Thursday morning with the potential for a few rain showers, but the majority of the day should end up dry. This will be followed by high pressure and calm weather for Thursday night and Friday. Temperatures should be within a few degrees of climatological normals Thursday/Friday. A potent low pressure system is then projected to move through the Great Lakes region Friday night into Saturday. This will bring strong southwest flow to the area out ahead of the front before the attendant cold front sweeps across the region sometime during the day, although model differences still exist on timing of frontal passage. This will bring increased chances of rain and gusty winds, in addition to a non-zero threat of convective activity. Temperatures will be near to somewhat above climo normals ahead of the front. Following the frontal passage, there will be gusty west to northwest flow with colder temperatures and the potential for upslope snow showers along the Allegheny Front and nearby higher elevations Sunday and Sunday night. && .AVIATION /02Z TUESDAY THROUGH SATURDAY/... VFR conditions are most likely through tonight. Patchy fog is possible and this may cause reduced vsbys overnight. Confidence too low to put into TAFS at this time since a light northerly flow is causing dewpoints to slowly drop. Primarily VFR expected Thursday through Friday night as high pressure builds into the area. Potential then exists for sub-VFR conditions and gusty winds/low level wind shear Saturday as a strong cold frontal system crosses the region. && .MARINE... Northerly winds are expected along the waters tonight. An SCA is in effect for most of the Bay and lower Tidal Potomac through this evening...then for the middle portion of the Bay overnight. Winds may come close to SCA levels over the Bay and lower Tidal Potomac River Tuesday...but confidence is too low for an advisory at this time. Winds will diminish Wed and Wed night. SCA gusts likely behind a departing cold front Thursday into Thursday evening before high pressure brings lighter winds later Thursday night and Friday. Winds will increase markedly with an approaching frontal system Friday night and Saturday with SCA likely and gale possible. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until 10 PM EST this evening for ANZ531>533-537-539>541. Small Craft Advisory until 11 AM EST Tuesday for ANZ534-543. && $$ SYNOPSIS...LFR NEAR TERM...BJL/LFR SHORT TERM...LFR LONG TERM...MM AVIATION...BJL/MM/LFR MARINE...BJL/MM/LFR

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