Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 280124 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 924 PM EDT Thu Apr 27 2017 .SYNOPSIS...
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A weak cold front crosses the area from the west tonight. High pressure over the area Friday, then dropping off the southeast coast Saturday. A cold front will move over Pennsylvania Saturday night before lifting north. A cold front will move through the region from the west Monday night. Canadian high pressure will then build over the area through the middle of next week.
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&& .NEAR TERM /THROUGH tonight/...
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As of 9pm, two clusters of prefrontal showers and thunderstorms continue to shift northeast from the eastern WV panhandle and central VA. Low level CIN will continue to repress original growth. Elevated CAPE of a few hundred j/kg and bulk shear of 45 knots allows ongoing activity to continue. Actual front is back over wrn WV and will continue to slowly push east. Despite good bulk shear, early prefrontal activity and a nocturnal trend should gradually reduce this activity with little expected east of the Allegheny Front. Lows ranging from the upper 40s in the Highlands to the mid 60s in the cities. Much of inland areas will drop to 60F.
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&& .SHORT TERM /FRIDAY THROUGH SATURDAY NIGHT/... Weak front will move offshore Friday morning. Light fog is possible but not expected to be as dense/widespread as previous two nights. We will be in a warming trend heading into the weekend as high pressure strengthens off the SC coast. This will pump warm air into the Mid Atlantic, and by Saturday temperatures will have a decent shot at topping 90. The record temperatures for April 29 - we`ll be close to these values: Highs max High min DCA 91 68 BWI 91 67 IAD 87 62 && .LONG TERM /SUNDAY THROUGH THURSDAY/... High pressure to the southeast will break down with a warm front sliding northward across the D.C. area Sunday into Sunday night. There is a chance for showers and a thunderstorm, mainly Sunday with the warm front nearby. An increasing southerly wind will usher in warmer and more humid air to help fuel showers and thunderstorms, mainly Monday afternoon and evening ahead of a strong cold front. A few thunderstorms could contain strong winds. Gusty westerly winds and drier and cooler air will filter into the region Tuesday and Tuesday night behind the cold front as high pressure builds in from the west. High pressure moves offshore Wednesday, while keeping conditions dry. A return flow will be an indication that a new warm front will try to push across the region late Wednesday into Thursday. The Thursday storm system that is expected to develop along the warm front could intensify over the Ohio Valley before sending energy eastward into the mid-Atlantic later in the day Thursday. && .AVIATION /01Z FRIDAY THROUGH TUESDAY/...
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VFR through the afternoon/early evening. Isolated showers and thunderstorms will be possible at TAF sites this evening. These are expected to weaken while progressing east of the mountains. Light fog possible Friday morning then VFR at all sites Friday into Saturday. Front lingers just north of the DC metros Saturday into Sunday. A backdoor cold front is now expected to be contained Mason-Dixon line and north Saturday night. Mvfr to ifr conditions expected Sunday and Sunday night with showers and a thunderstorm in the area near MRB, IAD, MTN and BWI terminals. Vfr conditions elsewhere. Ifr to lifr conditions Monday and Monday night with showers and thunderstorms. Winds east 5 to 10 knots Sunday, southerly 5 to 10 knots Sunday night, then southwest 10 to 15 knots Monday, and southwest 10 knots Monday night.
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&& .MARINE...
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SCA for southerly channeling into the overnight, will continue until a cold front over West Virginia crosses the waters. Light NWly flow behind the cold front Friday morning, becoming southerly Friday afternoon. A front lingers north of the waters Friday night through Saturday night with south flow continuing from a Bermuda high. No marine hazards expected Sunday and Sunday night. Small craft advisories possible Monday and Monday night. Winds east 10 knots Sunday, southeast 10 knots Sunday night, increasing southwest 15 knots gusts 20 knots Monday, and southwest 10 to 15 knots Monday night.
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&& .TIDES/COASTAL FLOODING...
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South flow has maintained water levels around three quarters of a foot above normal. This is enough to reach minor coastal flooding on the preferred high tide late tonight at Straits Point in St. Marys County. Annapolis will continue to be monitored as it will also approach minor coastal flooding late tonight as well.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...Coastal Flood Advisory from 1 AM to 6 AM EDT Friday for MDZ017. VA...None. WV...None. MARINE...Small Craft Advisory until 5 AM EDT Friday for ANZ531>534-537- 539>541-543.
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&& $$ Update...Jackson Previous...Woody!/KLW

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