Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 270137 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 937 PM EDT Wed Apr 26 2017 .SYNOPSIS...
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Low pressure east of New Jersey will continue to slowly move northeast through tonight. A weak cold front cross the area from the west Thursday night. A backdoor front will move west across the area Saturday night into Sunday before lifting north as a warm front early Monday. A stronger cold front will move through the region from the west Monday night.
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&& .NEAR TERM /THROUGH Tonight/...
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As of 9pm, there is a weak surface ridge extending from off the mouth of the Chesapeake Bay to to roughly Dulles and south of the low off the NJ shore. Light SE flow is across the CWA. A swath of low clouds persists over the Baltimore metro area. Northeastern sections of the area should see an increase in low level clouds through the night with patchy fog. West of there to the Blue Ridge, expect radiational fog to develop overnight in the clear and calming conditions. Min temps mid to uppers 50s inland to around 60F in urban centers per ER Superblend.
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&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/...
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After the low pressure area finally departs and moves east of Cape Cod Thursday skies should finally return to a mostly sunny condition - after morning fog/low clouds. South winds begin to mix after 10am with gusts 20 to 25 mph across the area through the afternoon. Well mixed 14C 850mb temps should result in low to mid 80s maxima. But the respite from clouds will be short. A weakening cold front will be pushing into the Mid Atlantic Thursday night bringing the chance of showers/isolated thunderstorms. This will not be coming through at a prime time for severe weather. Coverage will be spotty, so one place could pick up a few tenths of an inch of rain while ten miles away stays dry. The front is expected to be east of the region by Friday morning. Skies should improve, highs again in the lower to mid 80s.
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&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/...
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High pressure will be to our southeast with a front along the Mason- Dixon line Saturday and Saturday night. Temperatures will remain warm with a chance of showers or a thunderstorm mainly across the northern half of our region. By Sunday into Sunday night, the high to the southeast will break down with the front sliding across the D.C. area during the day before meandering northward as a warm front Sunday night. The chance for showers and thunderstorms will become more prominent, mainly Sunday with the front nearby and before the warm surge. An increasing southerly wind will usher in warmer and more humid air to help fuel showers and thunderstorms Monday into Monday evening. A strong cold front should works its way eastward across the region Monday night. 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 later Wednesday.
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&& .AVIATION /01Z THURSDAY THROUGH MONDAY/...
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MVFR cigs persists in the Baltimore metro...VFR elsewhere rest of the evening. Fog/low stratus development expected overnight. Still left visibilities in the 2-3SM range given potential presence of low clouds generally 08Z-14Z. VFR after 13-14Z Thursday with increasing southerly flow. Gusts 20 to 25 kt expected through the afternoon. Showers/isolated thunderstorms possible Thursday night as a weakening cold front moves through. VFR again Friday. Mvfr to ifr conditions expected Saturday through Sunday with showers and thunderstorms in the area near MRB, IAD, MTN and BWI terminals. Vfr conditions elsewhere. Mvfr to perhaps vfr conditions Sunday night. Winds southwest around 5 knots Saturday, becoming light and variable Saturday night, then east 5 to 10 knots Sunday, and southerly 5 to 10 knots Sunday night.
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&& .MARINE...
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Winds expected to remain below SCA values through tonight. Southerly flow increases through Thursday with 20 knot gusts warranting a small craft advisory from noon to midnight. Showers/isolated thunderstorms will be possible Thursday night as a weak cold front enters the Bay region. Southerly channeling ahead of this front warrants a continued SCA until 5 am Friday. No marine hazards expected Saturday through Sunday night. Winds southwest 5 to 10 knots Saturday, becoming light and variable Saturday night, then east 10 knots Sunday, and southeast 10 knots Sunday night.
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&& .TIDES/COASTAL FLOODING...
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Water levels have decreased slightly with northwest winds today but remain elevated, especially from the Potomac River southward. Straits Point will exceed minor flood stage through at least the overnight high tide cycle. Guidance shows steady to decreasing waters for the remainder of the week, but am a bit skeptical about this outcome considering winds will become south or southwesterly through that time. Thus minor flooding at sensitive sites will need to continue to be monitored. In terms of the current guidance, Friday morning will be the next targeted opportunity.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...Coastal Flood Advisory until 6 AM EDT Thursday for MDZ017. VA...None. WV...None. MARINE...Small Craft Advisory from noon Thursday to 5 AM EDT Friday for ANZ531>534-537-539>541-543. Small Craft Advisory from noon Thursday to midnight EDT Thursday night for ANZ530-535-536-538-542.
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&& $$ Update...Jackson Previous...Woody!/KLW/ADS

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