Area Forecast Discussion
Issued by NWS Sterling, VA

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 260752 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 352 AM EDT Fri May 26 2017 .SYNOPSIS...
-- Changed Discussion --
Weak high pressure will return to the area tonight before moving off the coast Saturday afternoon. A warm front will stall out overhead Saturday night through Sunday. A stronger cold front will pass through the area late Sunday night.
-- End Changed Discussion --
&& .NEAR TERM /THROUGH SATURDAY/...
-- Changed Discussion --
Low pressure is located over Long Island NY this morning. A closed upper low is across E PA/NJ and will continue to depart to the NE. Light showers will continue to move across the northern half of the outlook area this morning. Upslope showers along the Allegheny Front will continue through the day today. Light W-NW winds will also continue across the Mid-Atlantic region early this morning before ramping up after sunrise. Breezy conditions expected today with NW winds 15-20 mph with gusts up to 30 mph by afternoon. Partly sunny conditions expected today with temperatures rising into the 70s. Isolated showers can not be ruled out mainly across northern MD this afternoon. High pressure moves overhead tonight. Clearing is expected this evening but clouds return after midnight as the next system approaches from the Mid-West. Temps will drop into the mid to upper 50s tonight. Low pressure will move into the southern Great Lakes tonight while a warm front approaches the Ohio Valley/Appalachians Mtns. Showers are expected to move across the mtns into Saturday morning. The ECMWF-Hi Res is depicting a complex moving into the region Saturday morning that may bring widespread showers across the area. At this time conditions will likely be stable and due to the spread in QPF guidance confidence is low in the coverage. The warm front will move into the Mid-Atlantic region by Saturday afternoon. Showers and thunderstorms are expected in the warm sector mainly south of a line stretched from the Potomac Highlands to southern MD. 0-6 km bulk shear will increase to 40-50 kts across the warm sector. Dewpts will rise into the mid to upper 60s and 1-2 J/Kg of CAPE are expected. This will allow some thunderstorms to become strong to severe. There is a slight chance/15% of severe weather Saturday afternoon in the locations mentioned above. All threats, large hail, dmg winds and isolated tornadoes are possible. People planning to be outside Saturday should remain aware of changing weather conditions.
-- End Changed Discussion --
&& .SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY/...
-- Changed Discussion --
Low pressure from the Great Lakes will move east and stretch down into the Mid-Atlantic region Sat night. This will push the warm sector to the south and east. A shortwave trough is expected to dive south across New England Sat night and showers will be possible through the night mainly across northern MD. An upper level ridge will move overhead by Sun morning and a brief period of dry conditions are expected. The active period continues later Sunday as another low pressure system approaches from the Great Lakes. Showers will move across the Appalachians Sunday afternoon. At this time...areas east of the Blue Ridge should be mostly dry Sun afternoon however this system may speed up resulting in showers across the region Sunday. Temps will reach the 70s Sunday.
-- End Changed Discussion --
&& .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
-- Changed Discussion --
Sunday evening could be a very active period according to latest 00Z ECMWF as it shows a sharp cdfnt moving through the area. Flash flooding appears the biggest concern given very wet antecedent conditions. A flash flood watch may be needed for the 18Z Sun- 06Z Mon time frame for parts of the area. By 06Z Mon, the cdfnt should be east of the area with wx conditions improving. Next week, conditions look relatively bening compared to this week as dry westerly flow establishes. Memorial Day looks nice under weak high pressure. A weak cdfnt will bring a chance of showers around the Tue-Tue night time frame with weak high pressure building again for the second half of next week.
-- End Changed Discussion --
&& .AVIATION /07Z FRIDAY THROUGH TUESDAY/...
-- Changed Discussion --
BCFG reported around IAD this morning. There may be some patchy fog around IAD/BWI this morning prior to winds increasing. VFR conditions expected today through Saturday night. West to northwest winds will gust around 20 to 25 knots Friday. A few showers and thunderstorms are possible Saturday. Some storms may become strong to severe during the afternoon and evening hours. Sub-VFR conditions expected Sunday into Monday with rounds of showers and thunderstorms moving through our region with a boundaries stalled/moving through. Conditions will begin to improve late Sun night through the first half of next week as cdfnt pushes east and sw flow develops allowing for much needed drying.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
A Small Craft Advisory is in effect for most of the waters this mroning as westerly flow increases behind departing system. Gusts up to around 20 knots expected this morning. A Small Craft Advisory is in effect for all of the waters today due to gusty west to northwest winds expected behind departing low pressure. Winds will quickly diminish toward sunset. Weak high pressure will build overhead Friday night before moving offshore Saturday. A warm front will stall out near the waters later Saturday through Saturday night. Additional showers and thunderstorms are possible during this time...especially Saturday afternoon and evening. Winds remain below SCA through Sunday afternoon. Gradient winds will remain below SCA all of next week, but winds and waves can be locally higher near thunderstorms especially Sunday night.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING...
-- Changed Discussion --
Moderate coastal flooding is occurring at Straits Point. Minor coastal flooding is occurring elsewhere. This morning`s high tide should be the last with coastal flooding issues for most locations except at Straits Point where water anomalies are higher and will take longer to return to normal.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...Coastal Flood Advisory until 11 AM EDT this morning for DCZ001. MD...Coastal Flood Advisory until 10 AM EDT this morning for MDZ014- 018. Coastal Flood Advisory until 10 AM EDT this morning for MDZ011. Coastal Flood Warning until 4 AM EDT early this morning for MDZ017. Coastal Flood Advisory until 7 AM EDT this morning for MDZ017. VA...Coastal Flood Advisory until 11 AM EDT this morning for VAZ054. WV...None. MARINE...Small Craft Advisory until 6 PM EDT this evening for ANZ530>534-536>543. Small Craft Advisory until 6 PM EDT this evening for ANZ535.
-- End Changed Discussion --
&& $$ SYNOPSIS...LFR NEAR TERM...HSK SHORT TERM...HSK LONG TERM...LFR AVIATION...LFR MARINE...LFR TIDES/COASTAL FLOODING...LFR

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.