Area Forecast Discussion
Issued by NWS Sterling, VA

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 141425 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1025 AM EDT Wed Apr 14 2021 .SYNOPSIS... Low pressure and its associated cold front will move across the area Thursday afternoon. Weak high pressure will gradually build over the region Friday and into early next week. && .NEAR TERM /THROUGH TONIGHT/...
-- Changed Discussion --
Mid morning update: Showers have broken out across much of the area this morning. The main change made to the forecast was to speed up the arrival of showers. These showers are pushing to the east of the Blue Ridge (as of 10 AM), and should continue to spread eastward toward the bay over the next hour or two. Otherwise the previous forecast remains on track. Previous discussion follows.. Showers are expected to break out later this morning as heights aloft fall and upper diffluence increases ahead of an upper low dropping from the Great Lks into the northern Mid- Atlc region. At the surface, a low pressure center is expected to form over srn VA tonight and move east of the area Thursday afternoon. Showers will begin to taper off from west to east overnight this evening as drier works its way into the area behind exiting low pressure center. Areas of stratus and/or fog will likely develop overnight due to light onshore flow and wet soils.
-- End Changed Discussion --
&& .SHORT TERM /THURSDAY THROUGH FRIDAY NIGHT/... Upper low over southwestern Ontario Thursday will move ESE along the PA/NY border to srn New England by Fri afternoon. Upslope rain showers are likely Thu, while east of the mtns, strengthening NW downslope flow should discourage development of showers. Showers over the mtns will turn into snow showers Thu night with a coating to half inch of snow possible. Upper low/trough axis crosses the area late Thu night with mid- level subsidence/drying expected Fri into the weekend. However, it will be cloudy, cool, and breezy with gusts 30-35 mph possible. && .LONG TERM /SATURDAY THROUGH TUESDAY/...
-- Changed Discussion --
The blocked upper level flow pattern seen in the previous days will begin to break down on Saturday, with quasi-zonal flow returning. That being said, our region will reside under a fairly strong jet streak into Saturday evening, with an impulse of upper-level energy also sliding by near/north of the area. Could expect to see some showers on Saturday evening into Sunday as a result. Then another piece of upper-level energy swings through Sunday, with yet another chance for rain showers. The beginning of next week brings a lot more uncertainty into the forecast. The upper-level pattern remains very active, with both the polar and subtropical jets streams coming into play. Can`t rule out rain either day on Mon/Tue, so keeping chance POPs in there until a timeframe can be better nailed down. Temps during this period gradually warm from the mid 60s to upper 60s with overnight lows in the upper 30s (mountains) to mid 40s (elsewhere). High pressure should return to the region towards the middle of next week.
-- End Changed Discussion --
&& .AVIATION /14Z WEDNESDAY THROUGH SUNDAY/...
-- Changed Discussion --
Developing IFR cigs with showers this afternoon with LIFR conditions cigs/vsbys possible overnight as showers exit. Breezy/windy Thu night and Fri with bkn cigs 035. VFR conditions expected Saturday amid a break in the shower action. Off and on showers possible Saturday evening through Sunday though, with some restrictions possible at times, but should remain mostly VFR.
-- End Changed Discussion --
&& .MARINE... SCA conditions appear likely this evening over the lower and middle Chesapeake Bay and lower Potomac River, and then, all waters late Thursday through Friday night. No marine hazards expected for the weekend as light winds are expected over the waters. Off and on showers Saturday night through Sunday though, but don`t expect much in the way of wind from those either. && .TIDES/COASTAL FLOODING... Minor coastal flooding is expected at Annapolis and DC Waterfront through Wed night before winds become NW Thursday. && .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...Coastal Flood Advisory until noon EDT today for DCZ001. MD...Coastal Flood Advisory until 2 PM EDT this afternoon for MDZ508. VA...None. WV...None. MARINE...Small Craft Advisory from 6 PM this evening to 2 AM EDT Thursday for ANZ531>534-537-539>541-543.
-- End Changed Discussion --
&& $$ SYNOPSIS...LFR NEAR TERM...LFR/KJP SHORT TERM...LFR LONG TERM...CJL AVIATION...LFR/CJL MARINE...LFR/CJL 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.