Area Forecast Discussion
Issued by NWS Sterling, VA

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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 221355 AAA AFDLWX Area Forecast Discussion...UPDATED National Weather Service Baltimore MD/Washington DC 955 AM EDT Thu Sep 22 2016 .SYNOPSIS...
-- Changed Discussion --
Low Pressure remains off the Carolina coast while high pressure is centered over New England. A backdoor cold front will move through the area Saturday. High pressure returns to the region Sunday through early next week.
-- End Changed Discussion --
&& .NEAR TERM /TODAY/...
-- Changed Discussion --
Forecast on track...as we remain sandwiched between high pressure centered over New England and low pressure off the coast of the Carolinas. Satellite imagery depicts scattered high clouds from the low continuing to impinge on extreme S MD and the Central Foothills of VA. Elsewhere, it remains mostly sunny with a few thin high-level clouds. Guidance continues to indicate these trends will continue through the afternoon, with most places remaining mostly sunny. While a few spotty showers were observed across S MD earlier this morning, observations/guidance indicates showers will remain south of our area for the remainder of the day. Autumnal equinox is at 1021 AM EDT this morning...though it won`t feel much like fall by afternoon with high temperatures 5-10 F above normal and at least a hint of humidity, with dewpoints AOA 60F east of the Blue Ridge.
-- End Changed Discussion --
&& .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
-- Changed Discussion --
Skies should remain mostly clear tonight through Friday night. Fog development is possible during the overnight hours in the central Shenandoah Valley/I-81 corridor and point west. An approaching short wave/cold front should finally dislodge the weak coastal low. Lows tonight 60-65 east of the mountains...55-60 west. Friday should be an even warmer day on warm air advection ahead of the front. Friday night should see similar temperatures to Thursday night.
-- End Changed Discussion --
&& .LONG TERM /SATURDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
Dry stretch of weather likely to continue through the weekend and into next week. Cold front will be passing across the region Saturday morning with winds turning to the north and some increased cloud cover. However, will be a mainly dry frontal passage with really only chance of rain being a spot shower across the higher terrain. Mixing will increase behind front, so despite falling 850mb temperatures, still expecting an above normal temperature day with highs in the low 80s for most. The remainder of the extended period will be dominated by developing omega block with upper lows over the NW Atlantic and central US, with large amplified upper level ridge over the eastern US. This will continue to lead to a mainly dry forecast. However, position of surface ridge will eventually determine how early next week`s weather plays out. Current GFS/ECMWF depictions place surface ridge just offshore, which would promote an onshore flow with increased clouds, perhaps some nocturnal fog/drizzle, and cooler temperatures. Given strength of ridge/block, expecting any approaching frontal system to remain west of the region through Wednesday. Highs generally 70s, lows 50s/60s.
-- End Changed Discussion --
&& .AVIATION /14Z THURSDAY THROUGH MONDAY/... VFR conditions expected today. Fog could develop tonight at the more favored locations - CHO and MRB especially. VFR expected everywhere Friday and Friday night. Mainly VFR expected Saturday and Sunday, however, developing onshore flow may promote the development of Sub-VFR conditions by Monday. && .MARINE...
-- Changed Discussion --
A Marine Weather Statement was issued early this morning for isolated wind gusts near SCA criteria across lower portions of the Chesapeake Bay and lower Tidal Potomac. Statement is set to expire at 10 AM, as guidance indicates gusts AOA SCA criteria will be short-lived. Winds remain below SCA values this afternoon through Friday night. Small Craft Advisories will likely be needed Saturday and Saturday night with increased northerly flow behind frontal passage. Winds diminish for Sunday and Monday and Sub-SCA conditions likely.
-- End Changed Discussion --
&& .TIDES/COASTAL FLOODING... No coastal flooding anticipated with this morning`s/afternoon`s high tide cycle, however, our more sensitive sites may approach or exceed minor flood stage with this evening`s/tonight`s high tide cycle. Annapolis and DC/Alexandria most at risk. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ PRODUCTS...MELLIOTT/WOODY!/MJM

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