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
-- Highlight Changed Discussion --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KLWX 160751 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 351 AM EDT Mon Oct 16 2017 .SYNOPSIS...
-- Changed Discussion --
A cold front is pushing southeast of the Mid Atlantic today. High pressure will return by tonight and hold through next weekend.
-- End Changed Discussion --
&& .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
Cold front currently extends across the southern tip of St. Marys County. However, frontogenetical forcing aloft is resulting in fairly widespread showers behind the surface front. Guidance has had a good handle on this and is showing a much slower exit than previous forecasts. The last of the showers may not finally exit southern Maryland until around noon, give or take a couple hours. Behind this band of rain, there will be some clearing, although scattered to broken cumulus will likely persist in the cold air advection regime. It will also be breezy with gusts of 20-30 mph. Temperatures will likely keep falling through the morning, then rebound a little during the afternoon. Calendar day highs likely occurred during the overnight, with daytime highs in the lower to mid 60s.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
-- Changed Discussion --
After this evening, it`s mainly a temperature forecast through the middle of the week, with attention paid to frost/freeze concerns. High pressure will move in from the west tonight and then remain directly over the region through the middle of the week. Clouds will be minimal and winds light. Have trended forecast toward colder guidance for overnight lows given what should be fairly good radiational cooling conditions. Tonight may be a little tricky since some wind is likely to linger, but it does look like calmer conditions are likely toward dawn. A Freeze Watch will be in effect for portions of the highlands tonight. Would not be surprised if there were some pockets of near- freezing temperatures in the rest of the western valleys as well. Will let the day shift determine which areas will need a Frost Advisory, with locations west of the Blue Ridge looking most favorable. Temperatures will gradually moderate through the middle of the week, but not before another potential frost/freeze for outlying areas Tuesday night. Daytime highs will remain in the 60s Tuesday, but inch into the 70s for some areas on Wednesday.
-- End Changed Discussion --
&& .LONG TERM /THURSDAY THROUGH SUNDAY/...
-- Changed Discussion --
High pressure is expected to dominate through the long term, resulting in dry conditions through the weekend. Temperatures will be moderating as we head through time as ridging builds aloft and southwesterly flow comes to dominate as the high slowly pushes east off the coast. We are heading deeper into autumn, with diminishing sunlight and sun angle, so the level of warmth we saw early in the month is not likely...our current level of sunshine is about the same we would get in February. However, enough warmth will build northward from the tropics to make above normal temperatures very likely late in the week and this weekend (normals now having fallen into the 60s).
-- End Changed Discussion --
&& .AVIATION /08Z MONDAY THROUGH FRIDAY/...
-- Changed Discussion --
Brief MVFR cigs are possible (except MRB) as a post-frontal band of showers moves across the area early this morning. The rain itself should be light and end in the 10-14Z time frame from west to east. Gusty NW winds of 20-25 kt will be possible during the daylight hours today, with skies trending toward scattered/broken cumulus. High pressure begins moving over the area tonight and will remain in control through the middle of the week. No aviation concerns are expected. No significant aviation concerns are expected late in the week, though patchy fog or areas of low clouds can`t be entirely ruled out during the late night and early morning hours.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
A cold front has nearly cleared the local marine area with northwest winds being established. Light rain will take longer to exit though. Gusts may be sporadic through sunrise, but winds of 20-25 kt will be common through the day. Have extended the times of all segments of the Small Craft Advisory, since it looks like mixing will only slowly decrease this evening, and 20-25 kt winds aloft will remain over the warm waters of the Bay into Tuesday morning. By noontime on Tuesday, high pressure will be building overhead, and lighter winds can be expected through the middle of the week. Significant marine hazards are not anticipated to be a concern Thursday or Friday, though southerly channeling resulting in a small craft advisory can`t be entirely ruled out.
-- End Changed Discussion --
&& .LWX WATCHES/WARNINGS/ADVISORIES...
-- Changed Discussion --
DC...None. MD...None. VA...Freeze Watch from late tonight through Tuesday morning for VAZ503-504. WV...Freeze Watch from late tonight through Tuesday morning for WVZ501-502-505-506. MARINE...Small Craft Advisory until 6 AM EDT Tuesday for ANZ531>533- 539>542. Small Craft Advisory until midnight EDT tonight for ANZ530-535- 536-538. Small Craft Advisory until noon EDT Tuesday for ANZ534-537-543.
-- End Changed Discussion --
&& $$ SYNOPSIS...RCM NEAR TERM...ADS SHORT TERM...ADS LONG TERM...RCM AVIATION...ADS/RCM MARINE...ADS/RCM

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