Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 140057 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 857 PM EDT Sun Aug 13 2017 .SYNOPSIS...
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Weak high pressure will hold over the area through mid week. A weak frontal boundary will move into the Mid Atlantic late in the week.
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&& .NEAR TERM /THROUGH MONDAY/...
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High pressure is across the Mid-Atlantic region tonight. Clear and mainly calm conditions expected overnight. Patchy fog is expected in low-lying areas tonight. Mid-high level clouds are present across S WV and SW VA and will slowly move northward overnight and into Monday morning. This will likely slow fog from spreading and becoming more widespread into Monday morning. Temps in the 60s and low 70s in the metros and near the waters are expected tonight. Clouds thicken through the day Monday as moisture returns on backside of retreating sfc high.
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&& .SHORT TERM /MONDAY NIGHT THROUGH TUESDAY NIGHT/...
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Sct showers expected Mon into Tue morning mainly over western areas. Drying occurs on Tue afternoon and night as weak low pres over ern NC moves offshore.
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&& .LONG TERM /WEDNESDAY THROUGH SUNDAY/... Frontal boundary will remain south of the region on Wednesday, but warm advection will be starting already and clouds will be on the increase again as high pressure moves east across the Northeast. Warm front advances back across the region on Thursday with an increased risk of showers and t-storms. By Friday, uncertainty exists regarding speed of the wave of low pressure moving across the Great Lakes, with faster guidance having pushed it east of the region already, while slower guidance holds it over Quebec and Ontario still. This uncertainty in the speed of system progression continues Saturday, with slower guidance pushing the first system east, while faster guidance already bringing the next system in from the west. Sunday continues with this uncertainty, with potential for showers and storms remaining, though some guidance now tries to build high pressure back into the region. Bottom line is that there is a lot of uncertainty in the long term, but it looks like the unsettled pattern of recent weeks will be continuing. Temperatures looks to be fairly close to normal overall, with no signicant heat or cool swings. && .AVIATION /01Z MONDAY THROUGH FRIDAY/...
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Fog possible at CHO/MRB/IAD tonight. Mid-high level clouds will move across the terminals by Monday morning. MVFR vsbys possible late tonight. VFR conditions expected Monday-Monday night. Low clouds possible Tuesday morning as moisture increases northward. Best chance for restrictions will be at CHO. Main concern later this week will be possibility of reduced cigs and vis with showers and thunderstorms possible Wednesday and Thursday. Right now convection looks isolated for the most part, but could increase to scattered coverage at some point, most likely Thursday afternoon.
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&& .MARINE...
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Winds are expected to remain below SCA through the end of the week. Main concern later this week will be possibility of gusty winds with any thunderstorms Wednesday and Thursday. Risk is not high, but not zero. Otherwise, winds likely to stay mostly below SCA criteria.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...None. VA...None. WV...None. MARINE...None. && $$ SYNOPSIS...LFR NEAR TERM...HSK/LFR SHORT TERM...LFR LONG TERM...RCM AVIATION...HSK/RCM/LFR MARINE...HSK/RCM/LFR

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