Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 280754 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 354 AM EDT Wed Jun 28 2017 .SYNOPSIS...
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High pressure will build over the area late tonight and Wednesday before moving offshore Thursday. Warm conditions will return for the weekend.
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&& .NEAR TERM /TODAY/...
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As of 3am, a 1021mb surface high is centered over West Virginia. Light north wind persists over the LWX CWA at locales that have not decoupled. Cool with dewpoints around 50F. This is the coolest morning since June 9, about 10 degrees below normal for inland locales. The high pressure center drifts east across south-central Virginia this morning and off the coast at the mouth of the Chesapeake Bay (guidance has been very consistent with this departure point over the past few days) around midday. A return southerly flow will overspread the area this afternoon with 850mb temps increasing from 7C to 13C in the wake. This makes for a difficult temperature forecast, expect generally low 80s. Mid 80s are possible for areas where 850 temps rise into the teens by mid-afternoon. Southerly flow keeps min temps about 10 degrees higher for inland locales tonight, or near normal.
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&& .SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
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Return to summerlike conditions Thursday into this weekend as a Bermuda high sets up. 850mb temps in the upper teens both Thursday and Friday will allow Max temps into the low 90s with dewpoints rising into the low 60s Thursday and mid 60s Friday. Heat indices rise to the mid 90s Friday. Expect dry conditions through Thursday due to lack of moisture. Terrain driven convective thunderstorms can be expected Friday thanks to an increase in moisture from the continued southerly flow.
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&& .LONG TERM /SATURDAY THROUGH TUESDAY/...
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Earlier in the week there were more questions about when the best chance for rain would be this weekend - it has become clearer that the best chance will be Saturday night/early Sunday as upper trough/cold front track across the northeastern US. Precipitation chances will decrease Sunday afternoon. Highs around 90. Lows in the Low 70s east of the mountains/mid to upper 60s west. Monday is looking dry as east coast is in between shortwaves. Highs again right around climo norms for early July. The 4th. Temperatures area still looking to be around climo norms - no excessive heat but highs around 90 for many locales. The next shortwave/boundary appears be positioned to the northwest of the area Tuesday morning, and approaching the Mason-Dixon Line Tuesday evening. This will serve as a potantial trigger/focus for convection so have chance of thunderstorms in the 4th forecast.
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&& .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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VFR prevails through the week as high pressure drifts across the area today and to Bermuda through Thursday night. North winds this morning become southerly this afternoon and persist into this weekend. Summerlike conditions return Thursday. Thunderstorms in the terrain west of the DC metros Friday due to increased temperature and moisture. This weekend - majority of the time should see VFR conditions at all TAF sites. Chances of thunderstorms will be possible late Saturday afternoon into Saturday night.
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&& .MARINE...
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Surface high pressure drifts off the mouth of the Bay early this afternoon. Northerly flow gusting to 20 knots over southern MD waters will diminish through the mid morning. South winds begin late this afternoon with southerly channeling into marginal small craft advisory range at times tonight through Friday night. Gusts may reach SCA values late Saturday into Sunday morning. Isolated thunderstorms will be possible during this time as well.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory from 9 PM this evening to 6 AM EDT Thursday for ANZ530>534-536>543. Small Craft Advisory until 8 AM EDT this morning for ANZ534- 537-543. Small Craft Advisory until 6 AM EDT early this morning for ANZ532-533-540-541.
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&& $$ .PRODUCTS...BAJ/WOODY!

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