Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 141500 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1000 AM EST Thu Dec 14 2017 .SYNOPSIS...
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High pressure will build overhead through tonight. Low pressure will develop along the North Carolina coast Friday and move out to sea Friday night. High pressure will return for Saturday before weak low pressure impacts the area early next week.
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&& .NEAR TERM /THROUGH TONIGHT/...
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Cold front is currently crossing the region with clouds, a burst of gusty winds, and perhaps a few flurries/sprinkles. High pressure will then build overhead later today, with lower clouds scattering out before high clouds increase again towards evening. Max temps will range from the 30s in northern and western areas to the mid/upper 40s in southern Maryland and parts of central VA. A Wind Advisory remains in effect through Noon for the higher elevations of the Blue Ridge and Potomac/Allegheny Highlands. Gusts up to 50 mph are expected above 2000 feet. The winds will then subside heading into the afternoon. Elsewhere...gusts to 30-35 mph are expected late this morning into this afternoon. A jetmax will develop tonight in the westerly flow aloft and our region will be in the right entrance region...which will cause an increase of high and mid-level clouds but it should remain dry. Surface high pressure will build overhead. Light winds and dry air will allow for some radiational cooling. Min temps are forecast to be in the lower to middle 20s for most areas...but it could even be several degrees colder in rural and valley areas. Did not account for this in the forecast at this time due to the increasing high/mid-level clouds.
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&& .SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/... High pressure will move off to the east Friday morning and an upper-level trough axis will swing through the area late Friday into Friday evening. Northern stream energy is not expected to phase with the southern stream energy. Therefore...the coastal low that develops should be weak and it should move out to sea. This means that there is a much higher likelihood of dry conditions across our area during this time. Did still allow for the slight chance of snow showers across eastern areas...closer to the coastal low but even for these areas confidence of any snow is low at this time. High pressure will build overhead later Friday night...causing dry and seasonably chilly conditions. && .LONG TERM /SATURDAY THROUGH WEDNESDAY/... High pressure will remain over the area Saturday into Saturday night...bringing more dry and seasonably chilly conditions. Surface high pressure will reside along the Carolina coast Sunday morning, generating a light southerly flow across the region as it migrates eastward during the day. This will allow temperatures to crack the 50 degree mark, or about 5 degrees above normal for the middle of December. A shortwave trough will cross the area Sunday night in to Monday morning, bringing the chance for rain showers with temperatures at the surface and aloft above freezing. Locations near the Mason Dixon could possibly see a rain/snow mix, but with marginal temperatures at the surface and 850mb, do not expect any snow accumulation at this time. With multiple pieces of mid-level energy traversing the region Monday into Tuesday, slight chance pops will be retained in our gridded forecast. While temperatures continue their above normal trend with a mild west southwest flow aloft, precipitation will remain of the liquid variety. A cold front looks progged to press through the area late Tuesday or Tuesday evening, dropping temperatures back to more seasonable levels. High pressure builds in from the southwest Wednesday through Thursday, keeping conditions dry and temperatures slightly above normal. && .AVIATION /15Z THURSDAY THROUGH MONDAY/...
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VFR conditions are expected through Saturday night. Gusty northwest winds up to 25-30 knots are expected through today, diminishing by sunset. A period of light snow or snow showers are still possible across the eastern terminals later Friday into Friday evening...but confidence is low at this time and there is much higher likelihood that it will remain dry. With high pressure in control to our south, VFR conditions will prevail during the day on Sunday. A weak shortwave trough will cross the area Sunday evening and into Monday, bringing the chance for showers at the terminals with the potential for sub- VFR conditions. Winds will remain light out of the south Sunday, veering out of the southwest on Monday.
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&& .MARINE...
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A weak cold front will pass through the waters this morning. Gusty northwest winds are expected through the day, mainly in the 20 to 30 knot range, however a Gale Warning does remain in effect until Noon for some gusts around 35 knots across the Chesapeake Bay from Drum Point to Smith Point. Isolated gusts around 35 knots are possible with the cold front this morning...but winds will be brief and confidence is too low for a Gale Warning at this time. A Small Craft Advisory continues for most of the Bay and lower Tidal Potomac River tonight. High pressure will build overhead for later tonight into Friday. Low pressure will develop and move out to sea later Friday. Gusty winds are possible behind the front Friday night through Saturday. High pressure will reside to the south southeast Sunday into Monday, resulting in light southerly winds across the waters as a weak system crosses the area. Winds look to remain below advisory criteria through Monday night.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...Wind Advisory until noon EST today for MDZ501. VA...Wind Advisory until noon EST today for VAZ025-026-503-504-507- 508. WV...Wind Advisory until noon EST today for WVZ501>503-505-506. MARINE...Small Craft Advisory until midnight EST tonight for ANZ531>533- 537-539>541. Small Craft Advisory until 6 PM EST this evening for ANZ530- 535-536-538-542. Small Craft Advisory until midnight EST tonight for ANZ534-543. Gale Warning until noon EST today for ANZ534-543.
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&& $$ SYNOPSIS...BJL/MM NEAR TERM...BJL/MM SHORT TERM...BJL LONG TERM...BKF AVIATION...BJL/MM/BKF MARINE...BJL/MM/BKF

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