Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 170201 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 901 PM EST Thu Nov 16 2017 .SYNOPSIS... High pressure will build into the region tonight through Friday. A strong cold front will cross the area late Saturday night. High pressure will build to the south of the region late Sunday into the first half of next week. && .NEAR TERM /THROUGH FRIDAY/...
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Stratocumulus has been filling back in this evening as a mid level trough pivots through along with a secondary surge of cold advection/higher pressure. These features will keep winds elevated as well, especially northern parts of the area. Am thinking clouds thin late tonight as trough axis moves east. Minimal edits needed to the low temperature forecast of upper 20s to mid 30s. High pressure will build over the area Fri with winds diminishing. Some high clouds may arrive late in the day but otherwise it will be mainly sunny. High temperatures will be seasonably chilly in the upper 40s to mid 50s.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/... Clear and cool Fri under high pressure. High clouds begin to increase late Fri night in warm air advection pattern. Showers will develop Sat afternoon as moisture deepens in strong southerly flow. Strong cold front will blast through the area late Sat night with precip ending by Sun morning. && .LONG TERM /SUNDAY THROUGH THURSDAY/...
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Interaction between a departing strong cold front to the east and a building area of high pressure over the Tennessee Valley will yield some gusty west-northwest to northwest winds. Ensemble guidance is showing decent chances of 40 kt wind gusts across northern parts of the area and the higher elevations, so this period will need to be monitored. Upslope snow showers in the higher Appalachians in the west could result in a quick inch or two of snow. Temperatures will be chilly. High pressure will build into the region Sunday night through Monday night. Dry conditions expected with temperatures 5 to 10 degrees below average each period. The high pressure will move offshore Tuesday to allow for a strong cold front to plunge southeastward into the region Tuesday night. The front should be a dry front with the lack of moisture present. However, we can`t rule out a couple of upslope snow showers Tuesday night. High pressure will build into the region Wednesday through Thursday. Temperatures will remain chilly for this time in November with dry conditions and some sunshine.
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&& .AVIATION /02Z FRIDAY THROUGH TUESDAY/...
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Secondary pressure surge is keeping winds gusty this evening, but should see a diminishing trend late tonight, and especially by midday Friday as high pressure moves in. Stratocumulus has also filled in across northern parts of the area. It is VFR at the moment, but there is some chance of MVFR, especially at MRB. Clouds should begin to scatter out late tonight. Winds increase again Saturday afternoon and night with rain showers expected ahead of a strong cold front. VFR conditions possible Sunday through Monday night. Winds west- northwest around 15 knots with gusts 25 to 30 knots Sunday. Winds west-northwest around 10 knots gusts 15 to 20 knots Sunday night. Winds becoming west around 10 knots gusts 15 knots Monday. Winds becoming southwest 5 to 10 knots Monday night.
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&& .MARINE...
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Winds have strengthened over the waters early this evening as gradient tightens and CAA increases. Strongest winds will occur through midnight and begin to gradually weaken late tonight and Fri. A couple gusts have hit gale force but were transient at the leading edge of the surge. Otherwise winds will be 20-30 kt. Winds will taper off Fri afternoon and evening as high pressure builds overhead. Winds begin to strengthen again late Fri night and Sat. Gale conditions possible late Saturday through Sunday... 70% chance per ECMWF ensemble. Solid SCA conditions expected on Sunday. Small craft advisories likely continue into Sunday night. Winds west-northwest 10 to 15 knots gusts up to 20 knots. Small craft advisories possible Monday. Winds west 10 to 15 knots gusts up to 20 knots. No marine hazards Monday night. Winds becoming southwest around 10 knots.
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&& .TIDES/COASTAL FLOODING...
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Water level anomalies are now decreasing in northwest flow, so no flooding is expected over the next few cycles. Saturday will be the next period to monitor as winds become southerly again.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...None. MD...None. VA...None. WV...None. MARINE...Small Craft Advisory until noon EST Friday for ANZ530>532-535- 536-538>540. Small Craft Advisory until 6 PM EST Friday for ANZ533-534-537- 541>543.
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&& $$ SYNOPSIS...LFR NEAR TERM...ADS/LFR SHORT TERM...LFR LONG TERM...KLW AVIATION...ADS/LFR/KLW MARINE...ADS/LFR/KLW TIDES/COASTAL FLOODING...ADS

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