Area Forecast Discussion
Issued by NWS Sterling, VA

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850 FXUS61 KLWX 191831 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 231 PM EDT Tue Sep 19 2017 .SYNOPSIS...
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A ridge of high pressure will remain over the eastern United States through early next week. Meanwhile, Hurricane Jose is expected to track north off the Mid Atlantic coast through Wednesday. Refer to the National Hurricane Center`s website hurricanes.gov for the latest on Jose.
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&& .NEAR TERM /THROUGH TONIGHT/...
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A ridge of high pressure will remain overhead through tonight while surface high over northern New England wedges down into the Mid-Atlantic. Jose will continue to move northward...passing us by well offshore. Low clouds have given way to some sunshine...resulting in another warm afternoon. Max temps are expected to be in the lower to middle 80s across most locations. However...moisture from Jose will bring more clouds and perhaps even an isolated shower to locations along the western shore of the Bay. Highs in the mid to upper 70s are expected for these areas. Jose will continue to move off t the northeast tonight while high pressure builds overhead. More mild conditions are expected with min temps ranging from the 50s n the Potomac Highlands to the mid and upper 60s in downtown Washington and Baltimore. Areas of fog are expected overnight...especially across central Virginia and for valley locations west of the Blue Ridge Mountains. This is where the flow will light and the atmosphere is most likely to decouple. Farther east...fog is less likely because of a sustained light northwest flow behind Jose.
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&& .SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
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An upper-level ridge will remain over the area...but a weak disturbance will approach from the west. A northwest flow behind Jose will allow for sunshine and it will be unseasonably warm for this time of year due to subsidence associated with the upper-level ridge. Max temps will be in the mid to upper 80s across most locations. A few popup showers are possible later Wednesday afternoon and evening across the Potomac Highlands into central Virginia where there will be a little instability closer to the weak upper- level disturbance. However...coverage will be isolated to widely scattered due to the lack of a strong lifting mechanism. High pressure both at the surface and aloft will continue to build overhead Wednesday night through Thursday night. Dry warm conditions are expected during this time. Areas of fog are likely during the overnight and morning hours.
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/...
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Mainly dry conditions expected in the long term period as upper level ridge/surface high pressure continues over our area Friday into Tuesday. Some showers over the ridges cannot be ruled out, but looking dry over most of our CWA. High temperatures will be in the mid 80s, around 10 degrees higher than normal. Remnants of Jose might be lingering off of the Mid- Atlantic/New England coast, away from us, and Maria could be somewhere in the west Atlantic, but it is too early to tell. Check out the National Hurricane Center`s website: hurricanes.gov, for additional information in both Jose and Maria.
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&& .AVIATION /17Z TUESDAY THROUGH SATURDAY/...
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VFR conditions are expected this afternoon through this evening. Areas of fog are expected overnight into Wednesday morning. The best chance for fog will be in the western terminals where the flow is lighter. IFR vsbys are possible in KMRB and KCHO. High pressure will remain over the terminals for later Wednesday through Thursday night. Areas of fog are possible during the overnight and morning hours. VFR conditions expected Friday into Sunday with high pressure over our area.
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&& .MARINE...
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Jose will continue to move north well offshore this afternoon before moving away from the area tonight through Wednesday. Breezy conditions with gusts around 20 to 25 knots have occurred this afternoon...with the strongest winds over the southern Maryland Chesapeake Bay and lower Tidal Potomac. These winds will continue through early this evening before gradually dissipating. Will continue with the Small Craft Advisory for all of the waters...but it will be marginal for the upper Tidal Potomac River and northern Chesapeake Bay. A Small Craft Advisory remains in effect for tonight across the middle portion of the Bay and the lower Tidal Potomac River as north to northwest winds channel. Northwest winds will continue Wednesday. A few gusts around 20 knots cannot be ruled out...but latest forecast has gusts capped at 15 knots due to a weaker gradient as Jose moves away. High pressure will build overhead for Wednesday night through Thursday night. No small craft advisory expected between Friday and Sunday due to low wind speeds over our area.
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&& .TIDES/COASTAL FLOODING...
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A Coastal Flood Advisory remains in effect for Straits Point in St. Marys county through tonight. Elsewhere...a northwest wind may keep water levels below minor flood thresholds but confidence is low because of a build up of water near the mouth of the Chesapeake Bay. This water will try to come back north up the Bay during the next high tide cycle tonight or Wednesday/Thursday. Am leaning toward the surge coming up later Wednesday into Thursday when the northwest flow eases. Therefore...minor tidal flooding is possible during the high tide cycle later Wednesday into Thursday morning. Moderate flooding cannot be ruled out at Straits Point during this time.
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&& .LWX WATCHES/WARNINGS/ADVISORIES... DC...None. MD...Coastal Flood Advisory until 6 AM EDT Wednesday for MDZ017. VA...None. WV...None. MARINE...Small Craft Advisory until 8 PM EDT this evening for ANZ530- 531-535-536-538-539-542. Small Craft Advisory until 6 AM EDT Wednesday for ANZ532>534- 537-540-541-543. && $$ SYNOPSIS...BJL NEAR TERM...BJL SHORT TERM...BJL LONG TERM...IMR AVIATION...BJL/IMR MARINE...BJL/IMR TIDES/COASTAL FLOODING...BJL

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