Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 301459 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 1059 AM EDT Fri Sep 30 2016 .SYNOPSIS... Upper level low pressure over Kentucky will begin to lift northward towards the Great Lakes today and into the weekend. The low will pass by to the north early next week as it moves offshore. High pressure will build into the area late in the weekend and into early next week. && .NEAR TERM /THROUGH TONIGHT/... Our forecast area seems to be dodging the bullet this time. Rain continues to our east and west. Deep cloud cover continues as upper low spins over KY. For the afternoon rain chances will continue but not expecting any flooding. Highs only expected to be in the mid to upper 60s. Overcast skies...rain chances continue tonight. Little diurnal variation in temperature - lows in the low to mid 60s east of the mountains, mid to upper 50s west. && .SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/... Upper-level low will continue to track northward towards the Great Lakes and then pass by to our north as it moves eastward toward the weakening ridge over the Atlantic Saturday into Sunday. Impacts associated with the low will begin to lessen Saturday...with only a few spotty showers lingering (mainly across the northern half of the CWA). By 00Z Sunday...dry slot expected to have finally worked its way through the frontal boundary pushes off to the east. This will finally eliminate precipitation chances into Sunday...for all but upslope areas along the western slopes. Drying out Sunday with highs in the M/U70s. && .LONG TERM /MONDAY THROUGH THURSDAY/... Surface high pressure remains over New England through mid- week...with mostly dry and seasonable conditions across the Mid- Atlantic. Highs in the 70s early next week...though, as onshore flow develops around the surface high by mid-week...high temperatures will fall into the 60s. Hurricane Matthew is located along the north coast of South America. It is expected to cross Cuba Monday. It is far too early to discuss possible impacts to Mid-Atlantic region. && .AVIATION /14Z FRIDAY THROUGH TUESDAY/... Upper level low will continue to impact the area through Friday with onshore flow causing low ceilings at most terminals. Periodic drizzle/showers through tonight...with IFR conditions prevailing. Though, brief LIFR ceilings are possible in the heaviest showers. Improving conditions Saturday as upper-low begins to lose its influence over the area. Prevailing VFR conditions Saturday through early next week as high pressure builds into the area. && .MARINE... Winds have diminished from the previous two days but SCA remains in effect for all waters. Extended the SCA headline for the Chesapeake Bay into early Saturday guidance indicates SCA gusts lingering awhile longer there. Gradient relaxes for all locations by early Saturday...with winds remaining below SCA criteria into early next week as high pressure builds into the area. && .TIDES/COASTAL FLOODING... Water levels running 1.5 to 2 feet above astronomical predictions early this morning. With the continued east wind, do not expect much change. Moderate flooding still expected at St. George Island and Annapolis. Confidence is sufficient to extend most Advisories and Warnings for both tide cycles on Saturday. The exception: Southern Baltimore, where the tide cycle occurs Saturday evening (will only go through Saturday day). Skill, water level forecasting isn`t great beyond 36 hours. Consequently, have a Coastal Flood watch for Saturday evening in St. Marys and Anne Arundel Counties, where moderate is still forecast, but will less confidence. On the upper tidal Potomac, at least minor tidal flooding should occur through at least Saturday evening. A gradual decline in water levels should transpire Saturday night and Sunday. It is unclear at this time whether an additional tide cycle would be affected. There is plenty of time to figure that out. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Coastal Flood Warning until midnight EDT tonight for DCZ001. MD...Coastal Flood Advisory until midnight EDT tonight for MDZ013. Coastal Flood Warning until noon EDT Saturday for MDZ014-017. Coastal Flood Watch from Saturday afternoon through Saturday evening for MDZ014-017. Coastal Flood Advisory until 8 PM EDT Saturday for MDZ016-018. Coastal Flood Advisory until 2 PM EDT Saturday for MDZ011. VA...Coastal Flood Advisory until midnight EDT tonight for VAZ052>055. Coastal Flood Advisory until 8 PM EDT Saturday for VAZ057. WV...None. MARINE...Small Craft Advisory until 2 AM EDT Saturday for ANZ530>534- 538>543. Small Craft Advisory until 7 PM EDT this evening for ANZ535>537. && $$ UPDATE...WOODY! PREVIOUS...MSE/HTS is the U.S. government's official web portal to all federal, state and local government web resources and services.