Area Forecast Discussion
Issued by NWS Sterling, VA

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000 FXUS61 KLWX 292243 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 643 PM EDT Thu Sep 29 2016 .SYNOPSIS... Upper level low pressure will rotate over Kentucky through Friday before lifting north towards Michigan over the weekend. Persistent onshore flow and localized heavy rain will continue to occur over portions of the Mid-Atlantic through Friday. The low is forecast to track to the northeast early next week. High pressure will build into the area during the first part of the new week. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... Cancelled flash flood watch across most of Baltimore-Washington metro since confidence increased that the western shore of the Chesapeake Bay and the Virginia Blue Ridge would remain in drizzle and showers, not excessive rain overnight. Ongoing activity over Delmarva could shift NW to Baltimore metro overnight, so Baltimore and Harford counties were kept, despite lower amounts there thus far. The main threat area is now the VA Blue Ridge and west there mesoscale convergence is occurring along with instability and quite notable shear. the marginal risk does edge this area and localized severe/flash flooding is possible. rapid scan satellite operations were requested for this area with poor radar coverage. Elsewhere generally less than an inch additional rainfall overnight. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SATURDAY NIGHT/... Beginning Friday the upper level low will gradually retrograde and move north as it begins to weaken. Rain rates are expected to gradually become less intense as activity becomes more scattered through the day. Gradual drying trend continues into the upper low continues to weaken and drift northward. While not a washout by any means...scattered shower activity will remain possible. Temperatures should climb back into the low/mid 70s. && .LONG TERM /SUNDAY THROUGH THURSDAY/... Influence of upper-level low finally begins to diminish late in the weekend into early next week as it passes by to our north and moves out to sea...while high pressure builds into the area in its wake. Most of Sunday appears dry...aside from some possible lingering early morning showers. Remaining dry with temperatures near climatology as high pressure remains over the area through early next week. This is a week away...but the word "Matthew" may be on everyone`s minds next Tue or Wed. This is currently well south of Puerto Rico but is forecast to make a northward turn and be positioned between Cuba and Turks and Caicos in the first part of next week. GFS and Euro have very different solutions on location and timing but one solution has this along the Mid Atlantic coast during the middle of next week. But the middle of next week is along way away. && .AVIATION /00Z FRIDAY THROUGH TUESDAY/... Mainly drizzle and showers across the DC metros through tonight. Upper level low will continue to impact the area through Friday... bringing periods of IFR/LIFR to all the terminals. Low ceilings are possible through Friday night with persists onshore flow. Gradual improvement Saturday...with a return to VFR by Sunday. && .MARINE... Onshore flow continues to be strong. Gale warnings for lower southern MD waters until 2am. Solid SCA rest of the area into Friday afternoon. Gradient should begin to relax by later Friday evening...with SCA winds becoming less likely Saturday into the Weekend. && .TIDES/COASTAL FLOODING... Anomalies running around 1.5 feet to as much as 2 feet on the Potomac. Coastal Flood Warnings for SW DC waterfront and St. Marys County. These will likely expand to Alexandria and anne arundel over the next day. Coastal flooding expected to continue at least through Saturday with continued onshore flow. && .LWX WATCHES/WARNINGS/ADVISORIES... DC...Coastal Flood Warning until midnight EDT Friday night for DCZ001. MD...Flash Flood Watch through Friday morning for MDZ006-011-501- 502-507-508. Coastal Flood Advisory until midnight EDT Friday night for MDZ013. Coastal Flood Advisory until 8 PM EDT Friday for MDZ016. Coastal Flood Warning until 6 PM EDT Friday for MDZ017. Coastal Flood Advisory until 10 PM EDT Friday for MDZ011-014- 018. VA...Flash Flood Watch through Friday morning for VAZ025>030- 036>040-507-508. Coastal Flood Advisory until midnight EDT Friday night for VAZ052>055. Coastal Flood Advisory until 8 PM EDT Friday for VAZ057. WV...Flash Flood Watch through Friday morning for WVZ050-051-055- 501>504. MARINE...Small Craft Advisory until 7 PM EDT Friday for ANZ530>533-535- 536-538>542. Small Craft Advisory from 2 AM to 7 PM EDT Friday for ANZ534- 537-543. Gale Warning until 2 AM EDT Friday for ANZ534-537-543. && $$ update...Jackson previous...Woody!/ADS is the U.S. government's official web portal to all federal, state and local government web resources and services.