Area Forecast Discussion
Issued by NWS Sterling, VA

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039 FXUS61 KLWX 302301 AFDLWX Area Forecast Discussion National Weather Service Baltimore MD/Washington DC 701 PM 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 Sunday and the part of the week. && .NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
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Brief update of PoPs and tidal flooding (see section below). Rain continues to dissipate as it pushes north from southern VA. However, this will produce 1-3 tenths inch rain up the VA I-95 corridor which was not handled by the previous chance PoPs and drizzle forecast - so that was updated. Last lightning in the CWA was over King George county around 6:15pm per ENLTN data. previous... An area of upper level low pressure continues its slow spin over Kentucky. Arms of rainfall are still rotating into the Mid Atlantic - some places are receiving decent rainfall, but if these arms miss then the location remains cloudy and dry...or at worst areas of mist. The southwestern part of the forecast area remains most at risk for the bands of rain this evening...although cell in southcentral VA heading north will also need to be watched. River gages in central VA remain on the low side. Low temperatures fairly similar to last night - 55-60 west of the Blue Ridge...60 to 65 east.
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&& .SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY NIGHT/... As has been discussed for the past several days the upper low is expected to do a slow retrograde towards Michigan over the weekend. This should lead to a slow improvement in the weather in the forecast area. We`ve gotten several calls about outside events Saturday, and there will still be a chance for rain in the morning, but precipitation chances should be decreasing as the day progresses. Highs in the 70s. No problems expected for the remainder for Saturday night through Sunday night. A little warmer Sunday with high in the upper 70s. && .LONG TERM /MONDAY THROUGH FRIDAY/... A cold front will push off of the East Coast Sunday night. High pressure will build into the region Monday through Thursday. Mostly dry and seasonable conditions will develop and linger through much of the week. Highs in the 70s early next week as onshore flow develops around the surface high by mid-week...high temperatures will fall into the 60s. Hurricane Matthew is located over the Southern Caribbean Sea...just offshore of South America and due south of Hispaniola. It is expected to cross Cuba Monday. It is far too early to discuss possible impacts to Mid-Atlantic region. A cold front is expected to stall across the region Friday into Friday night. A spotty shower or thunderstorm cannot be ruled out along the boundary and mainly across the Central Shenandoah Valley and Virginia Piedmont. Temperatures will be warm. Highs will reach into the lower to middle 70s. High pressure will build in behind the front Saturday and Saturday night. Drier and slightly cooler air expected. Temperatures will be closer to normal. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... Ceilings to remain low overnight with areas of rain and drizzle. IFR will be the primary category. Ceilings/conditions are expected to begin to improve Saturday afternoon. Fog could be a problem at the usually favorable TAF sites Saturday night. VFR conditions expected Sunday night through Monday night. Winds light and variable Sunday night becoming northwest 5 to 10 knots Monday and Monday night. && .MARINE...
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SCA remains in effect for all waters but upper tidal potomac until midnight and for the central and northern MD portion of Chesapeake Bay rest of the night. Onshore flow weakens Saturday and shifts southerly (remaining light) for Saturday night and Sunday). Light north flow behind a weak cold front Monday afternoon into Tuesday. Onshore flow may reach SCA levels by Tuesday night.
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&& .TIDES/COASTAL FLOODING...
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Despite NEly flow, Anomalies remain between 1.5 and 2 feet. Added Harford County per trends on the flow of this high tide and the expectation of the next two. Annapolis did not reach moderate this afternoon, but still could Saturday morning, so the warning for the next high tide and the watch for the subsequent was left in place. Guidance indicates water levels should begin to drop Saturday night as low pressure pulls away, but by how much is in question due to light and variable flow. Coastal flooding issues are expected to linger, especially at sensitive locations, through Sunday evening.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...Coastal Flood Advisory until midnight EDT Saturday night for DCZ001. MD...Coastal Flood Advisory until 8 PM EDT Saturday for MDZ016-018. Coastal Flood Warning until 8 PM EDT Saturday for MDZ017. Coastal Flood Advisory until 2 AM EDT Sunday for MDZ011-508. Coastal Flood Warning until noon EDT Saturday for MDZ014. Coastal Flood Watch from Saturday afternoon through Saturday evening for MDZ014. VA...Coastal Flood Advisory until 8 PM EDT Saturday for VAZ057. Coastal Flood Advisory until midnight EDT Saturday night for VAZ054. WV...None. MARINE...Small Craft Advisory until 6 AM EDT Saturday for ANZ530>533- 538>541. Small Craft Advisory until midnight EDT tonight for ANZ534-536- 537-542-543.
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&& $$ Update...Jackson Previous...Woody!/KLW/ADS

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