Area Forecast Discussion
Issued by NWS Sterling, VA

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353 FXUS61 KLWX 051905 AFDLWX AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE BALTIMORE MD/WASHINGTON DC 305 PM EDT THU MAY 5 2016 .SYNOPSIS...
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LOW PRESSURE IMPACTS THE REGION TO END THE WEEK WITH A COLD FRONT SWINGING THROUGH SUNDAY. HIGH PRESSURE BRIEFLY BUILDS IN...WITH A WARM FRONT LIFTING NORTH FIRST HALF OF NEXT WEEK.
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&& .NEAR TERM /THROUGH FRIDAY/...
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WATER VAPOR IMAGERY EARLY THIS AFTN SHOWING CLOSED UPPER LVL LOW HAS SLIDE SLIGHTLY SOUTH INTO TN...WITH ENERGY SWINGING AROUND THE NORTHEAST FRINGE OF IT. RAIN ON GOING MAINLY SOUTH OF THE CWA WHERE BEST CONVERGENCE HAS ALIGNED WITH THIS ENERGY. COULD SEE SCT RAIN SHOWERS OVER THE SW CORNER AND ISO SHOWERS OVER THE REMAINDER OF THE CWA THRU THE AFTN INTO THIS EVENING. OVERALL...LOOKS LIKE MINIMAL FLOOD THREAT THRU THE DAYLIGHT HOURS TODAY. HEADING INTO TONIGHT AND INTO FRIDAY...AFOREMENTIONED UPPER LVL LOW PIVOTS TO THE SOUTH AND THEN EAST...BCMG NEARLY STATIONARY OVER THE DELMARVA REGION FOR MOST OF FRI INTO SATURDAY. A SHORTWAVE CURRENTLY OVER WESTERN CANADA WILL BE NEEDED TO EVENTUALLY PUSH THIS NEARLY STALLED CLOSED LOW OUT LATER THIS WEEKEND. BEFORE HAND HOWEVER...EXPECTING AN INCREASE IN COVERAGE AND INTENSITY OF RAIN SHOWERS TONIGHT ACROSS THE ENTIRE CWA...LASTING THRU A GOOD PORTION OF FRIDAY AS THE MAIN FORCING WITH THE UPPER LVL LOW SWINGS AROUND THE EASTERN PERIPHERY RIGHT THRU THE MID- ATLANTIC. MEANWHILE AT THE SFC...SFC LOW PUSHING OFF THE CAROLINA COAST WILL MOVE TO THE NORTHEAST...WITH A SECONDARY LOW FORMING JUST OFF THE SE VA COAST. CLOUDS AND NLY FLOW WILL KEEP TEMPS ON THE COOLER SIDE WITH TEMPS BELOW NORMAL.
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&& .SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
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THE UPPER LVL LOW REMAINS POSITIONED OVER THE REGION FOR THE TIME PERIOD...WITH THE SFC LOW HAVING BACKED OVER THE DELMARVA REGION...AND REMAINING NEARLY STATIONARY AS WELL. THIS WILL KEEP THE CHC FOR PCPN IN THE FORECAST THRU SATURDAY...THOUGH WITH THE BETTER FORCING WITH THE UPPER LVL LOW TO THE NE OF THE CWA...HEAVIER RAIN THREAT WILL BE ON THE LOWER END. SHORTWAVE DIGGING SOUTH OVER THE GREAT LAKES REGION SAT NIGHT WILL BRING AN ASSOCIATED SFC COLD FRONT THRU THE REGION...WHICH WILL CONTINUE TO BRING THE CHC OF RAIN SHOWERS TO THE AREA AS WELL AS FINALLY BEING ABLE TO NUDGE THE CLOSED LOW AND SFC LOW OUT OF THE MID-ATLANTIC.
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&& .LONG TERM /SUNDAY THROUGH THURSDAY/...
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COLD FRONT WILL MOVE ACROSS THE REGION SUN MORNING WITH A CHANCE OF RAIN SHOWERS. THE FRONT WILL STALL TO OUR SOUTH OVER THE CAROLINAS AS DRY CONDITIONS BUILD OVER OUR REGION LATER ON SUN AND INTO MON. THE FRONT WILL LIFT AS A WARM FRONT MON NIGHT INTO TUE BRINGING BACK THE CHANCE OF SHOWERS. GUIDANCE DIFFERS FOR TUES AND INTO WED AS OF PRECIP AND POSITION OF A SFC LOW THAT WILL MOVE E OR NE FROM THE PLAINS. ANOTHER COLD FRONT EXPECTED ON THU. HIGH TEMPS WILL BE IN THE 70S AND LOW 80S AND LOW TEMPS INCREASING FROM THE 40S AND 50S INTO THE UPR 50S AND LOW 60S.
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&& .AVIATION /19Z THURSDAY THROUGH TUESDAY/...
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CONDITIONS MAINLY MVFR AT ALL THE TERMINALS THIS AFTN. MODEL GUIDANCE HINTS AT SLIGHT IMPROVEMENT LATER THIS AFTN BUT CONFIDENCE IS LOW OUTSIDE OF KMRB OF THIS OCCURRING MORE THAN IS ALREADY NOTED IN TAFS. BY TONIGHT...INCREASED COVERAGE AND INTENSITY IN THE RAIN WILL KEEP CONDITIONS MAINLY IFR. WINDS NE BCMG N ON FRIDAY...10 KTS OR LESS. SUB-VFR CONDITIONS EXPECTED THRU SAT TO ACCOUNT FOR ON/OFF RAIN SHOWERS AND STRATUS. SUB-VFR CONDITIONS POSSIBLE EARLY ON SUN AS COLD FRONT MOVES THROUGH. VFR CONDITIONS EXPECTED LATER ON SUN AND INTO MON. SUB- VFR PSBL MON NIGHT INTO TUES AS WARM FRONT BRINGS BACK CHANCE OF SHOWERS TO THE REGION.
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&& .MARINE...
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OCNL GUSTS INTO THE UPPER TEENS LATE THIS AFTN...SO HAVE GONE WITH A SCA FOR JUST THE SOUTHERN EXTENT OF OUR FORECASTED WATERS THRU THE EVENING. SUB-SCA ON ALL WATERS FRI-SAT. INCRSG WINDS AHEAD OF THE APPROACHING COLD FRONT SAT NIGHT COULD BRING SCA GUSTS BACK IN AT LEAST ON THE CHESAPEAKE BAY. SCA CONDITIONS EXPECTED SUN... THEN WINDS WILL DECREASE...EXPECTING SUB-SCA CONDITIONS FOR MON AND TUE.
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&& .TIDES/COASTAL FLOODING...
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MINOR FLOODING IS OCCURRING DUE TO PERSISTENT ONSHORE NE FLOW. COASTAL FLOOD ADVISORY IN PLACE ALONG THE WESTERN SIDE OF CHESAPEAKE BAY SOUTH OF BALTIMORE AND THE DC WATERFRONT THRU TONIGHT TO ACCOUNT FOR MINOR LVLS BEING REACHED AROUND THE TIME OF HIGH TIDE. ANNAPOLIS MAY GET CLOSE TO MINOR LVLS LATE THIS AFTN...BUT WITH THE ANOMS LEVELING OFF...BELIEVE IT SHOULD STAY JUST BELOW. ALSO OF NOTE IS STRAITS POINT WHICH SOME GUIDANCE WANTS TO PUSH TO MODERATE LVL FOR TONIGHT. HAVE STAYED MORE CONSERVATIVE WITH THE FORECAST FOR THE TIME BEING...KEEPING JUST BELOW BUT WILL CONTINUE TO MONITOR. MINOR FLOODING IS EXPECTED ON FRIDAY WITH THE INCREASED ONSHORE FLOW...WHICH SUBSEQUENT SHIFTS WILL BE ABLE TO ISSUE. THE FLOODING THREAT MAY EXTEND INTO SAT ON THE WESTERN CHESAPEAKE BAY DEPENDING ON HOW QUICKLY THE WINDS SHIFT/WEAKEN.
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&& .LWX WATCHES/WARNINGS/ADVISORIES...
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DC...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR DCZ001. MD...COASTAL FLOOD ADVISORY UNTIL 6 AM EDT FRIDAY FOR MDZ017-018. COASTAL FLOOD ADVISORY FROM MIDNIGHT TONIGHT TO 9 AM EDT FRIDAY FOR MDZ014. VA...COASTAL FLOOD ADVISORY UNTIL MIDNIGHT EDT TONIGHT FOR VAZ054. WV...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 9 AM EDT FRIDAY FOR ANZ534-543.
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&& $$ SYNOPSIS...SEARS/IMR NEAR TERM...SEARS SHORT TERM...SEARS LONG TERM...IMR AVIATION...SEARS/IMR MARINE...SEARS/IMR TIDES/COASTAL FLOODING...LWX

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