Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS62 KRAH 060702 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 302 AM EDT FRI MAY 6 2016 .SYNOPSIS... DEEP LOW PRESSURE WILL LINGER OVER THE MIDATLANTIC REGION TODAY BEFORE MOVING NORTHEAST AWAY FROM THE AREA TONIGHT. HIGH PRESSURE WILL BUILD OVER THE SOUTHEAST STATES SATURDAY BRINGING A WARM SOUTHWEST FLOW INTO THE AREA. A COLD FRONT APPROACHING FROM THE NORTHWEST SATURDAY NIGHT WILL STALL OUT NEAR THE VIRGINIA NORTH CAROLINA BORDER SUNDAY INTO MONDAY. && .NEAR TERM /TONIGHT/... AS OF 945 PM THURSDAY... AN ANOMALOUSLY STRONG 546DM CLOSED UPPER LEVEL LOW PRESSURE SYSTEM WAS LOCATED OVER THE SANDHILLS OF NC THIS EVENING. THE H5 HEIGHTS ARE NOTED AS BEING BETWEEN 4 AND 5 STANDARD DEVIATIONS FROM NORMAL WITH A ROBUST 60-70KT JET EXTENDING FROM THE SAVANNAH RIVER VALLEY NORTHEAST UP THE ATLANTIC COAST. THE DRY SLOT WAS NOTED ON WV SATELLITE DATA WRAPPED INTO THE SANDHILLS AND SE PIEDMONT INTO THE COASTAL PLAIN LATE AFTERNOON AND EARLY EVENING... WITH STEADY RAINS WRAPPING AROUND THE NORTH AND WEST SIDE OF THE CIRCULATION WELL INTO NW NORTH CAROLINA INTO THE BLUE RIDGE. TRENDS WITH RADAR AND SATELLITE INDICATE THAT THE RAIN WILL SPREAD BACK INTO THE DRY SLOT AREA FROM THE NORTH IN THE NEXT FEW HOURS AS THE LOW SLOWLY MOVES NE. THIS IS FURTHER SUPPORTED BY THE LATEST HI-RES CONVECTION ALLOWING MODELS. AN ADDITIONAL 0.50 TO 1 INCH OF RAIN IS EXPECTED FROM RDU TO RWI TO GSB OVERNIGHT... WITH RAINS FINALLY ENDING FROM WEST TO EAST INTO THE WESTERN PIEDMONT TOWARD DAYBREAK. FLASH FLOOD GUIDANCE IS STILL HIGH CONSIDERING ALL THE RAIN IN THE LAST 5 DAYS (GOOD THING IT WAS DRY BEFORE)... WITH 2+ INCHES IN THE 3 HOURS... AND 2.5+ INCHES IN 6 HOURS BEING A THRESHOLD TO STRONGLY CONSIDER. IT APPEARS THAT LOCALLY 1.5 INCHES MAY OCCUR FROM RDU TO RWI THROUGH 15Z... BEFORE TAPERING OFF. THUS... WIDESPREAD FLASH FLOODING IS NOT ANTICIPATED. HOWEVER... SOME LOCALIZED URBAN FLOODING AND FLOODING OF TYPICAL AREAS MAY OCCUR. AS FOR LOWS... THIS IS A COLD CORE LOW AND TROUGH. THE TEMPERATURES WERE ALREADY IN THE 40S IN THE NW TO MID 50S SE AT MID-EVENING. LOWS OF 42-47 ARE EXPECTED NW... AND NEAR 50S SE BY 12Z. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/... AS OF 435 PM THURSDAY... THE UPPER LEVEL LOW PRESSURE SYSTEM WILL MOVE FROM NORTHEASTERN NC AT DAYBREAK FRIDAY TO THE WASHINGTON DC AREA ON FRIDAY AFTERNOON AND FRIDAY NIGHT. THE UPPER LOW WILL WOBBLE A BIT LATE IN THE PERIOD BUT LIKELY LINGER IN THE DC-PHILADELPHIA REGION BY SATURDAY MORNING. WHILE THE FORCING FOR ASCENT GRADUALLY WEAKENS ACROSS CENTRAL NC DURING THE PERIOD...THERE SHOULD BE ENOUGH MOISTURE PRESENT WITH ANOTHER COUPLE SHORT WAVE TROUGHS ROTATING AROUND THE BACK SIDE OF THE UPPER LOW TO WARRANT POPS ON FRIDAY. EXPECT THE COVERAGE AND INTENSITY TO BE MORE LIMITED ON FRIDAY AS COMPARED TO TODAY WITH THE BEST CHANCE DURING THE AFTERNOON WHEN SOME LIMITED HEATING SHOULD BE SUFFICIENT TO SUPPORT SCATTERED SHOWERS. HAVE INCLUDED THE MENTION OF A SLIGHT CHANCE OF THUNDERSTORMS IN THE EAST AND SOUTHEAST WHERE DEW POINTS IN THE LOWER 50S COMBINED WITH SOME DECENT LOW/MID LEVEL LAPSE RATES COULD BE SUFFICIENT TO GENERATE A FEW THUNDERSTORMS. BULK SHEAR VALUES WILL BE WEAK BUT WITH H5 RANGING BETWEEN -20 AND -23...CANT RULE OUT A LITTLE SMALL HAIL. THREAT OF PRECIPITATION DECREASES IN THE EVENING AND WILL TREND POPS DOWN TO SLIGHT CHANCE NORTH AND EAST IN THE EVENING WITH NO POPS OVERNIGHT AND DECREASING CLOUDS. HIGHS ON FRIDAY WILL RANGE IN THE LOWER 60S NORTHEAST TO UPPER 60S SOUTH AND LOWS FRIDAY NIGHT WILL RANGE AROUND 50. && .LONG TERM /SUNDAY THROUGH THURSDAY/...
-- Changed Discussion --
AS OF 300 AM FRIDAY... A COLD FRONT WILL CROSS THE AREA EARLY SUNDAY...BUT HOW FAR SOUTH INTO NC THE FRONT MAKES IT REMAINS TO BE SEEN WITH THE GFS PUSHING THE COOL AIR A LITTLE FURTHER SOUTH. IN THE WAKE OF THE FRONT...HIGH PRESSURE BUILDING IN OVER FLORIDA SHOULD HELP TO BUMP UP TEMPERATURES...ESPECIALLY IN THE SOUTHERN COUNTIES WHERE MID 80S WILL BE PROBABLE HIGHS WITH CLOSER TO 80 ACROSS THE NORTH. ALOFT...NORTHWESTERLY FLOW WILL GUIDE A FEW SMALL DISTURBANCES ACROSS THE AREA DURING THE DAY BUT ANY PRECIPITATION SHOULD BE LIGHT AND FLEETING. STILL WILL CARRY SLIGHT CHANCES ACROSS MUCH OF THE CWA SUNDAY AFTERNOON. LOWS SUNDAY NIGHT IN THE MID 50S TO NEAR 60 DEGREES. MONDAY AND MONDAY NIGHT...DETERMINISTIC MODELS ARE STILL IN FAIRLY GOOD AGREEMENT ABOUT THE DEVELOPMENT OF A LOW PRESSURE SYSTEM OVER THE CENTRAL PLAINS WITH A WARM FRONT HOVERING NORTH OF NC ON MONDAY AS SURFACE HIGH PRESSURE CAMPS OUT OVER THE WESTERN ATLANTIC. THIS SHOULD KEEP CONDITIONS DRY AND WARM WITH HIGHS IN THE LOW TO MID 80S AND LOWS MONDAY NIGHT IN THE LOW TO MIDDLE 60S. CONFIDENCE IN THE FORECAST BEGINS TO BREAK DOWN ON TUESDAY AS MODELS ARE IN DISARRAY OVER THE HANDLING OF THE NORTHERN STREAM SYSTEM AS THE GFS DEVELOPS AN UPPER LEVEL LOW THAT MAINTAINS THE CENTRAL PLAINS SURFACE LOW. THIS FEATURE DOES NOT EXIST IN THE ECMWF AND THE SURFACE LOW DEGRADES AND IS CARRIED OFF TO THE EAST. A BLEND OF THE MODELS WOULD SUGGEST NOT TOO MUCH PRECIPITATION ACROSS CENTRAL NC IF ANY AND CONTINUED WARM TEMPERATURES. BEST CHANCES WOULD BE ACROSS THE NORTH WITH THE POTENTIAL FOR A THUNDERSTORM IF CONVECTION DOES OCCUR. WEDNESDAY ONWARD...A BLEND OF THE ENSEMBLES IS THE MORE FAVORED SOLUTION WHICH WILL GENERALLY INCREASE POPS ON WEDNESDAY WITH CHANCES FOR SHOWERS AND THUNDERSTORMS IN THE AFTERNOON. EXTREME DIFFERENCES IN THE MODELS ON THURSDAY CAUSE EVEN A BLEND OF THE MODELS TO BE MEANINGLESS AT THIS POINT. THEREFORE WILL CONTINUE SLIGHT CHANCE/CHANCE POPS THROUGH THURSDAY BUT WITH NO REAL CONFIDENCE. LOW TO MID 80S THROUGH THE REST OF THE PERIOD WITH LOWS IN THE MID 60S.
-- End Changed Discussion --
&& .AVIATION /06Z FRIDAY THROUGH TUESDAY/... AS OF 105 AM FRIDAY... ADVERSE AVIATION CONDITIONS WILL PERSIST AT RDU/RWI/FAY THROUGH MUCH OF THE MORNING... MOSTLY MVFR WITH OCCASIONAL IFR CIGS... WHILE VFR CIGS AND MVFR/VFR VSBYS HOLD AT INT/GSO. DEEP LOW PRESSURE HOLDING OVER THE MIDATLANTIC COASTAL AREAS WILL CONTINUE TO BRING UNSETTLED WEATHER WITH PERIODS OF RAIN ESPECIALLY AT INT/GSO/RDU/RWI THROUGH MID MORNING. THE AXIS OF STEADY RAIN WILL THEN SHIFT INTO THE NORTHEAST SECTIONS... WITH RAIN CHANCES DWINDLING AT INT/GSO BUT PERSISTING AT RDU/RWI/FAY THROUGH THE AFTERNOON HOURS... BRINGING PERIODS OF MVFR VSBYS/CIGS. BUT OTHERWISE CIGS SHOULD TREND UP TO VFR BY 16-17Z TODAY AT RDU/FAY AND BY 18-19Z AT RWI... AS THE LOW PRESSURE STARTS TO MOVE NE AWAY FROM THE AREA. ANY REMAINING RAIN CHANCES NEAR RDU/RWI/FAY WILL DIMINISH SOON AFTER SUNSET... WITH DRY WEATHER AND VFR CIGS EXPECTED AFTER 03Z TONIGHT. SURFACE WINDS WILL BE MAINLY FROM THE NW THIS AFTERNOON AT 8-14 KTS. LOOKING BEYOND 06Z EARLY SAT MORNING... VFR CONDITIONS ARE LIKELY TO DOMINATE AT ALL SITES THROUGH TUESDAY... WITH HIGH PRESSURE BUILDING OVER THE GULF AND SOUTHEAST STATES... A SW LOW INTO NC... AND A FRONTAL ZONE WHICH STALLS OUT NEAR THE NC/VA LINE LATE IN THE WEEKEND. THIS FRONT WILL SHIFT NORTH AS A WARM FRONT MON/TUE... WITH SOUTHWEST FLOW PERSISTING... AND ISOLATED STORM CHANCES EACH AFTERNOON. -GIH && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...HARTFIELD NEAR TERM...BADGETT SHORT TERM...BLAES LONG TERM...ELLIS AVIATION...HARTFIELD

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.