Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 041444 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 1044 AM EDT WED MAY 4 2016 .SYNOPSIS... A LOW PRESSURE TROUGH WILL LINGER OVER THE REGION THROUGH FRIDAY AS A POTENT UPPER LEVEL LOW DIGS SOUTHEAST FROM THE OHIO VALLEY INTO THE CAROLINAS. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1030 AM WEDNESDAY... TODAY: A DRIER LOW-LEVEL AIRMASS HAS ADVECTED INTO CENTRAL NC THIS MORNING...IN THE WAKE OF A FRONT CURRENTLY LOCATED ALONG THE CAROLINA COAST. THOUGH STEEP MID-LEVEL LAPSE RATES REMAIN IN PLACE...LOW-LEVEL MOISTURE/HEATING ARE EXPECTED TO BE INSUFFICIENT TO SUPPORT CONVECTION IN CENTRAL NC...PARTICULARLY GIVEN THE ABSENCE OF ANY COMPACT/FOCUSED DPVA. EXPECT A HIGHER LIKELIHOOD OF SUBSIDENCE OVER THE AREA AS PRIOR SHORTWAVE ENERGY LIFTS NORTHEAST OFFSHORE THE MID-ATLANTIC COAST. A POSSIBLE EXCEPTION MAY BE FAR E/SE PORTIONS OF THE COASTAL PLAIN IN CLOSER VICINITY TO RICHER MOISTURE...THOUGH MOST SHOWER ACTIVITY WILL LIKELY REMAIN FURTHER EAST IN COASTAL NC. EXPECT HIGHS IN THE UPPER 60S TO LOWER 70S. TONIGHT: DESPITE DRIER LOW-LEVELS...CHANCES FOR SHOWER ACTIVITY WILL INCREASE AFTER MIDNIGHT TONIGHT IN ASSOC/W COOLING /STEEPENING LAPSE RATES/ ALOFT AND DPVA ATTENDANT SMALL AMPLITUDE WAVES ROTATING AROUND THE EASTERN PERIPHERY OF AN UPPER LEVEL LOW DIGGING SOUTHEAST FROM THE OH VALLEY TO THE SOUTHERN APPALACHIANS (NEAR THE TRI- CITIES) BY 12Z THU. EXPECT LOWS RANGING FROM THE UPPER 40S (NW) TO MID 50S (SE). -VINCENT && .SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
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AS OF 1045 AM WEDNESDAY... THU/THU NIGHT: A POTENT UPPER LEVEL LOW WILL TRACK ACROSS CENTRAL NC DRYING THE DAY THU. AS IS TYPICAL IN SUCH A SETUP...EXPECT SCT TO NUMEROUS CONVECTION AS STEEPENING LAPSE RATES ALOFT AID DIURNAL DESTABILIZATION...WITH THE GREATEST COVERAGE IN `BOUTS` ATTENDANT POTENT SHORTWAVE ENERGY /DPVA/ ROTATING AROUND THE UPPER LOW. ANY UPDRAFT STRONG ENOUGH TO PRODUCE LIGHTNING WILL BE SUFFICIENT TO PRODUCE SMALL HAIL GIVEN A LOWERING FREEZING LEVEL /COOLING ALOFT/. DEEP LAYER SHEAR WILL GENERALLY BE TOO WEAK TO SUPPORT ORGANIZED CONVECTION OVER CENTRAL NC THU AFTERNOON...EXCEPT IN THE NE COASTAL PLAIN WHERE 0-6 KM SHEAR (OR 0-8 KM) VALUES WILL BE SUFFICIENT TO SUPPORT SUPERCELLS...ESP IF WELL TIMED DPVA ROTATES INTO THAT REGION DURING THE MID/LATE AFTERNOON. SUCH ACTIVITY WOULD BE CAPABLE OF PRODUCING LARGE (1-2") HAIL...THOUGH THE THREAT WOULD BE SPATIO- TEMPORALLY LIMITED TO THE FAR NE COASTAL PLAIN FOR SEVERAL HOURS MID/LATE AFTERNOON. THE BEST POTENTIAL FOR SUPERCELLS WILL REMAIN OUTSIDE OF CENTRAL NC IN FAR NORTHEAST NC AND SOUTHEAST VA. EXPECT AREAS OF CONVECTION TO WRAP SOUTHWARD BACK INTO CENTRAL NC OVERNIGHT AS THE UPPER LOW PIVOTS NE TOWARD THE DELMARVA AND SHORTWAVE ENERGY DIGS SOUTHWARD INTO CENTRAL NC FROM VA. HIGHS WILL BE MODULATED BY CONVECTION...RANGING FROM THE UPPER 50S NW TO LOW/MID 60S SE. LOWS THU NIGHT ALSO MODULATED BY CONVECTION...RANGING FROM THE UPPER 40S WEST TO NEAR 50F EAST. -VINCENT
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&& .LONG TERM /FRIDAY THROUGH TUESDAY/... AS OF 300 AM WEDNESDAY... AN UPPER LEVEL LOW OVER CANADA WILL STRENGTHEN OVER THE WEEKEND...WITH THE TROUGH PUSHING SOUTHWARD TOWARD NC. THE ASSOCIATED BACKDOOR COLD FRONT AT THE SURFACE WILL SLIDE SOUTH...BUT FOR NOW APPEARS AS THOUGH IT WILL STAY NORTH OF THE VA BORDER. IT APPEARS SAT AND SUNDAY SHOULD LARGELY REMAIN DRY...HOWEVER A STRAY SHOWER CANNOT BE COMPLETELY RULED OUT. AS THE SURFACE FLOW SHIFTS TO MORE WEST AND SOUTHWESTERLY...TEMPS SHOULD REBOUND BACK INTO THE MID 70S SAT TO LOW 80S SUN. THE MEDIUM RANGE MODELS START TO DIFFER QUITE A BIT FROM SUNDAY ONWARD...RESULTING IN A LOW CONFIDENCE FORECAST FOR EARLY NEXT WEEK. WILL KEEP THE FORECAST DRY FOR NOW... WITH HIGHS GENERALLY IN THE LOW TO MID 80S AND LOWS IN THE LOW TO MID 60S. && .AVIATION /18Z WEDNESDAY THROUGH SUNDAY/... AS OF 1030 AM WEDNESDAY... ONCE SUB-VFR CEILINGS LIFT AT EASTERN TERMINALS...VFR CONDITIONS WILL PREVAIL THROUGH THIS EVENING IN ASSOC/W A DRIER LOW-LEVEL AIRMASS IN PLACE OVER THE REGION. EXPECT ANY DIURNAL CU TO BE BASED AT 4-5 KFT THIS AFTERNOON. EXPECT DETERIORATING CONDITIONS AT THE TRIAD TERMINALS BY OR SHORTLY AFTER MIDNIGHT TONIGHT AS SHOWERS DEVELOP IN ADVANCE OF AN APPROACHING UPPER LEVEL LOW. SUB-VFR CONDITIONS WILL BECOME INCREASINGLY LIKELY AT THE EASTERN TERMINALS BY THE END OF THE TAF PERIOD AS THE UPPER LEVEL LOW APPROACHES THE CAROLINAS. LOOKING AHEAD: EXPECT ADVERSE AVIATION CONDITIONS AT ALL TERMINALS THU INTO THU NIGHT IN ASSOC/W NUMEROUS SHOWERS AND SCT THUNDERSTORMS (ANY OF WHICH COULD PRODUCE SMALL HAIL) OVER CENTRAL NC IN ASSOC/W THE UPPER LEVEL LOW OVER THE REGION. CONDITIONS WILL BEGIN TO IMPROVE ON FRIDAY AS THE UPPER LOW SHIFTS TOWARD THE DELMARVA/ MID- ATLANTIC COAST...WITH VFR CONDITIONS FRI NIGHT THROUGH THE UPCOMING WEEKEND. -VINCENT && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...VINCENT NEAR TERM...VINCENT SHORT TERM...VINCENT/ LONG TERM...10 AVIATION...VINCENT

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