Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 032336 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 736 PM EDT FRI JUL 3 2015 .SYNOPSIS... SURFACE LOW PRESSURE WILL TRACK EAST ACROSS NC AND VA TONIGHT...ALONG A FRONTAL ZONE THAT WILL LINGER OVER THE REGION THROUGH THE HOLIDAY WEEKEND. && .NEAR TERM /THROUGH TONIGHT/... AS OF 340 PM FRIDAY... LATE AFTERNOON THROUGH TONIGHT... EXTENSIVE CLOUDS AND SCATTERED SHOWERS/STORMS HAS PREVENTED THE LOWER ATMOSPHERE FROM REALIZING MAXIMUM INSTABILITY POTENTIAL. THIS HAS HELPED TO KEEP ISOLATED STORMS IN CHECK THROUGH 19Z. LATEST VISIBLE SATELLITE IMAGERY DOES DEPICTS SOME THINNING OF THE CLOUDINESS ACROSS THE SOUTHERN COUNTIES. THIS PARTIAL SUN MAY BE ABLE TO GENERATE ENOUGH INSTABILITY TO INITIATE/SUSTAIN SCATTERED STRONG CONVECTION BETWEEN 21Z-02Z AS A MID LEVEL S/W CROSSES INTERACTS WITH THE VERY MOIST AIR MASS OVER THE REGION. WILL NEED TO MONITOR STORMS FOR SOME ROTATION AS LOW LEVEL JET ON THE ORDER OF 30- 35KTS IN VICINITY OF THE SC BORDER. WITH NEAR SFC FLOW MAINLY SLY AND 850MB SW...DECENT SFC-1KM STORM RELATIVE HELICITY PLAUSIBLE. WHILE MODERATE INSTABILITY MAY BE LACKING...ENOUGH SHEAR MAY EXIST FOR A LOCALLY DAMAGING WIND THREAT WITH THE STRONGER STORMS...MAINLY SOUTH OF HIGHWAY 64. EXPECT BULK OF CONVECTION TO DIMINISH PRIOR TO MIDNIGHT. WEAK PERTURBATIONS ALOFT COUPLED WITH THE MOISTURE RICH AIR MASS MAY SUSTAIN A FEW SHOWERS WELL INTO THE NIGHT. MIN TEMPS 67-73. && .SHORT TERM /SATURDAY AND SATURDAY NIGHT/... AS OF 340 PM FRIDAY... POSITIVELY TILTED MID-UPPER LEVEL TROUGH WILL REMAIN IN PLACE TO OUR WEST-NW WITH MINOR PERTURBATIONS LIFTING NEWD IN THE SW FLOW ALOFT. BULK OF THIS ENERGY WILL PASS TO OUR WEST-NW. WITH AFTERNOON HEATING...LOW LEVEL ATMOSPHERE SHOULD BECOME MODERATELY UNSTABLE...AND WITH AVAILABLE MOISTURE... GENERATE SCATTERED THUNDERSTORMS...MAINLY ACROSS THE NORTHERN PIEDMONT...BETWEEN 22Z- 03Z. LOW-MID LEVEL WIND STRENGTH OF 30-40KTS WILL CREATE DECENT SHEAR WITH STRAIGHT-LINE HODOGRAPHS HIGHLY PROBABLE. THIS SUGGEST BROKEN BANDS OF CONVECTION RATHER THAN SUPERCELLULAR STRUCTURE. STILL COULD SEE A STRONG/LOCALLY DAMAGING WINDS AND MARGINALLY LARGE HAIL (SIZE OF A QUARTER OR LESS) WITH THE STRONGER STORMS. PARTIAL-MOSTLY SUNNY SKIES THROUGH MID AFTERNOON SHOULD WARM TEMPS WELL INTO THE 80S TO AROUND 90. THE EXCEPTION WILL BE THE NW PIEDMONT WHERE CLOUDS MAY BE PROMINENT...HOLDING MAX TEMPS IN THE MID 80S. SIMILAR TO TONIGHT...EXPECT MAJORITY OF THE SHOWERS/STORMS TO DISSIPATE AROUND MIDNIGHT WITH A FEW SHOWERS PROBABLE WELL INTO THE NIGHT. MIN TEMPS 68-73. && .LONG TERM /SUNDAY THROUGH FRIDAY/... AS OF 225 PM FRIDAY... A CLOSED MID-LEVEL LOW WILL DRIFT NNE ACROSS THE SOUTHERN AND CENTRAL APPALACHIANS ON SUNDAY...WHILE A SFC BOUNDARY REMAINS ALONG THE NC/VA BORDER. AS THE CLOSED LOW LIFTS TO THE N...SO WILL THE SFC BOUNDARY...MOVING N INTO VA SUNDAY NIGHT. AS SUCH...THE BEST CHANCE FOR RAIN AND GREATEST COVERAGE OF SHOWERS/TSTMS DURING THE DAY SUNDAY WILL BE INVOF OF THE BOUNDARY...BASICALLY AREAS N OF HWY 64. FORECAST SOUNDINGS SHOW MODEST CAPE AND SHEAR...WITH INSTABILITY LIMITED BY EXTENSIVE CLOUD COVERAGE. BUT WITH HIGH PWAT (>1.75") AND RELATIVELY SLOW STORM MOTION...WILL HAVE TO KEEP A CLOSE WATCH ON LOCALIZED FLOOD POTENTIAL. ON MONDAY...THE SFC BOUNDARY WILL BE WELL TO OUR NORTH. MODELS SHOW THAT A MID LEVEL DISTURBANCE ROTATING AROUND THE AFOREMENTIONED CLOSED LOW WILL MOVE UP FROM THE SOUTH AND CROSS THE EASTERN HALF OF THE STATE DURING THE AFTERNOON. WITH THIS BEING THE PRIMARY FEATURE OF THE DAY...THE BEST CHANCE FOR RAIN IS EXPECTED ACROSS LOCATIONS FROM THE COASTAL PLAIN AND EASTWARD...WITH PERHAPS MOST OF OUR CWA WEST OF I-95 REMAINING DRY. FOR TUESDAY THROUGH FRIDAY...ALL INDICATIONS AT THIS POINT SUGGEST THE SUB-TROPICAL RIDGE WILL BECOME ESTABLISHED OVER THE CAROLINAS AND SOUTHEAST IN THE WAKE OF THE AFOREMENTIONED CLOSED LOW GETTING ABSORBED INTO THE WESTERLY FLOW TO OUR NORTH. THIS PATTERN SHOULD KEEP THE DEEPEST MOISTURE...BEST SYNOPTIC SCALE FORCING...AND BEST CHANCE FOR RAIN MAINLY TO OUR NORTH. BUT THIS TIME OF YEAR... ISOLATED SHOWERS/TSTMS CAN NEVER BE RULED OUT...ESP INVOF OF THE PIEDMONT TROUGH AND TO OUR EAST INVOF THE SEA BREEZE...SO WILL MAINTAIN NEAR-CLIMO POPS FOR WIDELY SCATTERED MAINLY-DIURNAL SHOWERS/TSTMS ACROSS OUR AREA EACH DAY. AS FOR TEMPS DURING THE LONG TERM...NEAR-NORMAL TEMPS SUNDAY AND MONDAY WILL GRADUALLY WARM TO A DEGREE OR SO ABOVE NORMAL BY MID- WEEK AS THE SUBTROPICAL RIDGE SETS UP OVER THE CAROLINAS. NORMAL HIGHS ARE UPPER 80S TO AROUND 90...AND NORMAL LOWS IN THE UPPER 60S. && .AVIATION /00Z SATURDAY THROUGH WEDNESDAY/... AS OF 735 PM FRIDAY... 24 HOUR TAF PERIOD: CONVECTION MOVING INTO THE TRIAD THIS HOUR WILL LAST FOR THE NEXT HOUR OR TWO BEFORE WANING. A WEAKER AREA OF SHOWERS AND THUNDERSTORMS IS APPROACHING KRDU FROM THE SOUTHWEST AND PROBABLY WONT REACH THE VICINITY FOR ANOTHER HOUR OR TWO. AT THE MOMENT KFAY AND KRWI ARE IN THE RELATIVE CLEAR WITH NO UPSTREAM DEVELOPMENT. TRIAD SITES WILL LIKELY EXPERIENCE AT LEAST MVFR CONDITIONS FOR THE NEXT COUPLE OF HOURS AND THEN MODELS INDICATING ANOTHER ROUND OF MVFR VISIBILITIES NEAR DAYBREAK. ALL OTHER SITES EXPECTED TO REMAIN VFR OUTSIDE OF CONVECTION. WINDS BE PREDOMINATELY SOUTHWESTERLY THROUGH THE END OF THE TAF PERIOD WITH ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS AGAIN POSSIBLE TOMORROW. GUSTY WINDS LATE SATURDAY AFTERNOON MAY ONLY REACH 15 KTS IN THE TRIAD AND KRDU BUT KFAY AND KRWI COULD SEE GUSTS OF 20 KTS UP UNTIL SUNSET. LONG TERM: LONG TERM MODELS SHOW THE UNSETTLED PATTERN HOLDING OVER CENTRAL NC...INDICATING A CHANCE FOR SHOWERS AND THUNDERSTORMS AS WELL AS ADVERSE AVIATION CONDITIONS AT LEAST THROUGH MIDWEEK. && ..RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...26 NEAR TERM...WSS SHORT TERM...WSS LONG TERM...WSS AVIATION...ELLIS

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