Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000 FXUS62 KRAH 221805 AFDRAH AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE RALEIGH NC 205 PM EDT MON SEP 22 2014 .SYNOPSIS...AN UPPER LEVEL LOW WILL DEVELOP OVER THE CAROLINAS TONIGHT...AND WILL SLOWLY WEAKEN OVER THE REGION THROUGH MID-WEEK. MEANWHILE...AT THE SURFACE...A STALLED FRONT WILL LINGER ALONG THE SOUTHEAST COAST AS HIGH PRESSURE EXTENDS INTO THE AREA FROM THE NORTH. && .NEAR TERM /TODAY AND TONIGHT/... AS OF 1045 AM MONDAY... TODAY: STOUT SHORTWAVE VORTMAX DIVING ESE TOWARD THE SOUTHERN APPALACHIANS AND ROUNDING THE BASE OF THE AMPLIFYING EASTERN US TROUGH WILL DECELERATE AND WILL CLOSE AND EVENTUALLY BECOME CUT-OFF OVER THE CAROLINAS OVERNIGHT. IN RESPONSE... SURFACE COLD FRONT...WHICH IS CURRENTLY IN THE PROCESS OF EXITING THE FORECAST AREA...WILL STALL OUT ALONG THE COAST. RAIN CHANCES: THE FAR SE COUNTIES WILL HAVE THE POTENTIAL FOR SOME SHOWERS THROUGH LATE MORNING(ANOTHER HOUR OR SO)...WITH DRY CONDITIONS THROUGH THE REMAINDER OF THE AFTERNOON AS DRIER AIR IN THE WAKE OF THE FRONTAL PASSAGE SURGES SOUTH. THEN LATE TONIGHT...LIGHT RAIN WILL ATTEMPT TO SPREAD BACK INLAND ACROSS THE EXTREME SE COUNTIES(SAMPSON/WAYNE COUNTIES)AS A WEAK WAVE DEVELOPS ALONG THE OFFSHORE FRONTAL ZONE...TRIGGERING WEAK OVERRUNNING. ISENTROPIC LOOKS FAIRLY WEAK...AND THUS EXPECT PREDOMINATELY CLOUDS WITH SOME LIGHT RAIN/SPRINKLES POSSIBLE. TEMPERATURES: COLD ADVECTION WILL BE PRESENT IN THE WAKE OF THE FRONTAL PASSAGE THROUGH THE REMAINDER OF THE DAY AND TONIGHT. UNDER SUNNY SKIES HIGHS RANGING LOWER TO MID 70S NW TO NEAR 80S SE. LOW TEMPERATURES TONIGHT WILL NOT BE QUITE AS COOL AS ORIGINALLY THOUGHT OWING TO THE RETURN OF CLOUDS...AT LEAST ACROSS THE COASTAL PLAIN AND CENTRAL PIEDMONT. LOWS RANGING FROM LOWER 50S N/NW PIEDMONT TO UPPER 50S/NEAR 60 SOUTHEAST. && .SHORT TERM /TUESDAY AND TUESDAY NIGHT/... AS OF 255 AM MONDAY... ...FORECAST RAPIDLY TRENDING CLOUDY/COOLER WITH A CHANCE FOR RAIN... AS MENTIONED IN THE NEAR TERM...THE LATEST MODEL GUIDANCE SUGGESTS THAT ROBUST SHORTWAVE ENERGY APPROACHING THE REGION TODAY WILL DIG FURTHER SOUTH AND AMPLIFY INTO AN UPPER LOW OVER SC TONIGHT... BECOMING CUT-OFF FROM THE NORTHERN STREAM AND STALLING OVER CENTRAL PORTIONS OF THE CAROLINAS THROUGH TUE NIGHT. IN THE LOWER LEVELS... AN INVERTED TROUGH WILL BE PRESENT IN VICINITY OF THE STALLED BAROCLINIC ZONE ALONG OR JUST OFFSHORE THE CAROLINA COAST WHILE AN INVERTED RIDGE EXTENDS SOUTHWARD INTO CENTRAL/WESTERN PORTIONS OF THE CAROLINAS FROM HIGH PRESSURE TO THE NORTH. THE 00Z GFS/NAM KEEP PRECIP LARGELY SOUTH/EAST OF CENTRAL NC TUE/TUE NIGHT...HOWEVER... THE LATEST 00Z ECMWF SHOWS THE COASTAL FRONT MOVING INLAND TUE NIGHT WITH WIDESPREAD PRECIPITATION OVERSPREADING CENTRAL NC FROM THE SOUTH/SE BY WED MORNING. WITH SUCH A LARGE DIFFERENCE IN THE 00Z OPERATIONAL GUIDANCE QPF...FORECAST CONFIDENCE IS BELOW AVERAGE. AT THIS TIME...WILL ADJUST THE FORECAST FOR CENTRAL NC TO REFLECT MOSTLY CLOUDY TO OVERCAST SKIES...COOLER TEMPERATURES (PERHAPS STRUGGLING TO EXCEED THE 60S TUE AFTERNOON) AND A CHANCE FOR RAIN IN THE SOUTHEAST COASTAL PLAIN...THOUGH PRECIP CHANCES MAY NEED TO BE EXTENDED WEST TO INCLUDE THE ENTIRE CWA TUE NIGHT IF THE 12Z GFS/NAM GUIDANCE TRENDS TOWARD THE 00Z ECMWF. -VINCENT && .LONG TERM /WEDNESDAY THROUGH SUNDAY/... AS OF 136 AM MONDAY... THERE ARE STILL A COUPLE OF DIFFERENT MODEL CAMPS WITH REGARD TO THE RAIN CHANCES MID TO LATE WEEK. THE FAVORED EC ENSEMBLES STILL SUGGEST A WEAK CUT OFF MID/UPPER LOW OVER THE SOUTHERN APPALACHIANS WITH A STRONGER INVERTED SURFACE TROUGH NEAR THE COAST. THE MID AND UPPER FLOW BECOMES SE-S WHILE THE LOW LEVEL FLOW REMAINS EASTERLY. THIS SUPPORTS PLENTY OF DEEP MOISTURE AND RAIN CHANCES THU-FRI... BECOMING SUPPRESSED TO THE SE OR COASTAL ZONES BY SAT-SUN. EVEN THOUGH WE ARE TRENDING WITH HIGHER POP WED NIGHT... THU... INTO FRI BASED ON THE FAVORED EC ENSEMBLE MEAN... THE LATEST OPERATIONS GFS REMAINED IN THE OPPOSITE CAMP WITH VERY LOW OR NO POP DURING THE SAME TIME FRAME (WED NIGHT-FRI). THEREFORE... CONFIDENCE REMAINS LOW WITH POP AND QPF. HOWEVER... CONFIDENCE IS INCREASING THERE BEING AN EXTENDED CLOUDY PERIOD DUE TO THE EASTERLY LOW LEVEL FLOW REGARDLESS. SENSIBLE WEATHER FOR WEDNESDAY... VARIABLY CLOUDY EAST AND PARTLY CLOUDY WEST. HIGHS 68-73 (7-10 DEG BELOW NORMAL). BECOMING CLOUDY WED NIGHT... CLOUDY THU-FRI WITH A CHANCE OF RAIN. LOWS 55-62. HIGHS IN THE MID 60S TO MID 70S. MOSTLY CLOUDY TO PARTLY CLOUDY OVER THE WEEKEND. LOWS IN THE 55-60. HIGHS IN THE MID TO UPPER 70S. && .AVIATION /18Z MONDAY THROUGH SATURDAY/... AS OF 205 PM MONDAY... 24-HR TAF PERIOD: DRY LOW-LEVEL AIR FILTERING IN THE AREA FROM THE NORTH...IN THE WAKE OF THIS MORNINGS COLD FRONTAL PASSAGE WILL SECURE VFR CONDITIONS THROUGH THE PERIOD. THE FRONT WILL STALL JUST OFFSHORE...ALONG THE SOUTHEAST COAST TONIGHT THROUGH MID-WEEK AS CLOSED/CUT-OFF LOW DEVELOPS OVER THE CAROLINAS. THIS WILL SPREAD MOISTURE IN THE 5-10KFT LAYER BACK INLAND TONIGHT THROUGH TUESDAY WITH INCREASING RAIN CHANCES ACROSS THE SOUTHEAST...AND POSSIBLY EASTERN/CENTRAL PIEDMONT. WINDS SHOULD REMAIN OUT OF THE NORTH AT 5-10KT THROUGH THE PERIOD. LOOKING AHEAD: PROXIMITY TO CUT-OFF UPPER LOW OVER THE CAROLINAS ALONG WITH INVERTED SFC TROUGH ALONG THE COAST WILL LIKELY RESULT IN A CONTINUATION OF BROKEN TO OVERCAST CLOUD COVER WITH BETTER RAIN CHANCES EXPECTED ALONG THE SOUTHEAST NEAR KFAY WITH THE POTENTIAL FOR SOME SUB-VFR CEILINGS TUESDAY NIGHT AND INTO WEDNESDAY. ELSEWHERE...VFR CONDITIONS ARE LIKELY TO PREVAIL FURTHER INLAND OVER CENTRAL NC AS DRY AIR SURFACE RIDGE EXTENDS SOUTH INTO PIEDMONT. && .RAH WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...CBL NEAR TERM...CBL SHORT TERM...VINCENT LONG TERM...BADGETT AVIATION...CBL

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