Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 220746
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
346 AM EDT MON SEP 22 2014

.SYNOPSIS...AN UPPER LEVEL LOW DIGGING SOUTHEAST ACROSS THE
TENNESSEE VALLEY TODAY WILL STALL OVER THE CAROLINAS TONIGHT THROUGH
MID-WEEK AS IT BECOMES CUT-OFF FROM THE NORTHERN BRANCH OF THE JET
STREAM. MEANWHILE...A COLD FRONT CROSSING THE AREA THIS MORNING WILL
STALL ALONG THE CAROLINA COAST THROUGH WEDNESDAY.

&&

.NEAR TERM /TODAY AND TONIGHT/...
AS OF 200 AM MONDAY...

TODAY: THE COLD FRONT PROGRESSING INTO THE NW PIEDMONT AT 05Z THIS
MORNING WILL TEMPORARILY STALL IN VICINITY OF THE COAST TODAY AS
STRONG HEIGHT FALLS /DPVA/ OVERSPREAD THE REGION IN ADVANCE OF
POTENT SHORTWAVE ENERGY DIGGING ESE THROUGH THE TN VALLEY. COLD
ADVECTION WILL BE PRESENT IN THE WAKE OF THE FRONT TODAY IN MOST
AREAS... THOUGH PRIMARILY IN THE N/NW PIEDMONT...WITH HIGHS RANGING
FROM THE MID 70S NW TO LOWER 80S SE. EXPECT DRY CONDITIONS IN
CENTRAL NC.

TONIGHT: PRIOR MODEL GUIDANCE WAS PROGRESSIVE WITH THE APPROACHING
SHORTWAVE AND INDICATED IT WOULD MOVE OFFSHORE BY 06-09Z TUE.
HOWEVER...THE LATEST GUIDANCE IS MARKEDLY DIFFERENT AND SHOWS A
STRONGER/MORE ROBUST WAVE DIGGING FURTHER SOUTH...CLOSING OFF INTO
AN UPPER LOW OVER UPSTATE SC TONIGHT...THEN STALLING OVER CENTRAL
PORTIONS OF THE CAROLINAS THROUGH TUE AND PERHAPS TUE NIGHT AS IT IS
CUT-OFF FROM THE NORTHERN STREAM. ALTHOUGH THE BULK OF CLOUD COVER
AND PRECIPITATION ASSOC/W THE UPPER LOW SHOULD REMAIN OVER COASTAL
PORTIONS OF THE CAROLINAS TONIGHT...THERE WILL BE A TIGHT GRADIENT
IN CLOUD COVER AND PRECIPITATION IN VICINITY OF THE SOUTHEAST
COASTAL PLAIN (CUMBERLAND/WAYNE/ SAMPSON)...AND THE FORECAST EAST OF
I-95 WILL LIKELY NEED TO ACCOUNT FOR MORE CLOUD COVER THAN
PREVIOUSLY EXPECTED...IN ADDITION TO A POTENTIAL FOR LIGHT RAIN
TONIGHT IN THE FAR SE COASTAL PLAIN. LOWS WILL RANGE FROM THE UPPER
40S TO LOWER 50S FAR N/NW PIEDMONT TO UPPER 50S FAR SE COASTAL
PLAIN. -VINCENT

&&

.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 /06Z MONDAY THROUGH FRIDAY/...
AS OF 200 AM MONDAY...

24-HR TAF PERIOD: VFR CONDITIONS WILL PREVAIL TODAY AS A COLD FRONT
PROGRESSES THROUGH CENTRAL NC BEFORE STALLING ALONG THE COAST.
EXPECT CEILINGS TO REMAIN AT OR ABOVE 5 KFT. A LIGHT NORTH/NORTHEAST
BREEZE WILL PREVAIL IN THE WAKE OF THE FRONT TODAY INTO TONIGHT.

LOOKING AHEAD: THOUGH THE FORECAST IS TRENDING COOLER/CLOUDIER WITH
A CHANCE FOR RAIN IN SOUTHEAST PORTIONS OF THE STATE TUE/WED...VFR
CONDITIONS ARE LIKELY TO PREVAIL FURTHER INLAND OVER CENTRAL NC
WHERE CEILINGS WILL GENERALLY REMAIN AT OR ABOVE 6 KFT. THE
EXCEPTION WOULD BE A POTENTIAL FOR A PERIOD OF SUB-VFR CEILINGS AND
LIGHT RAIN AT THE RWI/FAY TERMINALS TUE/WED. A NORTHEAST BREEZE WILL
PREVAIL THROUGH MID-WEEK. -VINCENT

&&

.RAH WATCHES/WARNINGS/ADVISORIES...
NONE.

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...BADGETT
AVIATION...VINCENT



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