Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 270541
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
141 AM EDT WED MAY 27 2015

.SYNOPSIS...THE WESTERN EXTENT OF UPPER LEVEL RIDGE OVER THE WESTERN
ATLANTIC...AND A SEASONABLY MOIST AIR MASS...WILL PREVAIL OVER THE
REGION FOR THE WORK WEEK.

&&

.NEAR TERM /OVERNIGHT/...
AS OF 920 PM TUESDAY...

AN AREA OF CONVECTION LIFTING NE ACROSS UPSTATE SC AND SW NC BEING
MAINTAINED BY A MID LEVEL TROUGH AND ATTENDANT SPEED CONVERGENCE
ALONG WITH UPPER DIVERGENCE...CENTERED MAINLY OVER THE SOUTHERN
APPALACHIANS. THE 00Z GSO SOUNDING DEPICTS A FAIRLY SUBSTANTIAL CAP
BETWEEN 750-700MB...A BIT STRONGER THAN PREDICTED BY THE NEAR TERM
MODELS. EXPECT THIS AREA OF CONVECTION TO GRADUALLY WEAKEN AS IT
ENCOUNTERS THE SLIGHTLY MORE STABLE AIR MASS OVER THE WESTERN
PIEDMONT...BUT COULD STILL SEE A FEW SHOWERS LATE THIS EVENING INTO
THE OVERNIGHT IN VICINITY OF THE TRIAD.

OTHERWISE VARIABLY CLOUDY SKIES AND A LIGHT BUT PERSISTENT SLY SFC
WIND WILL RESULT IN A MILD (THOUGH SLIGHTLY HUMID) NIGHT. MIN TEMPS
MAINLY IN THE UPPER 60S.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 305 PM TUESDAY...

INSTABILITY OVERALL INCREASES ACROSS CENTRAL NORTH CAROLINA
WEDNESDAY...WITH SURFACE-BASED CAPE RISING TO JUST OVER 1000J/KG
WHILE MLCAPE THROUGH THE LOWEST 3KM IS GENERALLY 500J/KG OR SO.
LIFTED INDICES ARE FORECAST TO BE SLIGHTLY LOWER COMPARED TO
TODAY... TO NEAR -5C WEDNESDAY AFTERNOON VERSUS ABOUT -3C.
ALOFT...THERE IS FORECAST WEAK AND BROAD DIFFLUENCE AND WEAK
CONVERGENCE AT 850MB...ALTHOUGH CERTAINLY THE NAM AND TO A LESSER
EXTENT THE GFS FORECAST MODEST LIFT OVER CENTRAL NORTH CAROLINA FOR
WEDNESDAY AFTERNOON. WINDS ALOFT ARE WEAK...AND ANY PIEDMONT TROUGH
SHOULD BE SOMEWHAT WEAK AS WELL...LEADING TO A DAY WHERE SCATTERED
MOSTLY DISORGANIZED SHOWERS AND THUNDERSTORMS SHOULD OCCUR AS THE
DAY PROGRESSES. ONCE AGAIN...0-3KM SHEAR IS LOW AND 850MB AND 925MB
WINDS ARE RELATIVELY LIGHT BY AFTERNOON...10 TO 20KT. HIGHS IN THE
80S.

OVERNIGHT...BUFR SOUNDINGS FROM BOTH THE NAM AND GFS SHOW INCREASING
STABILITY AS SURFACE HIGH PRESSURE IS FORECAST TO BUILD SOMEWHAT
BACK WEST. FOR THIS FORECAST WILL DIMINISH CHANCES EAST TO WEST AND
RETAIN A SLIGHT CHANCE OF SHOWERS IN THE OVERNIGHT HOURS ONLY TOWARD
THE YADKIN RIVER ESPECIALLY FOR FORECAST CONSISTENCY...BUT IF THE
NAM BUFR SOUNDINGS VERIFY IN PARTICULAR CENTRAL NORTH CAROLINA
SHOULD HAVE BELOW SLIGHT CHANCE POPS AFTER 06Z. LOWS IN THE MID TO
UPPER 60S.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 210 PM TUESDAY...

THE REMNANT MOISTURE AND SHEAR AXIS FROM THE SYSTEM CURRENTLY OVER
THE MISS RIVER VALLEY WILL MOVE EAST AND BECOME CENTERED OVER
CENTRAL NC BY THURSDAY. WHILE THE BEST MID/UPR ENERGY WILL HAVE
LIFTED WELL TO OUR NORTH...THERE SHOULD BE ENOUGH MOISTURE AND
FORCING FOR AT LEAST SCATTERED AFTERNOON/EVENING SHOWERS/TSTMS.
INSTABILITY AND SHEAR VALUES SUGGEST SUB-SEVERE ACTIVITY.

THE UPPER RIDGE OFF THE EAST COAST WILL THEN REBUILD OVER THE
SOUTHEAST COASTAL REGION FRIDAY THROUGH THE WEEKEND...AND SHOULD
HELP LIMIT THE COVERAGE OF SHOWER/TSTM ACTIVITY OVER OUR AREA FRIDAY
AND SATURDAY.

A COLD FRONT CROSSING THE MIDWEST ON FRIDAY IS PROGGED BY THE LATEST
GFS TO DROP SOUTH ACROSS OUR AREA BY SUNDAY AND DISSIPATE OVER US BY
MONDAY. DESPITE THE LIFT PROVIDED BY THIS FRONT...MODELS SUGGEST THE
AFOREMENTIONED RIDGE OVER THE SOUTHEAST WILL KEEP THE BULK OF THE
MOISTURE JUST TO OUR NORTH.  NEVERTHELESS...THERE`S ENOUGH FORCING
AND MOISTURE TO WARRANT A DECENT CHANCE POP ACROSS OUR AREA LATE IN
THE WEEKEND INTO EARLY NEXT WEEK.

AS FOR TEMPS...PERSISTENCE IS THE BEST FORECAST AT THIS POINT WITH
LITTLE CHANGE IN THE AIRMASS. HIGHS IN THE MID TO UPPER 80S AND
LOWS IN THE MID 60S EACH DAY DURING THE PERIOD.

&&

.AVIATION /06Z WEDNESDAY THROUGH SUNDAY/...
AS OF 140 AM WEDNESDAY...

CONVECTION ACROSS THE WESTERN PIEDMONT CONTINUES TO WEAKEN...AND
SHOULD DIMINISH OVER THE NEXT HOUR OR TWO WITH NO FURTHER AVIATION
IMPACTS AT KGSO...KINT OR KRDU.

SOUTH-SOUTHEASTERLY RETURN FLOW AROUND BERMUDA HIGH PRESSURE OVER
THE WESTERN ATLANTIC WILL MAINTAIN A MOIST LOW-LEVEL FEED OVER THE
AREA...CREATING FAVORABLE CONDITIONS FOR THE DEVELOPMENT OF SUB-VFR
STRATUS AT ALL TAF SITES BETWEEN 06 TO 14Z.

BY 15 TO 16Z...ANY SUB-VFR CEILINGS SHOULD LIFT TO VFR. MAINLY
DIURNAL ISOLATED TO SCATTERED SHOWERS AND STORMS ARE EXPECTED THIS
AFTERNOON. BUT THIS PROBABILITY APPEARS TOO LOW TO MENTION IN THE
TERMINAL FORECAST AT THIS TIME.

BEYOND THE 00Z VALID TAF PERIOD...THE THREAT FOR RESTRICTIONS IN
EARLY MORNING FOG/STRATUS WILL CONTINUE THE WEEKEND AS BERMUDA HIGH
PRESSURE HOLDS OVER THE AREA. ISOLATED TO SCATTERED MAINLY AFTERNOON
AND EVENING THUNDERSTORMS ARE EXPECTED AGAIN ON THURSDAY. RAIN
CHANCES WILL BEGIN TO INTO THE WEEKEND AS UPPER LEVEL RIDGE
RETROGRADES WEST OVER THE AREA.


&&

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

&&

$$

SYNOPSIS...DJF
NEAR TERM...WSS
SHORT TERM...DJF
LONG TERM...RAH
AVIATION...CBL



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