Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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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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