Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 031938
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
340 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 /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 155 PM FRIDAY...

AVIATION CONDITIONS WILL VARY ACROSS CENTRAL NC FROM VFR IN THE
NORTHERN COASTAL PLAIN TO IFR/LOW END MVFR OVER THE WESTERN SECTIONS
OF THE PIEDMONT. SCATTERED TO NUMEROUS SHOWERS AND STORMS WILL CROSS
THE AREA FROM THE SW THROUGH THE AFTERNOON HOURS. THE STRONGER
STORMS WILL PRODUCE WIND GUSTS 30-40KTS...MAINLY BETWEEN 20Z-02Z AND
ACROSS THE SOUTHERN COUNTIES INCLUDING IN VICINITY KFAY.

THE BULK OF THE CONVECTION WILL DIMINISH AFTER 02Z...LEAVING
GENERALLY VFR CONDITIONS IN THEIR WAKE. THERE MAY BE POCKETS OF MVFR
CEILING/FOG BY EARLY SATURDAY MORNING.

EXPECT MAINLY VFR CONDITIONS SATURDAY AND IT WILL BE BREEZY (FOR MID
SUMMER STANDARDS). NEAR SFC SW WINDS WILL BE 9-13KTS WITH GUSTS 20-
25KTS PROBABLE...WITH THE STRONGEST GUSTS ANTICIPATED IN THE
VICINITY OF KFAY. WITH AFTERNOON HEATING...EXPECT SCATTERED
CONVECTION TO OCCUR WITH THE GREATEST CONCENTRATION ACROSS THE NORTH
IN VICINITY OF THE TRIAD TERMINALS AND POSSIBLY KRDU BETWEEN 21Z-
02Z. MOST OF THE CONVECTION WILL DIMINISH PRIOR TO MIDNIGHT.

CONVECTION EXPECTED TO BE MORE NUMEROUS SUNDAY AS A MID LEVEL TROUGH
CROSSES THE REGION. THIS WILL LEAD TO AREAS OF SHOWERS AND STORMS
ALONG WITH MVFR CEILINGS/VISIBILITY.

A RETURN TO MORE TYPICAL SUMMER PATTERN ANTICIPATED FOR MONDAY
THROUGH WEDNESDAY WITH EARLY MORNING STRATUS/FOG GIVING WAY TO VFR
CONDITIONS ASIDE FROM SCATTERED AFTERNOON-EARLY EVENING CONVECTION.

WHILE VFR CONDITIONS WILL GENERALLY PREDOMINATE ACROSS CENTRAL NC
THROUGH FRIDAY AFTERNOON...SCATTERED CONVECTION THIS AFTERNOON
THROUGH THIS EVENING...AND AGAIN ON FRIDAY WILL CAUSE PERIODS OF
MVFR CEILING AND VISIBILITIES. IN VICINITY OF THE STORMS...EXPECT
GUSTY WINDS WITH GUSTS 30-40KTS LIKELY.

A STALLED SURFACE FRONT NEAR THE VIRGINIA BORDER COUPLED WITH A
SERIES OF UPPER LEVEL DISTURBANCES WILL CAUSE PERIODS OF SHOWERS AND
STORMS ACROSS CENTRAL NC THROUGH TUESDAY. THE SCATTERED CONVECTION
WILL BE MOST LIKELY IN THE AFTERNOON AND EVENING HOURS. IN VICINITY
OF THE SHOWERS AND STORMS...EXPECT BRIEF INTERVALS OF MVFR
CONDITIONS ALONG WITH WIND GUSTS UP TO 40 KTS. AT THIS TIME...IT
APPEARS THAT THE CONVECTIVE COVERAGE WILL BE MOST NUMEROUS ON FRIDAY
AND AGAIN MONDAY.

&&

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

&&

$$

SYNOPSIS...26
NEAR TERM...WSS
SHORT TERM...WSS
LONG TERM...WSS
AVIATION...WSS


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