Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 021734
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
134 PM EDT SUN AUG 2 2015

.SYNOPSIS...
AN AREA OF LOW PRESSURE OVER THE NORTHEAST GULF OF MEXICO WILL TRACK
SLOWLY NORTHEAST ALONG A NEARLY STATIONARY FRONT OVER THE SOUTHEAST
U.S. THROUGH MONDAY NIGHT. MEANWHILE WEAK HIGH PRESSURE WILL REMAIN
CENTERED FROM THE TN VALLEY TO THE CENTRAL APPALACHIANS.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1045 AM SUNDAY...

WEAK HIGH PRESSURE AT THE SURFACE WILL CONTINUE TO INFLUENCE THE
WEATHER ACROSS THE PIEDMONT TODAY WHILE A STALLED SURFACE FRONT IN
VICINITY OF THE NC COAST MAY CAUSE A FEW MORE CLOUDS AND A VERY
SLIGHT CHANCE OF A STORM OVER THE FAR SE COUNTIES.

A DRY WLY FLOW ALOFT COUPLED WITH THE SFC RIDGE SHOULD PROVIDE
PLENTY OF SUN TO MOST OF CENTRAL NC THIS AFTERNOON. WITH THICKNESSES
IN THE 1425-1435M RANGE...AFTERNOON TEMPS IN THE 90-95 DEGREE RANGE
APPEAR ATTAINABLE. SIMILAR TO SATURDAY...SFC DEWPOINTS WILL REMAIN
COMFORTABLE...IN THE 50S TO NEAR 60...THOUGH SLIGHTLY HIGHER IN THE
FAR COASTAL PLAIN WHERE DEWPOINTS IN THE LOWER 60S WILL BE COMMON.

IF A SHOWER OR STORM WERE TO OCCUR...IT WOULD MOST LIKELY BE TO THE
EAST AND SOUTH OF CLINTON AND GOLDSBORO AND LIKELY NOT UNTIL 5 PM OR
LATER. -WSS

FORECAST CONFIDENCE DECREASES LATER TONIGHT...AS A WEAK WAVE OF LOW
PRESSURE OVER THE NORTHEASTERN GULF OF MEXICO TRACKS SLOWLY UP THE
SOUTHEAST US COAST. MOIST SOUTHERLY FLOW AROUND THE LOW...DIRECTED
INTO THE EASTERN CAROLINAS...WILL LIKELY RESULT IN THE NORTHWARD
DEVELOPMENT/EXPANSION OF AN AREA OF LOW CLOUDS...AND EVEN A FEW
SHOWERS INTO THE SOUTHERN COASTAL PLAIN. THE ASSOCIATED LOW CLOUDS
MAY CREEP AS FAR WEST AS THE PIEDMONT PER THE 00Z/ECMWF... WHICH
INITIALIZED MUCH BETTER WITH LOW LEVEL MOISTURE VALUES THAN THE
DRIER/CLEARER GFS SOLUTIONS...THOUGH THE MOISTURE WOULD LIKELY BE
TOO SHALLOW AND CAPPED TO SUPPORT ANY PRECIPITATION THERE. LOWS
RANGING FROM THE MIDDLE 60S IN THE RESIDUALLY DRY/CONTINENTAL AIR
MASS OVER THE PIEDMONT...PARTICULARLY THE WESTERN HALF...TO AROUND
70 DEGREES OR SO OVER THE COASTAL PLAIN.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 415 AM SUNDAY...

MODEL SPREAD REMAINS RELATIVELY LARGE WITH THE TRACK AND SPEED OF
THE WAVE OF LOW PRESSURE FORECAST TO RIPPLE NORTHEAST ALONG THE
FRONT OVER THE EASTERN CAROLINAS MON AND MON NIGHT. GIVEN THE POORLY-
ANALYZED MOISTURE FIELDS IN THE GFS NOTED IN THE NEAR TERM...WILL
WEIGHT THE FORECAST TOWARD THE SLIGHTLY MORE WESTWARD TRACK AND
ASSOCIATED (MOSTLY) CLOUDIER AND WETTER CONDITIONS OVER THE COASTAL
PLAIN INDICATED BY THE 00Z/2ND ECMWF AND GEM. SUCH A SOLUTION WOULD
RESULT IN LESS HOT TEMPERATURES OVER THE COASTAL PLAIN...IN THE
UPPER 80S TO AROUND 90 DEGREES...TO LOWER 90S ACROSS THE REMAINDER
OF CENTRAL NC. IF THE DAY PROVES DRIER AND MOSTLY SUNNY AREA-
WIDE...PERSISTENCE HIGH TEMPERATURES IN THE LOWER TO MIDDLE 90S
WOULD AGAIN OCCUR. ANY LINGERING RAIN CHANCE SHOULD END OVER THE FAR
EASTERN NC COASTAL PLAIN BY MIDNIGHT...AS THE LOW LIFTS NE AND AWAY
FROM THE NC OUTER BANKS.

&&

.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
AS OF 130 PM SUNDAY...

WED-FRI: A DEEP UPPER LEVEL RIDGE CURRENTLY CENTERED OVER THE
WESTERN CONUS /INTERMOUNTAIN WEST/ WILL GRADUALLY SHIFT EASTWARD TO
THE ROCKIES BY MID-WEEK...WITH A MORE ACTIVE /ENERGETIC/ PATTERN
(NORTHWEST FLOW ALOFT) DEVELOPING DOWNSTREAM OF THE RIDGE OVER THE
TN/OH VALLEY AND MID-ATLANTIC. FROM A PATTERN RECOGNITION
STANDPOINT...ONE WOULD EXPECT NEAR NORMAL TEMPERATURES AND AT/ABOVE
NORMAL CHANCES FOR PRECIPITATION MID/LATE WEEK...PARTICULARLY LATE
IN THE WEEK (I.E. THU/FRI) WHEN 12Z MODEL GUIDANCE SUGGESTS A SERIES
OF SMALL AMPLITUDE SHORTWAVES WILL TRACK ACROSS NC/VA. GIVEN THAT
CONVECTIVE TIMING/COVERAGE/INTENSITY WILL BE HIGHLY SENSITIVE TO THE
PRECISE EVOLUTION AND DIURNAL TIMING OF SMALL AMPLITUDE
WAVES...UPSTREAM CONVECTION...AND/OR CONVECTIVE REMNANTS (I.E.
OUTFLOW/MCV`S)...FURTHER DETAILS REMAIN DIFFICULT IF NOT IMPOSSIBLE
TO DETERMINE AT THIS TIME. GIVEN THAT STRONGER DEEP LAYER SHEAR AND
STEEPER MID-LEVEL LAPSE RATES (I.E. A MODIFIED EML) ARE MORE LIKELY
TO BE PRESENT IN A SYNOPTIC PATTERN CHARACTERIZED BY NW FLOW ALOFT
THIS TIME OF YEAR...AN ENHANCED POTENTIAL FOR SEVERE THUNDERSTORMS
MAY BE PRESENT LATE THIS WEEK (I.E. THU/FRI)...PRIMARILY IF DIURNAL
TIMING IS FAVORABLE W/REGARD TO APPROACHING SHORTWAVE ENERGY.

SAT-SUN: GIVEN A RELATIVELY ENERGETIC PATTERN (FOR MID-SUMMER) IN
PLACE OVER THE LOWER 48...FORECAST CONFIDENCE IS LOWER THAN AVERAGE
IN THIS PERIOD. THE LATEST 12Z MODEL GUIDANCE SUGGESTS THE UPPER
LEVEL RIDGE OVER THE ROCKIES BY MID/LATE WEEK WILL BE SUPPRESSED
SOUTH/SOUTHEASTWARD TO THE LOWER MIDWEST BY SAT...EXTENDING EASTWARD
THROUGH THE DEEP SOUTH TOWARD THE SOUTHERN APPALACHIANS BY THE END
OF THE WEEKEND...WITH THE CAROLINAS ON THE FAR E/NE PERIPHERY OF THE
RIDGE. AT THIS TIME WILL INDICATE NEAR NORMAL TEMPERATURES AND
CLIMATOLOGICAL CHANCES FOR CONVECTION. -VINCENT

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 120 PM SUNDAY...

HIGH PROBABILITY THAT VFR CONDITIONS WILL PERSIST AT TAF SITES
ACROSS CENTRAL NC THROUGH MONDAY NIGHT. THE EXCEPTION WILL BE IN
VICINITY OF KFAY AND KRWI WHERE A BRIEF PERIOD OF MVFR/IFR
VISIBILITY DUE TO FOG AND POTENTIALLY IFR CEILINGS MAY OCCUR VERY
LATE TONIGHT THROUGH EARLY MONDAY MORNING.

ASIDE FROM A SMALL THREAT FOR EARLY MORNING MVFR/IFR FOG EACH
MORNING...EXPECT VFR CONDITIONS TUESDAY THROUGH WEDNESDAY. THE
PROBABILITY FOR MVFR CEILINGS WILL INCREASE THURSDAY AND MORE SO
FRIDAY AS THE ATMOSPHERE BECOMES MORE MOIST AND THE APPROACH OF AN
UPPER LEVEL DISTURBANCE WILL LIKELY ENHANCE THE CHANCE FOR SCATTERED
CONVECTION. CURRENT MODEL TIMING FAVORS THURSDAY NIGHT INTO FRIDAY
FOR SCATTERED CONVECTION AREAWIDE.

&&

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

&&

$$

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


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