Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 030245
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1045 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 PM SUNDAY...

A FEW ISOLATED SHOWERS HAVE DEVELOPED ALONG THE SEA BREEZE THIS
EVENING. WITH LOW-LEVEL LAPSE RATES AROUND 6.5 C/KM...THERE IS JUST
ENOUGH CAPE THAT THE SEA BREEZE IS A SUFFICIENT FORCING MECHANISM
FOR CONVECTION. ALTHOUGH A LIGHTNING STRIKE IS POSSIBLE...THESE
SHOWERS WILL GENERALLY BE FAIRLY BENIGN...WITH JUST SOME BRIEF
LOCALLY HEAVY RAIN. OTHERWISE...MOST LOCATIONS TONIGHT SHOULD REMAIN
DRY AND CLEAR WITH LOWS IN THE MID 60S NORTH TO LOW 70S SOUTH.

&&

.SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/...
AS OF 330 PM SUNDAY...

MONDAY AND MONDAY NIGHT... A WELL-DEFINED LOW LEVEL CIRCULATION OVER
THE FAR NE GULF WILL DRIFTING NEWD MONDAY AND MONDAY NIGHT IN
RESPONSE TO A S/W CROSSING THE LOWER OH AND TN VALLEYS. THIS SFC LOW
WILL INCREASES CONVERGENCE ALONG A STALLED SFC BOUNDARY IN VICINITY
OF THE NC COAST. THIS SFC FEATURE EXPECTED TO DRIFT INTO THE COASTAL
PLAIN BUT NOT LIKELY AS FAR WEST AS I-95. REGIONAL WRF MODELS
OFFERING VARYING SOLUTIONS WITH SOME DEPICTING VERY LITTLE OVER OUR
CWA...WHILE SOME SUGGEST SCATTERED CONVECTION AS FAR WEST AS THE
EASTERN PIEDMONT ON MONDAY AFTERNOON. THE TRUTH IS LIKELY SOMEWHERE
IN BETWEEN. WILL INCREASE RAIN CHANCE TO SOLIDLY CHANCE/LOW END
LIKELY OVER SECTIONS OF SAMPSON COUNTY...WITH POPS QUICKLY DWINDLING
TO THE WEST-NW OVER THE REMAINDER OF THE SOUTHERN COASTAL PLAIN AND
SANDHILLS. APPEARS THAT ANY CONVECTION THAT DEVELOPS OVER THE
PIEDMONT WILL BE ISOLATED (IF IT FORMS AT ALL) AS ATMOSPHERE
PROJECTED TO REMAIN RELATIVELY DRY (FOR EARLY AUGUST) AND
CONDITIONALLY STABLE.

FAIRLY CONFIDENT THAT A MIXTURE OF CLOUDS/SUN WILL PREVAIL OVER THE
PIEDMONT MONDAY...RESULTING IN AFTERNOON TEMPS NEAR 90-LOWER 90S.
OVER THE SE THIRD...CONFIDENCE NOT AS HIGH AS MAY SEE A DECENT VEIL
OF CLOUDS...LIMITING INSOLATION. AND IF CONVECTIVE COVERAGE IS MORE
THAN ANTICIPATED...AFTERNOON TEMPS IN THE MID 80S MAY BE ALL SHE
WROTE. USED ADJUSTED MAV MOS GUIDANCE FOR HIGH TEMPS MONDAY WITH
GENEROUS SMOOTHING/EDITING.

MAY SEE A FEW SHOWERS/STORMS PERSIST WELL INTO THE EARLY EVENING
HOURS MONDAY...MAINLY OVER THE CENTRAL-SOUTHERN COASTAL PLAIN.
ELSEWHERE EXPECT VARYING DEGREES OF CLOUDINESS...MORE SO SE VERSUS
NW. MIN TEMPS NEAR 70-LOWER 70S.

TUESDAY AND TUESDAY NIGHT... LOW LEVEL BECOMES MORE SLY AND USHER A
MOIST AIR MASS INTO CENTRAL NC. ALOFT...FLOW MAINLY WLY BUT STILL
RATHER STABLE. STRONG HEATING OF THE MOIST AIR IN THE LOWER LEVELS
SHOULD SUPPORT THE DEVELOPMENT OF ISOLATED CONVECTION..MAINLY IN THE
MID AFTERNOON THROUGH THE EARLY EVENING HOURS. A LEE-SIDE TROUGH
WILL INDUCE A SW FLOW OVER OUR REGION WHILE AIR MASS REMAINS
WARM/DRY ALOFT. THICKNESSES TOP OUT AROUND 1440M OVER THE
PIEDMONT...SUPPORTIVE OF AFTERNOON TEMPS IN THE MID 90S.

MOIST LOW LEVEL AIR MASS WILL LIKELY CAUSE AREAS OF STRATUS TO
DEVELOP LATE TUESDAY NIGHT. MIN TEMPS NEAR 70-LOWER 70S.

&&

.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 /00Z MONDAY THROUGH THURSDAY/...
AS OF 730 PM SUNDAY...

24-HOUR TAF PERIOD: FAIRLY HIGH CONFIDENCE THAT VFR CONDITIONS WILL
PREVAIL THROUGH THE TAF PERIOD. WINDS WILL BECOME LIGHT AND VARIABLE
OR CALM BY SUNDAY MORNING. AS WITH LAST NIGHT...THE UNCERTAINTY LIES
IN WHETHER THERE WILL BE A REDUCTION IN CIGS/VISBYS DURING THE PRE-
DAWN HOURS...MAINLY AT KFAY AND KRWI. AGAIN...THE NAM FORECAST
SOUNDINGS INDICATE A LAYER OF LOW LEVEL MOISTURE NEAR THE SURFACE
WHILE THE GFS IS DRY. FOR NOW...HAVE INCLUDED A TEMPO GROUP FOR
THESE POSSIBILITIES...AND ALTHOUGH CHANCES ARE SLIGHTLY BETTER...
CONFIDENCE THAT THEY WILL OCCUR IS LOW. WINDS ON MONDAY SHOULD BE
GENERALLY SOUTHERLY OR SOUTH-SOUTHWESTERLY AT 5-10 KTS. -RAH

LOOKING AHEAD: 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. -WSS

&&

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

&&

$$

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



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