Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 260727
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
327 AM EDT TUE MAY 26 2015

.SYNOPSIS...AN UPPER LEVEL RIDGE OVER THE REGION WILL SLOWLY SHIFT
OFFSHORE THROUGH MID-WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 300 AM TUESDAY...

A STRONG 592-593 DECAMETER MID-UPPER LEVEL RIDGE WILL
REMAIN ANCHORED ALONG THE EASTERN SEABOARD. MORE SUMMER-LIKE
CONDITIONS RETURN TODAY OWING TO THE RETURN OF LOW-LEVEL
MOISTURE/HUMIDITY...AND SUBSEQUENT WEAK INSTABILITY ON THE BACK SIDE
OF THE OFFSHORE SFC HIGH.

THE BETTER RAIN CHANCES SHOULD REMAIN CLOSELY ROOTED TO THE NC MTNS
AND FTHLS...FUELED BY AN UPSLOPE FLOW REGIME. HOWEVER THE THE
POTENTIAL FOR WEAK SUPPORT ALOFT IN THE FORM OF WEAK DPVA ATTENDANT
TO SMALL AMPLITUDE SHORTWAVE DISTURBANCES LIFTING NORTHWARD THROUGH
THE SOUTHERN APPALACHIANS IN ADVANCE OF THE PRIMARY SHORTWAVE BACK
OVER THE MS VALLEY JUSTIFIES SLIGHT CHANCE POPS INTO THE WESTERN
PIEDMONT. ADDITIONALLY...SOME OF THE CAMS SUGGEST A FEW
SHOWERS/STORMS OVER THE SANDHILLS AND SOUTHERN COASTAL PLAINS LATER
THIS AFTERNOON AS THE SEABREEZE WORKS INLAND. HAVE ADDED SLIGHT
CHANCE POPS TO ACCOUNT FOR THIS SCENARIO.

ALONG WITH RISING HUMIDITY LEVELS...LOW-LEVEL THICKNESSES ARE
PROGGED TO BE INCREASE ANOTHER ~10 METERS TODAY...WHICH SHOULD YIELD
MOST AREAS A GOOD CATEGORY WARMER THAN YESTERDAY. HIGHS IN THE MID
80S WEST TO UPPER 80S SOUTHEAST.

CONVECTION SHOULD BE LARGELY DIURNALLY DRIVEN...BUT WILL KEEP A
SLIGHT CHANCE ACROSS THE WESTERN PIEDMONT OVERNIGHT WHERE THE
POTENTIAL FOR GLANCING SHOT DPVA ATTENDANT TO UPPER
DISTURBANCES IS HIGHEST. LOWS IN THE MID TO UPPER 60S.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 300 AM TUESDAY...

MODELS GENERALLY AGREE THAT THE MID/UPPER LEVEL RIDGE MAY WEAKEN A
BIT WHILE DRIFTING EVER SO SLIGHTLY EASTWARD OVER THE WESTERN
ATLANTIC. FACTORS CONTRIBUTING TO RAIN CHANCES TODAY(DAYTIME HEATING
AND RESULTANT DESTABILIZATION...POTENTIAL FOR SHORTWAVE DISTURBANCES
ALOFT...AND SEABREEZE BOUNDARY) WILL ESSENTIALLY GOVERN RAIN CHANCES
AGAIN ON WEDNESDAY...BUT PERHAPS WITH MORE EQUITABLE RAIN CHANCES
EASTWARD INTO CENTRAL PIEDMONT.

HIGHER RAIN CHANCES AND CLOUD COVER MAY KNOCK A DEGREE OR TWO OFF OF
DAYTIME HIGHS. HIGHS IN THE LOWER/80S NORTHWEST TO MID/UPPER 80S
SOUTHEAST. LOWS IN THE MID/UPPER 60S.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 320 AM TUESDAY...

STRONG UPPER LEVEL RIDGING ALONG THE SOUTHEAST COAST SHOWS SOME
SIGNS OF WEAKENING BY THURSDAY BUT IS STILL STRONG ENOUGH TO DEFLECT
THE SHORTWAVE CURRENTLY OVER THE CENTRAL PLAINS NORTH TOWARD THE
GREAT LAKES AND KEEP THE ASSOCIATED FRONTAL ZONE TO OUR NORTHWEST.
THOUGH FORCING OVER CENTRAL NC WILL BE WEAK ON THURSDAY...A WEAK
REMNANT SHEAR AXIS AMIDST PW OVER 1.5 INCHES AND 600 TO 1200 J/KG OF
MLCAPE...HIGHEST OVER THE WESTERN PIEDMONT...SHOULD LEAD TO
INCREASED...THOUGH STILL SCATTERED COVERAGE OF AFTERNOON
SHOWERS/STORMS.  SHEAR WILL BE WEAK WITH THE UPPER TROUGH AND
STRONGEST WESTERLIES WELL WEST OF THE MOUNTAINS...SO SEVERE STORMS
WILL BE LIMITED.

THE UPPER RIDGE THEN LOOKS TO BUILD BACK SLIGHTLY FRIDAY INTO THE
WEEKEND WITH A LITTLE DRIER AIR ACTUALLY FORECAST TO FILTER IN FROM
THE EAST ON FRIDAY.  THUS EXPECT MAINLY ISOLATED SHOWERS AND STORMS
FRIDAY AND SATURDAY AS THE AIRMASS SLOWLY RE-MOISTENS THROUGH THE
WEEKEND.  ANOTHER SHORTWAVE AND COLD FRONT ARE FORECAST TO MOVE INTO
THE MIDWEST STATES EARLY NEXT WEEK...AND WHILE IT IS UNCERTAIN
WHETHER THAT FRONT WILL MAKE IT ALL THE WAY INTO NC AS WELL...THE
CHANCES OF CONVECTION WILL INCREASE FROM NORTH TO SOUTH SUNDAY
THROUGH TUESDAY.

THICKNESSES ARE PROJECTED TO BE NEARLY UNCHANGED THROUGH THE
PERIOD...WITH HIGHS MOSTLY IN THE MID TO UPPER 80S NEARLY
EVERYDAY...WITH SOME AREAS IN THE SOUTH REACHING 90 ON SATURDAY.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AS OF 120 AM TUESDAY...

LOW-LEVEL MOISTURE RETURN ON THE WESTERN PERIPHERY OF THE DEEP LAYER
RIDGE CENTERED JUST OFF THE EASTERN SEABOARD WILL SUPPORT AREAS OF
STRATUS...ESPECIALLY ACROSS WESTERN PORTIONS OF THE STATE. CEILINGS
IN THE IFR OR LOW END MVFR IS EXPECTED AT KINT AND KGSO WITH POCKETS
OF LIFR CEILINGS POSSIBLE. THE LOW CEILINGS WILL PERSIST THROUGH THE
MID MORNING HOURS...LIFTING INTO THE LOW END OF THE VFR CATEGORY
AROUND EARLY AFTERNOON. PROBABILITIES OF SUB-VFR CEILINGS DEVELOPING
THROUGH THIS MORNING SHOULD DECREASE WEST TO EAST...WITH A PERIOD OF
SCATTERED TO BROKEN STRATUS BETWEEN 700-1200FT POSSIBLE AT KRDU. AT
KRWI AND KFAY...THE STRATUS IS EXPECTED TO REMAIN FEW TO SCATTERED.

A SHOWER OR THUNDERSTORM MAY THREATEN THE TRIAD TERMINALS LATE
TUESDAY AFTERNOON THROUGH TUESDAY EVENING BUT THIS PROBABILITY
APPEARS TOO LOW TO MENTION IN THE TERMINAL FORECAST AT THIS TIME.

WIDESPREAD MVFR/IFR CEILINGS EXPECTED EACH MORNING THROUGH THE
REMAINDER OF THE WORK WEEK AS SLY FLOW CONTINUES TO INCREASE OR
MAINTAIN LOW LEVEL MOISTURE OVER CENTRAL NC. THERE WILL BE A BETTER
CHANCE FOR AFTERNOON CONVECTION BOTH WEDNESDAY AND THURSDAY WITH THE
GREATEST CHANCES ON WEDNESDAY OVER THE PIEDMONT...AND AREAWIDE
THURSDAY.

THE HIGH PRESSURE SYSTEM WILL BEGIN TO BUILD BACK INTO THE CAROLINAS
FRIDAY INTO SATURDAY. THIS WILL BEGIN TO LIMIT THE CHANCES FOR
AFTERNOON CONVECTION ON FRIDAY AND MORE SO SATURDAY. THERE WILL
CONTINUE TO BE DECENT THREAT FOR EARLY MORNING MVFR/IFR CEILING AND
FOG FRIDAY AND SATURDAY MORNINGS.

&&

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

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...CBL
SHORT TERM...CBL
LONG TERM...BLS
AVIATION...CBL/WSS


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