Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 260017
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
816 PM EDT TUE AUG 25 2015

.SYNOPSIS...A STALLED FRONT WILL PERSIST IN VICINITY OF THE CAROLINA
COAST THROUGH THE DURATION OF THE WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 100 PM TUESDAY...

CYCLONIC FLOW ALOFT WILL PREVAIL OVER THE MID-ATLANTIC AND CAROLINAS
THROUGH TONIGHT...EQUATORWARD OF AN UNSEASONABLY STRONG UPPER LEVEL
LOW STALLED ALONG THE NORTHERN PERIPHERY OF THE GREAT LAKES IN
SOUTHERN ONTARIO. A COLD FRONT PROGRESSING INTO THE COASTAL PLAIN
THIS MORNING WILL STALL IN VICINITY OF THE CAROLINA/SOUTHEAST COAST
THIS AFTERNOON INTO TONIGHT. PRECISELY WHERE THE FRONT WILL BE
LOCATED THIS EVE/TONIGHT REMAINS DIFFICULT TO ASCERTAIN GIVEN THAT A
WEAK WAVE OF LOW PRESSURE WILL DEVELOP ALONG THE BOUNDARY AS IT
APPROACHES STALLED SHORTWAVE ENERGY ALONG THE SOUTHEAST
COAST...AMIDST WEAK SYNOPTIC HEIGHT FALLS /STRENGTHENING CYCLONIC
FLOW ALOFT/. ADDITIONALLY...CONVECTION /OUTFLOW/ AND DIFFERENTIAL
HEATING THIS AFTERNOON MAY ALSO INFLUENCE THE POSITION OF THE FRONT.
GIVEN THE LATEST OBSERVATIONAL DATA...EXPECT DRY CONDITIONS
ALONG/WEST OF HWY 1 (TRIANGLE WESTWARD)...WITH A POTENTIAL FOR
ISOLD/SCT CONVECTION TO THE EAST...PRIMARILY IN THE SOUTHEAST
COASTAL PLAIN. EXPECT COOLER HIGHS IN THE MID TO UPPER 80S DEPENDING
ON CLOUD COVER AND CONVECTION/OUTFLOW. A DIURNAL WANE IN CONVECTIVE
COVERAGE IS EXPECTED AFTER SUNSET...THOUGH SOME POTENTIAL FOR ISOLD
CONVECTION WILL PERSIST OVERNIGHT IN VICINITY OF THE STALLED FRONTAL
ZONE/WEAK SURFACE LOW...PRIMARILY IN THE SOUTHEAST COASTAL PLAIN.
LOWS RANGING FROM THE LOWER 60S IN THE N/NW PIEDMONT TO THE UPPER
60S /NEAR 70F/ IN THE FAR SE COASTAL PLAIN. -VINCENT

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 100 PM TUESDAY...

LITTLE CHANGE IN THE OVERALL PATTERN IS EXPECTED ON WED...WITH THE
UNSEASONABLY STRONG UPPER LEVEL LOW STALLED NORTH OF THE GREAT
LAKES...CYCLONIC FLOW ALOFT ALONG THE EASTERN SEABOARD...AND A
STALLED FRONTAL ZONE IN VICINITY OF THE CAROLINA/SOUTHEAST COAST. AS
A RESULT...EXPECT CONDITIONS ON WED TO BE SIMILAR TO TODAY...WITH
THE BEST POTENTIAL FOR CONVECTION IN COASTAL/FAR-EASTERN NORTH
CAROLINA. WILL KEEP PRECIP CHANCES GENERALLY CONFINED TO THE FAR SE
COASTAL PLAIN COUNTIES (I.E. CUMBERLAND/SAMPSON/WAYNE). ADDITIONAL
SHORTWAVE ENERGY DIGGING SOUTHEAST ALONG THE WESTERN PERIPHERY OF
THE STALLED UPPER LOW IS PROGGED TO PROGRESS INTO THE CENTRAL
APPALACHIANS LATE WED NIGHT...AND IT IS POSSIBLE THAT THE FRONTAL
ZONE SHIFTS FURTHER INLAND (ALONG WITH A POTENTIAL FOR PRECIP) AFTER
MIDNIGHT AS LOW-LEVEL WIND/HEIGHT FIELDS RESPOND TO THE APPROACHING
SHORTWAVE. FORECAST CONFIDENCE REMAINS LOW WITH REGARD TO THE
EVOLUTION/TIMING OF THE APPROACHING WAVE...THE STALLED FRONTAL
ZONE...AND WHETHER AN INLAND SHIFT IN PRECIPITATION WILL OCCUR (AS
THE GFS SUGGESTS) OR PRECIPITATION REMAINS ALONG THE COAST (AS THE
NAM SUGGESTS). -VINCENT

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 115 PM TUESDAY...

FRONTAL ZONE REMAINS PINNED ALONG THE NC COAST AS MILD HIGH PRESSURE
BUILDS ACROSS THE GREAT LAKES AND SOUTH DOWN THE EASTERN SPINE OF
THE APPALACHIANS INTO THE WEEKEND. MEANWHILE...ALOFT...THE FRONTAL
ZONE LIES BETWEEN A WEAK UPPER TROF OVER THE ATLANTIC COAST AND
STRONGER OFFSHORE RIDGE WHICH WILL BEGIN TO RETROGRADE INTO THE
SOUTHEAST ATLANTIC COAST...PROVIDING ADDITIONAL MOISTURE AS WELL AS
NUDGING THE FRONT SLOWLY INLAND. WILL KEEP THE CHANCE OF RAIN ONLY
MARGINALLY ABOVE CLIMATOLOGICAL...~30%...AND FOCUSED PRIMARILY ON
THE SOUTHEAST THROUGH SATURDAY. CLOUDINESS WILL BECOME MORE
PREVALENT ON SATURDAY AS OVERRUNNING EASTERLY FLOW SETS UP...WHICH
COULD LEAD TO INCREASING POPS AS THE WEEKEND APPROACHES. HIGHS EACH
DAY WILL BE PRETTY NEAR CLIMATOLOGICAL...POTENTIALLY COOLER ON
SATURDAY...POSSIBLY SUNDAY AS WELL...IF THE DAMMING AND PRECIP
SCENARIO MATERIALIZES.

UNCERTAINTY INCREASES BY EARLY NEXT WEEK AS WE WILL POTENTIALLY BE
SUBJECT TO THE INFLUENCE OF TS ERIKA. WE WILL BE IN THE WEAK TROF
AREA BETWEEN AN AMPLIFYING RIDGE IN THE MIDWEST AND THE STRONGER AND
STILL RETROGRADING SUBTROPICAL RIDGE OVER THE SOUTHWEST
ATLANTIC...WHICH SHOULD BE THE DETERMINING STEERING MECHANISM FOR
ERIKA OR HER REMAINS. REGARDLESS...HEIGHTS WILL INCREASE EARLY NEXT
WEEK AND SHOULD SEE AN UPTICK IN TEMPS...UPPER 80S TO LOWER 90S
MONDAY AND TUESDAY...WITH AT LEAST WIDELY SCATTERED DIURNAL
CONVECTION IN THE MOIST AIRMASS. STAY TUNED.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 815 PM TUESDAY...

24 HOUR TAF PERIOD: VFR CONDITIONS ARE EXPECTED TO CONTINUE THIS
EVENING... OUTSIDE OF ISOLATED TO WIDELY SCATTERED SHOWERS AND
STORMS (MAINLY ACROSS EASTERN AND SOUTHERN SECTIONS OF CENTRAL NC...
KFAY/KRWI). HOWEVER... WITH A STALLED COLD FRONT LOCATED ACROSS THE
EASTERN HALF OF THE AREA AND GENERALLY A TROUGH OF LOW PRESSURE
ALOFT ACROSS THE EASTERN HALF OF THE COUNTRY... WE WILL HAVE AT
LEAST A SLIGHT CHANCE OF SEEING SOME SHOWERS OVERNIGHT. IN
ADDITION... MVFR/IFR CEILINGS MAY DEVELOP DURING THE PRE-DAWN
HOURS/NEAR SUNRISE WEDNESDAY MORNING AT THE KFAY/KRWI TERMINALS
(POSSIBLY EVEN KRDU)... PARTICULARLY THE KFAY TERMINAL IN CLOSER
VICINITY TO THE STALLED FRONTAL ZONE. FURTHER WEST AT THE KINT/KGSO
TERMINALS...VFR CONDITIONS AND A LIGHT NORTHERLY WIND ARE EXPECTED
TO PREVAIL THROUGH THE TAF PERIOD. WHERE STRATUS DOES DEVELOP...
EXPECT IT WILL SLOWLY LIFT ON WEDNESDAY MORNING... WITH GENERALLY
VFR CONDITIONS BY MID AFTERNOON OUTSIDE OF ANY ISOLATED TO WIDELY
SCATTERED CONVECTION (MAINLY ACROSS THE EASTERN HALF OF THE AREA
AGAIN... THOUGH TOO LOW TO INCLUDE IN THE TAFS AT THIS TIME).

LOOKING AHEAD: A POTENTIAL FOR CONVECTION AND LOW CEILINGS WILL
PERSIST AT FAY/RWI (PARTICULARLY FAY) THROUGH THE REMAINDER OF THE
WEEK AS A WEAK WAVE OF LOW PRESSURE DEVELOPS AND PERSISTS ALONG THE
STALLED FRONT IN VICINITY OF THE SOUTHEAST COAST.

&&

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

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...MLM
AVIATION...BSD/VINCENT


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