Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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000
FXUS62 KRAH 051922
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
325 PM EDT SUN JUL 5 2015

.SYNOPSIS... A SURFACE FRONT WILL REMAIN QUASI-STATIONARY NEAR THE
VA AND NC BORDER TODAY...AHEAD OF AN UPPER LEVEL TROUGH AND
ACCOMPANYING AREA OF SURFACE LOW PRESSURE THAT WILL DRIFT INTO THE
CENTRAL APPALACHIANS THROUGH THIS EVENING. THE FRONT WILL RETREAT
NORTHWARD WITH THE MIGRATION OF THE SURFACE LOW THROUGH THE MIDDLE
ATLANTIC STATES ON MON.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 255 PM SUNDAY...

EXPECT TO SEE AN INCREASE IN CONVECTION ACROSS MOST OF CENTRAL NC
THROUGH 6 PM AS ATMOSPHERE HAS BECOME SLIGHT TO MODERATELY UNSTABLE
WITH SFC BASED CAPE VALUES AROUND 3000 J/KG OVER SECTIONS OF THE
COASTAL PLAIN AND NORTHERN PIEDMONT. LOW LEVEL MOISTURE POOLING
ALONG A STALLED SFC BOUNDARY DRAPED WEST-TO-EAST NEAR THE VA BORDER.
IN ADDITION...NOTED SOME SPEED CONVERGENCE OVER OUR SOUTHERN
PIEDMONT AS A 925-850MB TROUGH APPROACHES FROM THE SW. THIS TROUGH A
LIKELY REFLECTION OF A SHEAR AXIS LIFTING SLOWLY N-NE WITH A CLOSED
UPPER LEVEL LOW WHICH IS EXITING MID TN INTO EASTERN KY AT MID
AFTERNOON. STARTING TO SEE LOW LEVEL LAPSE RATES NEAR 9 DEG C/KM
OVER THE SOUTHERN COUNTIES AND D-CAPE VALUES APPROACHING A 1K J/KG
IN VICINITY OR EAST OF I-95. THUS...THE STRONGER STORMS WILL BE
CAPABLE OF WIND GUSTS 35-45KTS WITH ISOLATED GUSTS AROUND 50KTS
POSSIBLE.

CONVECTION SHOULD BEGIN TO WANE/DIMINISH AFTER 9 PM THOUGH COULD SEE
A FEW SHOWERS/ISOLATED STORM PERSIST PAST MIDNIGHT...ESPECIALLY
ACROSS THE WEST AND NORTH SECTIONS IN CLOSER PROXIMITY TO BETTER
UPPER LEVEL SUPPORT. PARTIAL CLEARING ONCE THE CONVECTION DISSIPATES
WILL EVENTUALLY ALLOW A LOW STRATUS LAYER TO DEVELOP IN AREAS PRIOR
TO DAYBREAK. THUS EARLY MONDAY MAY START OUT BROKEN-OVERCAST SKIES
FOR MOST FOLKS. MIN TEMPS 68-73.

&&

.SHORT TERM /MONDAY AND MONDAY NIGHT/...
AS OF 325 PM SUNDAY...

A 850-700MB TROUGH WILL SLOWLY DRIFT EASTWARD ACROSS THE REGION.
WITH HEATING OF THE MOIST ATMOSPHERE...SCATTERED CONVECTION SHOULD
DEVELOP OVER MOST OF CENTRAL NC THOUGH COVERAGE SHOULD BE ENHANCED
OVER THE EASTERN PIEDMONT AND COASTAL PLAIN IN VICINITY OF THE LOW
LEVEL TROUGH. EFFECTIVE BULK SHEAR RELATIVELY WEAK AND AVAILABLE
INSTABILITY ALSO WEAK SO SEVERE THREAT APPEARS MINIMAL AT THIS TIME.

HIGH TEMPS DEPENDENT UPON EXTENT/DURATION OF LOW CLOUDS IN THE
MORNING...AND WHEN/EXTENT OF CONVECTION IN THE AFTERNOON. FAVOR MAX
TEMPS NEAR OR SLIGHTLY LOWER THAN MOS CONSENSUS (UPPER 80S FAR NORTH-
NW TO NEAR 90-LOWER 90S SOUTH).

MAJORITY OF CONVECTION WILL AGAIN DIMINISH/DISSIPATE WITHIN AN HOUR
OR TWO OF SUNSET. WITH BEST UPPER LEVEL SUPPORT LIFTING AWAY FROM
OUR REGION...DO NOT EXPECT ANY ISOLATED SHOWER DEVELOPMENT DURING
THE LATE NIGHT HOURS. MIN TEMPS 67-73.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
AS OF 230 PM SUNDAY...

THE SUBTROPICAL RIDGE WILL DEVELOP AND AMPLIFY OVER THE SOUTHEAST
THROUGH THE PERIOD...WITH LARGER SCALE SYNOPTIC FEATURES...INCLUDING
FRONTS...REMAINING TO OUR NORTH. TEMPS THROUGH THE PERIOD WILL RUN
ABOVE NORMAL...WITH HIGHS IN THE LOW-MID 90S AND LOWS IN THE LOW-MID
70S. THE LATEST GFS AND THE 00Z EURO GUIDANCE BOTH SUGGEST TEMPS MAY
TRY TO CLIMB INTO THE UPPER 90S LATER IN THE WEEK...AND THIS MAKE
SENSE GIVEN THE AMPLIFICATION OF THE RIDGE OVER THE SOUTHEAST DURING
THAT TIME. AS SUCH...WILL LIKELY NEED TO RAMP UP ADVERTISING HEAT
IMPACTS AND SAFETY ONCE AGAIN AS WE HEAD THROUGH THE WEEK. AS FOR
PRECIP CHANCES...THE BEST CHANCE FOR ANY WIDELY SCATTERED MAINLY-
DIURNAL SHOWER/TSTM ACTIVITY WILL BE TUE/WED BEFORE THE RIDGE
BECOMES WELL-ESTABLISHED...AND LATE IN THE WEEKEND AS THE RIDGE
BEGINS TO SHIFT WEST AND WEAKEN OVER THE SOUTHEAST. OVERALL...PRECIP
CHANCES AT OR BELOW CLIMO DURING THE PERIOD.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
AS OF 130 PM SUNDAY...

A MODERATELY UNSTABLE AND MOIST AIR MASS ALONG WITH THE APPROACH AND
CROSSING OVERHEAD OF A FEW DISTURBANCES ALOFT WILL RESULT IN
SCATTERED SHOWERS AND THUNDERSTORMS ACROSS CENTRAL NC THIS AFTERNOON
AND THIS EVENING. THIS SCATTERED CONVECTION MAY AFFECT OPERATIONS AT
ANY OF THE TAF SITES THROUGH 01Z. EXPECT MVFR CONDITIONS IN VICINITY
OF THE SHOWERS AND STORMS ALONG WITH GUSTY SFC WINDS 25-35KTS.

AFTER 01Z...SHOULD SEE A DECREASE IN CONVECTIVE COVERAGE.
OVERNIGHT...AND MAINLY AFTER 08Z...COULD SEE AREAS OF LOW STRATUS
DEVELOP AND POSSIBLY BECOMING WIDESPREAD AFTER 10Z. CONFIDENCE ABOUT
50/50 SO HAVE MENTIONED A TEMPO GROUP FOR CEILINGS. IF GUIDANCE OR
SATELLITE IMAGERY POINTS TOWARD ITS OCCURRENCE...THEN A PREDOMINATE
GROUP MAY BE NECESSARY.

THE WEATHER PATTERN WILL REMAIN UNSETTLED MONDAY AND POSSIBLY INTO
TUESDAY AS A WEAK UPPER LEVEL LOW DRIFTS THROUGH THE CENTRAL
APPALACHIANS AND MID ATLANTIC. THIS SHOULD CONTINUE A THREAT FOR
SCATTERED CONVECTION MONDAY AFTERNOON...AND A LITTLE LESS OF A
CHANCE ON TUESDAY. THERE WILL ALSO BE A CHANCE FOR EARLY MORNING
STRATUS.

THROUGH THE REMAINDER OF THE WORK WEEK...AN AREA OF HIGH PRESSURE
WILL BE STRENGTHENING OVER THE SOUTHERN PLAINS/LOWER MS VALLEY AND
EXPAND EAST TOWARD OUR REGION. THIS WEATHER FEATURE MAY LIMIT
AFTERNOON CONVECTIVE DEVELOPMENT TO NO MORE THAN 20 TO 30 PERCENT.

&&

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

&&

$$

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


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