Area Forecast Discussion
Issued by NWS Raleigh/Durham, NC

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FXUS62 KRAH 192349
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
749 PM EDT TUE MAY 19 2015

.SYNOPSIS...A COLD FRONT WILL MOVE ACROSS CENTRAL NORTH CAROLINA
TONIGHT...AND THEN STALL OVER SOUTH CAROLINA ON WEDNESDAY.  THE
FRONT WILL THEN RETREAT NORTH IN ADVANCE OF AN AREA OF LOW PRESSURE
THAT WILL CROSS THE CAROLINAS ON THURSDAY.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 225 PM TUESDAY...

SCATTERED SHOWERS AND ISOLD TSTMS HAVE BROKEN OUT ACROSS PARTS OF
CENTRAL NC AS EXPECTED...WITH ACTIVITY EXPECTED TO CONTINUE TO
EXPAND AND MOVE EAST THROUGH THE REMAINDER OF THE AFTERNOON. LATEST
MESOANALYSIS STILL SHOWS THE BEST MOISTURE AND INSTABILITY LOCATED
ACROSS OUR EASTERN ZONES...AND SUGGESTS THAT SHOWER/TSTM COVERAGE
SHOULD INCREASE AS THEY EVOLVE EASTWARD LATER THIS AFTERNOON.
ANOTHER NOTABLE FEATURE IS A MID LEVEL VORT CURRENTLY MOVING E
ACROSS NE SC. THIS FEATURE MAY AID THE DEVELOPMENT AND MAINTENANCE
OF SHOWER/TSTM ACTIVITY ACROSS OUR SE ZONES AS IT MOVES EAST THE
REST OF THIS AFTERNOON. OTHERWISE...GIVEN WEAK MID-LEVEL LAPSE RATES
AND WEAK SHEAR...CELL INTENSITY SHOULD BE LIMITED...BUT STILL
CAPABLE OF PRODUCING BRIEF INTENSE DOWNPOURS GIVEN THE ABUNDANT
MOISTURE AND ABOVE-CLIMO PWAT VALUES IN PLACE ACROSS THE AREA.
SHOWER/TSTM ACTIVITY IS THEN EXPECTED TO DIMINISH AND MOVE EAST
TOWARD THE COAST LATER THIS EVENING.

OVERNIGHT...THE COLD FRONT WHICH IS CURRENTLY EXTENDING FROM
PITTSBURGH TO NASHVILLE TO MEMPHIS WILL MOVE S AND E AND ACROSS OUR
CWA. LATEST HRRR SUGGESTS AN ISOLD SHOWER CAN`T BE RULED OUT WITH
PASSAGE OF THE FRONT...BUT MOST PLACES WILL REMAIN DRY AS THE FRONT
MOVES ACROSS. MORE LIKELY WILL BE THE FORMATION OF SOME FOG...ESP
ACROSS AREAS THAT RECEIVE HEAVIER RAINFALL THIS AFTERNOON AND
EVENING. LOW TEMPS WILL BE COOLEST ACROSS THE NW (AROUND 60) WHERE
THE FRONT WILL MOVE THROUGH EARLIER IN THE NIGHT...VERSUS OUR SE
ZONES WHERE THE FROPA WILL OCCUR LATER IN THE NIGHT AND THUS HAVE
LOW IN THE MID TO UPPER 60S.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 225 PM TUESDAY...

THE COLD FRONT WILL STALL TO OUR SOUTH ACROSS SC ON WEDNESDAY. THIS
WILL ALLOW DRIER AND SLIGHTLY COOLER AIR TO MOVE INTO OUR AREA FROM
THE NW. AS SUCH...LOOK FOR FAIR WEATHER WITH HIGHS FROM THE MID 80S
NORTH TO UPPER 80S SOUTH.

WEDNESDAY NIGHT...A SHORT WAVE OVER THE MISS VALLEY WILL MOVE EAST
AND INDUCE A LOW PRESSURE WAVE ALONG THE OLD BOUNDARY TO OUR SOUTH.
THERE ARE STILL MODEL DIFFERENCES REGARDING WHERE (PARTICULARLY HOW
FAR NORTH) THAT WAVE WILL SET UP...BUT EITHER WAY IT APPEARS THAT A
FEW SHOWERS WILL BE POSSIBLE ACROSS OUR PIEDMONT ZONES LATER
OVERNIGHT. LOWS WILL RANGE FROM AROUND 60 NW TO MID 60S SE.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
AS OF 315 PM TUESDAY...

THURSDAY TROUGH FRIDAY NIGHT: A QUICK MOVING S/W DISTURBANCE IS
EXPECTED TO MOVE FROM THE PLAINS TO OFF THE MID-ATLANTIC/NORTHEAST
U.S. COAST BY FRIDAY MORNING... SPREADING SHOWERS AND SOME STORMS
ACROSS CENTRAL ON THURSDAY. WHILE THE DISTURBANCE WILL TRACK JUST TO
OUR NORTH...AN AREA OF LOW PRESSURE IN RESPONSE WILL DEVELOP/DEEPEN
ALONG THE OLD FRONTAL ZONE NEAR THE NC/SC BORDER... THEN LIFT NORTH
AND EASTWARD ON THURSDAY NIGHT INTO FRIDAY. THIS SHOULD BRING A WIDE
RANGE IN TEMPS ACROSS CENTRAL NC ON THURSDAY... WITH THE POTENTIAL
FOR SOME ROTATING STORMS NEAR THE BOUNDARY... AS DEEP LAYER SHEAR IS
EXPECTED TO INCREASE TO 30 TO 35 KTS WITH A BACKED SURFACE FLOW AS
THE SURFACE APPROACHES. HOWEVER... WITH THE POSSIBILITY OF ON GOING
SHOWERS AND WIDESPREAD CLOUD COVER THERE IS QUITE A BIT OF
UNCERTAINTY WRT HOW MUCH DESTABILIZATION WE WILL SEE IN THE
DEVELOPING WARM SECTOR. THUS...SPC HAS PLACED SOUTHEASTERN/EASTERN
PORTIONS OF CENTRAL NC IN A MARGINAL RISK FOR SEVERE STORMS. FOR NOW
WILL CONTINUE TO MENTION A THREAT FOR ISOLATED SEVERE STORMS ACROSS
OUR SE/E COUNTIES IN THE HWO FOR THURSDAY. WILL GO WITH HIGHS TEMPS
ON THURSDAY RANGING FROM THE UPPER 60S/NEAR 70 (MAYBE NOT COOL
ENOUGH EVEN) NEAR THE NC/VA BORDER TO LOWER TO MID 80S
SOUTH/SOUTHEAST.

THE PRIMARY SURFACE LOW IS EXPECTED TO LIFT OFF TO THE NORTHEAST
LATE THURSDAY NIGHT INTO FRIDAY... BRINGING A RETURN TO DRY AND
QUIET WEATHER... WITH CLEARING/SUNNY SKIES BY FRIDAY AFTERNOON
ONWARD AS SURFACE HIGH PRESSURE BUILDS INTO THE AREA FROM THE
NORTHWEST. EXPECT HIGHS ON FRIDAY WILL BE IN THE UPPER 70S TO LOWER
80S. LOWS FRIDAY MORNING WILL BE DEPENDENT ON THE AMOUNT OF CLEARING
AND ANY LINGERING COOL STABLE AIRMASS. FOR NOW WILL GO WITH LOWS
RANGING FROM THE 50S NORTH TO THE MID 60S SE. LOWS SATURDAY... WITH
SURFACE HIGH PRESSURE TO THE NORTH OF THE REGION... ARE EXPECTED TO
BE IN THE MID TO UPPER 50S.

SATURDAY THROUGH TUESDAY: SURFACE HIGH PRESSURE WILL MOVE ACROSS THE
REGION THIS WEEKEND AND OFFSHORE EARLY NEXT WEEK AS MID LEVEL
RIDGING BEGINS TO BUILD AGAIN. THIS WILL YIELD A WARMING TREND EACH
DAY FROM HIGHS IN THE UPPER 70S TO LOWER 80S ON SATURDAY TO THE
UPPER 80S TO LOWER 90S ON TUESDAY. LOWS WILL FOLLOW A SIMILAR
TREND... 50S THIS WEEKEND TO THE MID TO UPPER 60S BY TUESDAY
MORNING. DRY CONDITIONS ARE GENERALLY EXPECTED FOR THIS PERIOD...
WITH INCREASING CHANCES OF AT LEAST SOME ISOLATED OR WIDELY
SCATTERED SHOWERS AND STORMS BY TUESDAY AFTERNOON (BEST CHANCE
NORTHWEST) AS LOW LEVEL MOISTURE INCREASES IN RETURN FLOW.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AS OF 745 PM TUESDAY...

SHOWER AND THUNDERSTORM ACTIVITY WILL CONTINUE TO DIMINISH AS THE
ACTIVITY MOVES EAST. THERE COULD BE A FEW ISOLATED SHOWERS THROUGH
THE FIRST HALF OF THE OVERNIGHT HOURS AS A FRONT CROSSES THE AREA.
HOWEVER...CONFIDENCE IS NOT HIGH OF THIS OCCURRENCE AND REGARDLESS
COVERAGE WOULD BE TOO MINIMAL TO INCLUDE IN THE TAFS NOW. THERE
COULD BE SOME PATCHY FOG OVERNIGHT MAINLY ACROSS THE EAST WHERE THE
DRIER AIR WILL BE LAST TO ARRIVE...AND ESPECIALLY WHERE THE RAIN
OCCURRED (KRDU/KFAY/KRWI). HOWEVER...CONFIDENCE IS STILL TOO LOW TO
INCLUDE IN THE TAFS. THEN...WITH DRIER AIR FILTERING INTO THE AREA
BEHIND THE FRONT...VFR CONDITIONS WILL PERSIST FOR THE REMAINDER OF
THE CURRENT TAF PERIOD.

OUTLOOK: AN AREA OF LOW PRESSURE WILL TRACK ACROSS THE CAROLINAS AND
RESULT IN A CHANCE OF SUB-VFR CEILINGS AND RAIN LATE WED NIGHT AND
EARLY THU...FOLLOWED BY SHOWERS AND STORMS THU AFTERNOON.

&&

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

&&

$$

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


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