-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 211727
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
127 PM EDT TUE MAY 21 2013

.SYNOPSIS...

AN UPPER LEVEL TROUGH WILL LINGER...BUT GRADUALLY WEAKEN OVER THE
CAROLINAS THROUGH WEDNESDAY. A COLD FRONT MOVES THROUGH THE REGION
THURSDAY...FOLLOWED BY COOL HIGH PRESSURE FOR MOST OF THE WEEKEND.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1027 AM TUESDAY...

AS OF 14Z OVERNIGHT SHOWER ACTIVITY WAS BEGINNING TO WIND DOWN AS A
MESO LOW CONTINUES TO PROGRESS SLOWLY OFF TO THE NORTHEAST. A VERY
MOIST ATMOSPHERE IS STILL PRESENT HOWEVER AS SURFACE DEWPOINTS
REMAIN IN THE UPPER 60S TO LOWER 70S ACROSS THE CWA. LOW STRATUS
STILL PRESENT ACROSS MUCH OF THE CWA BUT IS BEGINNING TO LIFT OUT AT
THIS TIME. AT LEAST MVFR CEILINGS ARE PROBABLE FOR THE NEXT SEVERAL
HOURS BUT WILL GRADUALLY SCATTER OUT HEADING INTO THE EARLY
AFTERNOON...ESPECIALLY IN THE WEST WHERE MORE CLEARING IS EXPECTED.
THIS AFTERNOON EXPECT MORE CONVECTIVE DIURNAL CUMULUS. THE BEST
MOISTURE TRANSPORT WILL BE IN THE EAST TODAY AND THERE IS A GREATER
CHANCE OF SHOWERS AND THUNDERSTORMS THERE. BACK TO THE WEST COVERAGE
SHOULD BE LESS THIS AFTERNOON BUT THERE IS A GREATER POTENTIAL FOR
STRONGER STORMS IN THE WEST WHERE INSTABILITY WILL BE HIGHER DUE TO
GREATER INSOLATION. SEVERE THREAT STILL REMAINS VERY LOW TODAY
DESPITE UPWARDS OF 2000 J/KG OF INSTABILITY THAT COULD BE REALIZED
IN THE WEST. EFFECTIVE SHEAR REMAINS NON EXISTENT AND LAPSE RATES
WILL BE WEAK THIS AFTERNOON IN THE 5-6 DEG/KM RANGE. HEAVY RAIN WILL
AGAIN BE THE MAIN THREAT WITH ANY SHOWERS OR STORMS THIS
AFTERNOON...ESPECIALLY THOSE AREAS THAT HAVE SEEN HEAVY RAINS OVER
THE PAST SEVERAL DAYS WHERE SMALLER CREEKS MAY BE HIGHER THAN
NORMAL. OTHERWISE SHOULD SEE LESS COVERAGE OVERALL COMPARED TO THE
LAST SEVERAL DAYS. WITH CLOUDS IN THE EAST EXPECT A MORE EVEN
TEMPERATURE DISTRIBUTION THIS AFTERNOON...MID 80S AT MOST LOCATIONS.

OVERNIGHT TONIGHT THE POTENTIAL REMAINS FOR MORE LOW CEILINGS AND
SUB-VFR VISIBILITIES. WITH DEWPOINTS REMAINING ELEVATED LOWS STILL
WILL ONLY GET DOWN INTO THE MIDDLE 60S IN MOST LOCATIONS.

&&

.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
AS OF 310 AM TUESDAY...

WEAK SHORTWAVE RIDGING OVER THE REGION WILL YIELD MOSTLY DRY AND
WARM WEATHER FOR ONE DAY (WED). HOWEVER...SUFFICIENT MOISTURE WILL
STILL BE IN PLACE OVER THE REGION...WITH PWAT VALUES HOVERING NEAR
1.5 INCHES OR SO. WIDELY SCATTERED AFTERNOON AND EVENING
THUNDERSTORMS CAN BE EXPECTED. HIGHS SHOULD BE IN THE MID/UPPER
80S... WITH OVERNIGHT LOWS IN THE MID/UPPER 60S.

&&

.LONG TERM /THURSDAY THROUGH MONDAY/...
AS OF 300 AM TUESDAY...

UPPER LEVEL TROUGH WILL MOVE EASTWARD FROM THE MIDWEST ON
THURSDAY...WHICH WILL PUT THE AREA IN DEEP SOUTH TO SOUTHWESTERLY
FLOW DURING THE DAY. WITH MOISTURE IN PLACE AND SUFFICIENT
INSTABILITY... WITH MLCAPE VALUES OF 500 TO 1000 J/KG...
THUNDERSTORMS WILL DEVELOP DURING THE DAY. BULK SHEAR VALUES NEAR 25
KTS WILL SUPPORT THE DEVELOPMENT OF SOME MULTICELL CLUSTERS... AND
FEW STRONGER STORMS WITH GUSTY WINDS ARE POSSIBLE. NO WIDESPREAD
SEVERE WEATHER IS EXPECTED... AS THE BEST UPPER LEVEL FORCING
REMAINS NORTH OF THE AREA. HIGHS IN THE LOW TO MID 80S... LOWS IN
THE MID 60S.

THE ASSOCIATED COLD FRONT WILL PROGRESS INTO WESTERN NORTH CAROLINA
THURSDAY EVENING... REACHING THE COAST BY ABOUT 12Z FRIDAY. MIDLEVEL
DRYING WILL SPREAD ACROSS THE AREA FRIDAY... ENDING PRECIPITATION
AND DECREASING CLOUD COVER THROUGH THE DAY FROM WEST TO EAST. COLD
ADVECTION WILL TEMPER HIGHS... WHICH WILL BE IN THE MID 70S TO LOW
80S. COOLER LOWS IN THE MID 50S.

THE TROUGH MOVES OFF THE COAST EARLY SATURDAY... WITH AN UPPER LEVEL
RIDGE ACROSS THE MIDDLE OF THE COUNTRY AND THE SURFACE HIGH
POSITIONED WEST OF THE AREA... PUTTING THE REGION IN A NORTHWEST
FLOW REGIME THROUGH THE WEEKEND... AND KEEPING TEMPERATURES
SEVERAL DEGREES BELOW NORMAL THROUGH MONDAY... WITH HIGHS IN THE
UPPER 70S TO NEAR 80.. AND LOWS IN THE MID TO UPPER 50S.

&&

.AVIATION /18Z TUESDAY THROUGH SATURDAY/...
-- Changed Discussion --
AS OF 115 PM TUESDAY...

24 HOUR TAF PERIOD:

SHOWERS AND THUNDERSTORMS BEGINNING TO POP UP THIS AFTERNOON ALONG A
BOUNDARY FROM LOUISBURG TO FAYETTEVILLE. THIS BOUNDARY AND
ASSOCIATED SHOWERS AND THUNDERSTORMS WILL SLOWLY MOVE EAST THIS
AFTERNOON. KRWI AND KFAY ARE THE TWO TERMINALS MOST AT RISK FOR
THUNDERSTORM ACTIVITY THIS AFTERNOON. WINDS WILL CONTINUE TO BE
SOUTH SOUTHWESTERLY AT 5-10 KNOTS AND SHOULD STAY THAT WAY THROUGH
THIS EVENING. OVERNIGHT EXPECT IFR/LIFR CEILINGS ONCE AGAIN AND MVFR
VISIBILITIES. THESE WILL BE QUICKER TO DEVELOP IN THE EAST...SOME
TIME AFTER 4Z AND WILL HOLD OFF TILL AFTER 6Z IN THE WEST. ONCE
CONDITIONS DETERIORATE THEY WILL MOST LIKELY REMAIN SUB-VFR THROUGH
SUNRISE. AFTER SUNRISE EXPECT A DRIER DAY TOMORROW WITH VFR CEILINGS
PREDOMINATE. WINDS WILL BE A BIT GUSTIER WEDNESDAY AFTERNOON...10
SUSTAINED GUSTING TO 15-20 KNOTS. SOME DIURNAL CONVECTION IS AGAIN
POSSIBLE WEDNESDAY BUT COVERAGE IS NOT EXPECTED TO BE AS LARGE.

LONG TERM: SUB VFR CONDITIONS ARE POSSIBLE AGAIN WEDNESDAY AND
THURSDAY AS SHOWERS AND THUNDERSTORMS WILL CONTINUE OUT AHEAD OF AN
APPROACHING FRONTAL SYSTEM THAT WILL MOVE THROUGH THE AREA LATE
THURSDAY INTO EARLY FRIDAY. VFR CONDITIONS SHOULD RETURN FOR FRIDAY.
-- End Changed Discussion --


&&

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

&&

$$

SYNOPSIS...DJF
NEAR TERM...ELLIS
SHORT TERM...BADGETT
LONG TERM...SEC
AVIATION...ELLIS