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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS62 KRAH 141851
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
250 PM EDT FRI JUN 14 2013

.SYNOPSIS...
HIGH PRESSURE WILL BUILD INTO THE REGION FROM THE NORTH TODAY AND
TONIGHT. THE HIGH PRESSURE WILL SHIFT OFFSHORE SUNDAY ALLOWING A
MOIST SOUTHERLY FLOW TO RETURN.

&&

.NEAR TERM /TODAY AND TONIGHT/...
AS OF 1045 AM FRIDAY...

THE MORNING UPPER AIR ANALYSIS SHOWS AN UNSEASONABLY SHARP TROUGH
SWINGING THROUGH THE MID ATLANTIC AND CAROLINAS WITH A MUCH DRIER
AND MORE STABLE AIR MASS MOVING INTO THE REGION. AT THE SURFACE A
COLD FRONT JUST OFF THE CAROLINA COAST CONTINUES TO PUSH AWAY FROM
THE REGION WHILE HIGH PRESSURE CENTERED OVER NORTHERN LAKE SUPERIOR
RIDGES SOUTH INTO THE MISSISSIPPI AND OHIO VALLEYS.

A COOL NORTHERLY SURFACE WIND AND DEW POINTS IN THE LOWER TO MID 50S
WILL RESULT IN MUCH MORE PLEASANT DAY TODAY COMPARED TO TEMPERATURES
IN THE MID TO UPPER 90S AND DEWPOINTS WELL INTO THE 60S ON THURSDAY.
FAIR WEATHER IS EXPECTED TODAY ALTHOUGH A STRONG MID LEVEL IMPULSE
IN THE NW FLOW ALOFT WILL BE MOVING ACROSS THE EASTERN HALF OF THE
CWA THIS AFTERNOON. MOISTURE WITH THIS SYSTEM IS MEAGER AND
GENERALLY CONFINED TO THE 850 TO 650 MB LAYER WITH A SMALL CAPPING
INVERSION PRESENT JUST BELOW 600 MB. THE RESULT SHOULD BE AN
ENHANCED CUMULUS FIELD ACROSS THE EASTERN PIEDMONT AND COASTAL PLAIN
THIS AFTERNOON. A HANDFUL OF NMM BASED CONVECTION ALLOWING MODELS
ALONG WITH THEIR COUSIN THE OPERATIONAL NAM GENERATE SOME ISOLATED
SHOWERS THIS AFTERNOON IN THE EAST. WILL OPT TO KEEP THE FORECAST
DRY WITH POPS BELOW 10 PERCENT ALTHOUGH A BRIEF SPRINKLE IS NOT OUT
OF THE REALM OF POSSIBILITIES.

HIGH TEMPERATURES SHOULD RANGE BETWEEN 79 DEGREES IN THE NORTHERN
COASTAL PLAIN TO THE 85 IN THE SOUTHERN PIEDMONT WITH LOWER 80S IN
MOST OTHER LOCATIONS. FAIR WEATHER WITH PARTLY TO MOSTLY CLEAR SKIES
ARE EXPECTED TONIGHT WITH LOWS IN THE UPPER 50S TO LOWER 60S.
-BLAES
&&

.SHORT TERM /SATURDAY AND SATURDAY NIGHT/...
AS OF 315 AM FRIDAY...

THE UPPER LEVEL TROUGH CENTERED IN VICINITY OF THE EASTERN SEABOARD
TONIGHT WILL MOVE OFFSHORE SAT MORNING...WITH RISING HEIGHTS ALOFT
AND SUBSIDENCE IN ITS WAKE ACROSS CENTRAL NC. FCST SOUNDINGS
INDICATE A STRONG MID-LEVEL SUBSIDENCE INVERSION...VERY DRY AIR
ALOFT...AND A CONTINUED DRY BOUNDARY LAYER WITH NO POTENTIAL FOR
DIURNAL DESTABILIZATION. EXPECT CLEAR SKIES AND DRY CONDITIONS.
HIGHS SAT SHOULD BE SEVERAL DEGREES WARMER THAN TODAY WITH RISING
HEIGHTS AND INCREASING WSW LOW-LEVEL FLOW...IN THE MID TO UPPER
80S...WARMEST SOUTH. LOWS SAT NIGHT WILL ACCORDINGLY BE SEVERAL
DEGREES WARMER...IN THE MID 60S. -VINCENT

&&

.LONG TERM /SUNDAY THROUGH FRIDAY/...
-- Changed Discussion --
AS OF 250 PM FRIDAY...

A BROAD UPPER TROUGH OVER THE EASTERN TWO-THIRDS OF THE NATION WILL
GRADUALLY AMPLIFY THIS PERIOD AS AN UPPER RIDGE BUILDS OVER THE
SOUTHERN PLAINS INTO THE ROCKIES. A SERIES OF S/WS IN THE DEVELOPING
W-NW FLOW ALOFT WILL BRING A THREAT FOR SHOWERS AND T-STORMS TO THE
REGION EARLY NEXT AND AGAIN LATE IN THE WEEK. THE MAIN WEATHER
HEADLINE FOR NEXT WEEK WILL BE THE GOOD PROBABILITY OF MAX TEMPS 4-7
DEGREES BELOW NORMAL FOR THE THIRD WEEK IN JUNE. THE UPPER LEVEL JET
FORECAST TO BE FARTHER SOUTH THAN NORMAL FOR THIS TIME OF YEAR. THIS
SWD POSITION WILL ALLOW COOLER CANADIAN AIR TO SPILL INTO THE
NORTHERN THIRD OF THE U.S. WITH SOME RESIDUAL AFFECTS BEING FELT IN
THE CAROLINAS.

SUNDAY...SURFACE HIGH OVER THE REGION EARLY IN THE DAY WILL MOVE
OFFSHORE. THE RESULTANT SLY FLOW ON THE BACK SIDE OF THE HIGH WILL
ADVECT WARM MOIST AIR INTO THE PIEDMONT BY AFTERNOON-EARLY EVENING.
IT APPEARS THAT ANY CONVECTION THAT DEVELOPS IN THE HIGHER TERRAIN
OF WESTERN NC WILL STAY JUST EAST OF THE PIEDMONT AS STEERING FLOW
SHOULD KEEP THE CONVECTION PARALLEL TO THE RIDGES. LOW LEVEL
THICKNESSES FAIRLY CLOSE TO NORMAL WHICH SUGGEST AFTERNOON TEMPS
SOLIDLY IN THE MID 80S.

MONDAY THROUGH TUESDAY...THE FIRST S/W IN THE W-NW FLOW ADVANCES
TOWARD OUR REGION MONDAY...AND EXITS THE REGION TUESDAY. THE
ASSOCIATED COLD FRONT WILL ENHANCE LOW LEVEL CONVERGENCE WHILE THE
SYSTEM ALOFT SUPPLIES ADDED LIFT. WITH PRECIP WATER VALUES PROJECTED
TO BE 1.75-1.9 INCHES...EXPECT SCATTERED TO NUMEROUS SHOWERS AND A
FEW THUNDERSTORMS WITH THIS SYSTEM...MAINLY IN THE WEST LATE MONDAY
AND AREAWIDE MONDAY NIGHT INTO TUESDAY. IF LATER MODEL GUIDANCE
REMAINS CONSISTENT...WILL NEED TO INCREASE POPS TO LIKELY OR LOW END
CATEGORICAL MONDAY NIGHT INTO TUESDAY.

WEDNESDAY THROUGH THURSDAY SHOULD SEE A RELATIVELY TRANQUIL WEATHER
PATTERN AS HIGH PRESSURE OVER THE LOWER GREAT LAKES NOSES SEWD INTO
OUR REGION. DEVELOPING ELY FLOW BY THURSDAY MAY ADVECT ATLANTIC
MOISTURE INTO CENTRAL NC RESULTING IN CONSIDERABLE CLOUDINESS.

MODEL GUIDANCE DIFFERS LATE IN THE WEEK AS THE GFS IS MUCH MORE
PROGRESSIVE WITH AN UPPER LEVEL CROSSING THE PACIFIC NW INTO THE
NORTHERN ROCKIES WHILE THE ECMWF IS SLOWER WITH THIS EWD
TRANSLATION DUE TO PRESENCE OF UPPER RIDGE OVER THE ROCKIES/HIGH
PLAIN. SINCE GFS HAS A HISTORY OF BEING TOO FAST IN THIS TYPE OF
PATTERN...PREFER THE ECMWF SOLUTION. THIS MODEL CHOICE SUGGEST
ANOTHER S/W APPROACHING CENTRAL NC BY FRIDAY. MOISTURE ADVECTION
AHEAD OF THIS SYSTEM MAY CAUSE A THREAT FOR LIGHT RAIN SHOWERS BY
THE END OF THE WEEK. DUE TO LIKELY MODEL ADJUSTMENTS IN TIMING OR
STRENGTH OF THE SYSTEM...PREFER TO KEEP POPS AT OR BELOW 20 PERCENT
FOR FRIDAY.
-- End Changed Discussion --

&&

.AVIATION /18Z FRIDAY THROUGH WEDNESDAY/...
AS OF 130 AM FRIDAY...

24-HR TAF PERIOD...
HIGH CONFIDENCE OF VFR CONDITIONS THROUGH THE 24 HOUR TAF PERIOD.
GENERALLY SCT FAIR WEATHER CUMULUS CLOUDS WITH BASES AROUND 5KFT ARE
EXPECTED THIS AFTERNOON...THE CLOUDS COULD BE BRIEFLY BKN AT TIMES
AT KRWI. FAIR WEATHER WITH FEW/SCT CLOUDS ARE EXPECTED TONIGHT WITH
ANOTHER PERIOD OF SCT TO BRIEFLY BKN FAIR WEATHER CUMULUS WITH BASES
AROUND 5KFT EXPECTED ON SUNDAY. NORTHERLY WINDS AT 10-15 KT
SUSTAINED WITH GUSTS UP TO 20KTS THIS AFTERNOON WILL BECOME LIGHT
TONIGHT AND THEN BECOME SOUTHWESTERLY AT 10KTS ON SATURDAY.

LOOKING FURTHER AHEAD...
HIGH PRESSURE JUST OFF THE SOUTHEAST COAST SHOULD PRODUCE FAIR
WEATHER ACROSS CENTRAL NC ON SUNDAY. AS THE FRONT MOVES FURTHER
OFFSHORE ON SUNDAY NIGHT...THE THREAT OF SHOWERS OR THUNDERSTORMS
WILL GROW IN AN INCREASINGLY MOIST PATTERN FROM SUNDAY EVENING
THROUGH TUESDAY WITH AN IMPROVING TREND ON WEDNESDAY. THE SHOWERS
AND STORMS WILL BE MOST NUMEROUS DURING THE AFT/EVE HOURS ON MONDAY
AND TUESDAY. -BLAES
&&

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

&&

$$

SYNOPSIS...VINCENT
NEAR TERM...VINCENT
SHORT TERM...VINCENT
LONG TERM...WSS
AVIATION...BLAES