FXUS62 KRAH 140308
AFDRAH

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
1000 PM EST SAT MAR 13 2010

.SYNOPSIS...
A STRONG UPPER LEVEL LOW WILL SLOWLY DRIFT EAST ACROSS THE REGION
THROUGH SUNDAY... THEN MOVE OFFSHORE SUNDAY NIGHT. HIGH PRESSURE
WILL GRADUALLY BUILD IN FROM THE WEST BRINGING DRY WEATHER EARLY
NEXT WEEK.
&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1000 PM SATURDAY...

THE WV SATELLITE DATA INDICATES THE MID LEVEL CIRCULATION WAS
LOCATED OVER UPSTATE SC MOVING SLOWLY EAST THIS EVENING. CONVECTIVE
TYPE PRECIPITATION HAS BEEN ASSOCIATED WITH THE CONVERGENCE AXIS
WRAPPING AROUND THE UPPER LOW CENTER. THIS MAIN PRECIPITATION AXIS
EXTENDED FROM THE MOUNTAINS OF NC... NE ACROSS OUR NW PIEDMONT AND
INTO VA. THIS CONVERGENCE AXIS IS EXPECTED TO GRADUALLY SHIFT EAST
OVER NC OVERNIGHT AS THE UPPER LOW TRACKS EAST ACROSS NORTHERN SC.
THE QPF HAS BEEN RATHER LIGHT THUS FAR EVEN DURING THE MAXIMUM
HEATING THIS AFTERNOON. THEREFORE... ONLY LIGHT AMOUNTS (AVERAGE
LESS THAN 0.25 OF AN INCH) ARE ANTICIPATED AS THE SHOWERS MOVE
THROUGH THE AREA OVERNIGHT.

WE WILL MAINTAIN LIKELY EITHER HIGH CHANCE OR LIKELY POP OVERNIGHT
WITH THE HIGHER POP OVER THE PIEDMONT PER CURRENT TRENDS AND THE
LATEST GUIDANCE. LOWS BY DAYBREAK SHOULD BE MOSTLY IN THE 40S WITH
NEAR 50 IN THE SE. NO OTHER CHANGES AT THIS TIME.


&&

.SHORT TERM /SUNDAY THROUGH TUESDAY/...
AS OF 230 AM SATURDAY...

SUNDAY...BANDED PRECIPITATION WITH THE MID/UPPER LEVEL LOW WILL EXIT
THE NE COUNTIES PRIOR TO 14Z. DOWNSLOPE COMPONENT TO LOW LEVEL WIND
WILL AID TO GRADUALLY DIMINISH CLOUDINESS BUT EXPECT CLOUD COVERAGE
TO BE PARTLY TO MOST CLOUDY THROUGH THE DAY. ASIDE FROM
HEATING...NOT MUCH ELSE TO TRIGGER ISOLATED SHOWERS IN THE AFTERNOON
IN RATHER SHALLOW MOISTURE LAYER AROUND 5000FT. THUS...WILL MAINTAIN
DRY FORECAST SUNDAY. MOS TEMPS APPEAR A LITTLE TOO WARM CONSIDERING
LOW LEVEL COLD AIR ADVECTION AND EXPECTED CLOUDINESS. FAVOR MAX
TEMPS A COUPLE OF DEGREES COOLER THAN MOS.

SUNDAY NIGHT...POTENT VORT MAX DIVES ON BACK SIDE OF UPPER LEVEL LOW
AND CROSSES NEAR OR JUST SOUTH OF THE FORECAST REGION. THIS SYSTEM
MAY PROVIDE ENOUGH LIGHT TO GENERATE SOME SPOTTY LIGHT RAIN.
MOISTURE CONFINED TO THE 5000-10000FT LAYER. MODELS CURRENTLY NOT
DEPICTING ANY LIFT THROUGH THIS PORTION OF THE COLUMN. WILL
INTRODUCE SOME SPRINKLES FRO LATE SUNDAY NIGHT EARLY MONDAY. WOULD
NOT BE SURPRISED IF WE HAVE TO ADD A SMALL POP IN LATER FORECAST.
LEANED MIN TEMPS TO THE WARM SIDE OF MOS GUIDANCE (LOW TO MID 40S).

MONDAY...CONTINUED CYCLONIC FLOW OVER THE REGION WILL MAINTAIN
VARIABLE CLOUDY SKIES. HOWEVER MOISTURE RATHER LIMITED IN DEPTH SO
DO NOT EXPECT ANY SHOWER DEVELOPMENT. LOW LEVEL CAA MARGINAL/WEAK ON
MONDAY BUT NEAR SURFACE NLY FLOW WILL KEEP TEMPS FROM REBOUNDING.
FAVOR MAX TEMPS ON COOL SIDE OF GUIDANCE (NEAR 60-LOWER 60S).

AS OF 140 PM SATURDAY...

MONDAY NIGHT AND TUESDAY:
MID/UPPER LOW... WHICH IS EXPECTED TO BE LOCATED JUST OFF THE MID
ATLANTIC COAST AT THE START TO OF THIS PERIOD (MONDAY NIGHT)... IS
FORECAST TO DRIFT OFF TO THE EAST-SOUTHEAST MONDAY NIGHT INTO
TUESDAY. HOWEVER... THE CYCLONIC FLOW ASSOCIATED WITH THE DEPARTING
SYSTEM WILL USER IN JUST ENOUGH MOISTURE BELOW THE MID LEVEL
INVERSION TO KEEP SKIES GENERALLY PARTLY SUNNY/CLOUDY. DO NOT EXPECT
ANY PRECIP THOUGH WITH THE LAST REMAINING PIECES OF S/W ENERGY
ROTATING THROUGH... AS MOISTURE IN THE COLUMN WILL NOT BE DEEP
ENOUGH... AND A STRONG CAPPING INVERSION WILL BE DEVELOPING AS
HEIGHTS ALOFT INCREASE. LOWS ON MONDAY NIGHT WILL FALL INTO THE
UPPER 30S TO LOWER 40S. HIGHS ON TUESDAY WILL BE QUITE CHILLY WITH
PARTLY CLOUDY SKIES AND LOW LEVEL THICKNESS VALUES FALLING TO SOME
20 TO 30 METERS BELOW NORMAL BY TUESDAY AFTERNOON... AS LOW LEVEL
FLOW VEERS AROUND TO MORE OF A NORTHERLY DIRECTION. FOR NOW WILL GO
WITH TEMPS RANGING FROM THE MID 50S NORTH TO THE UPPER 50S SOUTH.
HOWEVER... DRY ADIABATIC LOW LEVEL THICKNESS IN HOUSE TOOL INDICATES
THAT WE MAY NOT MAKE IT OUT OF THE LOWER 50S IN THE FAR NORTHEASTERN
PORTION OF THE RAH CWA ON TUESDAY AFTERNOON. HOWEVER... DO NOT WANT
TO GO THAT EXTREME YET.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/..
AS OF 100 PM SATURDAY...

DRY CONDITIONS WITH MODERATING TEMPERATURES ARE EXPECTED FOR THE
MEDIUM RANGE PORTION OF THE FORECAST.

TUESDAY NIGHT THROUGH THURSDAY NIGHT:
ANOTHER MID/UPPER LEVEL S/W TROUGH IS EXPECTED TO TRACK THROUGH THE
BROAD L/W TROUGH OVER THE EASTERN HALF OF THE COUNTRY TUESDAY
THROUGH THURSDAY. THE S/W IS FORECAST TO TRACK FROM THE UPPER
MIDWEST INTO THE DEEP SOUTH DURING THIS TIME... WHILE DEEPENING AND
CLOSING OFF. HOWEVER... THE SYSTEM IS EXPECTED TO PASS TO THE SOUTH
OF THE AREA AND WILL BE RELATIVELY MOISTURE STARVED. THUS... EXPECT
WE WILL ONLY SEE AN INCREASE IN CLOUDS ACROSS OUR AREA ON WEDNESDAY
INTO THURSDAY. THIS WILL LEAD TO TEMPS GENERALLY AROUND NORMAL
WEDNESDAY THROUGH THURSDAY... UPPER 50S TO LOWER 60S FOR HIGHS AND
UPPER 30S TO LOWER 40S FOR LOWS.

FRIDAY THROUGH SATURDAY:
AFOREMENTIONED MID/UPPER LOW IS EXPECTED TO MOVE OFF THE
SOUTHEASTERN U.S. COAST BY FRIDAY MORNING... ALLOWING MID LEVEL
RIDGING AND SURFACE HIGH PRESSURE TO BUILD INTO AND ACROSS THE AREA
DURING THIS TIME FRAME. THIS WILL ALLOW LOW LEVEL THICKNESS VALUES
TO RISE ABOVE NORMAL AGAIN... THUS... RESULTING IN ABOVE NORMAL
AFTERNOON HIGHS AND LOWS. EXPECT HIGHS ON FRIDAY TO TOP OUT IN THE
MID TO UPPER 60S... WHILE HIGHS ON SATURDAY MAY REACH THE UPPER 60S
TO LOWER 70S. OVERNIGHT LOWS ON SATURDAY MORNING LOOK TO BE IN THE
LOWER TO MID 40S. HPC STILL LIKES THE SLOWER EC... SO WILL KEEP THE
FORECAST DRY... AS THE NEXT SYSTEM HOLDS TO THE WEST OF THE AREA
THROUGH THE FORECAST PERIOD.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AS OF 700 PM SATURDAY...

VFR CONDITIONS ACROSS TAF SITES AS OF 23Z WILL GIVE WAVE TO MVFR
CONDITIONS THIS EVENING AND PERIODS OF IFR ACROSS THE NORTHERN TAF
SITES OF KINT/KGSO/KRDU. IMPRESSIVE VORTEX SEEN ON WV IMAGERY ACROSS
NE GA AND E TN IS EXPECTED TO PROVIDE FORCING FOR AN INCREASE IN
COVERAGE OF SHOWERS ACROSS THE W PIEDMONT THIS EVENING WHICH WILL
PUSH E AND NE OVERNIGHT. MOST SIGNIFICANT PRECIP WITH LOWEST CIGS
AND VSBYS REACHING IFR CAT SHOULD BE NOTED ACROSS THE KINT/KGSO
BETWEEN 04-08Z WITH A PERIOD OR TWO OF SHOWERS ACROSS AND REDUCED
CIGS AND VSBYS ACROSS KRDU AND KRWI AROUND 06-12Z. BEST FORCING AND
PRECIP COVERAGE SHOULD REMAIN JUST N OF KFAY. CONVECTIVE POTENTIAL
HAS ALL BUT ABATED AND NO TSRA EXPECTED OVERNIGHT. SFC TROF
ATTENDANT THE UPPER LEVEL VORTEX WILL RESULT IN WINDS VEERING
OVERNIGHT TO W AND NW.

VORTEX PUSHES E OF REGION BY DAYBREAK ON SUN ALLOWING CIGS AND VSBYS
TO IMPROVE MARKEDLY WITH VFR CONDITIONS DEVELOPING AFTER DAYBREAK.
MID LEVEL MOISTURE RETURNS OR PERSISTS ON SUN RESULTING IN A GOOD
DEAL OF ALTOCUMULUS WITH CIGS OF 5-8KFT.

LOOKING FURTHER AHEAD THRU THURSDAY...PERSISTENT UPPER TROF OVER E
CONUS WILL SLIP E OF CENTRAL NC ON MON ALLOWING CONDITIONS TO
GRADUALLY IMPROVE WITH MAINLY VFR CONDITIONS EXPECTED THROUGH
THURSDAY. NEXT SYSTEM ARRIVES TOWARD WED/THU WHICH COULD RESULT SOME
UNSETTLED WEATHER. -BLAES/PAGANO

&&


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

&&

$$

SYNOPSIS...BADGETT
NEAR TERM...BADGETT
SHORT TERM...WSS
LONG TERM...BSD
AVIATION...BLAES/PAGANO








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