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000
FXUS62 KGSP 071412
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
912 AM EST FRI MAR 7 2014

.SYNOPSIS...
A COASTAL LOW WILL STRENGTHEN AND MOVE FROM FLORIDA UP THE ATLANTIC
COAST TODAY. DRIER AND WARMER HIGH PRESSURE IS THEN EXPECTED TO
RETURN TO OUR REGION THIS WEEKEND AND PERSIST THROUGH EARLY NEXT
WEEK. ANOTHER LOW WILL APPROACH THE CAROLINAS FROM THE WEST DURING
THE MIDDLE OF NEXT WEEK.

&&

.NEAR TERM /THROUGH SATURDAY/...
AS OF 850 AM...RAIN HAS CHANGED TO SNOW ALONG THE BACK EDGE OF THE
DEFORMATION ZONE PRECIP BAND ACROSS THE NORTHERN NC FOOTHILLS.
MEANWHILE...CAD IS HOLDING STRONG ACROSS THE NORTHWEST PIEDMONT...
WHERE TEMPS ARE LOCKED IN AROUND FREEZING ACROSS DAVIE/ROWAN
COUNTIES...RESULTING IN A BIG P-TYPE MESS...WITH HEAVY/DAMAGING ICE
ACCUMS BEING REPORTED THESE AREAS. AS THE DEFORMATION ZONE CONTINUES
TO DRIFT EAST...WILL FEATURE A MENTION OF RAIN/SNOW ALONG THE BACK
EDGE ACROSS MUCH OF THE NC PIEDMONT THIS MORNING...ALTHOUGH
ADDITIONAL ACCUMS OF ICE/SNOW SHOULD BE CONFINED TO THE NORTHWEST
PIEDMONT...PARTICULARLY DAVIE AND ROWAN COUNTIES...WHERE ADDITIONAL
ACCUMS OF A TENTH INCH OF ICE ARE POSSIBLE BEFORE TEMPS FINALLY LIFT
ABOVE FREEZING.

AS OF 650 AM...COOLER TEMPS HAVE DEVELOPED ACROSS PORTIONS OF THE
WRN CWFA AS EXPECTED. RAIN STILL FALLING AT KAVL WHILE KHKY IS NOW
SNOW. STILL GETTING REPORTS OF SNOW IN ACROSS PORTIONS OF THE MTNS
WITH ONLY LIGHT ACCUMS SOUTH AND HIGHER ACCUMS NORTH. A WIDE VARIETY
OF P-TYPES AND AMOUNTS CONTINUE ACROSS THE I-40 CORRIDOR. ADDITIONAL
HEAVY RAIN ACROSS THE CLT METRO AREA HAS CAUSED ADDITIONAL FLOODING
TO DEVELOP...AND MORE COULD DEVELOP LATER THIS MORNING AS THE
HEAVY PRECIP ASSOCIATED WITH THE DEFORMATION ZONE ROTATES OVER THE
AREA. GOING FCST BASICALLY ON TRACK WITH ONLY MINOR CHANGES.

AS OF 355 AM...TRICKY FORECAST CONTINUES WITH A VARIETY OF THREATS
ACROSS THE CWFA. SFC TEMPS AND WET BULBS SHOW THE LARGEST THREAT OF
WINTRY PRECIP REMAINS ACROSS THE I-40 CORRIDOR AND THE NRN MTNS.
HAVE RECEIVED REPORTS OF SIGNIFICANT SNOW AND SLEET ACCUMS ACROSS
THE NRN MTNS AND BLUE RIDGE...WHILE SIGNIFICANT ICE ACCRETIONS HAVE
BEEN REPORTED ACROSS THE I-40 CORRIDOR. OF COURSE...EVEN IN THESE
AREAS...HEAVY ACCUMS HAVE BEEN SPOTTY. IN FACT...LATEST GUIDANCE
KEEPS THE COLD AIR IN PLACE ACROSS THE MTNS THIS MORNING THAT WOULD
LEAD TO ADDITIONAL SNOW ACROSS THE HIGH ELEVATIONS. THEREFORE...
ADDITIONAL ACCUMS ARE LIKELY...SO WILL LEAVE WARNING IN PLACE IN
THESE AREAS. ACCUMS HAVE BEEN MUCH MORE SPOTTY AND LIMITED TO THE
HIGHER ELEVATIONS OVER THE CENTRAL AND SRN MTNS. VERTICAL PROFILERS
FROM THE NOAA HMT-SE PROGRAM SHOW SNOW LEVELS REMAINING AROUND 5000
FT. LAST SOUNDING AT 06Z FROM THE SEMPE PROGRAM AND UNC-ASHEVILLE
SHOW THE WARM NOSE TEMP REMAINING UNCHANGED BUT THE DEPTH
DECREASING... WHILE THE SFC TEMPS HAD RISEN. THEREFORE...EXPECT
ACCUMULATING SNOW TO BE LIMITED TO THE HIGHER ELEVATIONS...WITH ONLY
A LIGHT ACCUMS OF WINTRY PRECIP IN THE VALLEYS. WILL DOWNGRADE
BUNCOMBE...HENDERSON AND THE SRN BLUE RIDGE TO AN ADVISORY. IN
ADDITION TO THE PRECIP... GUSTY NNE WINDS WILL HELP DOWN TREES WITH
THE WET GROUND AND POSSIBLY LEAD TO POWER OUTAGES.

CONDITIONS ARE EVEN LESS UNCERTAIN ACROSS THE SRN FOOTHILLS AND SRN
PIEDMONT. TEMPS AND WET BULBS ARE ABOVE FREEZING ACROSS THIS AREA...
BUT ARE HOLDING STEADY NEAR FREEZING. GIVEN THE UNCERTAINTY...WILL
LEAVE THE ADVISORY IN PLACE AS SOME LIGHT ICE ACCRETIONS ARE
POSSIBLE. ALSO...WITH THE GUSTY NNE WINDS AND WET GROUND...TREES ARE
LIKELY TO FALL AND POSSIBLY LEAD TO POWER OUTAGES.

OVER THE UPSTATE AND NE GA...TEMPS ARE EITHER HOLDING STEADY OR EVEN
INCREASING KEEPING THE CHC OF ANY WINTRY PRECIP TO A BARE MINIMUM AT
BEST. WINDS ARE NOT AS STRONG HERE EITHER...BUT CANNOT RULE OUT AN
ISOLATED TREE DOWN OR SPOTTY POWER OUTAGE.

THE FINAL THREAT IS THE HEAVY RAINFALL ROTATING INTO THE AREA IN THE
DEFORMATION ZONE AROUND THE APPROACHING UPPER LOW. MDLS KEEP QUITE A
BIT OF UPPER DIVERGENCE ACROSS THE AREA THRU THE MORNING AS THIS
ZONE ROTATES OVER THE AREA THIS MORNING. HAVE ALREADY HAD HEAVY
RAINFALL AND A QUICK RISE IN CREEKS ACROSS PORTIONS OF THE CLT METRO
AREA. WITH THE HEAVY RAINFALL REMAINING OVER THE AREA THIS
MORNING...ADDITIONAL AREAS OF EXCESSIVE RAINFALL AND RISING STREAMS
ARE POSSIBLE. AREAL COVERAGE OF ANY FLOODING UNCERTAIN ENUF TO
PRECLUDE THE ISSUANCE OF A WATCH...BUT WILL KEEP A CLOSE EYE ON
STREAMS AND RAINFALL AND ISSUE ANY FLOOD WARNINGS AS NEEDED.

THE GOOD NEWS IS THAT PRECIP HEAVY PRECIP SHUD QUICKLY TAPER OFF
AND MOVE EAST OF THE AREA DURING THE AFTERNOON AS TEMPS WARM ABOVE
FREEZING. ANY WINTRY PRECIP THREAT SHOULD END BY NOON...SO CURRENT
WSW EXPIRATION TIME STILL GOOD. WINDS SHOULD DROP OFF SIGNIFICANTLY
BY AFTERNOON...BUT CANNOT RULE OUT SOME LINGERING GUSTS. IT IS
POSSIBLE THAT A WIND ADV MAY BE NEEDED ACROSS PORTIONS OF THE AREA
FOR THE AFTERNOON.

CONDITIONS CONTINUE TO IMPROVE TONIGHT AS SHORT WAVE RIDGING MOVES
IN BEHIND THE DEPARTING UPPER LOW. SKIES CLEAR AND WINDS CONTINUE TO
DIMINISH. TEMPS WILL FALL TO NEAR FREEZING ACROSS PORTIONS OF NC...
SO LATER SHIFTS WILL HAVE TO ENTERTAIN ANY SPECIAL PRODUCTS FOR
POTENTIAL BLACK ICE. TEMPS SHUD REMAIN ABOVE FREEZING...BUT STILL
BELOW NORMAL...FOR THE UPSTATE AND NE GA.

&&

.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
AT 310 AM EST FRIDAY...CONDITIONS SHOULD WARM COMFORTABLY ACROSS THE
REGION ON SATURDAY. SHORT RANGE MODELS INDICATE THAT SFC HIGH
PRESSURE WILL SETTLE ACROSS THE DEEP SOUTH AS A WEAK FRONT SLIDES
OVER THE OHIO RIVER VALLEY. DOWNSLOPE FLOW...MOSTLY SUNNY SKY...AND
MILD THICKNESSES SHOULD RESULT IN HIGH TEMPERATURES IN THE MID 60S
WITHIN THE MTN VALLEYS AND AROUND 70 EAST. TEMPERATURES WILL REMAIN
AROUND 5 DEGREES ABOVE NORMAL SATURDAY NIGHT. THE MILD TEMPERATURES
WILL BE A RESULT OF RETURN FLOW AND INCREASING CLOUD COVER
PRECEDING THE COLD FRONT.

THE NAM AND GFS INDICATE THAT A LIGHT ROUND OF PRIMARILY RAIN WILL
OCCUR ACROSS THE TN BORDER COUNTIES EARLY SUNDAY MORNING. THE PRECIP
WILL LIKELY NOT ACCOMPANY THE WEAK FRONT ACROSS THE EASTERN SLOPES
AND FOOTHILLS. HOWEVER...I WILL INCREASE CLOUDS FOR SUNDAY.
TEMPERATURES ARE FORECAST NOT TO VARY MUCH FROM VALUES OBSERVED ON
SATURDAY.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 240 AM FRIDAY...THE MEDIUM RANGE FCST PICKS UP AT 12Z ON
MONDAY WITH AN UPPER SHORTWAVE MOVING OFF THE CAROLINA COAST AND A
CUTOFF SOUTHERN STREAM UPPER TROF OVER NORTHERN MEXICO AND PORTIONS
OF SW TEXAS. OVER THE NEXT 24 TO 36 HRS...THE PATTERN REMAINS FAIRLY
ZONAL OVER THE SE CONUS WHILE THE SOUTHERN STREAM TROF DRIFTS
EASTWARD AND BEGINS TO OPEN BACK UP. BY LATE WED...A BROAD UPPER
TROF OVER THE GREAT LAKES DIGS SOUTHWARD AND TOWARDS OUR FCST AREA.
BOTH THE GFS AND ECMWF SUGGEST THAT THE TROF AXIS WILL MOVE OVER THE
CWFA BY LATE THURS...WITH THE GFS BEING MORE PROGRESSIVE WITH THE
SYSTEM.

AT THE SFC..BROAD HIGH PRESSURE WILL BE OVER THE REGION AT THE START
OF THE MEDIUM RANGE AND IS EXPECTED TO REMAIN OVER THE REGION THRU
TUES. ANOTHER LOW WILL DEVELOP TO OUR WEST LATE TUES/EARLY WED
AND MOVE INTO THE CWFA ON WED. THE SPECIFIC TRACK AND SPEED OF THE
LOW AS IT MOVES OVER THE REGION REMAINS SOMEWHAT UNCLEAR AT THIS
POINT...HOWEVER THE APPEAR MORE CONSISTENT THAN THEY DID YESTERDAY
MORNING. THEY DO AGREE THAT BY THURS EVENING THE LOW SHOULD BE WELL
TO OUR NE WITH DRY HIGH PRESSURE PUSHING INTO THE CWFA. THE ONLY
SIGNIFICANT/NOTEWORTHY CHANGES I MADE TO THE SENSIBLE FCST INCLUDED
RAMPING UP POPS TO SOLID CHANCE BY 00Z WED OVER ESSENTIALLY THE
ENTIRE CWFA AND TAPERING THEM DOWN SOONER ON THURS. I NOW HAVE
PRECIP CHANCES PEAKING BY MIDDAY WEDNESDAY AS THE LOW IS EXPECTED TO
APPROACH THE FCST AREA ABOUT 12 HRS SOONER. TEMPS WILL START OUT
WELL ABOVE NORMAL ON MONDAY AND REMAIN ABOVE NORMAL THRU WEDNESDAY
AND THEN DROP ON THURS AS CAA WORKS ITS WAY INTO THE REGION.

&&

.AVIATION /14Z FRIDAY THROUGH TUESDAY/...
AT KCLT...TEMP AND WET BULB TEMP HAVE BEEN ABOVE FREEZING ALL NITE
AT THE AIRFIELD. CANNOT COMPLETELY RULE OUT A BRIEF PERIOD OF FZRA
AROUND DAYBREAK. HOWEVER...CHC IS VERY LOW AND EVENT WOULD NOT LAST
VERY LONG IF IT DID DEVELOP. OTHERWISE...EXPECT IFR CIGS AND MVFR TO
LOW VFR VSBY IN RAIN THIS MORNING AS RAIN CONTINUES TO ROTATE ACROSS
THE AREA. THIS RAIN PULLS EAST OF THE AREA WITH THE UPPER LOW BY
EARLY EVENING. IFR CIGS WILL BECOME MVFR THRU THE MORNING AND LINGER
INTO AFTERNOON. LOW CLOUDS SHUD SCATTER OUT EARLY EVENING WITH
MAINLY CIRRUS OVERNIGHT. MVFR SEEMS A GOOD BET BY DAYBREAK SAT WITH
THE WET GROUND AND GOOD RADIATIONAL CONDITIONS. GUSTY NNE WIND
BECOMES NLY BY AFTERNOON WITH DIMINISHING GUSTS. LIGHT NLY WIND THIS
EVENING BECOMES CALM OVERNIGHT.

AT KAVL...MAINLY RAIN EXPECTED THRU THE PERIOD AS SFC TEMPS AND WET
BULB TEMP REMAIN ABOVE FREEZING AND WARM NOSE CONTINUES ACROSS THE
AREA. EXPECT MAINLY MVFR CIGS WITH MVFR VSBY DURING THE HEAVIER
RAIN. MVFR CLOUDS SCATTER TOWARD SUNSET WITH ONLY HIGH CLOUDS
OVERNIGHT. MVFR FOG SHUD DEVELOP BY DAYBREAK SAT. LIGHT NLY WINDS
CONTINUE THRU THE PERIOD.

ELSEWHERE...THE UPSTATE TAF SITES WILL SEE RAIN WITH CONDITIONS
VARYING FROM LOW VFR TO IFR. GUSTY NNE WIND BECOMES NLY THRU THE DAY
WITH DIMINISHING GUSTS. CALM WIND EXPECTED TOWARD DAYBREAK SAT.
SNOW...POSSIBLY MIXED WITH RAIN AND SLEET...WILL CONTINUE THRU THE
MORNING AT KHKY BEFORE CHANGING ALL TO RAIN. IFR CONDITIONS WILL
BECOME MVFR FOR AFTERNOON THEN LOW VFR NEAR SUNSET.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-14Z
KCLT       MED   79%     MED   79%     HIGH 100%     MED   69%
KGSP       HIGH  84%     HIGH  85%     HIGH 100%     HIGH  85%
KAVL       MED   72%     HIGH  85%     HIGH 100%     HIGH  95%
KHKY       HIGH  80%     HIGH  88%     HIGH 100%     HIGH  80%
KGMU       MED   73%     HIGH  85%     HIGH 100%     HIGH  95%
KAND       HIGH  84%     HIGH  85%     HIGH 100%     HIGH  95%

THE PERCENTAGE REFLECTS THE NUMBER OF GUIDANCE MEMBERS AGREEING
WITH THE SCHEDULED TAF ISSUANCE FLIGHT RULE CATEGORY. COMPLETE
HOURLY EXPERIMENTAL AVIATION FORECAST CONSISTENCY TABLES AND ENSEMBLE
FORECASTS ARE AVAILABLE AT THE FOLLOWING LINK: (MUST BE LOWER CASE)

WWW.WEATHER.GOV/GSP/AVIATION_TABLES

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER STORM WARNING UNTIL NOON EST TODAY FOR NCZ033-035>037-
     049-050-056-057-501>506.
     WINTER WEATHER ADVISORY UNTIL NOON EST TODAY FOR NCZ053-065-
     072-507-509.
SC...NONE.

&&

$$
SYNOPSIS...JPT
NEAR TERM...JDL/RWH
SHORT TERM...NED
LONG TERM...JPT
AVIATION...RWH