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000
FXUS62 KGSP 110532
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
132 AM EDT TUE MAR 11 2014

.SYNOPSIS...
DRY AND WARM HIGH PRESSURE WILL MOVE OFF THE CAROLINA COAST LATE
TODAY AS A LOW PRESSURE SYSTEM APPROACHES FROM THE WEST.
TEMPERATURES BECOMING COLDER FOLLOWING THE ASSOCIATED COLD FRONTAL
PASSAGE. DRIER...MILD HIGH PRESSURE WILL RETURN FOR THE END OF THE
WORK WEEK.

&&

.NEAR TERM /THROUGH TODAY/...
AS OF 125 AM...RECENT OBSERVED TEMPERATURES ARE WARMER THAN THE
CURRENT HOURLY TRENDS. I WILL ADJUST TEMPERATURES TO SLOW OVERNIGHT
COOLING. OTHERWISE...THE CURRENT FORECAST IS IN GOOD SHAPE.

AS OF 745 PM...FCST IS ON TRACK. THERE IS SOME INCREASING OROGRAPHIC
CIRRUS ACRS THE I-40 CORRIDOR. GUIDANCE NOT PICKING UP ON IT ALL
THAT WELL...BUT THE GENERAL IDEA IS WITH UPR RIDGE BUILDING...THE
MOISTURE AND JET WILL LIFT N OF THE AREA THIS EVENING. SO I BUMPED
UP SKY COVER TO START OUT THE UPDATE...BUT SHUD CLEAR OUT FOR THE
MOST PART WITHIN THE NEXT 3-4 HOURS. NO CHANGES MADE TO MIN TEMPS.

AS OF 225 PM...MOSTLY CLEAR SKIES AND WARM TEMPS WILL PREVAIL OVER
THE FCST THE REST OF THIS AFTERNOON AND INTO THIS EVENING. I BUMPED
UP MAX TEMPS A DEGREE OR 2 FROM THE LAST UPDATE TO BETTER ACCOUNT
FOR THE WARMER THICKNESS VALUES. MIN TEMPS WERE NOT CHANGED
APPRECIABLY AND SHOULD REMAIN ABOVE CLIMATOLOGY OVERNIGHT EVEN WITH
THE CLEAR SKIES. MAX TEMPS TOMORROW ARE STILL ON TRACK TO BE EVEN
WARMER WITH VALUES OVER THE LOWER ELEVATIONS IN THE UPPER 70S AND
HIGHS OVER THE MTS IN THE LOW 70S. ALTHOUGH THIS WILL BE
UNSEASONABLY WARM FOR MID MARCH...IT LOOKS LIKE NO RECORD HIGHS WILL
BE REACHED/BROKEN. DEWPTS WERE ALSO LOWERED A FEW DEGREES OVER MOST
AREAS WHICH WILL KEEP RH VALUES DOWN THRU THE PERIOD. OTHER THAN
THAT...THE FCST IS DRY THROUGH TUES NIGHT WITH SOME GUSTY WINDS
RETURNING LATE TOMORROW MORNING/AFTERNOON OVER THE CENTRAL AND
NORTHERN NC MTS.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...
AS OF 245 PM MONDAY...THE MAIN CONCERN THROUGH THE SHORT RANGE WILL
BE THE PASSAGE OF A STRONG SHORT WAVE WEDNESDAY NIGHT THAT WILL
DRIVE A FAIRLY STRONG COLD FRONT ACROSS THE REGION LATE IN THE DAY
ON WEDNESDAY. THE MODELS ARE CONSISTENT IN SHOWING MOISTURE
RETURNING FROM THE SW TUESDAY NIGHT...BUT NOT BEFORE ABOUT 03Z...SO
WE CONTINUE TO IMPOSE A DELAY TO THE ONSET OF SHOWERS UNTIL WELL
AFTER DARK. OUT AHEAD OF THE APPROACHING SYSTEM...WARM ADVECTION AND
CLOUD COVER SHOULD KEEP MIN TEMPS MILD...AS LOW AS THE MID 40S OVER
THE MOUNTAIN PEAKS...SO PRECIPITATION TYPE WILL NOT BE AN ISSUE AT
ONSET. SHOWERS WILL DEVELOP OUT AHEAD OF THE FRONT EARLY WEDNESDAY
MORNING SO POP RAMPS UP TO LIKELY OVER THE WESTERN HALF OF THE FCST
AREA BY SUNRISE...AND CONTINUES GOING UP FROM THERE THROUGH MIDDAY.
MOISTURE LOOKS DEEP AND FORCING LOOKS ADEQUATE TO WARRANT A VERY
HIGH POP...INTO THE CATEGORICAL RANGE ACROSS MOST OF THE FCST AREA.
THE FIRST ISSUE WILL BE THE POSSIBILITY OF SEVERE WEATHER AHEAD OF
THE COLD FRONT. SHEAR LOOKS DECENT ENOUGH...COURTESY OF A 40KT WSW
LOW LEVEL JET AT 850MB IN THE AFTERNOON. BUOYANCY WILL BE THE KEY.
THE GFS ONLY MANAGES ABOUT 100 J/KG OF SURFACE-BASED CAPE...ALTHO
THE NAM AS USUAL HAS CONSIDERABLY MORE. IF THE NAM DEPICTION IS
CORRECT...THEN THE SEE TEXT AREA IN THE DAY 3 OUTLOOK FROM SPC LOOKS
WELL PLACED...AND WE WILL HAVE TO BE CONCERNED WITH HIGH SHEAR LOW
CAPE TYPE STORMS. FOR NOW...THE FCST WILL LIMIT THE THUNDER TO THE
CHANCE RANGE...BUT THIS WILL LIKELY GO HIGHER. AFTER THE FRONT MOVES
THROUGH...COLD AIR MOVES IN RAPIDLY IN THE LATE AFTERNOON OVER THE
MTNS. HIGH TEMPS WILL PROBABLY OCCUR BY MIDDAY OVER THE HIGHER
TERRAIN. THE PRECIP OVER THE MTNS WILL CHANGE OVER TO SNOW DURING
THE EVENING HOURS FROM HIGH TO LOW ELEVATION. THE MODELS ARE IN GOOD
AGREEMENT THAT A NW FLOW SNOW EVENT WILL CONTINUE THROUGH MOST OF
WEDNESDAY NIGHT...TAPERING OFF AROUND DAYBREAK THURSDAY. SNOW AMTS
APPEAR TO BE SUB-ADVISORY FOR THE TIME BEING...BUT IT IS POSSIBLE
THIS COULD GO HIGHER. IT SHOULD BE QUIET ON THURSDAY AS UPPER
RIDGING AND HIGH PRESSURE WILL MOVE IN FROM THE WEST.

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
AS OF 230 PM EDT MONDAY...HEIGHTS WILL RISE THU NIGHT THROUGH FRI AS
A DEPARTING E COAST TROUGH PULLS FARTHER E AND BROAD RIDGING SETTLES
OVER THE AREA. SFC HIGH PRES SLIPPING OFF THE SE COAST WILL ALLOW
LOW LEVEL FLOW TO ADJUST TO SOUTHWESTERLY AND PERMIT THICKNESSES TO
START REBOUNDING. A NRN STREAM WAVE CROSSING THE GREAT LAKES FRI
NIGHT WILL DRAG A SHALLOW TROUGH AXIS ACROSS THE FORECAST THROUGH
SAT. MODELS DIFFER ON THE DEGREE OF ANY MOISTURE...BUT WITH NO
APPARENT GULF FETCH...EXPECT MAINLY SOME INCREASED CLOUDS BEFORE
UPPER FLOW RETURNS TO ZONAL LATE SAT.

MAJOR MODEL DIFFERENCES THEN DEVELOP IN THE SPLIT FLOW REGIME ACROSS
THE CONUS THROUGH SUNDAY. A PREFERRED ECM/CMC/ENSEMBLE BLEND SENDS
ENERGY DIVING SE FROM THE ROCKIES SAT NIGHT AND CARVING OUT A SRN
TIER CUTOFF LOW OVER OK/TX ON SUNDAY. DEEP LAYER SW FLOW MAY THEN
SET UP OVER THE SE U.S. IN RESPONSE...WITH A WARM FRONT STEADILY
ACTIVATING EWD TOWARD THE FORECAST AREA THROUGH SUNDAY. SOME DEGREE
OF SFC REFLECTION FORMING FROM THE GULF COAST TO THE SE COAST THEN
LOOKS LIKELY THROUGH MONDAY...BUT WITH HIGH UNCERTAINTY GIVEN THE
TREMENDOUS MODEL SPREAD. WILL OPT FOR A SLOW STEADY INCREASE IN POPS
SUNDAY THROUGH MONDAY WITH ALL LIQUID PTYPES FOR LIGHT RAIN AT THIS
POINT.

&&

.AVIATION /06Z TUESDAY THROUGH SATURDAY/...
AT KCLT...CIRRUS CLOUDS WILL STEADILY INCREASE TODAY AND THIS
EVENING...SOURCED FROM LOW PRESSURE ACROSS THE SOUTHERN MISSISSIPPI
RIVER VALLEY. DEEP MOISTURE WILL LIFT NORTHEAST ACROSS NRN GA BY
6Z...BUT REMAIN SOUTHWEST OF THE TERMINAL. BY 0Z...SKY ACROSS THE
TERMINAL SHOULD BECOME BKN AROUND 10 KFT WITH SCT070. WINDS SHOULD
BACK FROM WEST THIS MORNING TO AROUND 220 DEGREES BY 17Z.
RESTRICTIVE CEILINGS AND VIS WILL LIKELY ARRIVE AFTER 6Z WED.

ELSEWHERE...CONDITIONS WILL BE SIMILAR TO CONDITIONS EXPECTED FOR
KCLT. HOWEVER...KAVL SHOULD OBSERVE NORTHWEST WINDS THROUGH THIS
MORNING...THE SOUTHWEST THIS AFTERNOON AND EVENING. UPSTATE
TERMINALS SHOULD SEE THICKER MID AND HIGH CLOUDS ARRIVE AN HOUR OR
TWO EARLIER THAN KCLT.

OUTLOOK...A LARGE LOW PRESSURE SYSTEM WILL RESULT IN WIDESPREAD
RESTRICTIVE CEILINGS AND VIS EARLY WEDNESDAY MORNING. A STRONG COLD
FRONT WILL SWEEP ACROSS THE REGION WEDNESDAY AFTERNOON...FOLLOWED BY
GUSTY NORTHWEST WINDS THROUGH THURSDAY MORNING. DRY HIGH PRESSURE
WILL REMAIN OVER THE WESTERN CAROLINAS THROUGH THE REMAINDER OF THE
WORK WEEK.

CONFIDENCE TABLE...

            05-11Z        11-17Z        17-23Z        23-05Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%

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...NONE.
SC...NONE.

&&

$$
SYNOPSIS...JOH
NEAR TERM...NED
SHORT TERM...PM
LONG TERM...HG
AVIATION...NED