000
FXUS62 KGSP 162324
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
724 PM EDT TUE MAR 16 2010

.SYNOPSIS...
A WEAK TROUGH OF LOW PRESSURE WILL PERSIST OVER THE SOUTHERN
APPALACHIANS THROUGH WEDNESDAY. HIGH PRESSURE WILL SLOWLY RETURN
FROM THE WEST ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA
THURSDAY THEN MOVE OFF THE CAROLINA COAST SATURDAY. A SHARP COLD
FRONT WILL CROSS THE MISSISSIPPI VALLEY LATE SATURDAY AND MOVE
EASTWARD THROUGH OUR REGION ON SUNDAY. HIGH PRESSURE RETURNS ON
MONDAY.

.NEAR TERM /THROUGH WEDNESDAY/...
A FLAT UPPER RIDGE WILL MOVE OFF THE CAROLINA COAST TONIGHT...AS AN
UPPER LOW MOVES ALONG THE GULF COAST FROM TX TO THE FL PANHANDLE.
THIS LOW MOVES TO THE SC COAST ON WEDNESDAY. SURFACE RIDGING MOVES
EAST ACROSS THE APPALACHIANS TONIGHT...CAUSING SURFACE WINDS TO VEER
FORM NORTH TO NORTHEAST...RESULTING IN A MOIST UPSLOPE FLOW INTO THE
SOUTHERN APPALACHIANS. CLOUD COVER WILL INCREASE THIS EVENING...AND
A SMALL POPS WILL BE CARRIED IN THE WEST BOTH TONIGHT AND WEDNESDAY.

INITIALLY...MODEL SOUNDINGS ARE RATHER WARM AT THE TOP OF THE MOIST
LAYER...BUT WITH TIME MOISTURE DEPTH INCREASES OT THE POINT WHERE
THE GFS IS AROUND MINUS 8 DEGREES C...AND THE NAM MINUS 5 DEGREES C.
A TOP DOWN APPROACH USING THE GFS YIELDS LIQUID PRECIPITATION...
EXCEPT FOR SOME ISOLATED FREEZING RAIN WHERE SURFACE TEMPERATURES
SUPPORT IT AT THE VERY HIGHEST ELEVATIONS. TEMPERATURES BOTH TONIGHT
AND WEDNESDAY WILL EXHIBIT A LIMITED DIURNAL RANGE UNDER CLOUD COVER.

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 230 PM TUESDAY...HPC FAVORS THE GFS AND ECMWF WHILE
CONSIDERING THE NAM AN OUTLIER. WITH THIS IN MIND EXPECT ANOTHER
SHORTWAVE TO DIG INTO THE LOWER MS VALLEY WED NIGHT AND PASS S OF
THE AREA THU. BEST DYNAMICS AND MOISTURE REMAIN WELL S OF THE CWA
BUT EXPECT WEAK FORCING AND DEEP ENOUGH MOISTURE FOR SLIGHT CHC POPS
OVER THE NC MTNS...PLUS THE FOOTHILLS AND PIEDMONT SW OF I-26.
VERTICAL TEMP PROFILES INDICATE LGT SNOW WILL BE PSBL HIGHER MTNS
WED NIGHT. LOW LEVEL MOISTURE SHOULD SCATTER OUT DURING THE DAY THU
AS RIDGE BUILDS IN FROM THE NW...WITH MAX TEMPS WARMING A CATEGORY
OR SO ABOVE AVG. RIDGE AXIS BUILDS OVER THE SE US FRI WITH SW FLOW
DEVELOPING IN THE AFTN. THIS SHOULD ALLOW TEMPS TO WARM TO NEAR 70
ACROSS THE PIEDMONT WITH 55 TO 65 OVER THE MTNS.

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 230 PM TUESDAY...THE MEDIUM RANGE MODELS ARE IN FAIRLY GOOD
AGREEMENT IN ARE GENERALLY DELAYING THE ARRIVAL OF THE NEXT FRONT.
THE GEM IS A BIT FASTER IN BRINGING IN THE FRONTAL CONVECTION AND BY
00Z MONDAY HAS IT MOVING ACROSS EASTERN NORTH CAROLINA.  PRIOR TO
THAT HOWEVER...THE MODELS AGREE ON NO PRECIP FRIDAY NIGHT AND WITH
THE UPSLOPE FLOW FROM THE GULF ON SATURDAY THERE WILL BE A GRADUAL
INCREASE IN SHOWERS OVER THE SOUTHERN EXTENT OF THE MOUNTAINS.
THERE IS A MARKED INCREASE IN WIND SPEED AHEAD OF THIS FRONT WITH 35
TO 50 KNOT WIND AT 850MB ON THE GFS AND ECMWF FOR MUCH OF SUNDAY.
CONSIDERING THE WIND SHEAR AND JUST A BIT OF CAPE...I MAINTAINED
ISOLATED THUNDER UPPER SAVANNAH VALLEY SUNDAY MORNING AND MID DAY
AND SLIGHT CHANGE THUNDER SOUTH OF CHARLOTTE SUNDAY AFTERNOON.
CONFIDENCE RATHER LOW ON WRAP AROUND NORTHWEST FLOW PRODUCING MUCH
AT THIS TIME BUT BARES WATCHING.  DRY OTHERWISE MONDAY THROUGH
TUESDAY NIGHT WITH HIGH PRESSURE SETTLING IN WITH DECREASING WIND
TUESDAY.

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...EXPECTING VARYING DEGREES OF SCT-BKN STRATOCU 4-5K FEET
THROUGH THE PERIOD WITH ENE WINDS LESS THAN 8 KTS.

ELSEWHERE ACROSS THE FA...MVFR CONDITIONS STILL EXPECTED TO DEVELOP
AT KAVL LATER THIS EVENING AND LINGER INTO WEDNESDAY MORNING.
OTHERWISE...STRATOCU WILL LINGER ACRS THE PIEDMONT TERMINALS WITH
CLOUD LEVELS 3-5K FEET THROUGH THE PERIOD.

OUTLOOK...GENERALLY REMAIN VFR THROUGH THE END OF THE WEEK. THE
MOUNTAIN VALLEYS COULD EXPERIENCE SUB-VFR CEILINGS AND VISIBILITIES
DURING THE EARLY MORNING HOURS THURSDAY.

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

SYNOPSIS...DEO
NEAR TERM...JAT
SHORT TERM...RB
LONG TERM...DEO
AVIATION...CSH/JAT