FXUS62 KGSP 150539
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
139 AM EDT MON MAR 15 2010

.SYNOPSIS...
A BROAD UPPER LEVEL LOW WILL MOVE SLOWLY EAST ACROSS THE CAROLINA
REGION THROUGH THE OVERNIGHT. THE LOW WILL CONTINUE TO DRIFT EAST
OVER THE ATLANTIC THROUGH TUESDAY...WHICH WILL ALLOW A CANADIAN HIGH
PRESSURE SYSTEM TO SETTLE ACROSS REGION THROUGH THE MIDDLE OF THE
WEEK. ANOTHER UPPER LEVEL LOW WILL TRANSITION ACROSS THE REGION LATE
WEDNESDAY INTO THURSDAY.

&&

.NEAR TERM /THROUGH TODAY/...
VORT WITHIN BROAD CYCLONIC FLOW ALOFT WILL CONTINUE TO TRANSLATE
DOWNSTREAM OF THE FA OVERNIGHT...EFFECTIVELY TERMINATING LIGHT SHOWER
CHANCES EAST OF THE BLUE RIDGE. UNDER SCT-BKN STRATOCU OVERNIGHT...
MIN TEMPS ACRS THE FTLHS AND PIEDMONT ARE EXPECTED TO SETTLE IN JUST
SLIGHTLY BELOW CLIMO. WEAK UPSLOPE FLOW WITHIN A MARGINALLY COLD
AIRMASS EXPECTED OVERNIGHT...ALTHOUGH RUC PROGS ANOTHER VORT TO
ROTATE IN. MAINLY ELEVATION DEPENDENT ADVISORY LVL SNOW ACCUMS
REMAIN LIKELY INTO MONDAY MORNING. THE NW FLOW SHOULD GRADUALLY WANE
THRU MONDAY. ANOTHER RELATIVE LULL WILL CONTINUE THROUGH THE MORNING
BUT MORE WEAK WAVES WILL DROP DOWN AGAIN IN THE AFTERNOON. WE SHOULD
SEE MORE CONVECTIVE CLOUDS OUTSIDE THE MOUNTAINS SO THE HIGH TEMPS
WERE KEPT CLOSER TO THE COOLER GUIDANCE.

&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...
AS OF 150 PM SUNDAY...SUFFICIENT MOISTURE AND MODESTLY STRONG LOW
LEVEL NW WINDS WILL RESULT IN A CONTINUATION OF SCATTERED SHOWERS
ALONG THE TENN BORDER MONDAY NIGHT. SNOW SHOULD REMAIN THE FAVORED
P-TYPE IN THE HIGHER ELEVATIONS...WITH MORE OF A RAIN/SNOW MIX
EXPECTED IN THE LOWER VALLEYS.

AS A RIDGE OF HIGH PRESSURE BUILDS INTO THE REGION FROM THE
NORTHWEST...THE FLOW WILL VEER TO THE NORTHEAST TUESDAY...LIKELY
BRINGING AN END TO SNOW/RAIN SHOWERS. HOWEVER...A CONTINUATION OF
ABUNDANT LOW LEVEL MOISTURE WILL PROMPT ME TO HOLD ON TO SLIGHT
CHANCES FOR SHOWERS INTO TUE NIGHT.

BY WEDNESDAY...A SW TROUGH WILL DIVE SOUTH ACROSS THE LOWER MISS
VALLEY. THIS WILL RESULT IN ESTABLISHMENT OF A WEAK EASTERLY FLOW
OVER THE AREA. WITH MOISTURE REMAINING CONFINED TO THE LOWER
LEVELS...POPS WILL BE HELD BELOW THE CHANCE RANGE ATTM. HOWEVER...
SLIGHT CHANCES FOR EASTERLY UPSLOPE SHOWERS WILL BE CARRIED FROM
LATE TUE NIGHT THROUGH THE DAY WEDNESDAY.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
AS OF 210 PM SUNDAY...THERE IS STILL VERY GOOD AGREEMENT BTW THE OP
MODELS WRT THE UPPER PATTERN WED NIGHT THROUGH THU. THE 12Z GFS IS
THE ONLY MODEL CLOSING OFF THE UPPER LOW...HOWEVER THE GGEM CLOSES
LATER ON AND THE ECMWF IS ON BOARD WITH THE TIMING REGARDLESS OF ITS
OPEN WAVE SOLN. SOME MEASURE OF LINGERING MOISTURE WILL REMAIN ALONG
THE BASE OF THE TROF...BUT THERE IS NO REASON TO BELIEVE HIGHER THAN
SLT POPS ARE WARRANTED WED NIGHT. MODEL SOUNDINGS INDICATE THE A VERY
SHALLOW SATURATED LAYER BETWEEN 3-5 KFT...HOWEVER ANY MECHANICAL
LIFT WILL BE LOST QUICKLY AS LAYERED WINDS VEER SIGNIFICANTLY AND
DYNAMICAL FORCING REMAINS WELL TO THE SOUTH.

A LOW AMPLITUDE STACKED RIDGE WILL BUILD IN FRI AND CROSS THE SE
REGION THROUGH SAT NIGHT. THIS IS WHEN THE MODELS BEGIN TO DIVERGE
WITH THE TIMING AND THE UPSTREAM PATTERN IDEAS. THE GFS IS FASTER
WITH THE RIDGE TRANSITIONING EAST...YET IT CLOSES OFF THE UPSTREAM
PATTERN AND REALLY SLOWS THE COLD FRONT DOWN IN COMPARISON TO THE
ECMWF. RIGHT NOW...THERE IS NO REASON TO GET TOO DETAILED WITH THE
TIMING...SO A LOW CHANCE POP ACROSS ALL ZONES SAT DAYTIME SEEMS
REASONABLE GIVEN THE LOWER CONFIDENCE AND THE DECENT AMOUNT OF GOM
MOISTURE FLUX EXPECTED. IN FACT...THE MOISTURE TRANSPORT SHOULD
BEGIN IN EARNEST SHORTLY AFT 00Z SAT...AND ACCORDING TO THE
SOUNDINGS THE SATURATION SHOULD BE RELATIVELY DEEP AND PREVENT MUCH
DESTABILIZATION THROUGHOUT THE DAY. HOWEVER...THE LLVL JET LOOKS TO
BE STRONG EARLY ON AND SOME T/STORMS DEVELOPMENT IS CERTAINLY NOT
OUT OF THE QUESTION. IN ANY REGARD...RAIN SHOWERS WILL BE
ADVERTISED IN THE GRIDS FOR NOW.

EXPECT AN UP/DOWN TEMP TREND THROUGHOUT THE EXT PERIOD...WITH AROUND
NORMAL MAXES THU AND A CAT OR SO ABOVE NORMAL FRI...THEN MAXES
SLIGHTLY DECREASING AGAIN SAT AND SUN TO RIGHT AROUND NORMAL. MINS
WILL BE AROUND NORMAL THU/FRI...HOWEVER WITH INCREASINGLY DEEP
CLOUD COVER...MINS ABOUT A CAT ABOVE NORMAL CAN BE EXPECTED
SAT/SUN.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
AT KCLT...LIGHT NORTHWEST WINDS WITH A CEILING AROUND 10 KFT WILL
REMAIN THROUGH THE REST OF THE PRE DAWN PERIOD. AFTER
SUNRISE...NORTHWEST WINDS WILL BEGIN TO STRENGTHEN...WITH GUSTS TO
20 KTS BY 17Z. INCREASING DOWNSLOPE FLOW WILL PROMOTE THE THINNING
AND SCT OF CLOUD COVER THROUGH THE DAY. GUSTY CONDITIONS MAY END
AROUND 23Z.

ELSEWHERE ACROSS THE FA...CONDITIONS ARE FORECAST TO REMAIN VFR
THROUGH THE PERIOD. KAVL...IS EXPECTED TO SEE AN MVFR CEILING EARLY
THIS MORNING...BECOMING VFR BY MID MORNING. NORTHWEST WINDS SHOULD
BECOME MARGINALLY GUSTY AROUND MID DAY AND REMAIN THROUGH THE
DAYTIME. GUSTS SHOULD END WITH SUNSET.

OUTLOOK...MAINLY VFR CONDITIONS ARE EXPECTED THRU MIDWEEK...BUT BRIEF
MVFR CIGS MAY LINGER AT KAVL TONIGHT. SOME LOW LEVEL MOISTURE
MAY PERSIST OVER THE MTNS THROUGH MUCH OF THE WEEK...BUT WITH LOW
CONFIDENCE ON ANY RESTRICTIONS.

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...WINTER WEATHER ADVISORY UNTIL 6 AM EDT EARLY THIS MORNING FOR
NCZ033-048>052-058-059.
SC...NONE.

&&

$$
SYNOPSIS...SBK
NEAR TERM...CSH/PM
SHORT TERM...JDL
LONG TERM...SBK
AVIATION...NED



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