000
FXUS62 KGSP 111057
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
657 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 TONIGHT/...
AS ON 535 AM...THE CURRENT FORECAST REMAINS ON TRACK. I WILL ALIGN
EARLY MORNING TEMPERATURE TRENDS TO OBSERVATIONS. LITTLE TO NO
CHANGE MADE TO THE REST OF THE FORECAST.

AS OF 315 AM...RECENT WATER VAPOR IMAGES SHOW A WELL DEVELOPED VORT
MAX OVER THE NORTH TEXAS COAST. IR SATELLITE INDICATES A WIDE AREA
OF CLOUD COVER ALONG AND AHEAD OF THE MID LEVEL DISTURBANCE...WITH
LITTLE TO NO CLOUD COVER ACROSS THE SOUTHEAST U.S. THE SKY COVER
ACROSS THE FORECAST AREA WILL REMAIN CLEAR THIS MORNING...WITH
INCREASING COVERAGE OF THIN HIGH CLOUDS DURING THIS AFTERNOON AND
EVENING. STRONG INSOLATION...MILD LLVL THICKNESSES...AND DOWNSLOPE
H85 WINDS SHOULD YIELD ANOTHER WARM DAY. A BLEND OF PREFERRED
TEMPERATURE GUIDANCE SUPPORTS HIGH TEMPERATURES RANGING FROM THE MID
70S WITHIN THE MTN VALLEYS TO THE UPPER 70S EAST OF THE MTNS.

TONIGHT...A POSITIVELY TILTED H5 TROUGH WILL RIPPLE EAST FROM THE
CENTRAL CONUS. NEAR TERM GUIDANCE INDICATES THAT THE MID CONUS
TROUGH WILL PHASE WITH THE TROUGH OVER THE LOWER MISSISSIPPI RIVER
VALLEY. AT THE SFC...A LARGE LOW PRESSURE SYSTEM IS FORECAST TO
QUICKLY ORGANIZE ACROSS THE WESTERN OHIO RIVER VALLEY. WEAK 305-315K
ISENTROPIC LIFT WILL DEVELOP AHEAD OF THE APPROACHING COLD FRONT.
THE COMBINATION OF LLVL ISENTROPIC LIFT AND DEEP MOISTURE SHOULD
SUPPORT LIGHT RAIN...ARRIVING FROM THE SW. I WILL INDICATE A SHARP
INCREASE IN POPS BETWEEN 6-12Z. QPF BEFORE 12Z WILL LIKELY RANGE
FROM 0.3 ACROSS THE UPPER SAVANNAH RIVER VALLEY TO AROUND 0.1 OF AN
INCH ACROSS THE UPPER I-77 CORRIDOR. TEMPERATURES OVERNIGHT WILL
REMAIN WELL ABOVE FREEZING...NEAR 50 ACROSS THE MTNS TO UPPER 50S
ACROSS THE FOOTHILLS AND PIEDMONT.

&&

.SHORT TERM /WEDNESDAY THROUGH THURSDAY NIGHT/...
AS OF 330 AM TUESDAY...THE MAIN CONCERN THROUGH THE SHORT RANGE
REMAINS 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 OUR CWFA BETWEEN
THE BEST SOURCES OF FORCING...THE DAMPENING UPPER LOW MOVING ALONG
THE GULF COAST AND THE MAIN PORTION OF THE STRONG SHORT WAVE MOVING
INTO THE MID ATLANTIC. THE LOW LEVEL FLOW TURNS MORE SWLY AHEAD OF
THIS SYSTEM DISRUPTING ANY STRONG LOW LEVEL MOISTURE ADVECTION. THAT
SAID...DEEP MOISTURE DOES MOVE IN WITH THE FRONT. NAM AND SREF SHOW
RELATIVELY WEAK INSTABILITY WITH THIS SYSTEM. THE GFS...WHILE
LESS...SHOWS WEAK INSTABILITY AS WELL. QUITE A BIT OF SHEAR MOVES
THRU AS WELL. HOWEVER...THERE IS A MINIMUM IN THESE FEATURES OVER
OUR CWFA. STRONGER SHEAR AND BETTER INSTABILITY WILL REMAIN NORTH
AND SOUTH OF THE CWFA. THEREFORE...STILL EXPECT ISOLATED TO SCT TSRA
TO MOVE THRU ON WED...BUT SEVERE CHANCES APPEAR TO BE LIMITED. OF
COURSE...THIS COULD CHANGE...SO WILL NEED TO KEEP AN EYE ON THIS
SYSTEM. PRECIP TAPERS OFF FROM SW TO NE BEHIND THE DEPARTING FRONT
WED AFTERNOON AND EVENING...LEAVING A BRIEF BUT POTENT NW FLOW SNOW
EVENT IN ITS WAKE WED NITE. ALTHOUGH THE EVENT IS BRIEF...STRONG
WINDS AND CAA WILL LEAD TO SOME INTENSE SNOW SHOWERS. FOR NOW...HAVE
SNOW AMOUNTS AROUND AN INCH ACROSS THE HIGHER ELEVATIONS OF THE TN
BORDER COUNTIES...BUT AMOUNTS COULD APPROACH 2 INCHES. IN ADDITION
TO THE TSRA...STRONG WINDS ARE LIKELY TO DEVELOP ACROSS THE AREA WED
AND CONTINUE ACROSS THE MTNS WED NITE. THE NAM AND GFS BOTH SUGGEST
WIND GUSTS COULD REACH WIND ADVISORY LEVEL ACROSS THE AREA WEDNESDAY
AND CONTINUE ACROSS THE MTNS WED NITE. HIGH WIND WARNING LEVEL GUSTS
ARE POSSIBLE ACROSS THE HIGHEST ELEVATIONS OF THE NC MTNS...BUT WILL
LIKELY NOT REACH THAT LEVEL IN THE VALLEYS.

SNOWFALL TAPERS OFF QUICKLY THU MORNING LEAVING A DRY BUT COLD AND
BREEZY FORECAST THU AFTERNOON AND NITE. HIGHS WILL BE 10 TO 15
DEGREES ABOVE NORMAL WED...BUT WILL COOL DURING THE AFTERNOON ACROSS
THE MTNS. HIGHS FALL TO 15 TO 20 DEGREES BELOW NORMAL ON THU. LOWS
WILL BE 10 TO 20 DEGREES BELOW NORMAL WED NITE AND REMAIN NEARLY
STEADY THU NITE.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
AS OF 210 AM EDT TUESDAY...THE MEDIUM RANGE BEGINS AT 12Z FRIDAY
WITH SURFACE HIGH PRESSURE AND A LOW AMPLITUDE UPPER RIDGE OVER THE
SOUTHEAST STATES. THIS SURFACE HIGH AND UPPER RIDGE MOVES WELL OFF
THE SE COAST FRIDAY NIGHT. THERE IS BIG DIFFERENCES BETWEEN THE
MODELS ON THE OUTCOME OF THE FORECAST FOR THE WEEKEND AND EARLY NEXT
WEEK. THE GFS AND CANADIAN ARE SIMILAR...HOWEVER...THE GFS IS MUCH
MORE PROGRESSIVE IN MOVING THE INITIAL SHORTWAVE ACROSS OUR REGION
DURING THE DAY SATURDAY. WE ARE FOR THE MOST PART DRY ON THE GFS
FROM SATURDAY NIGHT THROUGH THE END OF THE FORECAST MONDAY NIGHT.
THE SECOND WAVE ON THE GFS DIVES DEEP SOUTH OVER THE GULF ON MONDAY
CARRYING ALL REMAINING PRECIP WELL SOUTH OF US.  THE CANADIAN HAS A
STRONGER LOW TO FORM SATURDAY NIGHT OVER ARKANSAS AND PRECIP JUST
REACHING OUR WESTERN MOUNTAINS AT 12Z SUNDAY...BUT OF COURSE THE
CANADIAN ENDS AT 12Z SUNDAY. THE 12Z MONDAY ECMWF KEEPS US DRY UNTIL
LATE SUNDAY AS IT DIGS A DEEPER TROUGH OVER THE LOWER MISSISSIPPI
VALLEY FORMING A CLOSED OFF UPPER LOW OVER THE STATE OF MISSISSIPPI
BY 12Z MONDAY. ON THE ECMWF...WAVES OF PRECIP PASS OVER OUR AREA
FROM LATE SUNDAY THROUGH LATE MONDAY NIGHT. WE WILL LIKELY HAVE SOME
KIND OF ACTIVE WEATHER DURING THIS PERIOD...SAT THROUGH MON...JUST A
MATTER OF EXACTLY WHEN AND FOR HOW LONG. WE WILL TAKE SOME SORT OF
AVERAGE AND HOPE THAT WHEN WE GET CLOSER TO THE WEEKEND THE MODELS
WILL BE IN BETTER AGREEMENT.

TEMPERATURES START OUT A FEW DEGREES BELOW NORMAL FRIDAY...RISE TO
AROUND NORMAL DURING THE WEEKEND...THEN FALL BELOW AGAIN AS WHICH
EVER SYSTEM MOVE EAST OFF THE SE COAST.

&&

.AVIATION /12Z 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...REACHING THE TERMINAL AROUND 9Z. BY 0Z...SKY ACROSS THE
TERMINAL SHOULD BECOME BKN AROUND 10 KFT WITH SCT070. WINDS SHOULD
REMAIN FROM THE SOUTHWEST THROUGH THE TAF PERIOD. RESTRICTIVE
CEILINGS AND VIS WILL LIKELY ARRIVE BY 11Z WED. I WILL INCLUDE A
TEMPO AT THE END OF THE TAF TO INDICATE IFR CEILINGS WITH MVFR VIS
IN -SHRA.

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. TERMINALS WILL SEE RAIN AND RESTRICTIVE
CEILINGS AND VIS AFTER 6Z.

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...

            11-17Z        17-23Z        23-05Z        05-11Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  84%
KAVL       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  89%
KHKY       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  95%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  91%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  88%

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...DEO
NEAR TERM...NED
SHORT TERM...RWH
LONG TERM...DEO
AVIATION...NED