Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 021453
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1053 AM EDT THU OCT 2 2014

.SYNOPSIS...
DRIER HIGH PRESSURE WILL LINGER OVER THE REGION TODAY. A STRONG COLD
FRONT WILL SWEEP ACROSS THE CAROLINAS ON FRIDAY...THEN MOVING
OFFSHORE BY EARLY SATURDAY. IN THE WAKE OF THE FRONT...A COOL AND DRY
AIRMASS WILL MOVE BACK OVER THE REGION AND REMAIN IN PLACE OVER THE
WEEKEND. ANOTHER COLD FRONT WILL APPROACH THE SOUTHERN APPALACHIAN
REGION FROM THE NORTHWEST EARLY NEXT WEEK.

&&

.NEAR TERM /THROUGH TONIGHT/...
AS OF 1040 AM...LOW STRATUS AND FOG LINGERS THIS MORNING ACROSS THE
MTN VALLEYS AND A SMALL AREA OF THE NORTHWEST NC PIEDMONT. THIS WILL
DRY UP RATHER RAPIDLY OVER THE NEXT HOUR OR SO...LEAVING CLEAR SKIES
ACROSS THE AREA. MORNING RAOBS AND FORECAST SOUNDINGS DEPICT
MAINTENANCE OF A RATHER HEALTHY MID-LEVEL INVERSION BENEATH THE
UPPER RIDGE TODAY. NEVERTHELESS...SOME OF THE SHORT TERM AND
MESOSCALE MODELS HINT AT SOME SHOWER DEVELOPMENT LATER TODAY. I
SUPPOSE IT/S NOT OUT OF THE QUESTION THAT A SHOWER OR TWO COULD
DEVELOP BENEATH THE CAP ACROSS THE HIGH TERRAIN LATE TODAY (SIMILAR
TO YESTERDAY). NEVERTHELESS...COVERAGE SHOULD BE SUCH THAT NO POPS
ARE WARRANTED FOR THIS AFTERNOON. OTHERWISE...TEMPS WILL REMAIN 5-10
DEGREES ABOVE CLIMO THIS AFTERNOON.

AS OF 530 AM...PATCHES OF FOG HAD DEVELOPED ACROSS THE WESTERN
CAROLINAS AND NORTHEAST GEORGIA...SOME OF WHICH WAS LOCALLY DENSE IN
THE MOUNTAIN VALLEYS. THINK THE FOG SHOULD DISSIPATE QUICKLY AGAIN
THIS MORNING...WITHIN AN HOUR OR SO OF SUNRISE. TEMP TRENDS LOOK OK.

THE MAIN CONCERN FOR THE NEAR TERM WILL BE THE APPROACH OF A COLD
FRONT DURING THE EARLY MORNING HOURS ON FRIDAY. BEFORE WE GET
THERE...ONE MORE SEASONALLY WARM EARLY AUTUMN DAY WITH MOSTLY CLEAR
SKY AND TEMPS ABOVE NORMAL. THE AXIS OF AN UPPER RIDGE WILL MOVE
OVERHEAD TODAY AND THEN OFF TO THE EAST THIS EVENING. THIS SHOULD
CARRY SURFACE HIGH PRESSURE OFF THE E COAST BY THE END OF THE DAY
THAT WILL SET THE STAGE FOR AN INFLUX OF GULF MOISTURE TONIGHT. THE
NAM CONTINUES TO DEVELOP A FEW SHOWERS UNDERNEATH A SUBSIDENCE
INVERSION AGAIN TODAY...AND ONCE AGAIN THAT LOOKS TO BE LARGELY
OVERDONE. WILL NOT RULE OUT ONE OR TWO ISOLATED SHOWERS SOMEWHERE
NEAR THE HIGHER TERRAIN...BUT THE POSSIBILITY REMAINS TOO LOW TO
INCLUDE IN THE FCST. AFTER MIDNIGHT TONIGHT...CONDITIONS WILL BECOME
INCREASINGLY FAVORABLE FOR THE DEVELOPMENT OF SHOWERS AS UPPER
DIVERGENCE ARRIVES WITH THE RIGHT ENTRANCE REGION OF THE JET
TRANSLATING EWD ACROSS THE SOUTHEAST. WARM ADVECTION AND MID LEVEL
DPVA WILL ALSO ARRIVE AFTER 06Z FRIDAY AS A PRELIMINARY SHORT WAVE
LIFTS OUT OF THE TROF AXIS TO THE WEST. THE INCREASING FORCING
SHOULD ACT UPON THE INFLUX OF MOISTURE TO DEVELOP SHOWERS TO THE
WEST THAT COULD ARRIVE OVER THE WESTERN MOUNTAINS AND NE GEORGIA/WRN
UPSTATE BY SUNRISE ON FRIDAY. WILL START TO RAMP UP PRECIP CHANCES
FROM THE W IN THE 09Z TO 12Z TIME FRAME. MIN TEMPS SHOULD BE MILD
WITH INCREASING CLOUD COVER AND WARM ADVECTION.

&&

.SHORT TERM /FRIDAY THROUGH SATURDAY/...
AS OF 315 AM THURSDAY...ON FRIDAY...A DEEP MID LEVEL CLOSED LOW WILL
TRACK SW THE WESTERN GREAT LAKE REGION. SOUTH OF THE LOW...THE AXIS OF
THE MID LEVEL TROUGH WILL DIG EAST ACROSS THE SOUTHEAST REGION. AT
THE SFC...A STRONG COLD FRONT WILL PUSH FROM MIDDLE TN 12Z FRIDAY TO
THE CAROLINA COAST BY 12Z SATURDAY. MID AND UPPER LEVEL FORCING WILL
INCREASE AS A SHORT WAVE AND BAND OF JET DIVERGENCE CROSSES THE
SOUTHERN APPALACHIANS AFTER 12Z FRIDAY. THE LOW LEVEL ENVIRONMENT
WILL FEATURE CAPES BETWEEN 500-1200 J/KG WITH HELICITY VALUES
BETWEEN 100-200 M2/S2. EHI VALUES SURGE NORTHWARD ACROSS THE REGION
AFTER MID MORNING...WITH VALUES EXCEEDING 1 M2/S2 ACROSS THE NC
PIEDMONT DURING THE MID AFTERNOON. THIS ENVIRONMENT SHOULD SUPPORT
THE DAYTIME PASSAGE OF A PRE FRONTAL BAND OF SHOWERS AND THUNDERSTORMS
ACROSS THE HIGH TERRAIN. I WILL INCREASE POPS TO CATE TO HIGH LIKELY
ACROSS THE CWA...ESPECIALLY FRIDAY AFTERNOON. GIVEN THE
ENVIRONMENT...IT IS POSSIBLE THAT WELL ORGANIZED QLCS COULD DEVELOP
FRIDAY AFTERNOON OR EVENING. HOWEVER...THE POSSIBILITY OF SVR
WEATHER APPEARS TOO LIMITED TO HIGHLIGHT IN THIS MORNINGS HWO.
TEMPERATURES WILL BE LIMITED BY THICK CLOUDS AND RAINFALL...HIGHS
SHOULD REMAIN AROUND 5 DEGREES BELOW NORMAL.

ON SATURDAY...STRONG H85 CAA WILL OCCUR ACROSS THE REGION...FALLING
FROM 15C OVER AVL AT 0Z TO 2C BY 12Z. LOW TEMPERATURES ARE FORECAST
TO RANGE FROM THE 40S ACROSS THE HIGH TERRAIN TO THE MID 50S ACROSS
THE PIEDMONT. HIGH TEMPERATURES WILL LIKELY RANGE 10 TO 12 DEGREES
BELOW NORMAL.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
AS OF 330 AM THURSDAY...SUNDAY SHOULD SEE THE COOLEST TEMPERATURES
OF THE PERIOD. THE CENTER SFC HIGH PRESSURE IS FORECAST TO REACH THE
AL/GA LINE BY 12Z SUNDAY. CONDITIONS ACROSS THE REGION WILL FEATURE
DRY...CALM...AND LIMITED SKY COVER. IN ADDITION...CAA MAY PUSH H85
TEMPS ACROSS THE NRN MTNS FROM 0C TO -1C. SUNDAY MORNING...MINS IN
THE MID 30S SHOULD BE COMMON ACROSS MTN RIDGES. ELSEWHERE....VALUES
ARE FORECAST TO RANGE IN THE LOW TO MID 40S.

EARLY NEXT WEEK...THE CENTER OF HIGH PRESSURE WILL PUSH OFF THE
CAROLINA COAST AS A WEAK COLD FRONT APPROACHES FROM THE WEST. THIS
PATTERN SHOULD ADVECT WARMER TEMPERATURES AND MOISTURE ACROSS THE
SOUTHERN APPALACHIAN REGION. TEMPERATURES WILL MODIFY THROUGH THE
LATE EXTENDED PERIOD...RETURN TO NEAR NORMAL BY TUESDAY AND
WEDNESDAY. IN ADDITION...I WILL MENTION DEVELOPING WIDELY SCATTERED
SHOWERS ACROSS THE MTNS AND FOOTHILLS ON TUESDAY.

&&

.AVIATION /15Z THURSDAY THROUGH MONDAY/...
AT KCLT...SCATTERED MID LEVEL CLOUDS TO START. AS EXPECTED...FOG HAS
DEVELOPED IN THE OUTLYING AREAS WHICH HAS REDUCED THE VISIBILITY TO
MVFR. CANNOT RULE OUT A BRIEF PERIOD OF MVFR THROUGH 13Z...BUT THE
CHANCE IS NOT GREAT ENOUGH TO MENTION. EXPECT SCT STRATOCU TO
DEVELOP THIS MORNING AND PERSIST THROUGH THE DAY...WITH A LIGHT S TO
SW WIND AS HIGH PRESSURE MOVES OFF THE COAST. THERE APPEARS TO BE
LITTLE CHANCE THAT LOW CLOUDS AND PRECIP AHEAD OF THE NEXT FRONT
WILL REACH THE TERMINAL BEFORE 12Z FRIDAY.

ELSEWHERE...THE BIG PROBLEM WILL BE DENSE MOUNTAIN VALLEY FOG AT
KAVL...WHICH WAS REDUCING VSBY TO VLIFR AT ISSUANCE TIME. OTHER TAF
SITES MAY SEE A PERIOD OF MVFR VISIBILITY AND THAT WAS INCLUDED. THE
FOG SHOULD LIFT AND BURN OFF BY 13Z TO 14Z. OTHERWISE...SCT/FEW HIGH
BASED STRATOCU AGAIN TODAY WITH A LIGHT WIND FROM THE S TO SW. AFTER
SUNSET...WE WILL LOOK TOWARD THE WEST FOR THE APPROACHING CLOUDINESS
AND PRECIP AHEAD OF THE NEXT FRONT. SOME LOW CLOUD RESTRICTIONS AND
SHOWERS COULD REACH KAVL NEAR THE VERY END OF THE PERIOD...BUT FOG
IS MORE LIKELY AGAIN IN THE VALLEYS AROUND 12Z FRIDAY...SO THAT WAS
INCLUDED INSTEAD OF THE SHOWER CHANCE.

OUTLOOK...A COLD FRONT WILL MOVE ACROSS THE AREA ON FRI WHICH WILL
TRIGGER SHOWERS AND THUNDERSTORMS...WITH ASSOCIATED RESTRICTIONS
POSSIBLE. BEHIND THE FRONT FRI NIGHT...CLEARING WILL OCCUR WITH AN
EXTENDED PERIOD OF VFR WEATHER ANTICIPATED THROUGH EARLY NEXT WEEK.

CONFIDENCE TABLE...

            14-20Z        20-02Z        02-08Z        08-14Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH  95%
KAVL       HIGH  93%     HIGH 100%     HIGH  95%     HIGH  91%
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  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...NONE.
SC...NONE.

&&

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





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