Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 111008
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
608 AM EDT FRI JUL 11 2014

.SYNOPSIS...
A FRONTAL BOUNDARY WILL BE SOUTH OF OUR AREA TODAY AND GRADUALLY
WEAKEN AND DISSIPATE TONIGHT. WEAK HIGH PRESSURE WILL RETURN THROUGH
THE WEEKEND. A STRONG COLD FRONT IS EXPECTED TO REACH THE AREA ON
TUESDAY WITH THE POSSIBILITY OF STRONG STORMS.

&&

.NEAR TERM /THROUGH TONIGHT/...
1000 UTC UPDATE...AREAS OF FOG HAVE BEEN ADJUSTED PER RECENT
OBSERVATIONS...WITH THE LOWEST VISIBILITY ALONG THE INTERSTATE 40
CORRIDOR IN NC BETWEEN HICKORY AND STATESVILLE.

AT 230 AM EDT FRIDAY...AN UPPER TROUGH EXTENDED FROM NORTHERN QUEBEC
TO FL..WITH A SHORTWAVE MOVING THROUGH ITS BASE OVER THE SOUTHERN
APPALACHIANS. A QUASI-STATIONARY FRONT WAS LOCATED OVER THE SOUTHERN
APPALACHIANS. MOST CONVECTIVE ACTIVITY HAS DIMINISHED OVER OUR
AREA... WITH THE BULK OF ACTIVITY LOCATED CLOSER TO THE COAST IN
MORE UNSTABLE AIR.

OBSERVATIONS SHOW LOW CLOUDS AND FOG FORMING IN PORTIONS OF THE
PIEDMONT AND IN MOUNTAIN VALLEYS...AND THIS TREND IS EXPECTED TO
CONTINUE THROUGH DAWN...ESPECIALLY IN RAIN SOAKED AREAS.

THE SLOW MOVING SHORTWAVE IS EXPECTED TO CROSS OUR AREA TODAY...AND
MOVE TO THE COAST TONIGHT...AS IS THE ASSOCIATED FRONT. MODEL TIME
HEIGHTS SHOW LOW LEVEL FLOW VEERING FORM NE TO E TODAY...AND THEN SE
THIS EVENING. THIS WILL RESULT IN A MOIST UPSLOPE FLOW INTO THE BLUE
RIDGE. THE LIMITING FACTOR FOR CLOUD COVER AND CONVECTIVE COVERAGE
WILL BE THE SHALLOW DEPTH OF THE MOIST LAYER BEHIND THE FRONT. THE
BEST CONVECTIVE COVERAGE IS EXPECTED TO BE OVER THE MOUNTAINS...
WHERE OROGRAPHIC EFFECTS ENHANCE LIFT. MAXIMUM TEMPERATURES WILL BE
SLIGHTLY BELOW NORMAL.

DESPITE PERSISTENT SHALLOW MOIST UPSLOPE FLOW...CONVECTION IS
EXPECTED TO WAN EARLY IN THE EVENING AS HEATING ABATES...AND A WARM
NOSE STRENGTHENS AT 650 MB. MINIMUM TEMPERATURES ARE EXPECTED TO RUN
SLIGHTLY BELOW NORMAL.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
AS OF 107 AM FRI...WEAK HIGH PRESSURE WILL REMAIN RIDGED OVER THE
AREA SATURDAY THROUGH SUNDAY AS AN EXTENSION OF THE BERMUDA HIGH.
LIGHT LOW LEVEL E TO SE FLOW INDICATED ON THE GFS SATURDAY THEN
SHIFTS TO LIGHT SOUTHERLY WIND ON SUNDAY. LOW COVERAGE OF DIURNAL
CONVECTION IS EXPECTED ALMOST COMPLETELY OVER THE MTNS AND ADJACENT
FOOTHILLS SATURDAY PM WITH LIGHT UPSLOPE AND LIGHT LOW LEVEL
DIRECTIONAL CONVERGENCE FOCUSED ON MTNS. A BIT MORE
MOISTURE...SLIGHTLY MORE UNSTABLE ON SUNDAY ALONG WITH CONTINUED
LIGHT DIRECTIONAL LOW LEVEL WIND CONVERGENCE TO PRODUCE SOMEWHAT
MORE COVERAGE OF PM CONVECTION MAINLY OVER MTNS. MAX TEMPS SAT AND
SUN WILL BE AT OR JUST A DEGREE OR TWO ABOVE CLIMO NORMALS WITH MIN
TEMPS SAT NIGHT AND SUN NIGHT AT OR JUST ABOVE CLIMO NORMS AS WELL.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
AS OF 230 AM FRI...A DISTINCT UPPER LEVEL PATTERN CHANGE IS FORECAST
TO OCCUR IN THE EARLY TO MID WEEK PERIOD ACROSS THE EASTERN PART OF
THE NATION AS A DEEP UPPER LOW SWINGS SOUTH OUT OF NORTHERN CANADA
AND ESTABLISHES AN ANOMALOUS UPPER TROUGH OVER THE EAST BY MIDWEEK.
AS THE UPPER LOW MOVES SE AND HEIGHTS FALL...A SURFACE COLD FRONT
WILL BE DRIVEN SOUTHEASTWARD ACROSS THE GREAT LAKES SAT NIGHT...THEN
ACROSS THE OHIO VALLEY SUNDAY AND MONDAY. MEDIUM RANGE MODELS ARE IN
GOOD AGREEMENT THAT THE COLD FRONT WILL MOVE THROUGH OUR AREA DURING
THE TUESDAY AFTERNOON AND EVENING TIME PERIOD. THE FRONT WILL BE
WELL FORCED FOR JULY AND CAPES SHOULD POOL AHEAD OF THE FRONT TO
PERHAPS 2000J/KG...SO THERE IS A DISTINCT POSSIBILITY OF AN
ORGANIZED SEVERE STORM EVENT WITH THE FRONTAL PASSAGE. WIND SHEAR
WILL BE RATHER GOOD FOR JULY WITH GFS 925MB 5 TO 15KTS FROM SW TO W
LATE TUES AND 25 TO 30KTS AT 700MB FROM A GENERAL WEST DIRECTION.
THE FRONT MAY NOT CLEAR THE AREA COMPLETELY ON WED SO SOME LINGERING
SHOWERS MAY OCCUR PRIMARILY FROM NE GA TO THE CLT AREA. THE BIG
STORY BEHIND THE FRONT WILL BE THE COOLING. TEMPS ARE FORECAST TO BE
AT LEAST 2 STANDARD DEVIATIONS BELOW AVERAGE WED AND THU. THE
PREVIOUS VERY COOL CONSRAW GUIDANCE FOR WED HAD MAX TEMPS IN THE 70S
EVEN OVER PARTS OF THE PIEDMONT...BUT NOW HAS 80 TO 82 FOR THAT
REGION.  WE WILL NOT BE GOING THAT COOL YET...BUT THE POTENTIAL IS
THERE FOR EVEN COOLER THAN THE CURRENTLY FORECAST TEMPS. THE
ANOMALOUSLY COOL WEATHER WILL BE EVEN MORE PRONOUNCED TO THE NORTH.
THIS UPPER LOW WILL LIFT OUT TO THE NE FROM THE GREAT LAKES ON
THURSDAY TO LOCATIONS OVER EASTERN CANADA AT WEEKS END. 500MB
PATTERN BECOMES MORE ZONAL WEST TO EAST AT THE END OF THE WEEK WITH
MODERATING TEMPS. TO SUMMARIZE...MONDAY SHOULD BE A TYPICAL JULY DAY
WITH DIURNALLY DRIVEN SCATTERED SHOWERS AND THUNDERSTORMS WITH TEMPS
A COUPLE DEGREES ABOVE CLIMO NORMS. THUNDERSTORMS...POSSIBLY SEVERE
ARE A GOOD BET FOR TUE WITH THE COLD FRONT. MUCH COOLER WEATHER IS
EXPECTED WED AND THU WITH SOME LINGERING LOW SLIGHT CHANCE SHOWERS
POSSIBLE ON THU.

&&

.AVIATION /10Z FRIDAY THROUGH TUESDAY/...
AT KCLT...LOW RESTRICTIONS HAVE SET UP...AND WILL CONTINUE VERY
EARLY THIS MORNING. HEATING AND MIXING WILL ERODE RESTRICTIONS BY
MID MORNING. WINDS WILL VEER FROM NE TO W TODAY...AND THEN TO SE
THIS EVENING...THEN BACK TO NE BY DAYBREAK SATURDAY. THE BEST CHANCE
FOR AFTERNOON CONVECTION WILL BE IN THE MOUNTAINS WELL TO THE WEST.
GUIDANCE IS NOT VERY SUPPORTIVE OF CIG RESTRICTIONS ON SATURDAY
MORNING...BUT IS SUPPORTIVE OF VSBY RESTRICTIONS.

KAVL AND KHKY...ONGOING RESTRICTIONS WILL LINGER UNTIL MID
MORNING...WHEN HEATING AND MIXING TAKE PLACE. KHKY WINDS WINDS WILL
VEER FROM NE TO SE BY LATE AFTERNOON...THEN BACK TO NE OVERNIGHT.
KAVL WINDS WILL VEER FROM N TO SE TODAY...THEN BECOME NEARLY CALM
OVERNIGHT. WITH A MOIST UPSLOPE...KAVL HAS A DECENT SHOT AT
SOME AFTERNOON CONVECTION. GUIDANCE IS NOT AS SUPPORTIVE OF CIG
RESTRICTIONS TOWARD DAWN SATURDAY AT KHKY...BUT IS BECOMING SO AT
KAVL. GUIDANCE IS SUPPORTIVE OF VSBY RESTRICTIONS IN FOG.

AT SC SITES...SO FAR SC TAF SITES HAVE AVOIDED RESTRICTIONS...
DESPITE LOW DEW POINT DEPRESSION. WITH THE LOWER LEVELS SO
MOIST...TEMPORARY MVFR RESTRICTIONS CANNOT BE RULED OUT BEFORE MID
MORNING. WINDS WILL VEER FROM NE TO E TODAY...THEN BACK TO NE
OVERNIGHT. CONVECTIVE CHANCES WILL BE BETTER NEARER THE BLUE RIDGE.

OUTLOOK...HIGH PRESSURE WILL SLOWLY SETTLE OVER THE AREA THIS
WEEKEND. ANY RESTRICTIONS SHOULD MAINLY BE CONFINED TO DIURNAL TSTMS
AND MORNING VALLEY FOG EACH DAY.

CONFIDENCE TABLE...

            10-16Z        16-22Z        22-04Z        04-10Z
KCLT       MED   66%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH  88%     HIGH 100%     HIGH 100%     HIGH  97%
KAVL       LOW   52%     HIGH 100%     HIGH 100%     HIGH  80%
KHKY       LOW   56%     HIGH 100%     HIGH 100%     HIGH  94%
KGMU       HIGH  97%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH  86%     HIGH 100%     HIGH 100%     HIGH  97%

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...JAT
SHORT TERM...DEO
LONG TERM...DEO
AVIATION...JAT





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