Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 302350
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
750 PM EDT SAT AUG 30 2014

.SYNOPSIS...
A BERMUDA HIGH WILL DEVELOP AND LINGER INTO EARLY NEXT WEEK...
RESULTING IN TYPICAL SUMMERTIME HEAT AND SCATTERED AFTERNOON
THUNDERSTORMS EACH DAY.

&&

.NEAR TERM /THROUGH SUNDAY/...
730 PM EDT UPDATE...CONV ACTIVITY HAS WANED ACROSS THE CWFA WITH THE
BEST LIFT REMAINING WEST OF THE ULVL RIDGE. THE HRRR AND NAM BOTH
HAVE A LINE OF -SHRA/TSRA DEVELOPING ARND 06Z OR SO ACROSS THE SW/RN
ZONES AND SWEEPING EAST THROUGH THE MORNING HRS. THIS HAS BEEN
PICKED UP BY THE LATEST 18Z GFS AS WELL. ANYWAY...THIS SCENARIO WILL
BE LOOKED AT MORE CLOSELY WITH THE EVENING UPDATE. FOR THE REMAINDER
OF THE EVENING...EXPECT ISOL CONV ACTIVITY ACROSS THE SW/RN NC MTNS
AND NE GA. THE MAIN THREAT WITH THESE STORMS WILL BE CTG LIGHTNING
WITH GUSTY OUTFLOWS PROBABLE AS WELL.

430 PM EDT UPDATE...LATEST COMP RADAR TRENDS SHOW CONV ACTIVITY
CONFINED ACROSS THE WRN ZONES OF THE CWFA. A 4 DEGREE F DROP OF SFC
TD/S IN THE PAST 3 HRS HAS KEPT SBCAPE VALUES LOW EAST OF THIS AREA
WHILE STRONG H5 RIDGING HAS NULLIFIED MLVL LAPSE RATES. THIS GENERAL
PATTERN WILL CHANGE LITTLE OVER THE NEXT FEW HRS AND THE BEST H85
MOIST TRANSPORT WILL REMAIN ACROSS WRN TN. THUS...ISOL TO SCT CONV
WILL CONTINUE WEST ALIGNED IN MECH LIFT AND SOME MEASURE OF ULVL
DPVA...WITH ISOL CELLS LIKELY DEVELOPING EAST ACROSS THE UPSTATE AND
NC FTHILLS. NOT EXPECTING ANYTHING STRONG NOR SEVERE THRU 800 PM
WITH ECHO TOPS ONLY REACHING 35-40 KFT ASSOCIATED WITH FAIRLY WEAK
UPDRAFTS.

AS OF 215 PM...LATEST CAM`S SHOWING A LITTLE MORE CONVECTIVE
RESPONSE THIS AFTERNOON SO HAVE NUDGED THE POPS HIGHER OVER THE
WESTERN UPSTATE AND THE MOUNTAINS. IT STILL LOOKS LIKE CONVECTIVE
COVERAGE WILL INCREASE AS THE AFTERNOON PROGRESSES OVER NE GA AND
THE SW MOUNTAINS...WITH COVERAGE THEN SPREADING NE INTO THE CENTRAL
MOUNTAINS/NORTHERN MOUNTAINS DURING THE EVENING HOURS AS A WEAK
SHORT WAVE MOVES THROUGH TN. CAN`T RULE OUT SOME SHOWERS/STORMS
AFFECTING THE ADJACENT FOOTHILLS/PIEDMONT DURING THE EVENING SO HAVE
BUMPED POPS UPWARD THERE PER LATEST CAMS. HAVE DISCOUNTED THE
SPURIOUS DEEP CONVECTION AND HEAVY QPF THAT THE NAM DEVELOPS IN THE
NC PIEDMONT OVERNIGHT. DO NOT SEE THE TRIGGERING MECHANISM FOR SUCH
A RESPONSE AND THERE IS NO SUPPORT FROM ANY OTHER MODEL.

IN REGARD TO THE BIG PICTURE...THE UPPER HIGH WILL BE GRADUALLY
SUPPRESSED TO THE SE AS A SERIES OF SHORT WAVES MOVE THROUGH THE TN
VALLEY INTO THE MID-ATLANTIC STATES. THE FIRST OF THESE SHORT WAVES
WILL MOVE BY THIS EVENING AND THEN ANOTHER ON SUNDAY. AS THE FIRST
WAVE MOVES BY TO THE WEST TONIGHT...SCT SHOWERS AND STORMS WILL
OCCUR MAINLY OVER THE MOUNTAINS...POSSIBLY CONTINUING INTO THE EARLY
MORNING HOURS OF SUNDAY. WITH MOIST PROFILES AND WEAK WIND FIELDS...
SEVERE STORMS ARE NOT EXPECTED. HOWEVER...SOME LOCALLY HEAVY IS
POSSIBLE.

ON SUNDAY...SCT SHOWERS AND STORMS ARE EXPECTED TO DEVELOP AGAIN AS
ANOTHER SHORT WAVE MOVES BY TO THE WEST COINCIDING WITH MAX HEATING.
THE MODELS HAVE BEEN TRENDING AWAY FROM SHOWING MUCH QPF RESPONSE
OUTSIDE THE MOUNTAINS ON SUNDAY. HENCE...HAVE DIALED BACK POPS TO THE
SLIGHT CHANCE/CHANCE RANGE OVER THE PIEDMONT. THE BEST COVERAGE
SHOULD BE ALONG THE SPINE OF THE MOUNTAINS WHERE NUMEROUS STORMS MAY
OCCUR.

USED OUR CONSALL BLEND TO POPULATE MOST FIELDS. TEMPS WILL CONTINUE
ABOVE CLIMO. MAX TEMPS ON SUNDAY WILL BE CLOSE TO TODAY`S
NUMBERS...THOUGH PERHAPS A COUPLE DEGREES LESS WARM IN THE MOUNTAINS
DUE TO MORE CONVECTIVE COVERAGE.

&&

.SHORT TERM /SUNDAY NIGHT THROUGH TUESDAY/...
AS OF 200 PM SATURDAY...FAIRLY STANDARD LATE SUMMER WEATHER IS
EXPECTED THROUGH THE SHORT TERM...AS SUBTROPICAL/BERMUDA HIGH
PRESSURE REMAINS AS THE DOMINANT SYNOPTIC SCALE FEATURE ACROSS THE
SOUTHEAST. THIS SHOULD GENERALLY SUPPORT WARM AND HUMID CONDITIONS
THROUGH THE PERIOD...WITH CHANCES FOR DIURNAL CONVECTION GENERALLY
EXPECTED TO BE NEAR TO SLIGHTLY ABOVE CLIMO (30 PERCENT MTNS/20
PERCENT ACROSS THE LOWER TERRAIN) MON AND TUE AFTERNOONS. CONVECTIVE
CHANCES MAY INCREASE SLIGHTLY ACROSS OUR WESTERN AREAS BY TUE
EVENING...AS DEEP LAYER MOISTURE INCREASES AHEAD OF A WEAK FRONTAL
ZONE. TEMPERATURES ARE EXPECTED TO REMAIN ABOUT A CATEGORY ABOVE
NORMAL THROUGH THE PERIOD.

&&

.LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/...
AS OF 230 PM EDT SATURDAY...THE LATEST GLOBAL MODELS INDICATE THAT
H5 HEIGHTS WILL CONTINUE TO RISE OVER THE FORECAST AREA TUE NIGHT
INTO FRI AS A BROAD UPPER RIDGING AMPLIFIES ACROSS THE SOUTHEAST AND
GULF STATES. BY SAT...WEAK UPPER NWLY FLOW WILL SET UP AS THE CENTER
OF UPPER ANTICYCLONE RETROGRADES TOWARD THE WESTERN CONUS. AT THE
SURFACE...HIGH PRESSURE WILL WEAKEN AND SLIDE SOUTH OF THE AREA TUE
NIGHT AS A WEAK COLD FRONT APPROACHES FROM THE NW. THE FRONT WILL
PUSH THRU THE AREA ON WED AND BECOMES STATIONARY JUST TO OUR SOUTH
BY THU. A BERMUDA HIGH WILL THEN BUILD BACK IN FROM THE SE BY FRI
AND REMAIN IN PLACE THRU DAY 7. AS FOR OUR SENSIBLE WEATHER...HAVE
MENTIONED 30/40 POPS WED/THU DUE TO INCREASING MOISTURE AND BUOYANCY
ALONG AND AHEAD OF THE FRONT. FRI/SAT...DIURNAL BUOYANCY AND
MOISTURE UNDER THE INFLUENCE OF BERMUDA HIGH WILL BE SUPPORTIVE OF
SCATTERED AFTERNOON SHOWERS AND THUNDERSTORMS ON EACH
DAY...MAINTAINING POPS IN THE 30/40 RANGE. TEMPERATURES WILL STAY
AROUND 2-5 DEGREES ABOVE NORMAL WED/THU BEFORE COOLING TO NEAR
NORMAL BY FRI.

&&

.AVIATION /00Z SUNDAY THROUGH THURSDAY/...
AT KCLT...VFR CONDS THROUGH MOST OF THE OVERNIGHT TIL ARND 10Z OR SO
WHEN MVFR VSBY MAY FORM THROUGH 14Z. ACTUAL CLOUD COVER WILL BE THE
LIMITING FACTOR. THERE IS A LOW CHANCE OF A LINE OF -SHRA OR TSRA
REACHING THE TERMINAL VICINITY ARND 10Z...BUT IT WILL PROBABLY
DISIPATE TO THE WEST. ANOTHER LOW CHANCE FOR CONV SUN LATE AFTERNOON
AND WILL MENTION WITH A PROB30 AT 20Z.

ELSEWHERE...GOOD CLOUD COVER ACROSS THE MTNS WILL LIMIT RADIATIONAL
COOLING AT KAVL AND KHKY...BUT MVFR/IFR VSBY IS NOT OUT OF THE
QUESTION AFT 08Z....WILL GO MVFR FOR THIS ISSUANCE. A LINE OF
-SHRA/TSRA COULD WORK ACROSS THE MTNS AND INTO THE UPSTATE AFT 08Z
AS WELL AND THIS WILL BE COVERED WITH VCSH AT ALL TERMINALS...EXCEPT
VCTS AT KAVL THROUGH 12Z/13Z. CONV ACTIVITY WILL AFFECT MAINLY KAVL
AND KHKY SUN AFTERNOON...BUT ALL SITES HAVE HIGH ENOUGH CHANCES TO
WARRANT A LATE PERIOD PROB30 TSRA.

OUTLOOK...GENERALLY VFR CONDITIONS ARE EXPECTED THROUGH EARLY NEXT
WEEK WITH THE EXCEPTION FOR RESTRICTIONS IN THE EARLY MORNING DUE TO
LOW CLOUDS AND FOG...PRIMARILY IN THE MOUNTAIN VALLEYS. DIURNAL
CONVECTION IS EXPECTED EACH AFTERNOON WITH THE MOST COVERAGE OVER
THE MOUNTAINS.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z
KCLT       HIGH 100%     HIGH  86%     HIGH  90%     HIGH 100%
KGSP       HIGH 100%     MED   78%     HIGH  85%     HIGH 100%
KAVL       HIGH 100%     HIGH  87%     HIGH  94%     HIGH 100%
KHKY       HIGH 100%     HIGH  86%     HIGH  92%     HIGH 100%
KGMU       HIGH 100%     HIGH  89%     HIGH  88%     HIGH 100%
KAND       HIGH 100%     HIGH  88%     HIGH  95%     HIGH 100%

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...JOH
NEAR TERM...LG/SBK
SHORT TERM...JDL
LONG TERM...JOH
AVIATION...SBK






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