Area Forecast Discussion
Issued by NWS Greer, SC

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000
FXUS62 KGSP 011827
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
227 PM EDT TUE SEP 1 2015

.SYNOPSIS...
GENERAL HIGH PRESSURE WILL LINGER ACROSS THE REGION THIS WEEK WITH
WEAK UPPER LEVEL DISTURBANCES CROSSING OVERHEAD BEGINNING WEDNESDAY.
A COOL AND MOIST AREA OF HIGH PRESSURE IS EXPECTED TO SETTLE ACROSS
THE WESTERN CAROLINAS AND NORTHEAST GEORGIA THIS WEEKEND INTO EARLY
NEXT WEEK.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
ALTHOUGH THE LATEST VISIBLE SATELLITE IMAGERY INDICATES THE CU FIELD
CONTINUES TO APPEAR QUITE HEALTHY ACROSS THE MTNS...HAVE YET TO SEE
ANY DEEP CONVECTION INITIATE THIS AFTERNOON. THE ATM IS WEAKLY
UNSTABLE...AND IT/S APPEARING THAT COVERAGE WILL BE QUITE MINIMAL
THIS AFTERNOON. NEVERTHELESS...HAVEN/T GIVEN UP ON CONVECTION
YET...ESP IN LIGHT OF THE WELL-DEVELOPED CU FIELD...THUS  POPS WILL
BE RETAINED IN THE 20-30 PERCENT RANGE ACROSS MOST OF THE MTNS AND
FOOTHILLS. ANY CONVECTION THAT DOES DEVELOP WILL DISSIPATE QUICKLY
THIS EVENING. MIN TEMPS SHOULD BE ABOUT A DEGREE WARMER THAN THIS
MORNING/S READINGS...AS HEIGHTS CONTINUE TO INCREASE ALOFT.

CONTINUED GRADUAL AIR MASS RECOVERY/INCREASING DEWPOINTS AND EVEN
MORE WARMTH...WITH PROGGED LOW LEVEL THICKNESS VALUES SUPPORTING MAX
TEMPS ABOUT TWO CATEGORIES ABOVE CLIMO...WILL RESULT IN INCREASING
INSTABILITY FOR WED AFTERNOON...ALTHOUGH SBCAPE SHOULD REMAIN RATHER
MODEST AT LESS THAN 2000 J/KG. MEANWHILE...SHORT TERM GUIDANCE IS IN
GOOD AGREEMENT IN ALLOWING HEIGHT FALLS OVERSPREADING THE NORTH
CENTRAL CONUS TO KICK THE AREA OF VORTICITY...CURRENTLY SITTING OVER
INDIANA...TO KICK TOWARD THE CENTRAL APPALACHIANS AND MID-ATLANTIC
TONIGHT THROUGH TOMORROW. CHANCE POPS WILL ONCE AGAIN BE FEATURED
NEAR THE BLUE RIDGE...BUT ALSO ACROSS THE NC MTNS AND FHILLS...WHICH
WILL BE CLOSER TO THE AREA OF UPPER FORCING. SLIGHT CHANCE POPS WILL
BE FEATURED ACROSS MOST OF THE REMAINDER OF THE FORECAST AREA.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH THURSDAY NIGHT/...
AS OF 145 PM TUESDAY...THE SHORT TERM WILL FEATURE OVERALL HEIGHT
FALLS AT 500 MB ALONG THE APPALACHIAN CHAIN...AS A LARGE UPPER RIDGE
BUILDS OVER THE MS VALLEY TO THE GREAT LAKES. THE MID AND UPR FLOW
WILL REMAIN RATHER WEAK. HOWEVER...THE MODELS AGREE ON SOME Q-VECTOR
CONVERGENCE ATOP THE CWFA...ESP ON FRIDAY. AT THE SFC...WEAK HIGH
PRES WILL REMAIN CENTERED OVER THE AREA ON THURSDAY...BUT THEN GIVE
WAY TO A WEAK BACK DOOR COLD FRONT THAT WILL PUSH INTO THE AREA ON
FRIDAY. SO THURSDAY LOOKS LIKE ANOTHER VERY WARM DAY WITH ONLY
ISOLATED TO WIDELY SCATTERED AFTN CONVECTION...MAINLY IN THE MTNS.
WHILE FRIDAY LOOKS MORE ACTIVE...AS GUIDANCE IN GOOD AGREEMENT ON
BETTER INSTBY...WITH PLENTY OF LLVL MOISTURE POOLING ALONG THE
BNDRY. POPS RAMP UP TO SOLID CHC TO NEAR LIKELY IN THE MTNS AND
LOW-END CHC ACRS THE PIEDMONT BY FRIDAY AFTN. TEMPS WILL BE IN THE
LOW 90S ON THURSDAY ACRS THE PIEDMONT...AND A CATEGORY OR TWO COOLER
ON FRIDAY. LOW TEMPS WILL BE ABOVE NORMAL WITH INCREASING HUMIDITY.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
AS OF 200 PM TUESDAY...AN ULVL PATTERN CHANGE IS IN STORE OVER THE
WEEKEND. THERE IS GOOD GENERAL AGREEMENT WITH WITH THE DEVELOPMENT
OF A CLOSED LOW DROPPING SOUTH ACROSS THE NORTH ATL ENABLING A NA
OMEGA BLOCK AND A WEAKNESS OR BROAD CLOSED LOW DEVELOPING OVER THE
SE CONUS. THE PERSISTENT UPPER RIDGE WILL ANCHOR A SFC HIGH ACROSS
NEW ENG WITH SFC RIDGING INTO THE SE REGION TO SOME DEGREE. THERE IS
SOME UNCERTAINTY AS TO THE STRENGTH OF THE LLVL RIDGE AND THUS THE
QPF RESPONSE IN ISENT LIFTED ATL MOISTURE FLUX.

SAT LOOKS TO HAVE THE BEST CHANCE FOR SCT TO PERHAPS NUMEROUS
-SHRA...BUT WITH VARYING IDEAS TO THE PATTERN AND MOISTURE
TRANSPORT...WILL SIDE ON THE LOWER END AND KEEP POPS IN THE LOW TO
MID CHANCE RANGE. THE AMOUNT OF INSTABILITY WILL BE ANOTHER FACTOR
THAT SHOULD BE LOW-END PER MODEL SOUNDINGS AND WEAK MLVL
FORCING...THUS WILL LOWER GENERAL THUNDER MENTION TO ISOL COVERAGE.
DECENT CONFIDENCE IS HAD IN THE LAYERED E/LY FLOW HOWEVER...AND THIS
SHOULD LEAD TO A MODEST QPF RESPONSE MAINLY ACROSS THE BLUE RIDGE.
THE CAD LIKE RIDGE WILL REMAIN IN PLACE AND WEAKEN A LITTLE SUN.
WITH LESS ISENT LIFT AS THE SFC RIDGE WEAKENS...WILL FAVOR THE MTNS
WITH CHANCE POPS AND ISOL ELSEWHERE. INSTABILITY ON SUNDAY WILL BE
LESS THAN SAT AS WARMER AIR ALOFT DEVELOPS UNDER THE RIDGE
AXIS...THUS THUNDER WILL NOT BE MENTIONED. MAX TEMPS WILL BE HELD A
COUPLE CATS BELOW NORMAL BOTH SAT/SUN...WITH MINS RIGHT ARND OR A
BIT ABOVE NORMAL IN GOOD NOCTURNAL CLOUD COVER.

THE UPPER PATTERN SHIFTS SIGFNTLY AGAIN ON MON AS THE SE UPPER LOW
BECOMES DOMINANT AND THE NRN RIDGE AXIS PUSHES EAST. THIS WILL
WEAKEN THE SFC RIDGE FROM THE SOUTH THROUGH THE PERIOD AND DECREASE
THE AMOUNT OF MOISTURE FLUX AS A BROAD COASTAL TROF FORMS. THERE
WILL STILL BE A ENUF GENERAL LIFT AND INCREASING INSOL FOR AFTERNOON
SHRA/TSTMS. THUS...POPS WERE MAINTAINED IN THE SEASONAL RANGE. MAX
TEMPS AND TD/S WILL REMAIN RELATIVELY LOW AND RECOVER SLOWLY AS THE
SFC FLOW IS HELD IN A NE/LY TO E/LY CONFIG DUE TO THE COASTAL
TROF...SO ANY THUNDER MENTION WILL BE LIMITED TO THE SRN BLUE RIDGE
WITHIN MTN TOP CONVERG. MAX TEMPS SHOULD REBOUND TO NORMAL LEVELS BY
TUES.

&&

.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
AT KCLT AND ELSEWHERE...VFR CONDITIONS ARE EXPECTED THROUGH THE
PERIOD...WITH THE EXCEPTION OF ANOTHER ROUND OF MTN VALLEY LOW
STRATUS AND FOG TOMORROW MORNING. CONFIDENCE IS NOT REAL HIGH ON
CONDITIONS AT KAVL...BUT HAVE INCLUDED IFR VISBY THERE DURING THE
PRE-DAWN HOURS. THERE COULD ALSO BE A FEW SHOWERS DEVELOP ACROSS THE
HIGH TERRAIN THIS AFTERNOON...WHICH WOULD MOST LIKELY DRIFT TOWARD
THE SOUTH...BUT DO NOT FEEL CONFIDENT ENOUGH TO INCLUDE ANY MENTION
IN THE TAFS ATTM. OTHERWISE...FAIR WEATHER CU IN THE 040-060 RANGE
IS EXPECTED TO GIVE WAY TO GRADUALLY DISSIPATING STRATOCU THIS
EVENING. WINDS ARE EXPECTED TO REMAIN LIGHT...WITH A NORTHERLY
DIRECTION EXPECTED AT KCLT THIS AFTERNOON. OTHERWISE...WINDS SHOULD
GENERALLY REMAIN BETWEEN SSE AND SSW.

OUTLOOK...A PATTERN OF DIURNAL ISOLATED/WIDELY SCT SHOWERS AND
THUNDERSTORMS IS EXPECTED TO CONTINUE THROUGH THE WORK WEEK. BY THE
WEEKEND...A MOIST EASTERLY FLOW IS EXPECTED TO DEVELOP...BRINGING
BETTER CHANCES FOR SHOWERS AND RESTRICTIONS. LOW CLOUDS AND FOG
WILL BE POSSIBLE EACH NIGHT IN THE MOUNTAIN VALLEYS.

CONFIDENCE TABLE...

            18-24Z        00-06Z        06-12Z        12-18Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH 100%     HIGH  94%     HIGH 100%
KHKY       HIGH 100%     HIGH 100%     HIGH  94%     HIGH  94%
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAND       HIGH 100%     HIGH 100%     HIGH 100%     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

&&

.GSP WATCHES/WARNINGS/ADVISORIES...
GA...NONE.
NC...NONE.
SC...NONE.

&&

$$
SYNOPSIS...SBK
NEAR TERM...JDL
SHORT TERM...ARK
LONG TERM...SBK
AVIATION...JDL



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