Area Forecast Discussion
Issued by NWS Greer, SC

Home | Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary On
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
000
FXUS62 KGSP 292339
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
739 PM EDT TUE JUL 29 2014

.SYNOPSIS...
CANADIAN HIGH PRESSURE WILL DOMINATE THE SURFACE PATTERN THROUGH
MIDWEEK...LEADING TO WELL BELOW NORMAL TEMPERATURES MORE TYPICAL OF
LATE SUMMER OR EARLY AUTUMN. AS THE SURFACE HIGH WEAKENS...MOISTURE
WILL RETURN FOR THE WEEKEND INCREASING THE CHANCES OF WIDESPREAD
SHOWERS AND THUNDERSTORMS.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
730 PM EDT UPDATE...UPDATED POP/SKY GRIDS TO ACCOUNT FOR LINGERING
LEE WAVE CLOUDS ACROSS THE UPSTATE AND BRIEF -SHRA JUST SOUTH OF THE
UPSTATE ESCARPMENT. TEMPS TWEAKED AS HR/LYS RUNNING 2-3 DEGREES
ABOVE THE FCST CURVE...MAINLY NON/MTNS.

430 PM EDT UPDATE...MADE MINOR CHANGES TO THE T/TD AND SKY GRIDS.
REST OF FCST IS IN GOOD SHAPE WITH CU BECOMING A LITTLE MORE
ENHANCED ALONG THE ESCARPMENT WHICH COULD SUPPORT A FEW BRIEF -SHRA
OVER THE NEXT COUPLE HRS.

AS OF 200 PM TUE...THE AFTERNOON FORECAST STILL LOOKS ON
TRACK...ESPECIALLY WITH THE IDEA OF MINIMIZING THE MENTION OF ANY
SHOWERS IN THE MOUNTAINS. NO ECHOES YET ON RADAR AND THE SPC MESO
ANAL PAGE STILL SHOWS NO SBCAPE. HENCE...STILL THINK THAT CURRENT
SLIGHT CHC POPS OVER THE HIGHEST TERRAIN IN THE MOUNTAINS WILL HOLD
US DESPITE THE CONSIDERABLE QPF RESPONSE IN THE 12Z NAM AND GFS. ANY
ISOLATED SHOWERS THAT DO DEVELOP SHOULD DISSIPATE QUICKLY WITH THE
LOSS OF HEATING.

IN REGARD TO THE BIG PICTURE....THE ANOMALOUS UPPER TROUGH WILL
REMAIN IN PLACE OVER THE EASTERN U.S THROUGH WED. AT THE
SURFACE...COOL HIGH PRESSURE WILL REMAIN TO THE NORTH OF THE REGION.
THESE INGREDIENTS WILL PRODUCE A COOL NIGHT ACROSS THE AREA FOR LATE
JULY. IN FACT...OUR FORECAST IS REFLECTING TYING THE RECORD LOW FOR
THE DATE AT AVL WHICH IS 54 SET IN 1897. ELEVATIONS ABOVE 4000 FT OR
SO WILL SEE LOWS IN THE 40S. OUTSIDE THE MOUNTAINS...LOWS WILL BE
MAINLY IN THE 60-65 DEGREE RANGE...EXCEPT FOR SOME 50S IN THE NC
FOOTHILLS/NORTHERN NC PIEDMONT. NO RECORDS OUTSIDE THE MOUNTAINS
APPEAR TO BE IN PLAY TONIGHT. THE RECORD LOW IS 58 AT CLT/63
FORECAST AND 60 AT GSP/62 FORECAST.

WED SHOULD BE A SIMILAR DAY TO TUE WITH PARTLY TO MOSTLY SUNNY
CONDITIONS. FORECAST SOUNDINGS ARE ESSENTIALLY CAPPED SO THE CHANCE
OF AFTERNOON CONVECTION LOOKS TO BE EVEN LOWER ON WED. WILL ONLY
INCREASE POPS TO SLIGHT CHANCE OVER THE SW MOUNTAINS IN THE
AFTERNOON WHERE MODELS SHOW SOME LIGHT QPF RESPONSE. MAX TEMPS WILL
CONTINUE TO BE A COUPLE CATEGORIES BELOW CLIMO.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
AS OF 145 PM TUESDAY...THE UPPER TROF OVER THE EASTERN PART OF NORTH
AMERICA WILL REMAIN THE DOMINANT WEATHER FEATURE THROUGH THE SHORT
RANGE...BUT ITS EVOLUTION WILL HAVE IMPORTANT CONSEQUENCES. THE AXIS
OF THE UPPER TROF SHOULD BE LOCATED OVER THE MID-ATLANTIC AND
CAROLINAS ON WEDNESDAY NIGHT...BUT THIS WILL SHIFT TO THE MS
RIVER/GREAT LAKES ON THURSDAY IN RESPONSE TO NEW SHORT WAVES DIGGING
DOWN INTO THE TROF. A WEAK 850MB LOW WILL ALSO MOVE WEST WITH THE
UPPER TROF...AND IN DOING SO...THE LOW LEVEL FLOW WILL COME AROUND
TO SE FOR THURSDAY AND FRIDAY. ALTHO THE FLOW WILL BE LIGHT AND
MOISTURE TRANSPORT WILL BE WEAK...THERE SHOULD BE ENOUGH MOISTURE
RETURN TO FUEL AN INCREASE IN SHOWER COVERAGE BOTH DAYS. PRECIP
PROBABILITY CLIMBS UP TO THE CHANCE RANGE MAINLY OVER THE MTNS AND
FOOTHILLS FOR THURSDAY...AND THEN SOLIDLY IN THE CHANCE RANGE FOR
FRIDAY. BOUYANCY WILL ALSO INCREASE...SO THUNDERSTORMS ARE POSSIBLE
AGAIN FRIDAY AFTERNOON. NOT READY TO JUMP INTO THE LIKELY RANGE FOR
FRIDAY YET. THE POSITION AND TIMING OF A VORT CENTER MOVING THROUGH
THE REGION ON THE GFS IS VIEWED WITH A SUSPICIOUS EYE AT THIS TIME.
TEMPS WILL REMAIN BELOW NORMAL.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
AS OF 130 PM EDT TUESDAY...THE MEDIUM RANGE FCST PICKS UP AT 00Z ON
SATURDAY WITH THE PERSISTENT UPPER TROF AXIS OVER THE GREAT LAKES
AND MISS RIVER VALLEY AND UPPER RIDGING OVER THE WESTERN CONUS. THE
LONG RANGE MODELS SUGGEST THAT THE TROF WILL BEGIN TO DEAMPLIFY ON
SUNDAY AND CONTINUE TO LIFT THRU THE REST OF THE PERIOD. THIS WOULD
RESULT IN A SPLIT FLOW PATTERN OVER MUCH OF THE SE REGION SANDWICHED
BETWEEN UPPER RIDGING TO THE WEST AND THE BERMUDA HIGH TO THE EAST.

AT THE SFC...DEEPER LYR MOISTURE IS EXPECTED TO BE SPREAD OVER THE
CWFA BY THE START OF THE PERIOD AND REMAIN OVER THE REGION THRU DAY
7. BY SAT EVENING...THE BNDY LYR FLOW IS EXPECTED TO BECOME MORE
SELY AND REMAIN SLY TO SELY FOR THE REMAINDER OF THE FCST PERIOD.
PRECIP CHANCES WILL REMAIN GOOD THUR THE WEEKEND WITH POPS TAPERING
OFF SOME FOR DAYS 6 AND 7 AS SOME DRIER AIR COULD WORK ITS WAY IN
FROM THE NW. TEMPS SHOULD REMAIN WELL BELOW NORMAL FOR EARLY AUGUST
WITH VALUES EXPECTED TO WARM A FEW DEGREES BY THE END OF THE PERIOD.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...VERY WEAK FLOW WILL CONTINUE THROUGH THE TAF PERIOD WITH
GENERALLY A N/LY DIR. THE LLVL FLOW BTW H95-H85 DOES BACK DURING THE
DAY HOWEVER...SO WILL EXPECT A MORE NW/LY TREND IN THE AFTERNOON.
VFR CU FIELD WILL LIKELY DEVELOP ARND NOON WITH COVERAGE FEW TO
PERHAPS SCT BY LATE AFTERNOON.

ELSEWHERE...WITH GOOD DECOUPLING AND SFC COOLING...KAVL COULD SEE
SOME MVFR VSBY ARND DAYBREAK...BURNING OFF QUICKLY AFT 12Z. A
WEAKENING P/GRAD IS IN STORE...SO MAINLY N/LY WINDS WILL BECOME
OCCASIONALLY VRB/CALM IN THE AFTERNOON WITH MORE OF A NW/LY DIR
OVERALL. A VFR CU FIELD WILL BE FEW TO SCT.

OUTLOOK...HIGH PRESSURE WILL PREVAIL INTO THU MORNING WITH THE ONLY
POSSIBLE RESTRICTIONS BEING EARLY MORNING FOG/STRATUS IN THE
MOUNTAIN VALLEYS. MOISTURE WILL BE INCREASING DURING THURSDAY
INTO FRIDAY WHICH WILL YIELD UNSETTLED WEATHER WITH ENHANCED
PRECIPITATION/FOG/STRATUS CHANCES THROUGH THE WEEKEND.

CONFIDENCE TABLE...

            23-05Z        05-11Z        11-17Z        17-23Z
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KGSP       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%
KAVL       HIGH 100%     HIGH  97%     HIGH  94%     HIGH 100%
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 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...JPT
NEAR TERM...LG/SBK
SHORT TERM...PM
LONG TERM...JPT
AVIATION...SBK






USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.