Skip Navigation Linkswww.weather.gov 
NOAA logo - Click to go to the NOAA homepage National Weather Service Forecast Office   NWS logo - Click to go to the NWS homepage
WFO Greenville-Spartanburg, SC
 

Local forecast by
"City, St"
  
000
FXUS62 KGSP 302350
AFDGSP

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
750 PM EDT TUE SEP 30 2014

.SYNOPSIS...
DRIER HIGH PRESSURE WILL LINGER OVER THE REGION THROUGH THURSDAY. A 
COLD FRONT WILL THEN ARRIVE FROM THE NORTHWEST ON FRIDAY AND MOVE 
OFFSHORE BY EARLY SATURDAY. IN THE FRONTS WAKE...A COOL AND DRY 
AIRMASS WILL MOVE BACK OVER THE SOUTHEAST AND REMAIN IN PLACE OVER 
THE WEEKEND.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
AS OF 750 PM...CONVECTIVE CLOUDS DISSIPATING WITH LOSS OF HEATING 
BUT CIRRUS MOVING IN FROM THE WEST. GUIDANCE AND FCST SOUNDINGS NOT 
AS FAVORABLE FOR DENSE FOG OUTSIDE OF THE MTNS. SHUD SEE PATCHY FOG 
THOUGH...ESPECIALLY NEAR BODIES OF WATER. FCST STILL LOOKS GOOD FOR 
DENSE MTN VALLEY FOG OVERNIGHT...SO HAVE ADDED THAT TO THE FCST. 
OTHERWISE...GOING FCST STILL LOOKS GOOD...SO UPDATES MAINLY FOR 
CURRENT CONDITIONS.

AS OF 420 PM...STILL NO SIGN OF DEEP CONVECTION WITH ONLY SHALLOW CU 
FORMING. FCST GENERALLY ON TRACK...SO ONLY MINOR CHANGES FOR CURRENT 
CONDITIONS.

AT 215 PM EDT TUESDAY...A CLOSED UPPER LOW WILL MOVE FROM THE 
EASTERN GREAT LAKES THIS AFTERNOON...TO SOUTHERN NEW ENGLAND BY 
WEDNESDAY EVENING...WHILE THE TROUGH TO ITS SOUTH DEAMPLIFIES. 
MEANWHILE...AN UPPER RIDGE AXIS WILL PROGRESS FORM THE MS RIVER 
VALLEY TO THE OH AND TN RIVER VALLEYS. A COLD FRONT NOW IN THE OH 
RIVER VALLEY WILL STALL TO OUR NORTH...WHILE WEAK HIGH PRESSURE 
REMAINS OVER THE CAROLINAS AND GA.

MODEL TIME HEIGHTS SHOW LIMITED MOISTURE IN THE LOWER LEVELS...AND 
SCATTERED CLOUD COVER IS EXPECTED WITH HEATING THIS AFTERNOON. 
ALTHOUGH MODEL TIME HEIGHTS SHOW SOME WEAK INSTABILITY...A MID LEVEL 
SUBSIDENCE INVERSION SHOULD PREVENT CONVECTION FROM DEVELOPING. 
GUIDANCE SUPPORTS ANOTHER ROUND OF FOG IN THE MORNING...BUT OUTSIDE 
THE MOUNTAINS...GENERALLY DOES NOT SUPPORT DENSE FOG. WEDNESDAY 
FEATURES CONDITIONS MUCH LIKE TODAY...WITH SOME SCATTERED LOW CLOUDS 
AND A CAPPING INVERSION ABOVE. THE ONE CAVEAT WOULD BE IF THE FRONT 
TO THE NORTH CAN DROP INTO THE INTERSTATE 40 CORRIDOR BEFORE 
STALLING...WHICH WOULD RESULT IN A FEW MORE CLOUDS AND A WIND 
SHIFT FROM LIGHT SW TO LIGHT NE. TEMPERATURES ARE EXPECTED TO RUN A 
FEW DEGREES ABOVE NORMAL AS HEIGHTS SLOWLY RISE ALOFT.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY NIGHT/...
AS OF 215 PM TUESDAY...AN UPPER RIDGE AXIS WILL REMAIN ACRS THE CWFA 
ON THURSDAY...KEEPING THE AREA DRY WITH ABOVE NORMAL TEMPS.

HEIGHTS BEGIN TO FALL IN EARNEST THURSDAY NIGHT...AS A POTENT 
SHORTWAVE TROF DIVES INTO THE MIDWEST. IN THE LLVLS...S/SWLY FLOW 
WILL INCREASE...TRANSPORTING GULF MOISTURE INTO THE AREA. THERE MAY 
BE SOME UPSLOPE-ENHANCED SHOWER ACTIVITY DEVELOPING OVERNIGHT 
THURSDAY NIGHT IN THE WESTERN ZONES. OTHERWISE...SHUD BE GENERALLY 
DRY WITH INCREASING RETURN FLOW AND CLOUD COVER...TEMPS WILL BE WELL 
ABOVE NORMAL...MAINLY IN THE 60S.

MODELS ARE STILL IN GOOD AGREEMENT ON THE TIMING OF A COLD FRONT TO 
CROSS THE AREA ON FRIDAY. A PRE-FRONTAL BAND OF CONVECTION IS LIKELY 
TO CROSS THE AREA DURING THE DAYLIGHT HOURS...WITH THE SFC FRONT 
COMING THRU FRIDAY EVENING. AS AN 500 MB LOW CLOSES OFF INVOF MN...A 
VORT LOBE SHUD LIFT NE ACRS THE SRN APPALACHIANS...PROVIDING 
DEEP-LAYER Q-VECTOR CONVERGENCE. GUIDANCE ALSO SHOWS PLENTY OF UPPER 
DIVERGENCE WITH THE BAND OF PRECIP. SO CONFIDENCE IS INCREASING ON 
THE POP FOR FRIDAY. I HAVE CATEGORICAL POP IN THE MTNS AND LIKELY 
ACRS THE PIEDMONT...THEN TAPERING OFF FRIDAY NIGHT.

AS FOR HOW ROBUST THE CONVECTION WILL BE...THERE LOOKS TO BE ABOUT 
1000-1500 J/KG OF SBCAPE FOR THE LINE TO WORK WITH...WITH 0-6 KM 
BULK SHEAR OF 40-50 KTS. CERTAINLY ENUF FOR AT LEAST A LOW-TOPPED 
QUASI-LINEAR CONVECTIVE SYSTEM (QLCS). WE ARE NOT CURRENTLY 
MENTIONING SEVERE WX IN THE HWO...BUT I WOULDN/T BE SURPRISED IF SPC 
PLACES SOME AREA IN A SLGT FOR THE NEW DAY 3 TONIGHT FOR FRIDAY...IF 
MODEL TRENDS HOLD.

TEMPS WILL BE NEAR OR SLIGHTLY BELOW NORMAL FRIDAY AND FRIDAY NIGHT 
WITH THE PRECIP...AND PASSING COLD FRONT.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
AS OF 150 PM TUESDAY AFTERNOON...THE MEDIUM RANGE FCST PICKS UP AT 
12Z ON SATURDAY WITH A STEEP UPPER TROF TO OUR NORTH AND BROAD UPPER 
RIDGING BUILDING OVER THE WEST COAST. AS WE MOVE INTO THE LATTER 
PART OF THE WEEKEND...THE TROF AXIS LIFTS NE YET WE LIKELY WILL 
REMAIN UNDER BROAD UPPER TROFFING THRU THE END OF THE PERIOD. THE 
ECMWF CONTINUES TO REAMPLIFY THE TROF MORE THAN THE GFS ON DAYS 6 
AND 7 WITH CONSIDERABLY LOWER HEIGHTS OVER THE FCST AREA ON NEW DAY 
7...TUES. THE LATEST GFS DEVELOPS A VERY LARGE CLOSED H5 LOW OVER 
ONTARIO AND THUS MAINTAINS A MUCH LONGER WAVELENGTH TROF THRU NEW 
DAY 7. 

AT THE SFC...IN THE WAKE OF THE FROPA ON FRI AFTERNOON AND 
EVENING...COOL AND DRY HIGH PRESSURE WILL SPREAD OVER THE CWFA AND 
REMAIN THRU THE WEEKEND. THE MODELS CONTINUE TO DEVELOP SOME SORT OF 
GREAT LAKES LOW EARLY NEXT WEEK AND MOVE A SECOND COLD FRONT OVER 
OUR AREA. THE GFS HAS THE FROPA ON MON WHILE THE ECMWF IS ABOUT 24 
HRS SLOWER WITH THE FROPA ON TUES. BOTH MODELS SUGGEST A FAIRLY 
QUICK AND MOSTLY DRY FROPA WITH LITTLE IN THE WAY OF QPF. AS FOR THE 
SENSIBLE FCST...WE CAN EXPECT MOSTLY DRY AND COOL CONDITIONS THRU 
THE PERIOD WITH JUST SOME SLIGHT CHANCE POPS ON MON AFTERNOON THRU 
TUES TO ACCOUNT FOR THE NEXT FROPA. TEMP GUIDANCE HAS BEEN TRENDING 
COOLER WITH HIGHS IN THE UPPER 60S TO LOW 70S OVER THE WEEKEND AND 
WARMING BETWEEN 1 AND 2 CATEGORIES EARLY NEXT WEEK.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
AT KCLT...CONVECTIVE CU DISSIPATING WITH LOSS OF HEATING WHILE 
CIRRUS WILL SPREAD INTO THE AREA OVERNIGHT. GUIDANCE HAS GREATLY 
DECREASED THE CHC OF FOG OVERNIGHT WITH LITTLE TO NO LOW CLOUD CHC. 
HAVE GONE VFR GIVEN THE LOW CHC. THAT SAID...MVFR LIKELY AT THE 
NORMALLY FOGGIER SITES NEAR THE AREA. EXPECT ANOTHER ROUND OF 
CONVECTIVE CU WED AFTERNOON. WINDS WILL BE CALM OVERNIGHT BECOMING 
VERY LIGHT SLY BY AFTERNOON.

ELSEWHERE...SIMILAR CONDITIONS AS KCLT...ESP KGSP/KGMU. KHKY/KAND 
SHUD SEE MVFR FOG OVERNIGHT...WITH LITTLE TO NO CHC OF LOW CLOUDS. 
KAVL THE MAJOR EXCEPTION...AS USUAL...WITH ANOTHER ROUND OF VLIFR 
EXPECTED. STATISTICAL GUIDANCE AND FCST SOUNDINGS ARE IN LINE WITH 
THE RESTRICTIONS. SHUD BE A QUICK RETURN TO VFR WED MORNING...WITH 
CONVECTIVE CU DEVELOPING ONCE AGAIN ALL AREAS. LIGHT WIND BECOMES 
CALM OVERNIGHT THEN SSW WED AFTERNOON. KAVL WILL SEE NLY WIND DURING 
THE MORNING AND SLY WIND FOR THE AFTERNOON.

OUTLOOK...FOG/VSBY CONCERNS REMAIN THURSDAY. A FRONT WILL APPROACH 
ON FRIDAY WHICH COULD TRIGGER SOME SHOWERS AND THUNDERSTORMS...WITH 
ASSOCIATED RESTRICTIONS POSSIBLE. VFR RETURNS ON SATURDAY.

CONFIDENCE TABLE...

            00-06Z        06-12Z        12-18Z        18-24Z 
KCLT       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%     
KGSP       HIGH 100%     HIGH  94%     HIGH 100%     HIGH 100%     
KAVL       HIGH 100%     MED   74%     MED   69%     HIGH 100%     
KHKY       HIGH 100%     HIGH  97%     HIGH 100%     HIGH 100%     
KGMU       HIGH 100%     HIGH 100%     HIGH 100%     HIGH 100%     
KAND       HIGH 100%     HIGH  97%     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...JAT/RWH
SHORT TERM...ARK
LONG TERM...JPT
AVIATION...RWH





National Weather Service
Weather Forecast Office Greenville-Spartanburg
GSP International Airport
1549 GSP Drive
Greer, SC 29651
(864) 848-3859
Questions or Comments? Send us email
Page last modified: January 20, 2010

Disclaimer
Credits
Glossary
Privacy Policy
About Our Organization
Career Opportunities