361
FXUS62 KGSP 111800
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
200 PM EDT MON MAY 11 2026
WHAT HAS CHANGED
LOWERED THUNDER CHANCES THIS AFTERNOON, AND IN THE NORTHERN PORTION
OF THE CWA, LOWERED HIGH TEMPERATURES TODAY.
NO MAJOR CHANGES OTHERWISE.
KEY MESSAGES
1. SCATTERED SHOWERS THIS AFTERNOON NEAR A WEAK COLD FRONT,
PRODUCING ONLY LIGHT RAIN. ANY THUNDERSTORMS WOULD BE HIGHLY
ISOLATED AND NOT POSE A RISK OF SEVERE WEATHER.
2. ANOTHER WEAK COLD FRONT MAY BRING A FEW MORE SHOWERS AND
THUNDERSTORMS TO THE WESTERN CAROLINAS WEDNESDAY. DRY AND BRIEFLY
COOLER THURSDAY AND THURSDAY NIGHT, FOLLOWED BY A WARMING TREND
FRIDAY THROUGH THE WEEKEND.
DISCUSSION
KEY MESSAGE 1: SCATTERED SHOWERS THIS AFTERNOON NEAR A WEAK COLD
FRONT, PRODUCING ONLY LIGHT RAIN. ANY THUNDERSTORMS WOULD BE HIGHLY
ISOLATED AND NOT POSE A RISK OF SEVERE WEATHER.
COLD FRONT APPEARS TO HAVE PASSED THROUGH MOST OF THE CWA AS OF 2
PM EDT, WITH MOST OBS SITES HAVING EXPERIENCED A SHIFT TO GUSTY NE
WINDS. RAP SOUNDINGS FROM AROUND THE CWA DEPICT A SHALLOW LAYER
OF INSTABILITY NEAR OR JUST BEHIND THE FRONT, WHICH HAS LED TO
LOW STRATOCU BREAKING OUT, BUT SO FAR LITTLE IN THE WAY OF NEW
SHOWER ACTIVITY. BAND OF RADAR RETURNS NEAR THE TN/NC BORDER IS
ASSOCIATED WITH A SHORTWAVE TROUGH AXIS ADVECTING EASTWARD INTO
NC/VA. CAMS GENERALLY STILL DEPICT A FEW SHOWERS FORMING ALONG
EITHER THE FRONT OR THE TROUGH AXIS THROUGH THE AFTERNOON AND
EVENING. WE CONTINUE TO ADVERTISE 20-30% POPS SIMILAR TO WHAT WAS
SHOWN ON THE PREVIOUS FORECAST CYCLE, BUT IN LIGHT OF MODELS HAVING
BEEN SOMEWHAT OVERDONE SO FAR TODAY, AND THE SHALLOW NATURE OF THE
CONVECTIVE LAYER ON PROG SOUNDINGS, FELT IT WAS BEST TO CAP THUNDER
CHANCES BELOW SLIGHT-CHANCE (~10%). CAN'T ENTIRELY RULE OUT A STRAY
STORM GETTING TALL ENOUGH TO PRODUCE THUNDER, PARTICULARLY NEAR
THE SFC FRONT, SE OF I-85. WITH INSTABILITY REMAINING SO LIMITED,
NOT EXPECTING ANY SEVERE WEATHER TO RESULT.
THE FRONT WILL CONTINUE TO SAG SOUTHWARD TONIGHT; ABUNDANT MID
TO HIGH ALTITUDE CLOUD COVER WILL LINGER THROUGH THE EVENING BUT
CLEARING SHOULD OCCUR FROM N TO S LATE IN THE NIGHT. DRYING WILL
OCCUR ONLY SLOWLY AT THE SURFACE, AND AS WINDS TURN LIGHT IN THE
NORTHERN CWA, SOME FOG OR LOW STRATUS MAY DEVELOP THERE. SUNNIER
SKIES TUESDAY SHOULD RESULT IN MAX TEMPS TRENDING A FEW DEGREES
WARMER COMPARED TO MONDAY IN OUR NORTHERN ZONES, BUT A LITTLE COOLER
IN THE SOUTH. DRIER DEWPOINTS WILL MIX DOWN TO THE SURFACE ACROSS
THE AREA TUESDAY AND SOME LOCATIONS WILL SEE RH DIP TO NEAR 30%
BY MID-AFTERNOON.
KEY MESSAGE 2: ANOTHER WEAK COLD FRONT MAY BRING A FEW MORE SHOWERS
AND THUNDERSTORMS TO THE WESTERN CAROLINAS WEDNESDAY. DRY AND
BRIEFLY COOLER THURSDAY AND THURSDAY NIGHT, FOLLOWED BY A WARMING
TREND FRIDAY THROUGH THE WEEKEND.
DEEP SHORTWAVE WILL BEGIN TO CUT OFF OVER THE GREAT LAKES WEDNESDAY;
WHILE THE BEST DPVA LOOKS TO OCCUR TO OUR NORTH, HEIGHT FALLS
OCCUR OVER OUR AREA AS A RESULT, AND A COLD FRONT WILL APPROACH
THE SOUTHERN APPALACHIANS DURING THE DAY. MOISTURE RETURN AHEAD OF
THE FRONT APPEARS LIMITED, PARTLY OWING TO THE GOOD MIXING/DRYING
EXPECTED TUESDAY, AND VEERED LOW-LEVEL WINDS TUE NIGHT AND EARLY
WED. NEVERTHELESS, MODELS GENERALLY STILL DO DEPICT A NARROW BAND OF
ABOVE-NORMAL PWATS ADVECTING INTO THE AREA JUST PRIOR TO THE FROPA,
WITH SIMILAR PEAK VALUES IN OUR PIEDMONT, THOUGH VARYING IN THE
TIMING OF THAT PEAK. THE 12KM NAM AND ITS TYPICALLY SIMILAR CANADIAN
MODEL ARE MORE AGGRESSIVE IN BRINGING GULF AIR ABOVE THE BOUNDARY
LAYER EARLY WED MORNING, AND ACCORDINGLY ARE APPRECIABLY HIGHER
WITH AFTERNOON DEWPOINTS AND SBCAPE THAN THE GFS/EC OPERATIONAL
MODELS. LREF PROBS OF 500 J/KG SBCAPE HAVE ACTUALLY DECREASED IN OUR
CWA ON THE LATEST AVAILABLE CYCLE, BUT THAT APPEARS TO BE RELATED
TO A SLIGHTLY EARLIER DEPICTION OF THE FROPA. NOT MUCH CHANGE IN
NBM POPS VERSUS THE OVERNIGHT CYCLE, WHICH SEEMS REASONABLE IN
LIGHT OF MODEL SPREAD MAINLY BEING IN TIMING AND LITTLE CHANGE IN
CAPE POTENTIAL. LREF STILL SHOWS MEAN VALUES OF 50-60 KT SFC-500MB
BULK SHEAR, WITH EVEN THE 10TH PERCENTILE BEING NEAR 40 KT. IF THE
FRONT ENDS UP BEING TIMED TO INDUCE CONVECTION EAST OF THE MOUNTAINS
NEAR PEAK HEATING, AND WE MANAGE THE HIGHER-END CAPE, WE COULD BE
LOOKING AT A LOW-END SEVERE THREAT WEDNESDAY AFTERNOON, MAINLY FOR
DAMAGING WIND, WITH POTENTIAL FOR SOME LINEAR ORGANIZATION. THE
MOISTURE/CAPE STILL APPEARS THE LIMITING FACTOR.
BETWEEN THE CUTOFF LOW OVER THE NE CONUS, AND UPPER RIDGE IN THE
LOWER MS VALLEY, ALONG WITH CAA, GUSTY NW WINDS DEVELOP IN THE
WAKE OF THE FRONT WEDNESDAY NIGHT OVER THE MOUNTAINS AND SKIES
CLEAR. TEMPS TREND NOTICEABLY COOLER FOR THE MOUNTAINS THURSDAY, BUT
DOWNSLOPING APPEARS TO OFFSET THAT TREND FOR THE PIEDMONT. DEWPOINTS
LOOK TO TANK ACROSS THE CWA, WITH CONTINUING GUSTS LIKELY. WINDS
DECLINE THU NIGHT INTO FRI MORNING AS SFC HIGH SHIFTS OVER THE
AREA FROM THE NW. THE ENHANCED RADIATIONAL COOLING CONDITIONS
POTENTIALLY WILL BRING MORNING MINS AROUND 10 DEGREES BELOW NORMAL;
SOME PORTIONS OF THE MOUNTAINS COULD DIP INTO THE UPPER 30S, BUT
PROBABLY STILL TOO WARM FOR FROST. TEMPS REBOUND A BIT FRIDAY AS
UPPER LOW DEPARTS AND HEIGHTS RISE UNDER MOSTLY SUNNY SKIES.
ANOTHER LOW WILL PASS NORTH OF THE GREAT LAKES SATURDAY, WHICH
COULD BRING ANOTHER WEAK FRONT INTO THE LOWER OH AND TN VALLEYS,
REFLECTED IN THE RETURN OF SMALL POPS TO THE MOUNTAINS THEN AND
SUNDAY. HOWEVER, ASSUMING CLOUD COVER OR PRECIP DOES NOT IMPACT
TEMPS, TEMPS REMAIN ON AN UPWARD TREND, PARTICULARLY SUNDAY. MAX
TEMPS SUNDAY MAY HIT 90 IN A NUMBER OF SPOTS.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: A SHIFT TO N-NE WINDS HAS OCCURRED AT ALL
TAF SITES AS A FRONTAL BOUNDARY HAS SETTLED SOUTHWARD THROUGH THE
AREA. OCCASIONAL GUSTS CAN BE EXPECTED THIS AFTERNOON, POTENTIALLY
PEAKING AOA 25 KT. THE FRONT HAS LED TO A STRATOCU DECK AND CIGS
NEAR THE MVFR-VFR THRESHOLD ACROSS KCLT AND KHKY. THE OTHER SITES
ARE EXPECTED TO SEE ONLY FEW-SCT CLOUDS AT THAT LEVEL, AND ANY
CIGS SHOULD LIFT TO VFR BY MID-AFTERNOON, SCATTERING OUT IN THE
EVENING. GUSTS COULD PERSIST INTO EVENING WITH N TO NE WINDS STILL
PREVAILING UNTIL DECOUPLING OCCURS OVERNIGHT AND WINDS GO LIGHT/VRB
IN PARTS OF THE NC PIEDMONT. THERE IS POTENTIAL FOR IFR LEVEL CLOUDS
TO DEVELOP PRIOR TO DAYBREAK TUE AT KCLT AND KHKY, THOUGH WITH LOW
CONFIDENCE HAVE ONLY MENTIONED THESE AS FEW-SCT FOR NOW. WINDS
VEER TO SE AT KCLT AND KAVL PRIOR TO 18Z, WITH THE OTHER SITES
EITHER STILL LIGHT THRU 18Z, OR VEERING LATE ENOUGH NOT TO WARRANT
AN ADDITIONAL LINE TO REFLECT THE SHIFT THIS FAR OUT. LIKELY TOO
DRY IN THE BOUNDARY LAYER TO EXPECT DIURNAL CUMULUS TO DEVELOP TUE.
OUTLOOK: AFTER THE FRONT, DRY CONDITIONS PERSIST THROUGH EARLY
WEDNESDAY. A CLIPPER-TYPE LOW MAY CROSS TO OUR NORTH LATE WEDNESDAY,
BUT GUIDANCE SUGGESTS RAINFALL WILL BE PALTRY WITH THIS SYSTEM,
AND IT'S QUESTIONABLE WHETHER ANY FLIGHT RESTRICTIONS WILL DEVELOP.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
JCW
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