420
FXUS62 KGSP 281047
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
647 AM EDT FRI MAR 28 2025
SYNOPSIS
HIGH PRESSURE WILL DRIFT FURTHER OFF THE EAST COAST, ALLOWING A
GRADUAL INCREASE IN MOISTURE AND ABOVE NORMAL TEMPERATURES TO THE
REGION. SHOWER AND THUNDERSTORM CHANCES RETURN SUNDAY INTO MONDAY
AS A COLD FRONT CROSSES THE AREA FROM THE WEST. DRY HIGH PRESSURE
RETURNS TUESDAY, FOLLOWED BY ANOTHER APPROACHING FRONT WEDNESDAY
INTO THURSDAY.
NEAR TERM /THROUGH TONIGHT/
AS OF 630 AM: RELATIVELY STRONG AND WELL DEFINED SFC HIGH WILL
PERSIST OFF THE SOUTH ATLANTIC COAST TODAY. AN ELEVATED WARM
FRONT NORTH OF THE REGION IS RESPONSIBLE FOR THE PATCHY HIGH-BASED
CLOUD COVER NOW OVER THE NC PIEDMONT. A FEW SIMILAR PATCHES MAY BE
REENTER FROM THE WEST THIS MORNING, BUT THE FRONT AND MOISTURE WILL
ADVECT OUT AS MID TO UPPER LEVEL RIDGE AXIS DRIFTS EASTWARD AND
OVER THE CWA. THUS, THESE CLOUDS WILL BE SHORT-LIVED AND MOSTLY
SUNNY SKIES ARE EXPECTED, ALTHOUGH SOME WISPY CIRRUS STILL WILL
STREAM IN. WITH A MILDER START VICE THURSDAY, AND THICKNESSES
BEING HIGHER UNDER THE RIDGE, MAX TEMPS WILL BE AROUND 10 DEGREES
WARMER TODAY, HITTING 80 IN SOME PIEDMONT LOCATIONS. LOW LEVEL WINDS
WILL CONTINUE TO BE SOUTHWESTERLY, HELPING TO BUOY DEWPOINTS. THAT
SAID, MODIFYING PROG SOUNDINGS TO REFLECT WARMER TEMPERATURES THAN
THE RAW MODEL VALUES SUGGESTS DEEPER MIXING WILL OCCUR THAN WHAT
SAID MODELS DEPICT, TAPPING INTO A DRY SUBSIDENT LAYER ABOVE THE
PBL. RH SHOULD EASILY FALL BELOW 30 PERCENT, AND GUSTS OF 20-25
MPH WILL OCCUR ON RIDGETOPS AND PARTS OF THE PIEDMONT. RED FLAG
WARNING REMAINS IN EFFECT FOR A PORTION OF THE MOUNTAINS/FOOTHILLS;
AN INCREASED FIRE DANGER STATEMENT WILL BE ISSUED FOR THE REST OF
OUR ZONES. IT IS WORTH NOTING THAT A FEW CAMS FEATURE SLIGHT CAPE
DEVELOPING ATOP THE DEEP PBL, ON THE UPSTREAM SIDE OF THE RIDGE
(OUR WESTERN MOUNTAINS) WHICH LEADS TO SREF POPS OF UP TO AROUND 20%
IN THAT AREA. HOWEVER, THE SREF "RUNS HOT" WITH POPS, AND FORCING
WILL BE SO WEAK AND THE PBL SO DEEP/DRY IN THAT SCENARIO THAT NO
MENTION OF POP APPEARS NECESSARY IN THE OFFICIAL FCST.
FLOW AROUND THE RIDGE WILL CONTINUE TONIGHT WITH LARGELY S TO SW
WINDS AT 925-850 MB. INITIALLY MOSTLY CLEAR SKIES WILL ALLOW FOR
SOME DEGREE OF DECOUPLING, SO MIXING WILL WEAKEN. MOISTURE RETURN
WILL CONTINUE IN THAT LAYER, AND MECHANICAL LIFT PROBABLY WILL
RESULT IN CLOUD COVER ALONG THE SOUTH-FACING BLUE RIDGE ESCARPMENT
(MOUNTAINS ALONG THE SOUTHERN BORDER OF NC). STILL PROBABLY TOO
SHALLOW FOR PRECIP, BUT THIS WILL RESULT IN EXPANDING LOW CLOUD
COVER IN THAT AREA. CIRRUS INCREASE OTHERWISE. ALONG WITH LIGHT
SW WINDS, THE CLOUDS LEAD TO MIN TEMPS WILL BE AROUND 10 ABOVE
NORMAL SATURDAY MORNING.
SHORT TERM /SATURDAY THROUGH MONDAY/
AS OF 300 AM EDT FRIDAY...
KEY MESSAGES
1) DRY WITH LESS CRITICAL RELATIVE HUMIDITY ON SATURDAY BUT BREEZY
SOUTHERLY WINDS RETURN IN THE AFTERNOON
2) SHOWER AND THUNDERSTORM CHANCES RETURNING SATURDAY NIGHT INTO
MONDAY LIMITING FIRE WEATHER CONCERNS
3) STRONG TO SEVERE STORMS ARE POSSIBLE MONDAY AFTERNOON AND
EARLY EVENING
RETURN FLOW AROUND AN ANTICYCLONE CENTERED OFF THE EAST COAST
WILL CONTINUE TO GRADUALLY ADVECT MORE MOISTURE INTO THE REGION
OVER THE WEEKEND. SATURDAY STILL LOOKS DRY, BUT WITH MINIMUM RH
VALUES EXPECTED TO BE MAINLY IN THE 30-40% RANGE IN ELEVATIONS
BELOW 3500 FT. THERE WILL BE INCREASING CLOUD COVER, AND A FEW
SHOWERS MAY DEVELOP IN THE SOUTHERLY TO SOUTHWESTERLY UPSLOPE FLOW
AREAS BY EARLY EVENING. POPS START TO RAMP UP FROM WEST TO EAST
SATURDAY NIGHT THRU SUNDAY, AS MOISTURE DEEPENS AND EVEN SOME
SBCAPE DEVELOPS. WHILE THE QPF DOESN'T LOOK HEAVY, IT HOPEFULLY
WILL HELP WITH THE WILDFIRES. TEMPS WILL BE WELL-ABOVE NORMAL WITH
LOWS IN THE 50S SATURDAY NIGHT AND UPPER 50S TO LOWER 60S SUNDAY
NIGHT. HIGHS WILL BE MAINLY IN THE 70S SATURDAY AND SUNDAY.
A COLD FRONT ASSOCIATED WITH A LOW PRESSURE SYSTEM TRACKING THRU
THE GREAT LAKES WILL CROSS THE OHIO VALLEY SUNDAY, AND IS EXPECTED
TO CROSS OUR AREA MONDAY. THERE LOOKS TO BE SOME LULL IN SHOWER
ACTIVITY EARLY MONDAY, WITH LOW CLOUDS HAVING SOME OPPORTUNITY TO
SCATTER OUT. GUIDANCE IS IN DECENT AGREEMENT ON THE FRONT CROSSING
THE FORECAST AREA DURING PEAK HEATING, WITH SBCAPE OF 500-1000
J/KG AND 0-6 KM SHEAR OF 40-50 KT. UNLESS THE TIMING OF THE FRONT
SIGNIFICANTLY CHANGES, THERE LOOKS TO BE A DECENT THREAT OF STRONG
TO SEVERE STORMS. TEMPS WILL CONTINUE TO BE ABOVE NORMAL MONDAY.
LONG TERM /MONDAY NIGHT THROUGH THURSDAY/
AS OF 320 AM EDT FRIDAY...
KEY MESSAGES
1) DRIER CONDITIONS GRADUALLY RETURN MONDAY NIGHT INTO TUESDAY
2) RAIN CHANCES MAY RETURN WEDNESDAY INTO THURSDAY BUT CONFIDENCE
IS LOW
3) TEMPERATURES REMAIN ABOVE NORMAL THROUGH THE PERIOD
CONVECTION SHOULD EXIT TO THE EAST OF THE AREA MONDAY NIGHT, AS A
COLD FRONT PASSES THRU. DRY AIR RETURNS WITH HIGH PRESSURE RIDGING
IN FROM THE NORTH. THE FRONT ONLY BRINGS TEMPS DOWN SLIGHTLY, WITH
TEMPS REMAINING ABOVE NORMAL. RH VALUES WILL LIKELY FALL INTO THE
30-40% RANGE, BUT WINDS SHOULD BE RELATIVELY LIGHT. THE PATTERN
WILL BE PROGRESSIVE WITH THE HIGH QUICKLY EXITING TO THE EAST,
AND FLOW TURNING AROUND OUT OF THE SOUTH AGAIN BY WEDNESDAY. THE
00Z GUIDANCE REMAINS AT ODDS WITH HOW QUICKLY THE NEXT FRONT
CROSSES THE AREA. THE GFS HAS A FROPA WEDNESDAY INTO WED NIGHT,
WHILE THE ECMWF AND CANADIAN BASICALLY STALL THE FRONT OUT TO
OUR WEST THRU THURSDAY. EITHER WAY, WELL-ABOVE NORMAL TEMPS AND
RELATIVELY UNSETTLED WX IS EXPECTED.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: VFR THROUGH TONIGHT. AREAS OF CIGS ABOVE
FL100 NEAR KCLT/KHKY THIS MORNING WITH ONLY CIRRUS OTHERWISE. MAINLY
LIGHT SW WINDS WITH GUSTS DEVELOPING 16-18Z, MOSTLY 10-15 KT WITH
GUSTS OF 20-25 KT, BUT PERHAPS BRIEFLY EXCEEDING 25 KT. KAVL
COULD CONTINUE TO BE AFFECTED BY SMOKE PLUME FROM FIRES SOUTH
OF THE FIELD NEAR THE SC BORDER; MODELED CONCENTRATIONS SUGGEST
THIS IS MOST LIKELY FRI EVENING AS MIXING DIMINISHES, WITH MVFR
VSBY POTENTIALLY RESULTING. WITH LOW CONFIDENCE AT THIS RANGE
AND SUBTLE DEPENDENCE ON WIND DIRECTION, NOT MENTIONING SUCH THIS
ISSUANCE. LIGHT SOUTHERLY WINDS CONTINUE INTO EARLY SAT MORNING
AIDING IN RETURN FLOW. DEPICTIONS OF IFR STRATUS IN SOME GUIDANCE
ARE LIKELY OVERDONE AND EXPECT KCLT WILL REMAIN VFR THRU 18Z SAT.
OUTLOOK: A FRONTAL SYSTEM WILL BRING INCREASING CHANCES FOR SHOWERS
AND THUNDERSTORMS, ALONG WITH OCCASIONAL RESTRICTIONS ON SUNDAY
AND ESPECIALLY MONDAY. DRYING IS EXPECTED FOR TUESDAY.
FIRE WEATHER
TEMPERATURES WARM ENOUGH TODAY (COMPARED TO THURSDAY) THAT ALTHOUGH
DEWPOINTS WILL BE HIGHER, RH STILL IS EXPECTED TO FALL BELOW 30
PERCENT ACROSS ALL BUT THE HIGHER ELEVATIONS OF THE BALSAMS AND
THE HIGH RANGES NORTHEAST OF THE FRENCH BROAD VALLEY. MOST LOWER
ELEVATIONS WILL SEE RH FALL TO 20-25%. BREEZY CONDITIONS CAN
BE EXPECTED DURING THE AFTERNOON WITH GUSTS OF 15-25 MPH, WITH
ISOLATED SPOTS SEEING A BRIEF GUST TO 30 MPH. AN IMPACT-BASED RED
FLAG WARNING REMAINS IN EFFECT FOR PORTIONS OF THE MOUNTAINS OF
WESTERN NORTH CAROLINA, UPSTATE OF SOUTH CAROLINA AND RABUN COUNTY
IN NORTHEAST GEORGIA. THE WINDS MAY NOT MEET OBJECTIVE CRITERIA FOR
AN INCREASED FIRE DANGER STATEMENT ELSEWHERE IN NC/SC, BUT IN LIGHT
OF THE EXCEPTIONALLY DRY FUELS, LOW RH, AND MARGINALLY CRITICAL
WINDS, STATEMENTS HAVE BEEN ISSUED FOR ALL ZONES IN THOSE STATES,
AND IN NE GA FOR THE USUAL 4 HRS OF RH BELOW 25%.
GSP WATCHES/WARNINGS/ADVISORIES
GA...RED FLAG WARNING FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
GAZ010.
INCREASED FIRE DANGER FROM NOON EDT TODAY THROUGH THIS EVENING
FOR GAZ017-018-026-028-029.
NC...RED FLAG WARNING FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
NCZ048>053-058-059-062>065-303-505>510.
INCREASED FIRE DANGER FROM NOON EDT TODAY THROUGH THIS EVENING
FOR NCZ033-035>037-056-057-068>072-082-501>504.
SC...RED FLAG WARNING FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
SCZ101>106-108.
INCREASED FIRE DANGER FROM NOON EDT TODAY THROUGH THIS EVENING
FOR SCZ008>014-019-107-109.
SYNOPSIS...ARK
NEAR TERM...WIMBERLEY
SHORT TERM...ARK
LONG TERM...ARK
AVIATION...WIMBERLEY
FIRE WEATHER...WIMBERLEY
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