954
FXUS62 KGSP 011046
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
646 AM EDT FRI MAY 1 2026
WHAT HAS CHANGED
UPDATED DISCUSSION FOR 12Z TAF ISSUANCE. NO OTHER SIGNIFICANT
CHANGES AT THIS TIME.
KEY MESSAGES
1. LIKELY REMAINING DRY TODAY, BUT WITH RAIN CHANCES RETURNING
TONIGHT AND AT LEAST THE FIRST HALF OF THE DAY SATURDAY. BELOW
NORMAL HIGH TEMPERATURES CAN BE EXPECTED EACH AFTERNOON, ESPECIALLY
ON SATURDAY.
2. COOLER TEMPERATURES FOR THE WEEKEND WITH FROST POSSIBLE
FOR PORTIONS OF THE MOUNTAINS AND FREEZING TEMPS AT THE HIGHER
ELEVATIONS SATURDAY NIGHT. DRY WEATHER AND WARMER TEMPERATURES
EXPECTED THROUGH TUESDAY.
3. ANOTHER COLD FRONT MAY BRING RAIN CHANCES TO THE AREA BY
MIDWEEK, BUT FORECAST CONFIDENCE REMAINS LOW.
DISCUSSION
KEY MESSAGE 1: LIKELY REMAINING DRY TODAY, BUT WITH RAIN CHANCES
RETURNING TONIGHT AND AT LEAST THE FIRST HALF OF THE DAY
SATURDAY. BELOW NORMAL HIGH TEMPERATURES CAN BE EXPECTED EACH
AFTERNOON, ESPECIALLY ON SATURDAY.
A REINFORCING COLD FRONT HAS BROUGHT A WEAK BUT DRY AREA OF HIGH
PRESSURE OVER THE REGION THIS MORNING, CHARACTERIZED BY RELATIVELY
LOW DEWPOINTS IN THE 30S AND LOWER 40S. A MORE WELL DEFINED,
QUASISTATIONARY FRONT WILL REMAIN NEAR THE GULF COAST. THE HIGH
WILL MOVE OFFSHORE OVER THE COURSE OF THE DAY, AND LOW LEVEL
FLOW VEERS TO SOUTHERLY IN ADVANCE OF A DIGGING TROUGH TO OUR
WEST. A SHALLOW LAYER OF MOIST UPGLIDE WILL DEVELOP OVER THE DRY
SFC AIRMASS, MAINTAINING SOME STRATUS OVER AT LEAST THE SOUTHERN
PORTION OF THE CWA; PATCHY CIRRUS ALSO WILL BE SEEN. SOME OF THE
CAMS DEVELOP VERY LIGHT SHOWERS NEAR/SOUTH OF I-85 AND THIS IS
REFLECTED IN A SLIGHT-CHANCE POP IN THOSE AREAS. TEMPERATURES
WILL BE HELD MAINLY INTO THE UPPER 60S AND LOWER 70S BY THE COOL
AIRMASS AND TO SOME DEGREE BY CLOUD COVER
A WEAK SOUTHERN-STREAM SHORTWAVE IS SHOWN TO RIDE ALONG THE GULF
COAST BOUNDARY BY THIS EVENING, ACTIVATING IT AS A WARM FRONT AND
BRINGING MOIST UPGLIDE NORTHWARD TOWARD OUR AREA FRIDAY NIGHT. THIS
APPEARS LIKELY TO RESULT IN A DEEP SATURATED LAYER, AND DYNAMIC
LIFT FROM THE SHORTWAVE AND RIGHT-REAR QUAD OF JET STREAK DOES LOOK
TO ARRIVE EARLY SATURDAY. FOR THOSE REASONS IT IS REASONABLE TO
REFLECT A 60-90% POP WITH PEAK CHANCES DURING SATURDAY MORNING,
WHICH THEN TAPER OFF FROM MIDDAY ONWARD. THE HIGHEST VALUES
SHOULD BE ALONG OUR SOUTHEAST BORDER NEAREST THE FRONT. HOWEVER,
THE DRY SURFACE LAYER MAY STILL BE PRESENT THAT PRECIP WOULD HAVE
TO OVERCOME. FURTHERMORE, GUIDANCE MEMBERS CONTINUE TO DISAGREE AS
TO THE PRECISE LOCATION OF THE BOUNDARY, WHICH LOWERS CONFIDENCE
IN AMOUNTS AND MAY BE RESPONSIBLE FOR WASHING OUT WHAT COULD BE
A FAIRLY SHARP GRADIENT. IT APPEARS LIKELY THE BEST FRONTOGENETIC
QPF RESPONSE WILL BE TO OUR SOUTHEAST, AND STILL NOT MUCH CHANCE
OF SEEING MORE THAN 1" TOTAL EVEN SOUTH OF I-85. NBM IS RUNNING
A LITTLE ON THE HIGH SIDE OF THE ECMWF AND GFS ENSEMBLES, WHICH
TOGETHER SUGGEST LITTLE CHANCE OF EXCEEDING EVEN 0.5" IN ALL BUT
OUR IMMEDIATE SOUTHEASTERN BORDER. AS NOTED PREVIOUSLY, VERTICAL
PROFILES ARE GENERALLY UNFAVORABLE FOR CONVECTION AND STRATIFORM
MODE WILL PREVAIL, SO SEVERE THREAT LOOKS MINIMAL ASSUMING THE
BOUNDARY IS TO OUR SOUTHEAST.
THOUGH SATURDAY'S PATTERN DOES NOT FEATURE A SFC HIGH INDICATIVE
OF ANY FLAVOR OF COLD-AIR DAMMING, THE DRY SFC LAYER AT THE ONSET
OF PRECIP RESULTS IN NUMEROUS MODELS SHOWING DIABATIC COOLING
THAT IMPACTS TEMP TRENDS FRIDAY NIGHT AND SATURDAY. THERE THUS
IS POTENTIAL FOR A RAPID DROP ON THE ORDER OF 5-10 DEGREES EARLY
SATURDAY MORNING (RESULTING IN LOWS SLIGHTLY BELOW NORMAL), WHICH
MAY NOT BUDGE MUCH WHILE PRECIP IS ONGOING. THE LACK OF TRUE CAD
IS REFLECTED IN EVEN THE COOLER MODELS DEPICTING WARMING SATURDAY
AFTERNOON AS PRECIP ENDS; MAXES NONETHELESS NOW ARE FORECAST TO
BE AROUND 15 BELOW NORMAL. SOME BUST POTENTIAL EXISTS FOR MIN/MAX
TEMPS SATURDAY, MAINLY IN THAT IF PRECIP IS INSUFFICIENT TO INDUCE
THE DIABATIC EFFECT, TEMPS MAY PROVE APPRECIABLY WARMER.
KEY MESSAGE 2: COOLER TEMPERATURES FOR THE WEEKEND WITH FROST POSSIBLE
FOR PORTIONS OF THE MOUNTAINS AND FREEZING TEMPS AT THE HIGHER
ELEVATIONS SATURDAY NIGHT. DRY WEATHER AND WARMER TEMPERATURES
EXPECTED THROUGH TUESDAY.
AS THE COASTAL LOW DEPARTS, HIGH PRESSURE FROM THE NORTH FILTERS
INTO THE REGION, BRINGING MUCH COOLER AND DRIER AIR. WITH THIS, A
CHANCE FOR A BRIEF FROST IN THE MOUNTAIN VALLEYS AND FOOTHILLS AS
TEMPERATURES DIP TO NEAR FREEZING SATURDAY NIGHT. CURRENT GUIDANCE
SHOWS THE HIGHEST PROBABILITIES (50-70%) FOR TEMPERATURES DIPPING
BELOW FREEZING ARE AT THE HIGHEST ELEVATIONS. HOW THESE TEMPS TREND
WILL DEPEND ON HOW QUICKLY THE LOW DEPARTS, RAINFALL DIMINISHES AND
SKIES CLEAR OUT. EITHER WAY, NOT EXPECTING MUCH IN THE WAY OF
IMPACTS EXCEPT FOR ANY PLANTS THAT ARE OUTSIDE AND SENSITIVE TO THE
COLD. ANOTHER CHILLY NIGHT FOR SUNDAY NIGHT, HOWEVER TEMPS ARE
TRENDING WARMER AND WHILE FROST COULD OCCUR IN ISOLATED LOCATIONS IN
THE MOUNTAINS, CONFIDENCE IS MUCH LOWER. A WARMING TREND OCCURS TO
START THE WEEK AS THE AIR MASS MODIFIES AND WINDS TURN SOUTHERLY.
DRY WEATHER THROUGH MIDWEEK.
KEY MESSAGE 3: ANOTHER COLD FRONT MAY BRING RAIN CHANCES TO THE AREA
BY MIDWEEK, BUT FORECAST CONFIDENCE REMAINS LOW.
HIGH PRESSURE KEEPS THE WEATHER QUIET THROUGH MOST OF THE WEEK.
MODEL GUIDANCE HINTS AT ANOTHER POSSIBILITY FOR A FRONTAL BOUNDARY
TO CROSS THE AREA TOWARDS MIDWEEK, BUT CONFIDENCE IS VERY LOW AT
THIS POINT. THE GENERAL SYNOPTIC PATTERN LOOKS TO EVOLVE A TROUGH
THAT SWINGS SOUTHWARD AND SUPPORTS THE POTENTIAL FOR RAIN CHANCES.
DEPENDING ON HOW THE RIDGE OUT WEST PROGRESSES THROUGHOUT THE WEEK
WILL EITHER ENHANCE OR WEAKEN THE CHANCES FOR A FROPA. MEANWHILE AT
THE SURFACE, THE HIGH PRESSURE SLIDES OFFSHORE AND DEPENDING ON
WHERE IT POSITIONS, COULD INCREASE MOISTURE ADVECTION INTO THE
REGION AHEAD OF THE FRONT. STILL TOO EARLY TO PINPOINT DETAILS, BUT
IT'S SOMETHING TO CONTINUE TO WATCH.
AVIATION /12Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: VFR THROUGH THIS EVENING WITH CIRRUS AT
FL200-250, BUT ALSO A SCT-BKN LAYER OF STRATUS AT FL050-080 THIS
MORNING. WINDS START THE MORNING MAINLY NE, EXCEPT FOR KAVL
WHICH WILL BE INITIALLY CALM UT SHOULD COME UP FROM THE SE.
WINDS VEER TO LIGHT SOUTHERLY OVER THE FIRST FEW HOURS OF THE
DAY ELSEWHERE, GOING VRB OR NE AGAIN AFTER SUNSET. DEVELOPING
FRONTAL ZONE IS LIKELY TO BRING -RA UP FROM THE SOUTH TONIGHT,
POSSIBLY AS SOON AS 03Z OVER KGSP/KGMU/KAVL BUT MORE LIKELY NOT
UNTIL 07Z OR LATER. DRY SURFACE LAYER AT ONSET, AND INITIALLY
LIGHT PRECIP RATES, MAKES RESTRICTIONS UNLIKELY OVERALL, BUT
WITH HEAVIER RA NEAR THE END OF THE PERIOD, MVFR CIG/VSBY IS
POSSIBLE AND REFLECTED WITH PROB30S WHERE THE CHANCE IS
SUFFICIENTLY HIGH.
OUTLOOK: -RA TAPERING OFF SATURDAY AFTERNOON. DRY AND VFR CONDITIONS
RETURN BY SUNDAY AND LINGER THROUGH AT LEAST TUESDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
CP/JCW
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