942
FXUS62 KGSP 021834
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
234 PM EDT WED APR 2 2025
SYNOPSIS
WARMER TEMPERATURES EXPECTED THURSDAY EVEN AS RAIN CHANCES CONTINUE.
FAIR AFTERNOON SKIES AND EXCEPTIONALLY WARM WEATHER END THE WEEK. A
COLD FRONT BRINGS SHOWER AND THUNDERSTORM CHANCES ON SUNDAY, WITH
DRIER AND COOLER CONDITIONS THROUGH THE MIDDLE OF NEXT WEEK.
NEAR TERM /THROUGH THURSDAY/
AS OF 232 PM EDT WEDNESDAY: IT'S A DREARY WEDNESDAY FOR GSP.
HIGH PRESSURE ANALYZED JUST OFF THE NEW ENGLAND COASTLINE CONTINUES
TO DRIVE COLD AIR DAMMING, WHILE A FEW SHOWERS ARE UNDERWAY ACROSS
THE NORTHERN SC UPSTATE AND NC FOOTHILLS EMBEDDED WITHIN MOIST
ISENTROPIC ASCENT ATOP THE WEDGE. MOST ZONES REMAIN SUBJECT TO
THICK LOW STRATUS...WITH THE EXCEPTION OF PARTS OF THE SOUTHERN
UPSTATE AND I-77 CORRIDOR, WHICH HAVE MANAGED TO SCATTER OUT A BIT.
THESE ZONES THAT HAVE SCATTERED OUT (AND WILL CONTINUE TO DO SO FOR
THE NEXT FEW HOURS, DURING PEAK HEATING) HAVE THE BEST CHANCE OF
SEEING ACTIVE WEATHER THIS AFTERNOON. SHOWERS IN THE INTERIOR OF
THE DAMMED ZONE SHOULD WANE THIS AFTERNOON AS UPGLIDE WEAKENS...BUT
HI-RES GUIDANCE IS IN GOOD AGREEMENT THAT WHERE THE WEDGE SCATTERS
OUT ON THE SOUTHERN AND EASTERN FRINGES OF THE FORECAST AREA,
SURFACE-BASED INSTABILITY ON THE ORDER OF 6-1200 J/KG SBCAPE
WILL DEVELOP. DESPITE MODEST SHEAR, LOCALIZED ENHANCEMENT OF
LOW-LEVEL HELICITY NEAR THE WEDGE BOUNDARY WILL PUSH 0-1KM SRH
TO 140-180 J/KG, ENOUGH TO SUPPORT A LOW-END AND ISOLATED RISK OF
SEVERE WEATHER. OTHERWISE, HIGH TEMPS SHOULD REMAIN IN THE MID TO
UPPER 60S WITHIN THE WEDGE...BUT MAY SURGE TO THE MID 70S OUTSIDE
THE WEDGE.
TONIGHT, ANY IMPROVEMENT IN LOW STRATUS WILL BE WIPED OUT.
DESPITE THE SURFACE LOW MOVING FAR ENOUGH OFFSHORE THAT IT WON'T
REALLY BE IN POSITION TO ACTIVELY SUSTAIN THE WEDGE ANY LONGER,
THERE WON'T BE A MECHANISM TO ERODE IT; RATHER, THERE WILL BE THE
USUAL NIGHTTIME INVERSION AND MOIST SOUTHEASTERLY FLOW KEEPING
THE BOUNDARY LAYER SATURATED...WHICH ALL BUT GUARANTEES THE MURKY
CONDITIONS WILL PERSIST THROUGH THE NIGHT. LOWS WILL STRUGGLE
TO FALL BELOW THE UPPER 50S OR LOWER 60S. THE DAYLIGHT HOURS ON
THURSDAY WILL FEATURE SLOW CLEARING...AS DAYTIME HEATING VERY SLOWLY
MIXES THE RESIDUAL WEDGE. TEMPS FOR TOMORROW ARE TRICKY...SINCE
THE TEMPERATURE TREND WILL BE HIGHLY DEPENDENT ON HOW QUICKLY
THE WEDGE SCATTERS OUT. THE NBM AND A CONSENSUS OF THE 12Z CAMS
ARE FORECASTING HIGHS IN THE UPPER 70S OR EVEN LOWER 80S...BUT
THINK ACTUAL HIGHS COULD WIND UP COOLER SINCE THESE MODELS MAY BE
CLEARING OUT THE WEDGE UNREALISTICALLY FAST.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
AS OF 150 PM WED: UPPER RIDGE STARTS OUT OVER THE AREA THEN SLOWLY
MOVES EASTWARD AS A TROUGH DIGS INTO THE MIDWEST. THE MOIST UPSLOPE/
UPGLIDE WEAKENS THURSDAY EVENING BRINGING AN END TO ANY SHOWERS.
DESPITE THE RIDGE IN PLACE FRIDAY, THERE LOOKS TO BE ENOUGH MOISTURE
AND WEAK INSTABILITY FOR ISOLATED TO SCATTERED SHOWERS ACROSS THE
MOUNTAINS DURING THE AFTERNOON AND EARLY EVENING AS A FRONT MOVES
SOUTH TOWARD THE AREA BUT STALLS JUST TO OUR NORTH. AN ISOLATED
RIDGE TOP SHOWER CAN'T BE RULED OUT SATURDAY AFTERNOON, BUT OVERALL
CHANCE OF PRECIP IS LOW WITH LESS IN THE WAY OF MOISTURE AND
INSTABILITY AS THE FRONT MOVES NORTH AWAY FROM THE AREA AND A
SURFACE RIDGE REASSERTS ITSELF. THICKNESSES AND HEIGHTS REMAIN HIGH
UNDER THE RIDGE. THIS PUTS RECORD HIGHS IN JEOPARDY BOTH DAYS. LOWS
WILL BE AROUND 20 DEGREES ABOVE NORMAL.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
AS OF 210 PM WED: THE UPPER TROUGH MENTIONED AT THE END OF THE SHORT
RANGE MOVES EAST AND PUSHES A COLD FRONT INTO THE AREA SUNDAY. THERE
WILL BE PLENTY OF FORCING AND SHEAR, ALONG WITH HIGH PW VALUES,
ASSOCIATED WITH THE FRONT. THERE WILL BE SOME INSTABILITY, BUT THE
AMOUNT IS UNCERTAIN. THEREFORE, THERE IS A LOW SEVERE AND EXCESSIVE
RAINFALL THREAT WHICH WE'LL KEEP AN EYE ON AS THE EVENT APPROACHES.
A WAVE FORMS ALONG THE FRONT SLOWING ITS EASTWARD PROGRESSION
MONDAY. THIS WILL KEEP A CHANCE OF LINGERING SHOWERS ACROSS THE
AREA, BUT ANY SEVERE AND FLOOD THREAT WILL HAVE MOVED EASTWARD.
A WEAK SECONDARY FRONT/CLIPPER TYPE LOW MAY CROSS THE AREA TUESDAY,
BUT THE GUIDANCE KEEPS SHIFTING FROM LOW CHANCE PRECIP TO DRY. HAVE
KEPT THE FORECAST DRY FOR NOW. DRY AND COOLER HIGH PRESSURE MOVES IN
WEDNESDAY.
TEMPERATURES ARE COOLER BUT STILL ABOVE NORMAL SUNDAY AND FALLING TO
NEAR NORMAL MONDAY. TEMPS DRIP BELOW NORMAL FOR TUESDAY AND
WEDNESDAY. THIS BRINGS A FROST CONCERN FOR THE NON-MOUNTAIN AREAS OF
THE UPSTATE AND NE GA AND THE NC SOUTHERN FOOTHILLS AND PIEDMONT,
WHERE THE GROWING SEASON HAS STARTED.
AVIATION /19Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: DREARY CONDITIONS ACROSS THE AREA TODAY AS
COLD AIR DAMMING LINGERS. LIGHT, ALMOST-IMPERCEPTIBLE SHRA OR DZ
IS ONGOING ACROSS THE NORTHERN SC UPSTATE AND THE NC FOOTHILLS,
WITH INTERMITTENT IMPACTS AT KHKY, KGSP, AND KGMU. IN GENERAL,
ALL THE TAF SITES EXCEPT KCLT REMAIN IFR TO LIFR WITH LOW CEILINGS.
LATEST GFS LAMP AND NBM GUIDANCE STILL SUGGEST THAT THERE WILL BE A
BRIEF PERIOD OF IMPROVEMENT TO AT LEAST MVFR LATER THIS AFTERNOON,
WHEN RAINFALL LETS UP AND CLOUDS ARE PERMITTED TO SCATTER OUT AT
LEAST A BIT. AT KCLT, CONDITIONS HAVE ALREADY IMPROVED TO MVFR,
AND KCLT HAS THE BEST CHANCE OF A BRIEF WINDOW OF VFR IN THE
NEXT FEW HOURS. CEILINGS SHOULD TANK AT ALL THE TERMINALS AGAIN
THIS EVENING, WITH IFR TO LIFR RESTRICTIONS EXPECTED EVERYWHERE
BY MIDNIGHT AND THEREAFTER. IMPROVEMENT WILL ONCE AGAIN BE SLOW
TOMORROW...BUT PERHAPS NOT AS SLOW, SINCE THE LARGE-SCALE FEATURES
DRIVING COLD AIR DAMMING WILL NO LONGER BE IN PLACE.
OTHERWISE, EXPECT WINDS TO SLOWLY VEER OVER THE COURSE OF THE TAF
PERIOD, FROM ESE THIS AFTERNOON TO SSE THIS EVENING AND S OVERNIGHT
INTO TOMORROW AS THE WEDGE RETREATS ENTIRELY.
OUTLOOK: SCATTERED SHOWERS AS WELL AS CIG RESTRICTIONS MAY LINGER
INTO THURSDAY AFTERNOON. IFR TO MVFR CIGS MAY RETURN AGAIN LATE
THURSDAY NIGHT INTO FRIDAY MORNING. DRIER CONDITIONS RETURN THURSDAY
NIGHT INTO SATURDAY NIGHT BEFORE ANOTHER COLD FRONT BRINGS SHOWER
AND THUNDERSTORM CHANCES, AND ASSOCIATED FLIGHT RESTRICTIONS,
BACK ON SUNDAY.
CLIMATE
RECORDS FOR 04-03
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 88 1963 31 1936 64 1946 23 1936
KCLT 90 1946 42 1915 62 1986 26 2021
1946
KGSP 87 1967 44 1901 62 2014 27 2021
1963 1993
1946 1902
RECORDS FOR 04-04
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 83 1999 33 1891 61 1893 22 1936
1978
KCLT 87 1999 43 1911 63 1986 29 1936
1899 1945
1934
KGSP 88 1963 44 1936 62 1999 25 1975
1934
RECORDS FOR 04-05
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 86 1909 30 1891 60 2023 20 1944
1910
KCLT 88 1942 38 1891 62 1910 26 1891
KGSP 90 1934 43 1899 60 2023 25 1904
1888
RECORDS FOR 04-06
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 88 1967 36 1950 64 2023 22 1898
KCLT 90 2010 43 1931 67 2023 28 1891
1929
KGSP 88 2010 47 1950 65 2023 26 1904
1945
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...RWH
NEAR TERM...MPR
SHORT TERM...RWH
LONG TERM...RWH
AVIATION...MPR
CLIMATE...
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