639
FXUS62 KGSP 031228
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
728 AM EST SAT JAN 3 2026
SYNOPSIS
A COOL WEDGE OF HIGH PRESSURE, AND DEVELOPING LOW PRESSURE SOUTH OF
THE AREA, TOGETHER RESULT IN A CHILLY AND DAMP DAY FOR THE FORECAST
AREA. DRY AND WARMER CONDITIONS RETURN SUNDAY, WITH TEMPERATURES
TRENDING WELL ABOVE NORMAL FOR MOST OF NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
AS OF 720 AM SATURDAY...
KEY MESSAGE #1: RAIN CONTINUES THIS MORNING WITH SOME LIGHT RAIN
AND/OR DRIZZLE LINGERING THROUGH THIS AFTERNOON AS A WEAK COLD AIR
DAMMING DEVELOPS.
THE FORECAST REMAINS LARGELY ON TRACK AS A WEAK, BUT PERTURBED BELT
OF SOUTHERN STREAM WESTERLIES EXTENDS FROM THE SOUTHERN PLAINS INTO
THE SOUTHEAST STATES. A LEAD IMPULSE AND ASSOCIATED SURFACE LOW
CONTINUES TO SLIDE EAST ALONG THE I-20 CORRIDOR AND WILL BRING
INCREASING RAIN CHANCES ACROSS MUCH OF THE AREA THROUGH THIS
MORNING. FORCING AND MOISTURE TRANSPORT AREN'T ANYTHING TO WRITE
HOME ABOUT, SO GENERALLY LIGHT PRECIPITATION AMOUNTS OF 0.1-0.25"
ARE EXPECTED WITH THE HIGHEST AMOUNTS CLOSER TO 0.5" OVER THE FAR
SOUTHERN TIER OF COUNTIES FROM ELBERT TO GREENWOOD. TEMPERATURES
WILL STRUGGLE TO WARM TODAY AS A WEAK IN-SITU CAD WEDGE DEVELOPS
EAST OF THE MOUNTAINS, ESPECIALLY ACROSS THE I-40 CORRIDOR. THIS
WILL ALSO KEEP DRIZZLE AND SCATTERED RAIN AROUND THIS AFTERNOON
WITHIN THE CAD WEDGE. SUBSEQUENT TEMPERATURES WILL BE NOTICEABLY
COOLER COMPARED TO YESTERDAY WITH HIGHS IN THE LOW 40S TO LOW 50S.
KEY MESSAGE #2: FOG IS POSSIBLE EARLY SUNDAY MORNING.
HEADING INTO TONIGHT, SPRAWLING SURFACE HIGH PRESSURE SETTLING
ACROSS THE GREAT PLAINS WILL HELP TO PUSH A STALLED FRONTAL BOUNDARY
INTO THE MOUNTAINS AND PERHAPS THE FOOTHILLS BY DAYBREAK. THIS WILL
BE A DRY BOUNDARY WITH JUST A WIND SHIFT AND ARRIVAL OF DRIER AIR.
MID-LEVEL MOISTURE WILL GET SCOURED OUT WITH JUST A SHALLOW POOL OF
SURFACE MOISTURE HANGING ON. THIS WILL FOSTER THE POTENTIAL FOR FOG
DEVELOPMENT AHEAD OF THE BOUNDARY EAST OF THE MOUNTAINS.
SHORT TERM /SUNDAY/
AS OF 1120 PM FRI:
KEY MESSAGE: DRY SUNDAY AND MONDAY WITH ABOVE-NORMAL TEMPERATURES AND
MODERATELY LOW RELATIVE HUMIDITY.
THERE STILL MAY BE SOME AREAS OF LOW CLOUD COVER LINGERING OVER THE
CWA AT DAYBREAK SUNDAY, THE LAST VESTIGE OF CAD, BUT NW FLOW SHOULD
CLEAR THAT OUT IN TIME FOR A DAY GENERALLY FREE OF LOW CLOUDS, AS
CONTINENTAL SFC HIGH BUILDS FROM THE OHIO VALLEY TOWARD THE EAST
COAST. SOME CIRRUS MAY RETURN BY AFTERNOON AS JET STREAK ROUNDS THE
UPPER RIDGE CENTERED OVER THE PLAINS. AFTERNOON MIXING SHOULD ALLOW
DEWPOINTS TO DROP A BIT WITH DIURNAL HEATING ALTHOUGH EVEN ONE TAKES
INTO ACCOUNT THE OFTEN "REASONABLE WORST CASE" NBM 10TH PERCENTILE
VALUES, MOST AREAS SHOULD SEE RH REMAIN ABOVE 30% AND THUS NOT
CRITICALLY LOW FOR FIRE WX. MAX TEMPS WILL BE ON THE ORDER OF 5 ABOVE
NORMAL.
500MB SHORTWAVE WILL ROUND THE RIDGE AXIS AND CROSS THE NORTHERN
GREAT LAKES EARLY MONDAY MORNING. A BROAD AREA OF SOUTHWESTERLY WAA
WILL OCCUR DOWNSTREAM OF THE RIDGE ACROSS THE INLAND EAST, AND
RESULTANT UPGLIDE OVER THE SFC HIGH IS LIKELY TO DEVELOP SOME CLOUD
COVER OVER PARTS OF THE UPSTATE AND NC ESCARPMENT/FOOTHILLS, AT
LEAST. THE MOISTURE AND LIFT ARE TOO SHALLOW TO RESULT IN MODEL QPF
SO POPS REMAIN NEAR ZERO, BUT THE ASSOCIATED CLOUD COVER IS ENOUGH TO
BRING MAX TEMPS SLIGHTLY COOLER THAN SUNDAY; SLIGHTLY LOWER PARTIAL
THICKNESSES ALSO OCCUR UNDER THE HIGH. HOWEVER, TEMPS STILL ARE
FORECAST A FEW DEGREES ABOVE NORMAL. MOISTURE ALOFT SUGGEST LESSER
POTENTIAL FOR DEWPOINT MIXING SO MIN RH IS EVEN LESS OF A CONCERN.
LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/
AS OF 1210 AM SAT:
KEY MESSAGE 1: TEMPERATURES TREND WARMER TUESDAY AND REMAIN
CONSIDERABLY ABOVE NORMAL THROUGH THE END OF THE PERIOD.
AS EAST COAST SFC HIGH AND GREAT LAKES SHORTWAVE BOTH MIGRATE EAST,
QUASI-ZONAL UPPER FLOW IS LEFT OVERHEAD. WEAK SW'LY LOW-LEVEL FLOW
WILL RESULT IN SLIGHT WAA TUESDAY, POSSIBLY RESULTING IN PARTIAL
CLOUD COVER BUT NOTABLY GIVING TUESDAY A WARMER START, AND THUS
WARMER AFTERNOON TEMPERATURES ALSO. ANOTHER SHORTWAVE PASSING NORTH
OF THE REGION WILL BE ASSOCIATED WITH A WEAK COLD FRONT ENTERING THE
OHIO VALLEY BUT SEEMINGLY STALLING AT THE SOUTHERN APPALACHIANS AND
PIVOTING ACROSS VA/NC WEDNESDAY AS THE SHORTWAVE MOVES OFFSHORE.
SMALL POPS CONTINUE TO BE FORECAST ALONG THE NC/TN BORDER.
DOWNSLOPING AND MODIFICATION OF THE EXISTING AIRMASS SUGGEST STILL
WARMER TEMPS WEDNESDAY, ENDING UP AROUND 15 ABOVE NORMAL DESPITE
POSSIBILITY OF SOME CLOUD COVER NEAR THE BOUNDARY.
THE PATTERN AMPLIFIES WED-THU AS FULL-LATITUDE TROUGH COMES TOGETHER
OVER THE WESTERN CONUS AND NEXT CYCLONE GINS UP IN THE PLAINS OR MS
VALLEY, WITH HEIGHTS RISING OVER THE EASTERN SEABOARD. EXCEPT FOR THE
POSSIBILITY OF CAD OR A LOOKALIKE UPGLIDE EVENT HAPPENING IN OUR AREA
THURSDAY, THE WARMING TREND SHOULD CONTINUE THROUGH THE END OF THE
PERIOD. EVEN THOSE SOLUTIONS SHOWING CLOUDS AND COOLER TEMPS THU
DEPICT TEMPS BEING ABOVE NORMAL.
KEY MESSAGE 2: ACTIVE WEATHER GENERALLY TO REMAIN OVER OR WEST OF THE
APPALACHIANS THROUGH THURSDAY, WITH RAIN CHANCES TICKING UPWARD
THURSDAY NIGHT AS FRONTAL ZONE INCHES CLOSER.
THERE IS INSUFFICIENT FORCING TO WARRANT ANY POP EAST OF THE
APPALACHIAN SPINE UNTIL THURSDAY. BY THEN, AS NOTED ABOVE, WAA SHOULD
BEGIN ACROSS THE SOUTHEAST AHEAD OF THE DEVELOPING CENTRAL CONUS
SYSTEM, AND A WEAK SFC HIGH MAY BE IN PLACE OVER NC/SC/GA TO ENHANCE
UPGLIDE AND PRODUCE LIGHT PRECIP EAST OF THE MOUNTAINS. THE CANADIAN
GDPS IS ONE MODEL DEPICTING THAT ALONG WITH AN AREA OF COOLER
AFTERNOON TEMPS ASSOCIATED WITH DIABATIC COOLING; THE ECMWF AND GFS
ARE A LITTLE FURTHER WEST WITH THE FRONTAL ZONE, SO THE CHANCES
REMAIN VERY LOW AND MAINLY JUST OVER THE ESCARPMENT/FOOTHILLS.
CHANCES INCREASE THU NIGHT THRU FRIDAY NIGHT AS MODELS COME IN LINE
IN DEPICTING THE FRONT DEVELOPING AND SHIFTING EAST TOWARD THE CWA.
PER ENSEMBLES, THE SURFACE FRONT HOWEVER DOES LOOK LIKELY TO REMAIN
TO OUR WEST UNTIL AFTER THE END OF THE PERIOD AT 12Z NEXT SATURDAY.
BEST CHANCE OVERALL THUS DOES REMAIN 30-50% OVER THE NC MOUNTAINS
AND NEAR THE SOUTH-FACING ESCARPMENT ALONG THE SOUTHWEST BORDER OF
NC. BETTER DYNAMIC FORCING MAY DEVELOP NEXT SAT AND/OR SUN AS THE
SHORTWAVE AXIS AND JET STREAK ADVECT CLOSER TO THE AREA SO THE NEXT
COUPLE OF CYCLES MAY INCORPORATE MORE IMPACTS FROM RAINFALL OR EVEN
THUNDER.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: WIDESPREAD RESTRICTIONS WILL BECOME COMMON
THROUGH THE DAY TODAY AS MORNING SHOWERS MOVE OUT AND A WEAK COLD
AIR DAMMING WEDGE BECOMES ESTABLISHED. WHILE THE MOST WIDESPREAD
COVERAGE OF SHOWERS IS PUSHING EAST OF THE AREA, AT LEAST SCATTERED
SHOWERS AND MIST/DRIZZLE WILL LIKELY CONTINUE INTO THE AFTERNOON.
ASSOCIATED VISIBILITY RESTRICTIONS WILL BE POSSIBLE. CEILINGS WILL
ALSO LOWER TO MVFR AND EVENTUALLY IFR, BUT THE TIMING HAS BEEN
PUSHED BACK AS ATMOSPHERIC PROFILES HAVE BEEN SLOWER TO SATURATE.
RESTRICTIONS WILL CONTINUE OVERNIGHT WITH SHALLOW MOISTURE PROMOTING
THE DEVELOPMENT OF FOG AND CONTINUATION OF WIDESPREAD IFR STRATUS. A
FEW INSTANCES OF DENSE FOG CANNOT BE RULED OUT, BUT CONFIDENCE ON
WHEN AND WHERE REMAINS TO BE SEEN AT THIS TIME RANGE.
OUTLOOK: CEILING AND VISIBILITY RESTRICTIONS SHOULD LIFT ENTIRELY BY
SUNDAY MORNING INTO THE AFTERNOON HOURS. DRY AND VFR CONDITIONS WILL
LINGER THROUGH THE MIDDLE OF NEXT WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...JCW
NEAR TERM...TW
SHORT TERM...JCW
LONG TERM...JCW
AVIATION...TW
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page