104
FXUS62 KGSP 120529
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1229 AM EST MON JAN 12 2026
WHAT HAS CHANGED
THE FORMAT OF THE AREA FORECAST DISCUSSION HAS BEEN CHANGED TO
REFERENCE KEY MESSAGES RELATED TO THE WEATHER FORECAST AND ITS
IMPACTS.
NO MAJOR CHANGES HAVE BEEN MADE TO THE FORECAST ITSELF. SEE
DISCUSSION BELOW.
KEY MESSAGES
1. LOW RELATIVE HUMIDITY IS EXPECTED THIS AFTERNOON, MAINLY EAST
OF THE MOUNTAINS, BUT A LACK OF WIND SHOULD PROVIDE A CHECK ON
THE FIRE DANGER.
2. WIDESPREAD RAINFALL AND MOUNTAIN SNOW WILL DEVELOP ON WEDNESDAY
NIGHT AND THURSDAY.
3. SIGNIFICANTLY COLDER TEMPERATURES ARRIVE THROUGH THE END OF
THE WEEK. DANGEROUSLY COLD WIND CHILLS DEVELOP AS A RESULT.
DISCUSSION
KEY MESSAGE 1: LOW RELATIVE HUMIDITY IS EXPECTED THIS AFTERNOON,
MAINLY EAST OF THE MOUNTAINS, BUT A LACK OF WIND SHOULD PROVIDE
A CHECK ON THE FIRE DANGER.
AS A SPRAWLING SFC HIGH BUILDS OVER THE FCST AREA, WE SHOULD BE
ABLE TO MIX DOWN SOME DRIER AIR FROM THE LOWEST SEVERAL THOUSAND
FEET ALOFT STARTING IN THE LATE MORNING AND CONTINUING THROUGH THE
AFTERNOON. THE MODEL BLEND TENDS TO NOT DROP THE DEWPOINT ENOUGH
IN THESE SITUATIONS, SO WE UNDERCUT THE MODEL DEWPOINTS BY A FEW
DEGREES, WHICH RESULTS IN THE RH DROPPING DOWN INTO THE MID-20S
ACROSS A GOOD CHUNK OF NORTHEAST GA, UPSTATE SC, AND THE SOUTHERN
PIEDMONT OF NC...ESSENTIALLY ALONG AND S/E OF I-85. THE CONCERN
IS THAT THE SAME AREA FAILED TO GET ANY MEANINGFUL RAIN FROM THIS
PAST SYSTEM. FORTUNATELY, THE WIND WILL BE MUCH BETTER BEHAVED THAN
YESTERDAY, AND IT SHOULD STAY MAINLY SW AT 5-10 MPH AT MOST. THUS,
WE SHOULD NOT MEET INCREASED FIRE DANGER CRITERIA THE WAY THE
FORECAST IS PRESENTLY CONSTRUCTED. THAT BEING SAID, A FIRE DANGER
STATEMENT COULD STILL BE ISSUED FOR THIS AFTERNOON AT THE BEHEST
OF LAND MANAGEMENT AGENCIES, SO THAT'S SOMETHING TO KEEP IN MIND.
KEY MESSAGE 2: WIDESPREAD RAINFALL AND MOUNTAIN SNOW WILL DEVELOP
ON WEDNESDAY NIGHT AND THURSDAY.
FOLLOWING A PROTRACTED PERIOD OF DRY WEATHER ON TUESDAY AND TUESDAY
NIGHT AS SURFACE HIGH PRESSURE MIGRATES OFFSHORE, THE PATTERN WILL
BECOME ACTIVE AGAIN AS A HIGH-AMPITUDE Z500 TROUGH SHARPENS UP OVER
THE MIDWEST. BY THIS POINT IN TIME, MODEL GUIDANCE IS IN DECENT
AGREEMENT THAT A BAROCLINIC ZONE WILL BE DRAPED ACROSS THE TENNESSEE
VALLEY JUST TO OUR WEST, WHILE A COASTAL FRONT WILL BE LOCATED OFF
THE ATLANTIC COAST. THE ADVANCING TROUGH WILL INCITE ACTIVATION OF
BOTH FEATURES, RESULTING IN THE ONSET OF PRECIPITATION ACROSS THE
APPALACHIANS ON WEDNESDAY AFTERNOON...CONTINUING INTO WEDNESDAY
NIGHT AS THE TROUGH PASSES OVERHEAD. THOUGH RECENT GUIDANCE HAS
WAFFLED ON THE EXACT EVOLUTION OF THE ADVANCING SURFACE WAVE, A
CONSENSUS APPEARS TO BE FORMING THAT RATHER THAN CYCLOGENESIS, WE'LL
JUST SEE A ROBUST COLD FRONTAL PASSAGE. THE RESULT, THEN, WILL BE
MAINLY NW FLOW SNOW SHOWERS ACROSS THE NC MOUNTAINS. MOISTURE
OUTSIDE THE MOUNTAINS WILL BE SEVERELY LIMITED BY THE INFLUENCE OF
THE COASTAL FRONT, SO WHILE A FEW ENSEMBLES SUPPORT THE DEVELOPMENT
OF PRECIPITATION ALONG THE I-40 CORRIDOR IN THE NC FOOTHILLS AND
PIEDMONT, ACCUMS SHOULD BE LIGHT TO NONEXISTENT, AND IT'S UNCERTAIN
WHETHER TEMPERATURES WILL EVEN BE COLD ENOUGH FOR ANY FLAKES. THE
FORECAST WILL NEED TO BE MONITORED FOR POTENTIAL WINTER WEATHER
ADVISORIES ACROSS THE MOUNTAINS AS WE GET CLOSER TO THIS EVENT.
THE TROUGH SHOULD EVOLVE INTO A CLOSED UPPER LOW OVER THE NORTHERN
MID-ATLANTIC BY THURSDAY MORNING, AND IN RESPONSE, THE BULK OF
DETERMINISTIC MODELS AND LONG-RANGE ENSEMBLES STILL DEPICT
CYCLOGENESIS ALONG THE COASTAL FRONT. HOWEVER, THE THINKING HAS NOT
CHANGED THAT THIS FEATURE WILL BE FAR ENOUGH EAST TO PRECLUDE ANY
NOTABLE IMPACTS FOR OUR AREA. RATHER, PRECIPITATION SHOULD TAPER
OFF SMOOTHLY THROUGH THE DAY THURSDAY AS THE FRONT PUSHES EAST OF
US, UNTIL WE'RE MOSTLY DRY AGAIN BY THURSDAY EVENING APART FROM SOME
LINGERING NW FLOW SNOW FLURRIES ALONG THE TENNESSEE BORDER.
KEY MESSAGE 3: SIGNIFICANTLY COLDER TEMPERATURES ARRIVE THROUGH THE
END OF THE WEEK. DANGEROUSLY COLD WIND CHILLS DEVELOP AS A RESULT.
AS CONTINENTAL HIGH PRESSURE ARRIVES IN THE CAROLINAS ON THURSDAY
AFTERNOON, TEMPERATURES SHOULD PLUMMET. DETERMINISTIC GUIDANCE
DEPICTS ROBUST LOW-LEVEL CAA THROUGH THE SECOND HALF OF THE DAY
THURSDAY, CONTINUING INTO THURSDAY NIGHT BEFORE MOSTLY SUBSIDING
FRIDAY. AS A RESULT, TEMPERATURES WILL DROP INTO THE LOW 20S AND
UPPER TEENS ACROSS MOST OF THE LOW TERRAIN, WITH LOW TEENS AND
ISOLATED SINGLE DIGIT TEMPERATURES POSSIBLE AT HIGH ELEVATIONS! IN
CONJUNCTION, BLUSTERY NW WINDS WILL DEVELOP WITH GUSTS AS HIGH AS 20-
25KTS. ALTHOUGH WINDS WILL LIKELY BEGIN TO TAPER OFF LATE THURSDAY
EVENING WHEN TEMPERATURES REALLY START TO TANK, WE SHOULD
NONETHELESS SEE WIND CHILLS IN THE LOW TEENS OR SINGLE DIGITS
THURSDAY NIGHT, WITH SOME HIGHER PEAKS EVEN SEEING WIND CHILLS NEAR
OR BELOW ZERO. COLD WEATHER PRODUCTS MAY WELL BE NEEDED AS WE GET
CLOSER.
WITH CAA ESSENTIALLY GONE BY FRIDAY NIGHT, WINDS WILL BE MUCH
QUIETER, AND SO DESPITE TEMPERATURES ONCE AGAIN FALLING INTO THE 20S
ACROSS MOST OF THE FORECAST AREA, DANGEROUSLY COLD WIND CHILLS ARE
EXPECTED TO BE MORE ISOLATED. RATHER, IT LOOKS LIKE WE'LL GET A
BRIEF BOUT OF QUIET WEATHER PERSISTING THROUGH FRIDAY NIGHT, BEFORE
ANOTHER COLD FRONT APPROACHES THE AREA ON SATURDAY. GUIDANCE STILL
HAS A POOR HANDLE ON THIS FRONT, BUT ENSEMBLES ARE IN TENTATIVE
AGREEMENT THAT IT SHOULD PRODUCE SOME SCATTERED NW FLOW SNOW
ACCUMULATIONS ALONG THE NC-TN BORDER. IT'S TOO SOON TO IDENTIFY ANY
IMPACTS WITH MUCH CERTAINTY.
AVIATION /06Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: VFR AT ALL TERMINALS THROUGH THE
PERIOD. SATELLITE IMAGERY SHOWS A SMALL AREA OF UPSLOPE LOW
CLOUDS HANGING ON ALONG THE TN BORDER OF THE NRN MOUNTAINS, BUT
THAT WILL STAY WELL AWAY FROM KAVL AND IT WON'T MAKE IT OVER
THE MOUNTAIN. THUS, MOSTLY CLEAR, WITH SOME THIN CIRRUS LATER
TODAY. SOME LOW END GUSTS PERSIST AT KAVL AT THIS LATE HOUR,
BUT THE GRADIENT CONTINUES TO RELAX AND THE GUSTINESS SHOULD
GO AWAY BEFORE THE START OF MORNING OPS. WIND SHOULD BE CALM OR
LIGHT/VARIABLE AT ALL OTHER TERMINALS THROUGH MIDDAY, AT WHICH
TIME A LIGHT SW WIND WILL DEVELOP. EXPECT MORE LIGHT/VARIABLE WIND
AGAIN FROM SUNSET ONWARD.
OUTLOOK: EXPECT DRY VFR CONDITIONS FOR TUESDAY AND MOST OF
WEDNESDAY. MOISTURE WILL RETURN WEDNESDAY EVENING AND COULD BRING
A CEILING RESTRICTION FOR WEDNESDAY NIGHT, PARTICULARLY OVER THE
MOUNTAINS. SOME WINTRY PRECIP COULD AFFECT KAVL AND PERHAPS KHKY
EARLY THURSDAY MORNING. DRIER CONDITIONS RETURN FRIDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
MPR/PM
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