625
FXUS62 KGSP 210235
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
935 PM EST MON JAN 20 2025
SYNOPSIS
ARCTIC HIGH PRESSURE SPREADING OVER THE AREA WILL BRING BITTER
COLD TO THE REGION FOR MOST OF THIS WEEK. A LOW PRESSURE SYSTEM
IS EXPECTED TO TRACK FROM THE NORTHERN GULF OF MEXICO TO JUST OFF
THE SOUTHEAST COAST BY MID-WEEK, HOWEVER THE POTENTIAL FOR SNOW
APPEARS MINIMAL FOR OUR AREA. THE AIRMASS IS EXPECTED TO MODIFY BY
THIS WEEKEND.
NEAR TERM /THROUGH TUESDAY/
AS OF 930 PM EST MONDAY: NO CHANGES WERE NEEDED THIS UPDATE AS THE
FORECAST REMAINS ON TRACK. OTHERWISE, CLEAR SKIES AND LIGHT WINDS
WILL ALLOW TEMPS TO RADIATE AWAY QUICKLY. IN SPITE OF THE LIGHT
WINDS, THE TEMPS WILL GET LOW ENOUGH SO AS TO BRING OUR APPARENT
TEMPS DOWN RIGHT AROUND COLD WEATHER ADVISORY CRITERIA IN AVERY
COUNTY, THE MAJORITY OF THE SC UPSTATE, AND PORTIONS OF THE SOUTHERN
NC PIEDMONT. THE ONE CONCERN IS THAT HIGH CLOUDS COULD ARRIVE
QUICKER THAN EXPECTED AND KEEP TEMPS FROM DROPPING OFF QUITE AS MUCH
AROUND DAYBREAK.
WHICH BRINGS US TO TUESDAY...WHICH WE HAVE BEEN MONITORING FOR
SEVERAL DAYS NOW. VERY LITTLE HAS CHANGED OVERALL WITH THE EXPECTED
TRACK OF THE SYSTEM BECAUSE OF THE LOW AMPLITUDE OF THE UPPER
TROF. THE PREPONDERANCE OF THE GUIDANCE CONTINUES TO SHOW THE BULK
OF THE PRECIP STRETCHED OUT WELL TO THE SOUTH OF THE FORECAST AREA
WITHOUT MUCH (IF ANY) POTENTIAL FOR SIGNIFICANT PRECIP REACHING THIS
FAR NORTH. THE BEST FORCING AND MOISTURE REMAINS AT MID AND UPPER
LEVELS, WHILE LOW LEVELS REMAIN VERY DRY. MID-LEVEL ISENTROPIC
LIFT WILL SPREAD NORTHEAST ACROSS THE REGION IN THE AFTERNOON,
BUT WITH SUCH A DRY AND DEEP SUB-CLOUD LAYER, MUCH OF WHAT SHOULD
DEVELOP FROM THE MID-LEVEL CLOUDS WILL BE LOST TO EVAPORATION. SNOW
FLURRIES ARE PROBABLE IN THE AFTERNOON AS THIS LIFT STRENGTHENS, BUT
THE CHANCES OF ANYTHING REACHING THE GROUND AND ACCUMULATING ARE NO
BETTER THAN SLIGHT ACROSS NORTHEAST GA AND THE UPSTATE SOUTH/EAST
OF I-85, MAYBE UP TO 30 PCT ACROSS THE LAKELANDS/LOWER PIEDMONT IN
THE VERY LATE AFTERNOON. ONE COULD TURN THIS AROUND AND SAY THAT IT
IS LIKELY (OR MORE THAN LIKELY) THAT NO ACCUMULATION WILL HAPPEN
IN THESE AREAS. EVEN IF SOMETHING WERE TO ACCUMULATE, IT WOULD
MORE THAN LIKELY AMOUNT TO LESS THAN ONE-QUARTER INCH OF A FLUFFY
DRY SNOW. THIS IS NOT ENOUGH TO SUPPORT ISSUING A WINTER WEATHER
ADVISORY. IN THE MEAN TIME, WE WILL MIND THE FORECAST GUIDANCE AND
CONSIDER A REASONABLE WORST-CASE SCENARIO THAT WOULD BE AROUND
ONE INCH OR SO SOUTHEAST OF I-85. BUT, AGAIN, THE OVERWHELMING
CONSENSUS OF THE GUIDANCE IS FOR A NON-EVENT. TEMPS, MEANWHILE, WILL
CONTINUE TO BE WELL BELOW NORMAL, STAYING BELOW 32F IN MUCH OF THE
FCST AREA AND ONLY GETTING A FEW DEGREES ABOVE THAT OVER THE SOUTH.
SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/
AS OF 150 PM EST MONDAY: AN UPPER TROUGH STRETCHING ACROSS THE
EASTERN-THIRD OF THE CONUS WILL BE IN THE MIDST OF SHIFTING ACROSS
THE CFWA TUESDAY NIGHT AS A WINTER STORM WILL BE ONGOING, MAINLY
SOUTH AND EAST OF THE AREA. MODEL GUIDANCE HAVE NUDGED NORTHWESTWARD
IN THE LATEST 12Z RUNS, BUT WITH TONS OF DRY AIR TO OVERCOME. MOST
OF THE SNOW THAT DOES FALL WILL SUBLIMATE BEFORE REACHING THE
SURFACE. HOWEVER, THERE IS MORE SUPPORT OF AT LEAST FLURRIES ACROSS
THE I-85 CORRIDOR AND POINTS SOUTH/EAST. THE NORTHERN EXTENT OF THE
PRECIP SHIELD WILL HAVE A SHARP CUTOFF, WITH LOCATIONS SOUTH/EAST OF
I-85 HAVING THE BEST CHANCE OF ANY TYPE OF SNOW ACCUMULATION. RIGHT
NOW, THE HREF GIVES THESE LOCATIONS A 30-40% CHANCE OF MEASURABLE
SNOW (=>0.1") AND THE FORECAST LINES UP WITH THAT THINKING. THE
SURFACE LOW WILL TRANSITION ACROSS THE FLORIDA PENINSULA AND WELL
OUT TO SEA OFF THE SOUTHEAST COAST BY WEDNESDAY. THERE MAY BE A
QUICK BURST OF SNOW, BUT WILL BE SHORT-LIVED AS THE LOW WILL BE
QUICK TO SHIFT FROM WEST TO EAST OFFSHORE. STILL THINK THE CLT
METRO, UPSTATE, AND NORTHEAST GEORGIA WILL SEE SOME FLAKES FLY,
BUT NOT EXPECTING T MAJOR IMPACTS. IF THE TREND CONTINUES NORTHWEST
AND MORE SNOW ACCUMULATION ENTERS THE FORECAST, WATCH OUT ON THE
ROADS AS TEMPERATURES IN 20S WITH SNOW WILL CAUSE ISSUES ON MAJOR
ROADS, ESPECIALLY ROADS THAT ARE LEFT UNTREATED.
TUESDAY NIGHT OVERNIGHT LOWS ARE IN THE TEENS OVER THE
FOOTHILLS/PIEDMONT, WHILE SINGLE DIGITS PREVAIL ACROSS THE
MOUNTAINS. TUESDAY NIGHT MAY BE THE COLDEST NIGHT OF THE WEEK AS
THE SURFACE HIGH BECOMES REINFORCED WITH MORE ARCTIC AIR BEHIND THE
AFOREMENTIONED STORM SYSTEM AND LOW-END GUSTS FILTER IN. EXPECT AT
LEAST A COLD WEATHER ADVISORY FOR THE MOUNTAINS WITH THE POSSIBILITY
OF AN EXTREME COLD WARNING IN THE HIGHER ELEVATIONS, WHERE WIND
CHILL VALUES WILL RANGE FROM -5F TO -15F. THE TROUGH AXIS LOOKS
TO SLIP EAST OF THE CFWA BY WEDNESDAY AS THE SURFACE HIGH SLIDES
OVER THE MID-ATLANTIC. WITH A SECOND PULSE OF BRUTAL COLD SETTLING
OVER THE AREA, AFTERNOON HIGHS WEDNESDAY WILL BE IN THE LOW TO
MID 30S OVER THE MAJOR MOUNTAIN VALLEYS AND FOOTHILLS/PIEDMONT,
WHILE THE MOUNTAINS REMAIN IN THE 20S. TEMPERATURES THURSDAY
REBOUND SLIGHTLY AS MORE SUNSHINE AND A LIGHT RETURN FLOW SHIFTS
INTO THE REGION. AFTERNOON HIGHS WILL CONTINUE TO RUN BELOW NORMAL,
BUT VALUES SHOULD UPTICK INTO UPPER 30S AND LOWER 40S ACROSS THE
AREA, WITH UPPER 20S TO LOWER 30S IN THE HIGHER ELEVATIONS.
LONG TERM /THURSDAY NIGHT THROUGH MONDAY/
AS OF 230 PM EST MONDAY: A SECONDARY SHORTWAVE LOOKS TO DIG OVER
THE PLAINS AND RACE EAST TOWARDS THE CFWA THURSDAY AND FRIDAY. THIS
SHORTWAVE WILL HELP TO DEVELOP A COASTAL LOW OVER THE REMNANT
BAROCLINIC ZONE OFF THE SOUTHEAST COAST AND LIFT IT NORTH ALONG
THE EASTERN SEABOARD THURSDAY INTO FRIDAY AS THE TROUGH SWINGS
ACROSS THE EASTERN-THIRD OF THE CONUS. ANOTHER SHOT OF PRECIP MAY
DEVELOP OVER THE EASTERN CAROLINAS, BUT MODEL GUIDANCE SUGGESTS ANY
PRECIP SHOULD REMAIN WELL EAST OF THE CFWA THURSDAY INTO THURSDAY
NIGHT. THE REST OF THE FORECAST REMAINS MOSTLY DRY AS THE FLOW
ALOFT FLATTENS AND THE AIRMASS SLOWLY MODIFIES BY THE FOLLOWING
WEEKEND. TEMPERATURES REMAIN WELL-BELOW NORMAL AND REBOUND TO
NEAR-NORMAL VALUES BY THE WEEKEND. MODEL GUIDANCE TRY TO PAINT
OUR NEXT STORM SYSTEM BY D7, BUT TEMPERATURES WILL BE TOO WARM
FOR ANY P-TYPE CONCERNS, ESPECIALLY OUTSIDE OF THE MOUNTAINS.
AVIATION /03Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: DRY AND VFR THROUGH THE 00Z TAF FORECAST
PERIOD THANKS TO ARCTIC HIGH PRESSURE OVERHEAD. SKIES REMAIN CLEAR
THROUGH LATE TONIGHT BEFORE UPPER VFR CLOUD COVER GRADUALLY
INCREASES EARLY TUESDAY MORNING BECOMING BKN TO OVC BY DAYBREAK. OVC
VFR CLOUD COVER LINGERS THROUGH THE END OF THE TAF PERIOD. WINDS
REMAIN NW AT KAVL THROUGH THE TAF PERIOD. WIND DIRECTION WILL START
OUT N/NE EAST OF THE MOUNTAINS THIS EVENING INTO DAYBREAK TUESDAY.
WINDS EAST OF THE MOUNTAINS WILL GRADUALLY TURN NW/W TOWARDS THE END
OF THE TAF PERIOD.
OUTLOOK: CHANCE OF SNOW REMAINS POSSIBLE TUESDAY EVENING INTO
TUESDAY NIGHT MAINLY ALONG AND SOUTH OF I-85. VFR AND DRY MOST OF
THE WEEK THANKS TO THE ARCTIC AIRMASS LINGERING OVER THE TERMINALS.
EXCEPTIONALLY COLD TEMPERATURES CONTINUE THROUGH WEDNESDAY NIGHT.
CLIMATE
RECORDS FOR 01-20
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 69 1906 24 2009 53 1954 -13 1985
1890
KCLT 71 1951 30 1983 53 1890 -2 1985
1929 1893
1927
KGSP 72 1933 30 1983 56 1922 1 1985
RECORDS FOR 01-21
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 72 1927 8 1985 59 1927 -16 1985
KCLT 73 1935 24 1985 58 1954 -5 1985
KGSP 73 1927 26 1985 59 1933 -4 1985
RECORDS FOR 01-22
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 73 1932 21 1960 59 1933 0 1970
KCLT 74 1937 29 1970 60 1906 5 1970
KGSP 72 1938 31 1970 58 1933 3 1893
1921
RECORDS FOR 01-23
MAX TEMPERATURE MIN TEMPERATURE
STATION HIGH LOW HIGH LOW
------- ---------- ---------- ---------- ----------
KAVL 73 1927 20 2005 54 1999 1 1936
1936
KCLT 75 1927 27 1970 59 1999 9 2003
KGSP 73 1974 30 1970 58 1999 5 1893
1927
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...COLD WEATHER ADVISORY UNTIL 11 AM EST TUESDAY FOR NCZ033.
COLD WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR NCZ070>072-
082.
SC...COLD WEATHER ADVISORY UNTIL 10 AM EST TUESDAY FOR SCZ008>014-
019-102-103-105>109.
SYNOPSIS...CAC
NEAR TERM...AR/PM
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...AR
CLIMATE...GSP
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