912
FXUS62 KGSP 192032
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
332 PM EST SUN JAN 19 2025
SYNOPSIS
A ROUND OF SNOW SHOWERS WILL CONTINUE NEAR THE TENNESSEE BORDER AND
LINGER THROUGH MONDAY MORNING, WITH GOOD SNOW ACCUMULATION LIKELY AT
THE HIGHER ELEVATIONS. ARCTIC HIGH PRESSURE MOVING IN TONIGHT WILL
BRING BITTER COLD TO THE REGION FOR MOST OF THIS WEEK. A STORM
SYSTEM IS EXPECTED TO TRACK FROM THE NORTHERN GULF OF MEXICO TO OFF
THE SOUTHEAST COAST MID-WEEK, BUT THE POTENTIAL FOR SNOW CONTINUES
ON A DOWNWARD TREND FOR OUR AREA.
NEAR TERM /THROUGH MONDAY/
AS OF 235 PM SUNDAY...THE POSITION OF THE COLD FRONT HAS APPEARED
ON THE RADAR MOSAIC AS A BAND OF SHOWERS OVER THE WESTERN PIEDMONT
OF NC. EXPECT THIS SHOWER BAND TO MAKE STEADY EASTWARD PROGRESS
WITH THE FRONT THROUGH MID/LATE AFTERNOON, AS IT APPARENTLY
HAS A SMALL AMOUNT OF SFC-BASED CAPE TO WORK WITH. WILL HAVE TO
ADD IN A CHANCE OF SHOWERS IN THOSE ZONES TO ACCOUNT FOR THIS
DEVELOPMENT. MEANWHILE, THE KMRX RADAR CONTINUES TO SHOW A LARGE
AREA OF RADAR RETURNS MOVING UPSLOPE INTO WESTERN NC, WHICH WAS
PROBABLY FALLING AS SNOW ON THE TN BORDER AS CLOUD TOP TEMPS ARE
IN THE DENDRITIC GROWTH ZONE. THAT PART OF THE FCST LOOKS TO BE ON
TRACK THRU THE REST OF THE AFTERNOON. AS FOR TEMPS, THEY WILL BE
MODULATED BY THE FRONTAL PASSAGE. THE COLD AIR WAS ALREADY MOVING
IN FROM THE WEST. GUSTY WINDS WILL CONTINUE BEHIND THE FRONT.
THE SITUATION HASN'T CHANGED REMARKABLY WITH THIS FORECAST
PACKAGE. WE STILL HAVE A VERY GOOD SIGNAL IN THE MODEL GUIDANCE
FOR CONTINUED NW FLOW UPSLOPE SNOW ALONG THE TN BORDER THROUGH
THE EVENING. WE STILL EXPECT A PERIOD FROM LATE AFTERNOON
THROUGH LATE EVENING WITH DEEP MOISTURE THAT EXTENDS UP THROUGH
THE DENDRITIC GROWTH ZONE, ONCE THE DEEP COLD AIR ARRIVES. THE
COLD COLUMN SUPPORTS HIGH SNOW-TO-LIQUID RATIOS ON THE ORDER OF
20-TO-1 THAT WILL HELP TO RAISE THE SNOW TOTALS, EVEN THOUGH THE
OVERALL QPF HAS DROPPED JUST A BIT. TEMPS WILL DROP QUICK ENOUGH
TO SUGGEST A POTENTIAL FLASH FREEZE, WHICH COULD RAISE CONCERNS
FOR SLIPPERY ROADS. NO CHANGES WILL BE MADE TO THE WINTER STORM
WARNINGS/ADVISORIES AT THIS POINT. STILL THINK THE SNOW WILL TAPER
OFF AROUND DAYBREAK MONDAY. AT THE SAME TIME, NO BIG CHANGES WERE
MADE TO THE TEMPS AND WIND, EITHER, SO THE COLLECTION OF EXTREME
COLD WARNINGS/ADVISORIES LOOK GOOD. THE EXCEPTION IS ALEXANDER
COUNTY, WHICH HAD A SMALL DOWNWARD ADJUSTMENT ENOUGH TO EXPAND
THE ADVISORY INTO THAT ZONE. OF NOTE...AS COLD AS IT WILL GET
TONIGHT...IT WILL BE NOWHERE NEAR RECORD COLD FOR THIS DATE.
MONDAY LOOKS SUNNY AND COLD AS THE ARCTIC HIGH BUILDS IN FROM THE
WEST. HIGH TEMPS SHOULD BE ON THE ORDER OF 20 DEGREES BELOW NORMAL,
SO CERTAINLY A COLD AND BLUSTERY WINTER DAY, EVEN IF MOST PEOPLE
DON'T HAVE ANY SNOW ON THE GROUND.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
AS OF 130 PM EST SUNDAY: BROAD UPPER TROUGHINESS OVERLAYS THE
EASTERN TWO-THIRDS OF THE CONUS, WHILE AN UPPER RIDGE NOSES OVER
THE WEST COAST/EASTERN PACIFIC. A SHORTWAVE TROUGH WILL CARVE OUT
OVER THE DESERT SOUTHWEST IN RESPONSE AND SLIDES OVER THE PLAINS
AND MS VALLEY TUESDAY AS SURFACE CYCLOGENESIS GETS UNDERWAY OVER
THE GULF OF MEXICO AS THE TROUGH TAPS INTO THE COASTAL BAROCLINIC
ZONE. STOUT ARCTIC AIRMASS WILL ALREADY BE ESTABLISHED OVER THE
AREA BY THE BEGINNING PORTIONS OF THE FORECAST PERIOD AS THE SURFACE
HIGH SETS UP SHOP OVER THE EAST COAST AND STOUT CAA CONTINUES. THE
SURFACE LOW IS EXPECTED TO MOVE ACROSS THE GULF OF MEXICO FROM WEST
TO EAST AND PRODUCE A LIKELY RECORD BREAKING WINTER STORM ALONG THE
GULF COAST REGIONS. THE QUESTION IS HOW MUCH MOISTURE CAN OVERCOME
THE VERY DRY ATMOSPHERIC PROFILES OVER OUR CFWA. IF ANY PRECIP WERE
TO FALL, TEMPERATURES WILL BE VERY COLD AND THE ONLY P-TYPE THAT
WOULD DEVELOP IS SNOW. THE BEST CHANCES ARE IN LOCATIONS SOUTH/EAST
OF I-85 FOR ANY TYPE OF SNOW TO FALL. THE LATEST MODEL GUIDANCE,
INCLUDING THE NAM AND DETERMINISTIC MODELS SHOW VERY LITTLE SNOW AND
KEEP THE SYSTEM SUPPRESSED WELL SOUTH OF THE AREA AS THE LOW MOVES
ACROSS THE FLORIDA PENINSULA AND OFF THE SOUTHEAST COAST BY
WEDNESDAY. THE NORTHERN GRADIENT OF PRECIP WILL HAVE A SHARP CUTOFF
AND BASED ON RECENT TRENDS, THE CUTOFF MAY HAPPEN OVER THE MIDLANDS,
WHILE OUR CFWA JUST STAYS MOSTLY DRY. THERE IS TIME FOR A
NORTHWESTWARD TREND AND THE CHANCES FOR SNOW ALONG AND SOUTH/EAST OF
I-85 ISN'T ZERO, BUT DEFINITELY LOW. FOR NOW, ONLY CHANCE POPS ARE
IN THE FORECAST AND VERY MINIMAL SNOW. THE LREF ENSEMBLE GIVES THE
AREA ONLY A 30-50% CHANCE OF MEASURABLE SNOW (=>0.1") THROUGH THE
ENTIRE EVENT AND THAT'S DOWN COMPARED TO THIS TIME YESTERDAY. ALL OF
THE GEFS MEMBERS ARE COMPLETELY DRY AND THIS ACTUALLY INCREASES OUR
CONFIDENCE THAT VERY MINIMAL SNOW WILL EVEN DEVELOP ACROSS THE CFWA.
THE MOST LIKELY SCENARIO WOULD BE A FEW HOURS OF FLURRIES WITH
LITTLE TO NO ACCUMULATION FOR PORTIONS OF THE CLT METRO, UPSTATE,
AND NORTHEAST GEORGIA, WHILE THE REST OF THE AREA REMAINS VERY COLD
AND DRY. ANY SNOW THAT DEVELOPS WOULD BE IMPACTFUL AS TEMPERATURES
WILL BE VERY COLD AND CREATE TREACHEROUS ROAD CONDITIONS,
PARTICULARLY ON UNTREATED ROADS, SO THIS IS SOMETHING TO CONTINUE
MONITORING.
MONDAY AND TUESDAY NIGHT BOTH HAVE OVERNIGHT LOWS IN THE TEENS
OVER THE FOOTHILLS/PIEDMONT, WHILE SINGLE DIGITS PREVAIL ACROSS THE
MOUNTAINS. THE HIGHER ELEVATIONS (>3500') WILL RECEIVE BELOW ZERO
WIND CHILL VALUES, BUT THANKFULLY THE WINDS LIGHTEN AS THE CENTER
OF THE SURFACE HIGH SETS UP SHOP OVER THE CENTRAL AND SOUTHERN
APPALACHIANS BY MONDAY NIGHT. 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. 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
TUESDAY AND WEDNESDAY WILL REMAIN RELATIVELY THE SAME AS LOW TO MID
30S RESIDE OVER THE MAJOR MOUNTAIN VALLEYS AND FOOTHILLS/PIEDMONT,
WHILE THE MOUNTAINS REMAIN IN THE 20S BOTH DAYS. THE SENSIBLE
WEATHER REMAINS MOSTLY QUIET THROUGH THE PERIOD, BUT ONE THING IS
FOR CERTAIN, THE COLDEST AIR OF THE SEASON BECOMES ESTABLISHED
ACROSS THE WESTERN CAROLINAS AND NORTHEAST GEORGIA DURING THE
SHORT-TERM FORECAST PERIOD.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS OF 240 PM EST SUNDAY: STILL UNDER FLAT UPPER TROUGHINESS
WEDNESDAY NIGHT, A SECONDARY SHORTWAVE LOOKS TO DIG OVER THE
PLAINS AND RACE EAST TOWARDS THE CFWA. 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
EAST OF THE CFWA THURSDAY INTO THURSDAY NIGHT. THE GFS TRIES
TO CREATE SOME NWFS FRIDAY ALONG THE NC/TN BORDER AS THE TROUGH
AXIS SWINGS ACROSS THE AREA, WHILE THE ECMWF IS DRY AND THE CMC
IS SOMEWHERE IN BETWEEN. THE REST OF THE FORECAST REMAINS 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 D6/D7.
AVIATION /21Z SUNDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: SATELLITE IMAGERY SHOWS LOW CLOUDS LINGERING
ACROSS THE WESTERN PIEDMONT AND UPSTATE SC BEHIND A DEPARTING
SFC LOW. THINK THE CEILING WILL MAKE IT TO MVFR IN SHORT ORDER AT
KCLT. ALL TERMINALS SHOULD BE IN-AND-OUT OF AN MVFR BKN CEILING
RESTRICTION THROUGH LATE AFTERNOON WHEN HEATING IS LOST AND THE
ARCTIC FRONT SWEEPS THROUGH. SPEAKING OF WHICH, THE FRONT WAS
LOCATED OVER THE NC FOOTHILLS AND WAS MOVING SOUTHEAST, BUT THE
WIND PROFILE AT TCLT WAS STILL SW UP TO ABOUT 5K FEET, SO THINK
THE WIND SHIFT WILL OCCUR AT KCLT CLOSER TO 20Z. WINDS WILL BE
GUSTY SW AHEAD OF THE FRONT, AND THEN STRONGER AND MORE GUSTY
BEHIND THE BOUNDARY THROUGH THE EVENING. CONDITIONS WILL BE VFR
FROM LATE AFTERNOON ONWARD OUTSIDE THE MTNS. AT KAVL, WITH THE
DEVELOPING NW FLOW PUSHING MOISTURE UP THE VALLEY, EXPECT THE MVFR
RESTRICTION TO PERSIST INTO THE LATE EVENING. CANNOT RULE OUT A FEW
PASSING SNOW SHOWERS, BUT FOR NOW THE PROBABILITY LOOKS TOO SMALL
TO INCLUDE. THE MOISTURE PULLS OUT IN THE EARLY MORNING HOURS,
WITH ALL TERMINALS VFR BY THE START OF MORNING OPERATIONS. SKY
SHOULD CLEAR, BUT WIND WILL REMAIN NW AND GUSTY.
OUTLOOK: GUSTY NW WINDS LINGER AT KAVL THROUGH MONDAY AFTERNOON. AN
ARCTIC AIRMASS WILL SPREAD OVER THE REGION SUNDAY NIGHT, LINGERING
MUCH OF THE WEEK, BRINGING EXCEPTIONALLY COLD TEMPERATURES BUT
MOSTLY VFR. THERE IS A SMALL POTENTIAL FOR SNOW TUESDAY EVENING
INTO TUESDAY NIGHT BUT CONFIDENCE REMAINS LOW.
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...COLD WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST MONDAY
FOR GAZ010-017-018-026.
NC...COLD WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST MONDAY
FOR NCZ033-035-048>053-058-059-062>065-501>510.
WINTER STORM WARNING UNTIL 7 AM EST MONDAY FOR NCZ033-048>052-
058.
EXTREME COLD WARNING FROM MIDNIGHT TONIGHT TO NOON EST MONDAY
FOR NCZ033-048>053-058-059-062>064.
WINTER WEATHER ADVISORY UNTIL 7 AM EST MONDAY FOR NCZ051-053-
058-059.
SC...COLD WEATHER ADVISORY FROM MIDNIGHT TONIGHT TO NOON EST MONDAY
FOR SCZ101>103.
SYNOPSIS...
NEAR TERM...PM
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...PM
CLIMATE...
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