220
FXUS62 KGSP 190322
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1022 PM EST SAT JAN 18 2025
SYNOPSIS
A ROUND OF SNOW SHOWERS WILL DEVELOP LATE TONIGHT OR SUNDAY NEAR THE
TENNESSEE BORDER AND LINGER THROUGH MONDAY MORNING WITH GOOD SNOW
ACCUMULATION AT THE HIGHER ELEVATIONS. ARCTIC HIGH PRESSURE RETURNS
MONDAY BRINGING BITTER COLD TO THE REGION FOR NEXT WEEK. A STORM
SYSTEM IS EXPECTED TO TRACK FROM THE NORTHERN GULF OF MEXICO TO OFF
THE SOUTHEAST COAST MIDWEEK, BRINGING THE POTENTIAL FOR SNOW SHOWERS
ACROSS PORTIONS OF THE AREA.
NEAR TERM /THROUGH SUNDAY NIGHT/
AS OF 1020 PM EST SATURDAY: ONLY A FEW TWEAKS TO POPS WERE NEEDED
OVER THE NEXT FEW HOURS BASED ON THE LATEST KGSP RADAR MOSAIC.
OTHERWISE, THE FORECAST REMAINS ON TRACK. SOME NW FLOW RAIN SHOWERS
CONTINUE ACROSS THE NC/TN BORDER THIS EVENING AND THICK LOW CLOUDS
CONTINUE FOR MOST LOCATIONS. HOWEVER, POCKETS OF CLEAR SKIES
CONTINUE ACROSS THE NC FOOTHILLS AND PIEDMONT.
TONIGHT SHOULD BE FAIRLY QUIET, WITH THE MAIN UPPER TROF AXIS TO
OUR WEST AND AN OLD FRONTAL BOUNDARY TO OUR SOUTH, AND THE ARCTIC
FRONT STILL WELL TO OUR NORTHWEST. A WEAK SFC LOW DEVELOPING
NEAR THE OLD BOUNDARY ALONG THE NRN GULF COAST IS EXPECTED TO
SLOWLY ORGANIZE AND APPROACH FROM THE SW TONIGHT. WEAK WARM MOIST
ADVECTION AT LOW LEVELS TONIGHT AHEAD OF THIS FEATURE WILL ACT TO
KEEP TEMPS RELATIVELY MILD...AND PERHAPS AS MUCH AS TEN DEGREES
ABOVE NORMAL EAST OF THE MTNS. YOU WILL MISS THIS 24 HOURS FROM NOW.
EAST OF THE MTNS, SOME OF THE GUIDANCE IS SUGGESTING THE DEVELOPMENT
OF WIDESPREAD DENSE FOG, SO WE WILL BE KEEPING AN EYE OUT FOR THAT.
MEANWHILE, ON THE WEST SIDE OF THE MTNS, BETTER FORCING CLOSER TO
THE REAL COLD FRONT MAY KEEP SOME PATCHES OF LIGHT RAIN MOVING
NORTHEAST UP THE GREAT VALLEY OF TN AND BRUSHING THE NC MTNS.
EXPECTED TEMPS AND THERMAL PROFILES SUGGEST ANY LIGHT PRECIP WILL BE
ALL RAIN, WITH THE EXCEPTION OF THE VERY HIGHEST ELEVATIONS OF THE
SMOKIES TOWARD DAYBREAK. OF THIS, GOOD AGREEMENT IS SEEN IN THE
GUIDANCE.
ON SUNDAY, A SHORT WAVE DIGGING DOWN INTO THE BOTTOM OF THE TROF
TO OUR WEST WILL PICK UP THE LOW AS IT CONTINUES TO DEEPEN WHILE
MOVING ACROSS THE AREA EAST OF THE MTNS IN THE EARLY HALF OF THE
DAY. CONFIDENCE IS RELATIVELY HIGH WITH THE COLDER AIR RUSHING
EASTWARD AS THE LOW PASSES IN THE AFTERNOON. THIS WILL HAVE
PROFOUND EFFECTS MAINLY ACROSS THE HIGHER TERRAIN IN TERMS OF
THE TEMPS AND PRECIP. WE WILL COVER TEMPS FIRST, WHICH PLUMMET IN
THE LATE AFTERNOON AND EVENING ACROSS THE ENTIRE REGION. HOWEVER,
OVER THE MTNS, THE COMBINATION OF STRONG NW WINDS BEHIND THE LOW
AND ARCTIC AIR SURGE IS EXPECTED TO DROP THE APPARENT TEMPS DOWN
INTO THE NEGATIVE TEENS ABOVE 3500 FEET AND LOW SINGLE DIGITS
IN THE VALLEY LOCATIONS AFTER MIDNIGHT SUNDAY NIGHT AND BEFORE
DAYBREAK MONDAY. THIS WILL BE THE COLDEST AIR WE'VE HAD IN SOME
TIME, WITH LOWS 15 TO 20 DEGREES BELOW NORMAL. THE HIGH ELEVATIONS
MAY REACH OUR NEW EXTREME COLD WARNING CRITERIA, WHILE THE LOWER
ELEVATIONS COULD EASILY REACH OUR NEW COLD WEATHER ADVISORY. WE
WILL OPT FOR AN EXTREME COLD WATCH FOR THE NC MOUNTAINS AND THE
MOUNTAINS OF NORTHEAST GA FOR SUNDAY NIGHT AND MONDAY MORNING TO
ACCOUNT FOR THIS. ELSEWHERE, EAST OF THE MTNS, TEMPS WILL BE COLD,
BUT MOST LIKELY ABOVE THE ADVISORY CRITERIA.
MEANWHILE, DURING THE DAY ON SUNDAY, AS THE LOW MOVES PAST AND OFF
TO THE NORTHEAST SUNDAY NIGHT, PLENTY OF MOISTURE WILL BE FORCED
UPSLOPE BY THE STRENGTHENING NW FLOW AND TEMPS DROPPING QUICKLY IN
THE AFTERNOON. LOOKS LIKE AN EXCELLENT SCENARIO FOR UPSLOPE SNOW,
WITH DEEP MOISTURE INTO THE DENDRITIC GROWTH ZONE IN THE AFTERNOON
AND EVENING, AN ENTIRE COLUMN WELL BELOW FREEZING THAT SHOULD ALLOW
FOR A DRY FLUFFY SNOW, AND SFC TEMPS DROPPING DOWN THROUGH THE
20S AND TEENS. AREAS RIGHT ALONG THE TN BORDER ARE LIKELY TO REACH
WARNING CRITERIA BECAUSE OF THE HIGH SNOW-TO-LIQUID RATIO, BUT THE
OTHER CONCERN IS THE AREAS AWAY FROM THE TN BORDER. ALTHOUGH THE
INDICATION IS THAT ACCUMS MIGHT ONLY BE ON THE ORDER OF 1-3 INCHES
IN THE TN BORDER COUNTIES AWAY FROM THE UPSLOPE AREAS, THE DRY
SNOW FALLING INTO TEMPS BELOW THE UPPER 20S SHOULD RESULT IN VERY
SLIPPERY ROAD CONDITIONS IN PLACES WHERE ROADS ARE NOT TREATED. THIS
COULD RESULT IN A HIGH IMPACT TO TRANSPORTATION. THEREFORE, THE
WINTER STORM WARNING AND THE WINTER WEATHER ADVISORY WILL REMAIN IN
EFFECT FOR PORTIONS OF THE NC MOUNTAINS SUNDAY MORNING INTO EARLY
MONDAY MORNING.
SHORT TERM /MONDAY THROUGH TUESDAY NIGHT/
AS OF 200 PM EST SATURDAY: STRONG ARCTIC AIRMASS WILL BE IN THE
MIDST OF SPILLING OVER THE SOUTHEASTERN CONUS MONDAY AS A STRONG
ARCTIC SURFACE HIGH MOVES IN ACROSS THE PLAINS AND STOUT CAA
FILTERS IN ACROSS THE AREA. FACTOR IN VERY BROAD UPPER TROUGHINESS
OVER MOST OF THE CONUS AND THE STAGE WILL BE SET FOR A VERY COLD
AND DRY AIRMASS. AN UPPER RIDGE WILL BEGIN TO BUILD OVER THE WEST
COAST AND EASTERN PACIFIC MONDAY INTO TUESDAY AND WILL ALLOW FOR A
SHORTWAVE TO CARVE OUT ACROSS THE SOUTHERN PLAINS BY TUESDAY. AS THE
TROUGH BEGINS TO SHARPEN FROM THE GREAT LAKES REGION THROUGH THE MS
VALLEY, SURFACE CYCLOGENESIS WILL BE UNDERWAY WITHIN THE COASTAL
BAROCLINIC ZONE OVER THE GULF OF MEXICO. IN THIS CASE, A SURFACE
LOW IS EXPECTED TO DEVELOP OVER THE WESTERN GULF OF MEXICO AND PUSH
ACROSS THE GULF OF MEXICO TUESDAY THROUGH WEDNESDAY. DEPENDING ON
THE TRACK OF THE LOW AND HOW CLOSE OR NOT CLOSE IT WILL BE TO THE
GULF COAST WILL PLAY A VITAL ROLE INTO WHAT THE CFWA RECEIVES. THE
COLD AIR THROUGH THE VERTICAL COLUMN WILL BE ESTABLISHED, SO ANY
PRECIPITATION THAT DOES FALL WILL BE ALL SNOW. THIS IS A RARE
OCCASION WHERE THE BEST CHANCES OF SNOW WILL ACTUALLY BE ALONG AND
SOUTH/EAST OF I-85. RIGHT NOW, MODEL GUIDANCE ONLY GIVE OUR CFWA
A GLIMPSE OF SNOW AS THERE IS A LOT OF DRY AIR IN PLACE FOR THE
ATMOSPHERE TO OVERCOME FOR SNOW TO REACH THE SURFACE. THE BETTER
ISENTROPIC LIFT AND AVAILABLE MOISTURE WILL BE TO OUR SOUTH AND
EAST, MAINLY OVER THE MIDLANDS/PEE DEE/LOW COUNTRY. IF THE SURFACE
LOW TRENDS NORTHWESTWARD, CLOSER ALONG THE GULF COAST, THEN THE I-85
CORRIDOR POINTS SOUTH WILL BE IN BUSINESS FOR A DECENT WINTER STORM
THAT WILL BE ALL SNOW. P-TYPE CONCERNS WILL REMAIN WELL TO THE SOUTH
WHERE WAA IN THE MID-LEVELS COULD CREATE THIS CONCERN. THERE IS THE
INSTANCE THAT THE AREA DOESN'T RECEIVE MUCH AS THE DRY AIR WILL
EAT INTO OUR SNOW CHANCES AND THE STORM TRACK BECOMES SUPPRESSED
TOO FAR SOUTH AND THE AREAS JUST MENTIONED END UP BEING THE BIG
WINNERS AS FAR AS SNOW AMOUNTS. MODEL GUIDANCE STILL FAVOR A MORE
COASTAL TRACK, BUT THERE ARE STILL UNCERTAINTIES AS THE GUIDANCE
CONTINUES TO WAFFLE ON THE LOCATION OF THE SURFACE LOW AND HOW MUCH
MOISTURE IS AVAILABLE. ONCE THE HIGH RESOLUTION MODELS GET A HOLD OF
THE SYSTEM, THEN WE WILL HAVE A MUCH BETTER UNDERSTANDING OF WHAT WE
WILL SEE AND HOW MUCH. A NORTHWESTWARD TREND OF ~50 MILES FOR THE
SURFACE LOW AND FROM WHAT THE MODEL GUIDANCE CURRENTLY INDICATE
COULD BE THE DIFFERENCE BETWEEN HARDLY ANYTHING AT ALL AND A MAJOR
SNOW STORM.
HOWEVER, THE BIG WEATHER HEADLINE WILL BE THE BRUTAL COLD IN
PLACE. THERE'S ENOUGH EVIDENCE IN PLACE THAT MOST OF THE CFWA
WILL STRUGGLE TO GET ABOVE FREEZING THROUGH THE ENTIRE SHORT-TERM
PERIOD. OVERNIGHT LOWS MONDAY AND TUESDAY WILL BE IN THE TEENS
ACROSS THE FOOTHILLS/PIEDMONT, WHILE THE MOUNTAINS WILL LIKELY
DIP INTO THE SINGLE DIGITS. ANY SNOW THAT FALLS WITH TEMPERATURES
THIS COLD WILL ALMOST STICK IMMEDIATELY AND WILL CAUSE TREACHEROUS
ROAD CONDITIONS, ESPECIALLY ON UNTREATED ROADS. DEFINITELY TAKE
THIS INTO ACCOUNT FOR LATE TUESDAY EVENING INTO WEDNESDAY MORNING
IF YOUR LOCATION RECEIVES SNOW. AFTERNOON HIGHS MONDAY WILL BE IN
THE LOW 30S FOR THE FOOTHILLS/PIEDMONT WITH SOME OF OUR SOUTHERN
LOCATIONS POTENTIALLY GETTING ABOVE FREEZING FOR A SHORT PERIOD
OF TIME DURING PEAK HEATING, WHILE THE MOUNTAINS REMAIN IN THE
TEENS AND 20S. GUSTY WINDS WILL CONTINUE ACROSS THE MOUNTAINS
ESPECIALLY, KEEPING THE WIND CHILL VALUES IN THE SINGLE DIGITS
TO EVEN BELOW ZERO FOR THE HIGHER ELEVATIONS, MAINLY DURING THE
NIGHTTIME THROUGH THE FORECAST PERIOD. AFTERNOON HIGHS ON TUESDAY
WON'T CHANGE MUCH FROM MONDAY AS THE BRUTAL COLD CONDITIONS LINGER
THANKS TO THE ARCTIC HIGH BEING REINFORCED BEHIND THE STORM SYSTEM.
LONG TERM /WEDNESDAY THROUGH SATURDAY/
AS OF 230 PM EST SATURDAY: ONCE THE WINTER WEATHER SCARES SLIP
OFFSHORE, THE ARCTIC HIGH WILL BECOME REINFORCED OVER THE EAST
COAST. EXPECT THE VERY COLD AIRMASS TO STICK AROUND THROUGH MUCH
OF THE WORKWEEK AS A RESULT, WITH AFTERNOON HIGHS IN THE 30S FOR
WEDNESDAY AND A SLIGHT REBOUND THURSDAY AND FRIDAY AS THE AIRMASS
VERY GRADUALLY MODIFIES. GREAT RADIATIONAL COOLING CONDITIONS
AND THE CHANCE FOR THE SNOWPACK TO LINGER WILL SET THE STAGE FOR
VERY COLD NIGHTS DURING THE SAME TIMEFRAME, WITH VALUES 10-15+
DEGREES BELOW NORMAL AND THE COLDEST NIGHT SET TO BE WEDNESDAY NIGHT
WITH WIDESPREAD TEENS AND SINGLE DIGITS FOR THE MOUNTAINS. MODEL
GUIDANCE HINT AT THE POTENTIAL FOR A COASTAL LOW TO DEVELOP OFF
THE SOUTHEAST COAST AND POTENTIALLY SEND SOME PRECIP BACK OVER
THE AREA THURSDAY INTO THURSDAY NIGHT, WHICH COULD CAUSE SOME
P-TYPES ISSUES DEPENDING ON THE TIMING. A LOT OF UNCERTAINTY WITH
THIS DEVELOPMENT, BUT WILL NEED TO BE MONITORED. GOOD AGREEMENT
FOR ANOTHER SHORTWAVE TROUGH TO MOVE ACROSS THE AREA FRIDAY INTO
SATURDAY WITHOUT MUCH FANFARE. SURFACE HIGH SETS UP SHOP OVER THE
SOUTHEASTERN CONUS BY D6/D7, LEADING TO QUIETER SENSIBLE WEATHER
WITH SLIGHTLY WARMER CONDITIONS, ESPECIALLY COMPARED TO WHAT'S TO
COME DURING THE NEW WORKWEEK.
AVIATION /04Z SUNDAY THROUGH THURSDAY/
AT KCLT AND ELSEWHERE: KAND IS ALREADY SEEING IFR CIGS WHILE KGMU IS
ALREADY SEEING MVFR CIGS AS OF 00Z SUNDAY. CIGS AND VSBYS WILL
GRADUALLY LOWER THIS EVENING INTO THE OVERNIGHT HOURS, BECOMING IFR
TO LIFR. WINDS WILL GENERALLY BE LIGHT AND VRB THIS EVENING INTO
TONIGHT. IFR/LIFR RESTRICTIONS WILL LINGER THROUGH THE LATE
MORNING/EARLY AFTERNOON HOURS SUNDAY BEFORE VFR RETURNS BY THE EARLY
TO MID-AFTERNOON HOURS. SOME SPOTTY -SHRA MAY DEVELOP OVERNIGHT INTO
EARLY SUNDAY MORNING AT KGSP,KGMU, KHKY, AND KCLT SO INTRODUCED
PROB30S DURING THIS TIMEFRAME. NW FLOW -SHRA LOOKS TO HOLD OFF AT
KAVL UNTIL THE LATE MORNING/EARLY AFTERNOON HOURS SUNDAY SO
MAINTAINED A PROB30 DURING THIS TIMEFRAME. WINDS WILL GRADUALLY TURN
NW AT KAVL OVERNIGHT, REMAINING NW THROUGH THE END OF THE 00Z TAF
PERIOD. WINDS EAST OF THE MOUNTAINS WILL PICK UP OUT OF THE W/WSW
LATE SUNDAY MORNING INTO SUNDAY AFTERNOON BEFORE TURNING NW SUNDAY
EVENING. WIND SPEEDS WILL GRADUALLY INCREASE THROUGHOUT SUNDAY,
BECOMING GUSTY. WIND SPEEDS EAST OF THE MOUNTAINS WILL GRADUALLY
TAPER OFF SUNDAY NIGHT.
OUTLOOK: GUSTY NW WINDS LINGER AT KAVL THROUGH MONDAY. VFR
CONDITIONS LINGER THROUGH EARLY NEXT WEEK. AN ARCTIC AIRMASS WILL
SPREAD OVER THE REGION SUNDAY NIGHT, LINGERING INTO MUCH OF NEXT
WEEK, BRINGING EXCEPTIONALLY COLD TEMPERATURES. 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...EXTREME COLD WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY
MORNING FOR GAZ010-017.
NC...EXTREME COLD WATCH FROM LATE SUNDAY NIGHT THROUGH MONDAY
MORNING FOR NCZ033-048>053-058-059-062>065.
WINTER STORM WARNING FROM 7 AM SUNDAY TO 7 AM EST MONDAY FOR
NCZ033-048>052-058.
WINTER WEATHER ADVISORY FROM 7 AM SUNDAY TO 7 AM EST MONDAY
FOR NCZ051-058-059.
SC...NONE.
SYNOPSIS...CAC
NEAR TERM...AR/PM
SHORT TERM...CAC
LONG TERM...CAC
AVIATION...AR
CLIMATE...
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