471
FXUS62 KGSP 170852
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
352 AM EST FRI JAN 17 2025
SYNOPSIS
SUNNY AND MILD TODAY. LOW PRESSURE MOVING ACROSS THE REGION WILL
PROVIDE WIDESPREAD RAIN, WITH A WINTRY MIX ACROSS PORTIONS OF
THE MOUNTAINS, LATE TONIGHT AND EARLY SATURDAY MORNING, AND THEN
A ROUND OF LIGHT SNOW SHOWERS NEAR THE TENNESSEE BORDER LATER IN
THE WEEKEND. ARCTIC HIGH PRESSURE RETURNS MONDAY BRINGING BITTER
COLD TO THE REGION FOR NEXT WEEK.
NEAR TERM /THROUGH SATURDAY/
AS OF 300 AM FRI: COLD FRONT HAS SETTLED THROUGH MOST IF NOT ALL OF
THE AREA; WINDS WILL DIMINISH THIS MORNING AND VEER TOWARD NORTHWEST
WHERE NOT ALREADY THERE. A SURFACE RIDGE WILL SHIFT EAST AND OVER
THE AREA THIS MORNING IN THE WAKE OF THE FRONT. SKIES ARE EXPECTED
TO BE VIRTUALLY CLEAR THRU MOST OF THE DAY SAVE FOR A FEW UPSLOPE
CLOUDS NEAR THE NC/TN BORDER MAINLY THIS MORNING. TEMPS WILL BE
PRETTY CLOSE TO NORMAL.
ALTHOUGH THE AIR ABOVE THE PBL WILL BE EXTREMELY DRY TODAY,
SUBSIDENCE INVERSION WILL BE VERY STRONG AND WINDS WILL VEER
AROUND TO SOUTHERLY AND THEN SOUTHWESTERLY AS SFC HIGH MIGRATES
EAST, WHICH IS EXPECTED TO LIMIT DIURNAL MIXING OF DEWPOINTS MORE
THAN A FEW DEGREES FROM THEIR CURRENT READINGS. FURTHERMORE IT
LOOKS UNLIKELY THIS SETUP WILL FOSTER CAD. HIGH ALTITUDE CLOUDS
WILL BEGIN TO BE SEEN BY AROUND SUNSET, AHEAD OF A COMPACT,
FAST-MOVING SHORTWAVE TROUGH THEN MOVING ACROSS THE SOUTHERN
PLAINS. THE SOUTHWEST WINDS WILL PERMIT WARM UPGLIDE AND MOISTURE
ADVECTION ABOVE THE PBL BY LATE DAY; CLOUDS WILL LOWER FROM WEST
TO EAST AFTER SUNSET, AS MOISTENING OCCURS FROM THE TOP DOWN IN
ADVANCE OF THE TROUGH AXIS. WINDS WILL BE LIGHT, HOWEVER, AND
RADIATIONAL COOLING MAY BE VERY EFFECTIVE IF CLOUDS DO NOT FILL
IN QUICKLY. PRECIP CHANCES DEVELOP AS SATURATION OCCURS NEAR THE
SURFACE, BUT IT LOOKS UNLIKELY THIS WILL OCCUR BEFORE MIDNIGHT,
BUT THE RAPID MOTION OF THE SHORTWAVE IS LIKELY TO RESULT IN
MEASURABLE PRECIP OVER THE WESTERN HALF OF THE CWA BY 7 AM SAT.
DIABATIC COOLING (WET-BULBING) CAN BE EXPECTED WITHIN THE MOISTENING
COLUMN, AND IT WILL BE A CHALLENGING PRECIP TYPE FORECAST EARLY
SATURDAY MORNING. IT APPEARS LOWER ELEVATIONS IN GA/SC SHOULD
REMAIN IN THE MID TO UPPER 30S AND ASIDE FROM THE USUAL NOVELTY
SLEET AT ONSET, ACCUMULATION WILL BE ONLY LIQUID. IN THE MOUNTAINS
OF NC OR PERHAPS A FEW PEAKS IN SC/GA, PRECIP PROBABLY WILL START
AS SNOW--A WARM NOSE WILL BE PRESENT ALOFT AT ONSET BUT DIABATIC
COOLING QUICKLY BRINGS THE COLUMN BELOW FREEZING ALOFT. WAA AND
MOISTURE ADVECTION PROBABLY WILL RESTORE A WEAK WARM NOSE CLOSER TO
DAYBREAK SAT, OR AT THE VERY LEAST SHOULD MAKE FOR AN ISOTHERMAL
LAYER NEAR 0C, WHICH WOULD TRANSLATE TO WETTER SNOW. WHERE/WHEN
THE WARM NOSE IS SLIGHTLY WARMER PRECIP COULD CHANGE TO SLEET
OR FREEZING RAIN. ANY FZRA WOULD CHANGE OVER TO RAIN AS TEMPS
WARM AFTER DAYBREAK. FORCING IS NOT ESPECIALLY IMPRESSIVE AND
THERE IS ALMOST NO MUCAPE, SO QPF IS ON THE LOW END AND THE MOST
IMPACTFUL ACCUMULATION (SNOW AND PERHAPS SOME SLEET MIXED IN) WILL
BE UNDER AN INCH, EXCEPT AT HIGH ELEVATIONS WHERE THERE IS ALMOST
NO PERMANENT POPULATION. A COUPLE HUNDREDTHS OF AN INCH OF ICE
COULD ACCUMULATE AT SOME LOWER ELEVATIONS WHERE TEMPS DO MANAGE TO
STAY BELOW FREEZING THE LONGEST, BUT IT CURRENTLY APPEARS ISOLATED
ENOUGH THAT WE WILL CARRY JUST A MENTION IN THE HWO FOR NOW. FWIW,
CAMS DEPICT VERY LITTLE TO NO FZRA, MOSTLY SNOW/SLEET.
PRECIP WILL DIMINISH IN THE MID TO LATE MORNING AS DPVA EXITS WITH
THE SHORTWAVE, WHICH WILL PHASE WITH A BROADER WAVE MOVING ACROSS
THE MIDWEST. THE UPPER LEVELS DRY OUT, BUT WEAK WAA CONTINUES
NEARER THE SURFACE. CLOUDS WILL HANG ON IN THE SOUTH AND WEST MUCH
OF THE DAY SAT AND SMALL POPS ALSO LINGER THERE...WITH TEMPS ABOVE
FREEZING FORTUNATELY. HIGHS AGAIN GENERALLY NEAR CLIMO. NORTHWEST
FLOW PRECIP MAY PICK BACK UP BY LATE AFTERNOON AS THE FRONT
ASSOCIATED WITH THE MIDWEST TROUGH IMPINGES ON THE MOUNTAINS,
BEGINNING A TRANSITION TO SNOW WHICH WILL CONTINUE SAT EVENING.
SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/
AS OF 3:15 AM EST FRIDAY...THE SHORT-TERM FCST PICKS UP AT 00Z ON
SUNDAY WITH AN H5 SHORTWAVE LIFTING OFF THE ATLANTIC COAST AS VERY
BROAD UPPER TROFING AMPLIFIES OVER THE CENTRAL CONUS. THIS TROF WILL
BE EXPANSIVE AND COVER MOST OF THE CONUS THRU THE PERIOD. THE TROF
DOES BEGIN TO SHIFT EAST BY THE END OF THE PERIOD LATE MONDAY AS
UPPER RIDGING BUILDS OVER THE WEST COAST. AT THE SFC, A TRAILING
MOIST COLD FRONT WILL BE OVER OUR AREA AS THE PERIOD BEGINS LATE
SATURDAY. ON SUNDAY, AS THE FRONT IS MOVING EAST, ANOTHER LOW WILL
SPIN UP OVER THE CAROLINAS ALONG THE LINGERING FRONTAL BOUNDARY.
THIS LOW IS EXPECTED TO QUICKLY LIFT NE AND OFF THE ATLANTIC COAST
BY SUNDAY NIGHT WITH BROAD, ARCTIC HIGH PRESSURE SPREADING OVER THE
SOUTHEAST IN ITS WAKE. AS THE FRONT PUSHES EAST SATURDAY NIGHT INTO
SUNDAY, WINDS ARE EXPECTED TO BECOME NWLY, ALLOWING FOR SNOW SHOWERS
TO DEVELOP ALONG THE NC/TN BORDER ON SUNDAY. SNOW AMOUNTS CONTINUE
TO TREND UPWARDS, BUT STILL APPEAR TO REMAIN BELOW ADVISORY CRITERIA
UNLESS YOU ARE NEAR THE NC/TN BORDER. TEMPS SHOULD REMAIN WARM ENOUGH
OUTSIDE THE MTNS FOR MOSTLY RAIN. GUSTY WINDS WILL DEVELOP BEHIND THE
FRONT ON SUNDAY, ESPECIALLY ACROSS THE MTNS, WITH GUSTS IN THE 30 TO
40 MPH RANGE THRU EARLY MONDAY. IN ADDITION, WIND CHILLS WILL PLUMMET
TO BELOW ZERO ACROSS MOST OF THE MTNS EARLY MONDAY, WITH SINGLE DIGIT
TO LOW TEENS POSSIBLE FOR MOST OF OUR LOWER TERRAIN. AS SUCH, IT IS
LIKELY THAT A COLD WX ADVISORY WILL BE NEEDED FOR A GOOD PORTION OF
OUR FCST AREA.
LONG TERM /TUESDAY THROUGH THURSDAY/
AS OF 2:55 AM EST FRIDAY...THE EXTENDED FCST PICKS UP AT 00Z ON
TUESDAY WITH EXPANSIVE UPPER TROFING SHIFTING EAST BUT STILL CO-
VERING THE MAJORITY OF THE CONUS. OVER THE NEXT COUPLE OF DAYS,
THE UPPER TROF WILL RETREAT NORTHWARD AND MOVE OFF THE ATLANTIC
COAST. HEIGHTS WILL BRIEFLY RECOVER IN ITS WAKE, HOWEVER MOST OF
THE LONG-RANGE GUIDANCE HAS ANOTHER UPPER TROF DIGGING DOWN ACROSS
THE CENTRAL CONUS BY THE END OF THE PERIOD NEXT THURSDAY. AT THE
SFC, BROAD HIGH PRESSURE WILL BE IN PLACE OVER THE SOUTHEAST AS
THE PERIOD BEGINS. OVER THE NEXT 24 HRS OR SO, A WEAK LOW WILL
QUICKLY SPIN UP OVER THE GULF OF MEXICO AND RAPIDLY MOVE NE AND
OUT OVER THE ATLANTIC. AT THE SAME TIME, HIGH PRESSURE GETS RE-
INFORCED FROM THE WEST ACROSS OUR AREA AND LINGERS THRU THE END
OF THE PERIOD. THIS HIGH APPEARS PARTICULARLY ROBUST WITH VERY
COLD/DRY AIR ASSOCIATED WITH IT. OVERALL, THE LONG-RANGE GUIDANCE
HAS BEEN TRENDING DRIER WRT THE LOW ON TUES/WED. WITH THE COLD AIR
IN PLACE DURING THAT TIME, ANY PRECIP THAT DOES MATERIALIZE WOULD
LIKELY BE SNOW FOR OUR CWA, BUT I LIMIT POPS TO CHANCE AT THIS TIME.
THE MAIN CONCERN FOR THE PERIOD WILL BE THE ARCTIC HIGH BUILDING
OVER THE REGION THRU THURSDAY. THIS AIRMASS WILL BRING VERY COLD
TEMPERATURES AND WIND CHILLS, ESPECIALLY ACROSS THE MTNS. HIGH
TEMPERATURES WILL STRUGGLE TO GET ABOVE FREEZING BOTH TUESDAY AND
WEDNESDAY EVEN ACROSS THE LOWER TERRAIN, WITH TEMPS REBOUNDING
SOMEWHAT ON THURSDAY. LOWS EARLY TUESDAY AND WEDNESDAY WILL DROP
INTO THE SINGLE DIGITS IN THE MTNS AND TEENS OUTSIDE THE MTNS.
WIND CHILL VALUES WILL BE DANGEROUSLY COLD, ESPECIALLY ACROSS THE
MTNS, WITH SINGLE DIGIT TO BELOW ZERO WIND CHILLS EXPECTED BOTH
TUESDAY AND WEDNESDAY MORNING. WIND CHILLS OUTSIDE THE MTNS ARE
EXPECTED TO RANGE FROM THE SINGLE DIGITS TO THE TEENS EACH MORNING.
THUS, A COLD WEATHER ADVISORY LOOKS LIKELY FOR AT LEAST A PORTION
OF OUR AREA NEXT WEEK.
AVIATION /09Z FRIDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: VFR AT THE TAF TERMINALS THROUGH THEIR
RESPECTIVE PERIODS. A FEW UPSLOPE GENERATED CLOUDS MAY SPILL
UP THE VALLEY TO KAVL THIS MORNING BUT CHANCE OF CIG VIRTUALLY
NIL. OTHERWISE SKC INTO EARLY AFTERNOON. WINDS ARE MOSTLY ON EITHER
SIDE OF WEST AT 06Z, BUT SHOULD VEER TO NW WHERE NOT ALREADY BY
DAYBREAK AND ALSO WEAKEN. CONTINUED VEERING SHOULD OCCUR TODAY,
ROUNDING THE DIAL AND ENDING UP AT SW BEFORE THE END OF THE DAY
VIA SFC HIGH MIGRATING ACROSS THE REGION. HIGH ALTITUDE MOISTURE
WILL INCREASE THIS EVENING BRINGING FEW-SCT CLOUDS MOSTLY ABOVE
15, WITH MOISTENING CONTINUING THRU MID-MORNING SATURDAY ALONG
WITH DEVELOPING PRECIP CHANCES AFTER 06Z. KCLT'S LONGER PERIOD
WARRANTS ONSET OF LOW VFR BASES AND ASSOCIATED VCSH MENTION.
OUTLOOK: PRECIP AND ASSOCIATED RESTRICTIONS WILL DEVELOP IN THE
MOUNTAINS BY DAYBREAK SATURDAY, A FEW HOURS LATER ELSEWHERE;
RESTRICTIVE CIGS WILL PERSIST MOST OF THE DAY. CONDITIONS WILL
STEADILY DRY OUT SATURDAY NIGHT/SUNDAY. A VERY COLD AND DRY AIR
MASS WILL SETTLE INTO THE AREA EARLY NEXT WEEK.
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...NONE.
SC...NONE.
SYNOPSIS...WIMBERLEY
NEAR TERM...WIMBERLEY
SHORT TERM...JPT
LONG TERM...JPT
AVIATION...WIMBERLEY
CLIMATE...GSP
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page