937
FXUS62 KGSP 161722
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1222 PM EST SUN FEB 16 2025
SYNOPSIS
GUSTY WINDS DEVELOP BEHIND THE FRONT AND CONTINUE THROUGH
TONIGHT. DRY HIGH PRESSURE BUILDS IN MONDAY AND LINGERS THROUGH
TUESDAY. ANOTHER LOW PRESSURE SYSTEM CROSSES THE AREA WEDNESDAY,
BRINGING A CHANCE FOR WINTRY WEATHER. COLD AND DRY HIGH
PRESSURE RETURN LATE NEXT WEEK.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGES:
1) WIND ADVISORY FOR THE ENTIRE CWA IN EFFECT THROUGH THE AFTERNOON
FOR GUSTY WINDS OF 30-40 MPH EAST OF THE MOUNTAINS AND 45+ MPH IN
THE MOUNTAINS THROUGH EARLY MONDAY MORNING.
2) NW FLOW SNOW SHOWERS ALONG THE TN/NC BORDER BEHIND THE FRONT THIS
AFTERNOON THROUGH TONIGHT WITH LIGHT ACCUMULATIONS.
AS OF 1123 AM EST SUNDAY: FOR THIS UPDATE, A FEW SCATTERED SHOWERS
ARE QUICKLY MOVING ACROSS THE CWA AS THE CAA STARTS TO FILTER IN
BEHIND FROM THE WEST. SATELLITE SHOWS CLOUDS STARTING TO SCATTER OUT
AS DRIER AIR FILTERS IN. TEMPERATURES ARE BEGINNING TO DECREASE WITH
THE CAA IN THE WESTERN ZONES. EXPECT THIS TO SPREAD EAST THROUGHOUT
THE DAY.
OTHERWISE, CLOUDS LINGER ALONG THE TN BORDER DUE TO WESTERLY TO WEST-
NORTHWESTERLY UPSLOPE FLOW. GUIDANCE IS IN GOOD AGREEMENT ON UPSLOPE
SHOWERS TURNING FROM RAIN TO SNOW FAIRLY QUICKLY THIS AFTN, BUT SNOW
ACCUMS ARE EXPECTED TO BE LIGHT AND MAINLY ON THE HIGHEST PEAKS.
TEMPS WILL BE TRICKY AS THEY START OUT SO WARM IN THE HIGH TERRAIN,
WHILE THE COLD WEDGE AIR MASS WILL BE SCOURED OUT BY DOWNSLOPE FLOW,
THEN STRONG CAA. DEFINITELY EXPECT FALLING TEMPS ACROSS THE
MOUNTAINS THRU THE DAY, WHILE THERE IS BUST POTENTIAL ON WHETHER
TEMPS WILL BE ABLE TO GET INTO THE 60S EAST OF THE MOUNTAINS, AS THE
NBM SHOWS.
WINDS SHOULD START TO DECREASE, BUT MAY REMAIN BREEZY THRU
THE EVENING EAST OF THE MOUNTAINS, WHILE WINDS MAY INCREASE
FURTHER ACROSS THE HIGHER TERRAIN, ESPECIALLY IN THE NORTHERN
MOUNTAINS. SO THE WIND ADVISORY CONTINUES IN THE MOUNTAINS THRU
MONDAY MORNING. MEANWHILE, SNOW SHOWER ACTIVITY LOOKS TO PEAK EARLY
IN THE EVENING, THEN GRADUALLY TAPER OFF OVERNIGHT. STORM TOTAL
SNOW AMOUNTS ARE HIGHLY ELEVATION DEPENDENT AND GENERALLY 1-2"
ALONG THE TN BORDER, WHICH IS SHY OF ADVISORY CRITERIA. TEMPS
WILL FALL TONIGHT INTO THE TEENS TO LOW 20S IN THE MOUNTAINS AND
IN THE MID TO UPPER 20S ELSEWHERE.
SHORT TERM /MONDAY THROUGH WEDNESDAY NIGHT/
AS OF 245 AM EST SUNDAY: THE SHORT TERM WILL BEGIN WITH COOL HIGH
PRESSURE BUILDING IN TO THE AREA UNDER STRONG WESTERLY/ZONAL FLOW
ALOFT, PROBABLY STILL SOME MOUNTAIN WAVE ACTIVITY LEADING TO SOME
GUSTS MIXING DOWN IN THE MOUNTAINS AS WE START THE PERIOD. HIGHS
MONDAY AND LOWS MONDAY NIGHT 5 OR SO DEGREES BELOW SEASONAL NORMALS.
WILL SEE SOME MODIFICATION TO THE AIRMASS ON TUESDAY AS THE FLOW
ALOFT SHIFT SLIGHTLY MORE OUT OF THE WSW, WITH HIGHS TUESDAY MUCH
CLOSER TO SEASONAL NORMALS.
MEANWHILE, A TROUGH WILL BEGIN TO DIG OUT OF THE ROCKIES ON TUESDAY
FROM A PARENT CUTTING OFF IN THE NORTHERN PLAINS BY TUESDAY NIGHT.
WEAK SOUTHERN STREAM SHORTWAVE TRAVERSING NORTHERN GULF COAST
UNDERNEATH RIGHT ENTRANCE REGION OF THE STRONG UPPER JET HELPS TO
INDUCE SURFACE CYCLOGENESIS THAT TRAVERSES THE GULF COAST TUESDAY
NIGHT INTO WEDNESDAY IN A BEAUTIFUL MILLER-A SETUP. VERY STRONG
(1050MB) ARCTIC HIGH PRESSURE OVER THE NORTHERN PLAINS WILL
PRIMARILY RIDGE SOUTH BUT AN ARM OF RIDGING WILL STRETCH EAST AND
THEN DOWN THE EASTERN SEABOARD. AS MOISTURE FROM THE GULF LOW STARTS
SPREADING NORTH, INSITU DAMMING WILL REINFORCE THE RIDGING. ALL THIS
LEADS TO A VERY COMPLICATED WINTRY PRECIP EVENT WEDNESDAY INTO
WEDNESDAY NIGHT.
ENSEMBLE GUIDANCE AS WELL AS OPERATIONAL MODELS ARE POINTING TO A
MAINLY SNOW EVENT FOR THE NORTHERN TIER OF COUNTIES, BUT
UNSURPRISINGLY UNCERTAINTY COMES INTO PLAY THE FARTHER SOUTH WE GO.
THERE IS SOME QUESTION AS TO THE DEPTH OF MOISTURE AS WELL AS
PRESENCE/EXTENT OF WARM NOSE WITH CAA ALOFT AROUND THE 850MB WESTERN
ATLANTIC ANTICYCLONE. WITH THIS CURRENT PACKAGE, TEMPERATURE
PROFILES SEEM TO INDICATE THAT THE HIGHEST LIKELIHOOD OF FREEZING
RAIN OR PERHAPS SLEET WOULD BE WEDNESDAY NIGHT INTO EARLY THURSDAY
AS WE LOSE ICE NUCLEI. DIFFERENT GUIDANCE BRINGS SNOW TOTALS FARTHER
SOUTH; E.G., ECMWF MORE BULLISH WITH SNOW AMOUNTS, GFS IS MORE LIKE
WHAT SNOW? (EXCEPT FOR THE NC MOUNTAINS OF COURSE). ENSEMBLE MEMBERS
OF EACH ARE SLIGHTLY DIFFERENT BUT IN GENERAL THERE DOES SEEM TO BE
A DIVIDING LINE AROUND THE NC/SC STATE LINE. UNCERTAINTY OF COURSE
REMAINS QUITE HIGH ON EXTENT OF ACCUMULATING SNOW, AMOUNTS, HOW MUCH
ICE MAY (OR MAY NOT) MIX IN. MILLER-A TYPE SYSTEMS ARE TYPICALLY
LESS LIKELY TO HAVE "MIXED BAG" P-TYPES WITH THE LOCATION OF THE LOW
ACROSS THE COAST, SO TAKING PATTERN RECOGNITION INTO ACCOUNT VS PURE
MODEL OUTPUT, WILL BE INTERESTING TO SEE HOW THE FORECAST EVOLVES AS
WE GET CLOSER.
FOR NOW, TEMPERATURES WEDNESDAY ARE FORECAST TO BE MID 30S IN THE
MOUNTAINS AND I-40 CORRIDOR TO LOWER 40S SOUTH, BUT THIS MAY BE TOO
HIGH. WELL BELOW NORMAL FOR WEDNESDAY NIGHT AND WITH WINDS PICKING
UP, WIND CHILLS IN THE HIGHER ELEVATIONS WILL BE DIPPING BELOW 0
TOWARDS DAYBREAK AS THE FRONT PUSHES THROUGH.
LONG TERM /THURSDAY THROUGH SATURDAY/
AS OF 315 AM EST SUNDAY: EXTENDED STARTS OFF UNSEASONABLY COLD AND
BREEZY ON THURSDAY IN THE WAKE OF THE WINTER WEATHER EVENT. THE
UPPER LOW WILL BE PASSING JUST TO OUR NORTH ACROSS THE MID-ATLANTIC
STATES AND STRONG UPPER GRADIENT WILL LEAD TO CONTINUED MOUNTAIN
WAVE ACTIVITY AND GUSTY WINDS THROUGH THE DAY. CONTINUED
UNSEASONABLY COLD THROUGH THE REST OF THE PERIOD WITH ONLY SLIGHT
MODIFICATION TO HIGHS.
ANOTHER SHORTWAVE MOVING THROUGH ON SATURDAY MAY BRING SOME WINTRY
PRECIP TO THE MOUNTAINS AND COLD RAIN TO SOUTHERN ZONES, BUT A BIT
TOO FAR OUT TO NARROW DOWN DETAILS ON THIS.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS QUICKLY RETURN AND PREVAIL
THROUGH THE END OF THE TAF PERIOD. A COLD FRONT CONTINUES TO MOVE
ACROSS THE AREA, BRINGING VERY GUSTY WINDS AT ALL TERMINALS. EXPECT
WINDS TO TURN FROM THE SW TO NW/N TODAY, WITH GUSTS OF 25-40 KTS
THROUGH THE AFTERNOON. WINDS SHOULD BEGIN TO DIMINISH LATE TONIGHT
FOR TERMINALS EAST OF THE MOUNTAINS, WHILE REMAINING GUSTY THROUGH
MONDAY MORNING AT KAVL AND KHKY. CIGS ARE CONTINUING TO LIFT AND
SHOULD IMPROVE TO VFR AT ALL TERMINALS THROUGH THE AFTERNOON. NO
VSBY CONCERNS AT THIS TIME.
OUTLOOK: VFR CONDITIONS EXPECTED MONDAY THRU TUESDAY. ANOTHER SYSTEM
MAY BRING WINTRY PRECIP AND RESTRICTIONS TO THE REGION ON WEDNESDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR GAZ010-017-018-
026-028-029.
NC...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR NCZ035>037-056-
057-068>072-082-502-504-506-508-510.
WIND ADVISORY UNTIL NOON EST MONDAY FOR NCZ033-048>053-058-059-
062>065-501-503-505-507-509.
SC...WIND ADVISORY UNTIL 6 PM EST THIS EVENING FOR SCZ008>014-019-
101>109.
SYNOPSIS...CP
NEAR TERM...ARK/CP
SHORT TERM...TDP
LONG TERM...TDP
AVIATION...CP
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