054
FXUS62 KGSP 170012
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
712 PM EST SUN FEB 16 2025
SYNOPSIS
GUSTY WINDS CONTINUE INTO TONIGHT BEHIND A DEPARTED COLD FRONT. DRY
HIGH PRESSURE BUILDS IN MONDAY AND LINGERS THROUGH TUESDAY. WINTRY
WEATHER IS LIKELY FOR PARTS OF THE AREA ON WEDNESDAY AS A
FAST-MOVING LOW PRESSURE SYSTEM PASSES ACROSS THE SOUTHEAST. DRY
HIGH PRESSURE RETURNS THURSDAY BRINGING VERY COLD WEATHER TO END
THE WEEK.
NEAR TERM /THROUGH MONDAY/
KEY MESSAGES:
1) A WIND ADVISORY REMAINS IN EFFECT FOR THE NC MTNS UNTIL NOON MONDAY.
2) EXPECT SCATTERED NW FLOW SNOW SHOWERS ALONG THE NC/TN BORDER THRU
LATE TONIGHT. SOME LIGHT ACCUMULATIONS ARE POSSIBLE, MOSTLY OVER THE
HIGHER PEAKS AND RIDGES.
AS OF 6:35 PM EST SUNDAY: THE COLD FRONT HAS NOW MOVED EAST OF OUR CWA
WITH ITS PARENT LOW LIFTING NE OVER THE NEW ENGLAND COAST. BEHIND IT,
ROBUST HIGH PRESSURE CONTINUES TO FILTER INTO THE REGION AND A TIGHT
PRESSURE GRADIENT IS KEEPING WINDS GUSTY ACROSS THE REGION. THE PRESSURE
GRADIENT SHOULD GRADUALLY DIMINISH TONIGHT AND INTO MONDAY, BUT WINDS
ARE EXPECTED TO REMAIN GUSTY ACROSS THE MTNS INTO MONDAY MORNING. THUS,
A WIND ADVISORY REMAINS IN EFFECT THRU NOON MONDAY. THE LATEST GUIDANCE
DOES HINT AT WINDS DECREASING SOMEWHAT OVERNIGHT OVER THE MTNS AND IF
NEEDED, THE WIND ADVISORY COULD BE CANCELED EARLY. WILL CONTINUE TO
MONITOR. AS NW WINDS CONTINUE, THERE IS A DECENT CHANCE FOR SOME WRAP-
AROUND LOW-LEVEL MOISTURE TO LINGER OVER THE NC/TN BORDER AND CREATE
SOME NW FLOW SNOW THRU THE OVERNIGHT HOURS BEFORE TAPERING OFF BY MON-
DAY MORNING. LIGHT ACCUMULATIONS OF AROUND AN INCH ARE POSSIBLE. ONCE
THE WINDS CALM DOWN AND NW FLOW SNOW TAPERS OFF, THE NEAR-TERM IS RELA-
TIVELY QUIET AS HIGH PRESSURE PERSISTS ON MONDAY. AS FOR TEMPERATURES,
SUNDAY'S HIGH WAS ACHIEVED AFTER THE FRONT MOVED THROUGH AS CAA IS
DECREASING TEMPS THROUGHOUT THE AREA. EXPECT FREEZING OVERNIGHT TEMPS
AND HIGHS IN THE UPPER 40S FOR MONDAY FOR MOST OF THE CWA.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/
AS OF 130 PM SUN: TUESDAY THROUGH EARLY WEDNESDAY, A SFC RIDGE WILL
EXTEND ACROSS THE OHIO VALLEY AND TO THE MID-ATLANTIC COAST, AN
EXTENSION OF ARCTIC HIGH PRESSURE CENTERED ON THE NORTHERN HIGH
PLAINS AND CANADIAN ROCKIES. THIS EXTENSION WILL BE PROMOTED BY
LOW-AMPLITUDE UPPER RIDGING DOWNSTREAM OF A SHORTWAVE, WHICH WILL
SKIRT ALONG THE GULF COAST, INITIATING SFC CYCLOGENESIS IN MILLER-A
FASHION; THE INCIPIENT LOW WILL TRACK ACROSS THE SE COASTAL PLAIN TO
OUR SOUTH. COUPLED WITH COLD TEMPERATURES NEAR FREEZING AT THE ONSET
OF PRECIPITATION WED MORNING, AND THE LIKELIHOOD OF EVAPORATIVE
COOLING AND/OR COLD ADVECTION OCCURRING DURING THE DAY WEDNESDAY,
SOME FORM OF WINTRY PRECIPITATION APPEARS LIKELY FOR MOST OF OUR
AREA. CONFIDENCE IS INCREASING THAT WINTRY WEATHER WILL OCCUR ACROSS
MUCH OF OUR FORECAST AREA, GIVEN CONSISTENCY IN THIS GENERAL
EVOLUTION OVER SEVERAL MODEL CYCLES NOW. HOWEVER, CONFIDENCE REMAINS
RELATIVELY LOW IN THE EXTENT AND IMPACT OF SNOW AND/OR ICE
ACCUMULATIONS.
THE MAJOR DETERMINSTIC MODELS DO NOT BRING MEASURABLE PRECIP INTO THE
AREA UNTIL AFTER 12Z WED, BUT THERE IS SOME ENSEMBLE SUPPORT FOR
PRECIP TO BEGIN UP TO 6 HOURS EARLIER. LARGE DEWPOINT DEPRESSIONS
APPEAR LIKELY IN THIS TIMEFRAME, AND MOISTENING THUS IS EXPECTED FROM
THE TOP DOWN AND SO SNOW AND/OR SLEET WOULD BE THE MAIN CONCERN IN
THE EARLY STAGE OF THE EVENT, WHEREVER TEMPS ARE NEAR FREEZING. THE
MOST WIDESPREAD COVERAGE OF PRECIP IS EXPECTED BETWEEN LATE MORNING
AND MID-AFTERNOON, POTENTIALLY DIMINISHING FROM WEST TO EAST (OUTSIDE
THE MOUNTAINS) AS THE SFC LOW PASSES INTO THE ATLANTIC. THE ECMWF HAD
BEEN WETTER THAN THE GFS OR GDPS UP THRU THE 16/06Z RUN, BUT THE 12Z
CAME IN DRIER FOR MOST OF OUR AREA, BUT RETAINS A STRONGER
FRONTOGENETIC RESPONSE OVER CENTRAL NC AND A PORTION OF OUR EASTERN
PIEDMONT, WHICH LED IT TO INCREASE QPF IN THAT REGION. ITS LOW TRACK
HAS TRENDED TOWARD THE COAST MORE IN LINE WITH THE OTHER GUIDANCE,
BUT IT STILL DEEPENS THE LOW OFFSHORE MORE THAN THE OTHER MODELS.
TEMP TRENDS REMAIN A POINT OF CONTENTION; A NONDIURNAL TEMP TREND
APPEARS LIKELY DURING THE DAY WED WITH MAXES IN THE MORNING FOR MUCH
OF THE AREA. PREVIOUSLY WE NOTED THAT THE ECMWF DEPICTED VERY RAPID
COOLING DURING THE DAY; IT STILL DOES THAT AND IS THE COLDEST MODEL
OVERALL, BUT NOW BETTER MATCHES THE TRENDS IN GFS/CANADIAN TEMPS
WHICH HAVE TRENDED CLOSER TO THE EC. THE NAM IS A WARM OUTLIER
DESPITE SIMILARITIES IN OTHER REGARDS, KEEPING MUCH OF THE PIEDMONT
ABOVE FREEZING THRU THE BULK OF THE EVENT, WHICH SEEMS IMPROBABLE
GIVEN NE SFC FLOW IN THAT AREA UNDER ONLY PARTLY CLOUDY SKIES MOST OF
TUE NIGHT, AND THE TRENDS SEEN IN THE OTHER MODELS AFTER PRECIP
BEGINS.
AS NOTED ABOVE, ICE NUCLEATION IS NOT MUCH OF AN ISSUE EARLY AND RAIN
OR SNOW IS LIKELY DEPENDENT ON SFC WET-BULB TEMP. WARM NOSE HOWEVER
DEVELOPS BY LATE WED MORNING, AND WHERE TEMPS REMAIN OR FALL BELOW
FREEZING, SOME FREEZING RAIN WILL BE POSSIBLE IN ADDITION TO SNOW AND
SLEET; FZRA MAY BECOME THE DOMINANT TYPE OVER THE REMAINDER OF THE
DAY. AS DRIER AIR IS PULLED IN ALOFT ON THE BACK SIDE OF THE LOW AS
IT DEPARTS LATE WED OR WED NIGHT, ICE NUCLEI ARE INCREASINGLY
UNLIKELY TO BE PRESENT, SO FREEZING RAIN BECOMES THE MOST LIKELY TYPE
EAST OF THE MOUNTAINS, ALTHOUGH PRECIP IS LIKELY TO END ALTOGETHER BY
LATE EVENING. THE MOUNTAINS WILL SEE NORTHWEST FLOW SNOW DEVELOP AND
CONTINUE THRU DAYBREAK THURSDAY WITH LIGHT ADDITIONAL ACCUMS.
SNOW AMOUNTS OF AROUND 4" ARE EXPECTED ACROSS THE NORTHERN CWA AND
COULD WARRANT EVENTUAL ISSUANCE OF WINTER STORM WATCH/WARNING. ICE
ACCUMS ARE CURRENTLY NO MORE THAN ABOUT 0.20" OVER THE PEAK AREA
(GENERALLY THE CHARLOTTE VICINITY) WHICH WOULD BE ADVISORY CRTIERIA
ALONE, BUT THE COMBINATION WITH SNOW MAY LEAD TO WARNING TYPE
IMPACTS. CONFIDENCE NEEDS TO INCREASE A BIT MORE BEFORE WE CONSIDER
ANY HEADLINES.
LONG TERM /THURSDAY THROUGH SUNDAY/
AS OF 240 PM SUN: A FEW FLURRIES VERY WELL COULD CONTINUE
ALONG THE NC/TN BORDER ON THURSDAY PARTICULARLY DUE TO VERY COLD
TEMPERATURES AND MOST OF THE MOISTURE IN THE UPSLOPE LAYER BEING AT
GOOD TEMPERATURES FOR DENDRITIC CRYSTAL GROWTH. MAX TEMPS THURSDAY
WILL BE EXCEPTIONALLY COLD, 20 DEGREES OR MORE BELOW NORMAL. LOWS
THURSDAY NIGHT WILL BE IN THE TEENS ACROSS MOST OF THE NC ZONES
(SINGLE DIGITS IN HIGH ELEVATIONS) AND LOWER 20S ELSEWHERE. OUR
DEFINITION OF A "COLD WAVE" MAY BE MET THURSDAY-FRIDAY. THE DRY
ARCTIC HIGH WILL CONTINUE TO BUILD INTO THE AREA THROUGH THE
WEEKEND. AS IT MODIFIES TEMPERATURES GRADUALLY TREND WARMER,
BUT RISE ONLY BACK TO ABOUT 10 BELOW NORMAL SATURDAY. THERE ARE
HINTS FROM SOME MODEL RUNS THAT A CLIPPER SHORTWAVE COULD MOVE
ACROSS THE APPALACHIANS SATURDAY OR SATURDAY NIGHT, BUT WILL BE
MOISTURE-STARVED AND PRECIP TOO UNLIKELY TO MENTION PARTICULARLY
GIVEN MODEL DIFFERENCES. LIKEWISE, SOME GUIDANCE GENERATES PRECIP
ALONG THE PREVIOUS FRONT NEAR THE GULF COAST AS THE TRAILING
SHORTWAVE MOVES ACROSS TX/LA AROUND THE SAME TIME, BUT EARLIER
DEPICTIONS OF PRECIP HAVE TRENDED A LITTLE FURTHER SOUTH AND THAT
TOO RESULTS IN POPS TOO LOW TO MENTION.
AVIATION /00Z MONDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: EXPECT VFR CONDITIONS TO PREVAIL THRU THE
00Z TAF PERIOD. THE COLD FRONT IS NOW EAST OF OUR FCST AREA, YET
THE PRESSURE GRADIENT REMAINS FAIRLY TIGHT ACROSS THE REGION. THUS,
THE GUSTY WINDS ARE EXPECTED TO CONTINUE AT ALL TERMINALS THRU THE
EVENING. WINDS WILL WEAKEN AND GUSTS WILL TAPER OFF OVER THE UPSTATE
SITES LATER TONIGHT, BUT LOW-END GUSTS WILL LIKELY LINGER INTO THE
OVERNIGHT/MORNING AT KCLT AND KHKY. AT KAVL, WINDS WILL WEAKEN SOME-
WHAT BY TOMORROW MORNING, BUT THEY WILL LIKELY CONTINUE TO SEE LOW-
END GUSTS THRU TOMORROW AFTERNOON. OTHERWISE, WINDS SHOULD REMAIN
NORTH OF WEST THRU TOMORROW AFTERNOON WITH MOSTLY CLEAR SKIES.
OUTLOOK: EXPECT VFR CONDITIONS TO CONTINUE THRU TUESDAY. ANOTHER LOW
PRESSURE SYSTEM MAY BRING WINTRY PRECIPITATION AND RESTRICTIONS TO
THE REGION ON WEDNESDAY.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...WIND ADVISORY UNTIL NOON EST MONDAY FOR NCZ033-048>053-058-059-
062>065-501-503-505-507-509.
SC...NONE.
SYNOPSIS...WIMBERLEY
NEAR TERM...CP/JPT
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...JPT
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