922
FXUS62 KGSP 192000
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
300 PM EST WED FEB 19 2025
SYNOPSIS
ANOTHER ROUND OF SNOW SHOWERS MAY IMPACT OUR AREA THURSDAY MORNING.
DRY HIGH PRESSURE WILL THEN RETURN LATER THURSDAY, BRINGING VERY
COLD WEATHER TO END THE WEEK. A DRY PATTERN WITH A WARMING TREND IS
EXPECTED TO BEGIN OVER THE WEEKEND, WITH ABOVE-NORMAL TEMPERATURES
EXPECTED TO RETURN EARLY NEXT WEEK.
NEAR TERM /THROUGH THURSDAY/
AS OF 300 PM EST WEDNESDAY: THE LAST BIT OF SNOW FROM THIS FIRST
WAVE IS SHIFTING ACROSS THE CLT METRO AREA AND WILL EXIT THE CFWA
OVER THE NEXT COUPLE OF HOURS. OTHERWISE, THE FORECAST REMAINS
MOSTLY ON TRACK.
STOUT CLOSED UPPER LOW CURRENTLY SETTLED OVER THE NORTHERN GREAT
PLAINS WILL TRAVERSE ACROSS THE MIDWEST/UPPER GREAT LAKES THROUGH
WEDNESDAY NIGHT BEFORE SETTING UP SHOP OVER THE NORTHEASTERN
CONUS BY THE END OF THE FORECAST PERIOD. CURRENT SURFACE ANALYSIS
INDICATES A COASTAL LOW DEVELOPING JUST OFF THE GA/SC COAST
AND WILL PUSH UP THE CAROLINA COAST OVERNIGHT, LEAVING THE CFWA
MOISTURE STARVED BY THIS EVENING AS THE INITIAL WAVE SLIPS ACROSS
THE CFWA. WETBULB TEMPERATURES ARE COLD ENOUGH TO SUPPORT SNOW
BASICALLY ALONG AND NORTH OF I-85 THROUGH THE AFTERNOON, WITH ONLY
LIGHT ACCUMULATION EXPECTED. AMBIENT TEMPERATURES SUGGESTS THAT MOST
OF THE SNOW IS HAVING A HARD TIME STICKING AS TEMPERATURE READINGS
OUTSIDE OF THE MOUNTAINS ARE A FEW DEGREES ABOVE FREEZING. A LULL IN
THE PRECIP WILL BE EVIDENT THIS EVENING AND INTO THE EARLY PORTIONS
OF THE OVERNIGHT HOURS BEFORE A SECOND WAVE DEVELOPS. THE MID-LEVEL
CLOSED LOW IS SHOW SINKING JUST SOUTH ACROSS THE OH VALLEY, WHILE
A SHORTWAVE ROUNDS THE BASE OF THE LOW AND NICE HEIGHT FALLS
SPREAD IN FROM THE NORTHWEST. IN THIS CASE, NORTHWEST FLOW SNOW
SHOWERS SHOULD REDEVELOP OVER THE NC/TN BORDER AND ACTUALLY BREAK
CONTAINMENT THANKS TO THE PIECE OF ENERGY PROVIDING ENOUGH FORCING
FOR ASCENT FOR PRECIP TO SPREAD EAST OF THE MOUNTAINS. SATURATED
LOW-LEVEL PROFILES SHOULD BE ENOUGH TO TAP INTO THE SNOW DENDRITIC
GROWTH ZONE AND PROVIDE THE OPPORTUNITY FOR A SECOND ROUND OF SNOW
SHOWERS ACROSS THE NC/SC PIEDMONT AROUND DAYBREAK THURSDAY THROUGH
THE REST OF THE MORNING HOURS BEFORE SLIPPING EAST OF THE CFWA.
CAMS HAVE PICKED UP ON THE DEVELOPMENT OF A 700-850MB FRONTOGENESIS
BAND IN ASSOCIATION WITH THE SECONDARY WAVE OF SNOW THAT SHOULD
FORM. IN THIS CASE, LOCALIZED SNOWFALL RATES COULD BECOME
MODERATE TO HEAVY AT TIMES, WITH SOMEWHERE BETWEEN GREENVILLE,
SC TO CHARLOTTE, NC AND THE I-77 CORRIDOR POSSIBLY PICKING UP A
SURPRISE INCH OF SNOWFALL. MOST PLACES WILL LIKELY SEE A TENTH
OF AN INCH OR SO ON ELEVATED SURFACES, BUT THE DYNAMICS ARE IN
PLACE FOR A LOCALIZED DEFORMATION BAND TO SET UP OVER SOMEWHERE
IN THE PIEDMONT OF THE CFWA. IF THIS HAPPENS TO OCCUR OUTSIDE OF
THE CURRENT WINTER WEATHER ADVISORY AREA, DON'T BE SURPRISED IF
A SHORT-FUSED WINTER WEATHER ADVISORY WILL BE NEED FOR SOME OF
THE UPSTATE SC COUNTIES. THE LATEST HREF SUGGESTS THAT THIS WOULD
LIKELY OCCUR IN THE CLT METRO AREA. NORTHWEST FLOW SNOW SHOWERS WILL
BE ONGOING ALONG THE NC/TN BORDER THROUGH THE END OF THE FORECAST
PERIOD AND ADD ANOTHER 2-4+" OF SNOW IN THE FAVORED UPSLOPE REGIONS
(ABOVE 3500') BEFORE THE DRY AIR ADVECTION OVERCOMES THE NORTHWEST
FLOW SNOW SHOWERS. CLOUDS SHOULD QUICKLY SCATTER OUTSIDE OF THE
MOUNTAINS BY THURSDAY AFTERNOON AS STRONG DOWNSLOPE COMPONENT
HELPS CLEAR THE SKIES AND PRECIP IS WELL EAST OF THE AREA.
OTHERWISE, VERY STRONG CAA WILL FILTER IN BEHIND THE SECONDARY
SHORTWAVE AS A STRONG CANADIAN HIGH (1040+MB) SINKS IN ACROSS
THE CENTRAL PLAINS. A TIGHT PRESSURE GRADIENT IS SHOWN ACROSS
THE MOUNTAINS BETWEEN THE STRONG CANADIAN HIGH AND COASTAL LOW
THAT WILL BE IN THE PROCESS OF SHIFTING OFFSHORE THE MID-ATLANTIC
COAST. FACTOR IN HEIGHT FALLS AND LOW-LEVEL CAA AND WATCH WIND
CHILL VALUES DIP WELL BELOW ZERO AND EVEN TO -15 TO -20 DEGREES
IN THE HIGHER ELEVATIONS. IN THIS CASE, DECIDED TO ISSUE A COLD
WEATHER ADVISORY FOR THE MOUNTAIN COUNTIES ALONG THE TN BORDER FOR
ELEVATIONS ABOVE 3500' AND ALL OF AVERY COUNTY. A WIND ADVISORY
CAN'T BE RULED OUT AS WELL AS GUSTS WILL FLIRT WITH ADVISORY-LEVEL
CRITERIA AT THE SAME TIME AND IN THE SAME LOCATIONS. ACTUAL
TEMPERATURES ARE 15-20 DEGREES BELOW NORMAL THIS AFTERNOON, WITH
VALUES RUNNING 5-10 DEGREES BELOW NORMAL TONIGHT THANKS TO COLDER
THICKNESSES SPREADING ACROSS THE AREA DESPITE ONGOING CLOUD COVER
AND EVENTUAL PRECIP. TEMPERATURES WILL RUN 20-25 DEGREES BELOW
NORMAL AS THE AFOREMENTIONED CAA QUICKLY SHIFTS INTO THE REGION AND
CLOUD COVER NOT ABLE TO FULLY SCATTER OUT BY PEAK HEATING.
SHORT TERM /THURSDAY NIGHT THROUGH SATURDAY/
AS OF 200 PM WEDNESDAY: COLD NW FLOW WILL CONTINUE INTO THE SOUTHERN
APPALACHIANS AND VICINITY THU NIGHT INTO EARLY FRI. ALTHOUGH
MOISTURE ON THE WESTERN SLOPES WILL BE SHALLOW DURING THIS TIME
FRAME, TEMPS IN THE MOIST LAYER WILL BE MORE THAN COLD ENOUGH TO
SUPPORT ICE CRYSTAL NUCLEATION...SO LIGHT SNOW SHOWERS AND FLURRIES
WILL REMAIN POSSIBLE ALONG THE TN/NC BORDER BEFORE THE MOISTURE
DEPLETES BY AROUND DAYBREAK FRIDAY. OTHERWISE, SPRAWLING SURFACE
HIGH PRESSURE WILL SETTLE OVER THE REGION THROUGH THE END OF THE
PERIOD, RESULTING IN A RELAXING PRESSURE GRADIENT, DRY AIR, AND
BELOW NORMAL TEMPERATURES. SOME DEGREE OF ENHANCED WILDFIRE DANGER
APPEARS LIKELY FOR AT LEAST FRIDAY, AS MINIMUM RH IS FORECAST AT
20-25% FOR MUCH OF THE AREA OUTSIDE THE MOUNTAINS. TEMPS WILL
GRADUALLY MODIFY THROUGH THE PERIOD...WITH THU NIGHT LOWS EXPECTED
TO BE AROUND 20 DEGREES BELOW NORMAL...AND FRI NIGHT MINS ABOUT 15
DEGREES BELOW. MAX TEMPS WILL BE 5-10 DEGREES BELOW CLIMO.
LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/
AS OF 220 PM WEDNESDAY: A GENERALLY DRY/FAST WNW FLOW ALOFT IS
EXPECTED TO IMPACT THE SOUTHEAST AND MID-ATLANTIC THROUGH THE MEDIUM
RANGE. THE PROGRESSIVE NATURE OF THE PATTERN WILL BRING MULTIPLE,
DAMPENING SHORT WAVE TROUGHS THROUGH OR NEAR THE FORECAST AREA
THROUGH THE PERIOD. ONE OF THESE MAY INITIATE A COASTAL SURFACE
WAVE CLOSE ENOUGH TO THE CWA TO BRING RAIN CHANCES TO THE PIEDMONT
SUN NIGHT/MON...BUT THE CONSENSUS OF GLOBAL MODEL GUIDANCE INDICATES
A POP-FREE FORECAST SHOULD BE MAINTAINED FOR THE TIME BEING. OTHER
DISTURBANCES COULD BRING MOUNTAIN/NW FLOW SHOWERS, BUT AGAIN, THE
EXPECTATION OF A GENERALLY DRY AIR MASS WILL PRECLUDE A POP MENTION
FOR THIS. OTHERWISE, MAX TEMPS WILL ARM THROUGH THE PERIOD...
ALTHOUGH THE RELATIVELY DRY AIR IS GENERALLY EXPECTED TO SUPPORT
LARGE DIURNAL TEMP RANGES SUCH THAT FORECAST HIGHS ARE 5-10 DEGREES
ABOVE NORMAL MON-WED, WHILE MIN TEMPS ARE EXPECTED TO BE WITHIN THE
BALLPARK OF NORMAL.
AVIATION /20Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: FIRST AREA OF PRECIP IS CURRENTLY PUSHING
THROUGH THE TERMINALS WITH A CHANCE FOR -SN AT THE NC SITES AND
-RASN AT THE SC SITES THROUGH 20Z-22Z BEFORE SHIFTING TO THE
EAST. CIGS WILL GRADUALLY LOWER THROUGH THE AFTERNOON AS MOST TAF
SITES ARE FORECASTED TO BE MVFR/IFR BY 00Z THURSDAY. NORTHEASTERLY
WINDS WILL CONTINUE THROUGH THIS EVENING AND INTO THE OVERNIGHT
HOURS, WHILE CIGS LIKELY GO PREVAILING IFR OVERNIGHT TONIGHT
AT ALL TERMINALS. KAVL WILL MAINTAIN A SOUTHEASTERLY COMPONENT
THROUGH SUNSET BEFORE MAKING A SWITCH OUT OF THE NORTHWEST. A
SECOND WAVE OF SNOW IS SHOWING UP VIA MODEL GUIDANCE JUST BEFORE
DAYBREAK THURSDAY AND MOVES FROM WEST TO EAST THROUGH THE REST OF
THE MORNING HOURS. INCLUDED A PROB30 FOR ALL TAF SITES AS THERE
IS STILL SOME UNCERTAINTY ON HOW WIDESPREAD COVERAGE WILL BE, BUT
A QUICK BURST OF LIGHT TO MODERATE SNOW HAS ENTERED THE FORECAST,
WITH ASSOCIATED RESTRICTIONS. BEHIND THE AREA OF SNOW, CLOUDS ARE
EXPECTED TO QUICKLY SCATTER OUT BY LATE MORNING TO EARLY AFTERNOON
WITH ALL SITES TOGGLING TO A NORTHWESTERLY DIRECTION WITH LOW-END
GUSTS FILTERING IN AS WELL THROUGH THE END OF THE FORECAST PERIOD.
OUTLOOK: WET SURFACES MAY FREEZE AS TEMPERATURES FALL BELOW
FREEZING DEICING COULD BE NECESSARY THURSDAY MORNING. DRY HIGH
PRESSURE RETURNS LATE THURSDAY AND LINGERS INTO THE WEEKEND.
GSP WATCHES/WARNINGS/ADVISORIES
GA...WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR GAZ010.
NC...WINTER WEATHER ADVISORY UNTIL NOON EST THURSDAY FOR NCZ033-
035>037-048>053-056>059-062>065-068>072-082-501>510.
COLD WEATHER ADVISORY FROM 7 AM THURSDAY TO 10 AM EST FRIDAY
FOR NCZ033-048>052-058.
SC...NONE.
SYNOPSIS...JDL
NEAR TERM...CAC
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...CAC
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