564
FXUS62 KGSP 200314
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1014 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 958 PM WEDNESDAY: THE NEXT FEW HOURS OF THE FORECAST HEADING
INTO THE OVERNIGHT REMAIN ON TRACK AS A LULL IN PRECIPITATION HAS
ARRIVED FOLLOWING THE GRADUAL DEPARTURE OF A COASTAL LOW. FARTHER
UPSTREAM, A STRONG ARCTIC COLD FRONT IS QUICKLY MOVING TOWARDS THE
AREA AND WILL BE THE IMPETUS FOR ANOTHER BOUT OF SNOW SHOWERS WITH
POTENTIAL FOR LIGHT ACCUMULATIONS EAST OF THE MOUNTAINS. MORE
DETAILS CAN BE FOUND BELOW.
OTHERWISE, STOUT CLOSED UPPER LOW CURRENTLY SETTLED OVER THE
NORTHERN GREAT PLAINS WILL TRAVERSE ACROSS THE MIDWEST/UPPER GREAT
LAKES THROUGH TONIGHT BEFORE SETTING UP SHOP OVER THE NORTHEASTERN
CONUS BY THE END OF THE FORECAST PERIOD. 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
AS THE INITIAL WAVE SLIPS ACROSS THE CFWA. A LULL IN THE PRECIP WILL
CONTINUE INTO THE EARLY PORTIONS OF THE OVERNIGHT HOURS BEFORE A
SECOND WAVE DEVELOPS. THE MID-LEVEL CLOSED LOW IS 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
WITH ADDITIONAL SNOW SHOWERS DEVELOPING EAST OF THE MOUNTAINS HEAD
OF AN ADVANCING ARCTIC FRONT BENEATH FAVORABLE UPPER JET DYNAMICS
AND SUFFICIENT FORCING FOR ASCENT. 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 QUICK 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
FRONTOGENETICAL 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 NEEDED FOR SOME OF THE UPSTATE SC COUNTIES. THE
LATEST 00Z CAMS SUGGESTS THAT THIS WOULD LIKELY OCCUR IN THE
VICINITY OF THE I-85 CORRIDOR FROM THE UPSTATE TO 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 /03Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: RESTRICTIONS WILL CONTINUE TO PLAGUE ALL
TERMINALS THROUGH MUCH OF THE TAF PERIOD BEFORE QUICKLY IMPROVING
LATE THURSDAY MORNING INTO THURSDAY AFTERNOON. THE BULK OF INITIAL
SNOW SHOWERS HAS PUSHED OUT OF THE AREA, BUT A COUPLE SCATTERED SNOW
SHOWERS REMAIN AND COULD RESULT IN BRIEF VISIBILITY RESTRICTIONS
OVER THE NEXT COUPLE HOURS. THEREAFTER, A LULL IN THE PRECIPITATION
IS EXPECTED WITH THE MAIN FOCUS SHIFTING TO THE DEVELOPMENT OF IFR
CEILINGS THAT WILL PERSIST THROUGH THE REMAINDER OF THE OVERNIGHT.
AN ARCTIC FRONT ARRIVES FROM THE WEST EARLY IN THE MORNING WITH SNOW
SHOWERS EXPECTED TO REDEVELOP ALONG THE ADVANCING FRONT. IMPACTS ARE
MOST LIKELY AT KHKY AND KCLT, BUT CANNOT BE RULED OUT AT ANY GIVEN
TERMINAL INCLUDING KGSP/KGMU. CONDITIONS RAPIDLY IMPROVE BEHIND THE
ARCTIC FRONT WITH LOW STRATUS SCATTERING OUT A FAST RETURN TO VFR AT
ALL TERMINALS. GUSTY NORTHWEST WINDS WILL ARRIVE BEHIND THE FRONT
AND CONTINUE THROUGH THE REMAINDER OF THE FORECAST PERIOD.
OUTLOOK: DRY HIGH PRESSURE RETURNS THURSDAY AFTERNOON 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/TW
SHORT TERM...JDL
LONG TERM...JDL
AVIATION...TW
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