907
FXUS62 KGSP 141744
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
1244 PM EST THU NOV 14 2024
SYNOPSIS
CLOUDS AND PRECIPITATION WILL MAKE FOR A VERY DAMP AND CHILLY
DAY. DRY WEATHER AND A WARMING TREND ARE EXPECTED FRIDAY THROUGH
MONDAY. RAIN MAY RETURN TO THE AREA TUESDAY OR WEDNESDAY BUT
TEMPERATURES WILL REMAIN MILD AT THAT TIME.
NEAR TERM /THROUGH TONIGHT/
AS OF 1240 PM EST THURSDAY...
KEY MESSAGES:
1) CHILLY, RAINY, AND MOSTLY CLOUDY TODAY THANKS TO COLD AIR
DAMMING IN PLACE AHEAD OF A COLD FRONT
2) BREEZY WINDS CONTINUE ACROSS THE MOUNTAINS THROUGH EARLY THIS
AFTERNOON BEFORE RETURNING AGAIN THIS EVENING INTO TONIGHT
3) DRIER BEHIND THE FRONT THIS EVENING INTO TONIGHT OUTSIDE OF
NORTHWEST FLOW RAIN SHOWERS ALONG THE NC/TN BORDER
PRECIP BEHIND TO TAPER OFF IN THE FAR WESTERN ZONES, BUT CONTINUES
ACROSS MOST OF THE FORECAST AREA, LOCKING IN A CHILLY WEDGE. NO
CHANGES NEEDED WITH THE MIDDAY UPDATE, EXCEPT TWEAKS TO SKY AND
WIND GRIDS FOR THE AVIATION FORECAST.
OTHERWISE...COLD AIR DAMMING (CAD) WILL REMAIN IN FULL FORCE TODAY
AHEAD OF AN APPROACHING COLD FRONT. THE ENTIRE FORECAST AREA WILL
SEE OVERCAST SKIES AND WIDESPREAD RAIN INTO THIS AFTERNOON, THEN
TAPERING OFF LATE AFTN INTO EARLY THIS EVENING. CAD, RAIN, AND
CLOUD COVER WILL ALL WORK TOGETHER TO LIMIT TEMPS THIS AFTERNOON,
SO HIGHS WILL END UP ~10-15 DEGREES BELOW NORMAL. BREEZY E/SE'LY
WINDS WILL CONTINUE ACROSS THE NC MOUNTAINS THROUGH EARLY THIS
AFTERNOON BEFORE TAPERING OFF BRIEFLY BY LATE AFTERNOON. THERE
WILL BE A FEW HUNDRED J/KG OF MUCAPE TODAY AHEAD OF THE FRONT SO AN
ELEVATED THUNDERSTORM OR TWO CANNOT BE ENTIRELY RULED OUT. HOWEVER,
TYPICALLY WHEN WE ARE SOCKED IN CAD, WE REMAIN VERY STABLE. THUS,
THE THUNDER POTENTIAL WILL BE VERY LOW TODAY. NO FLOODING IS
EXPECTED WITH TODAY'S RAIN DUE TO THE DRY ANTECEDENT CONDITIONS.
RAINFALL AMOUNTS WILL GENERALLY RANGE FROM 0.75"-1.25" ACROSS THE
CWA. HOWEVER, UPSLOPE ZONES IN THE MOUNTAINS COULD SEE RAINFALL
TOTALS FROM 1.50"-2.00", WITH LOCALLY HIGHER AMOUNTS POSSIBLE IN
THE SMOKIES. THE LOWEST AMOUNTS ARE EXPECTED FOR THE NW FACING
RAIN SHADOW LOCATIONS, WHERE ONLY 0.50"-0.75" IS EXPECTED.
THE COLD FRONT WILL PUSH ACROSS THE FORECAST AREA THIS EVENING INTO
TONIGHT ALLOWING TO CAA TO FILTER INTO THE FORECAST AREA. THIS WILL
SCOUR OUT THE WEDGE LEADING TO GRADUALLY DECREASING CLOUD COVER AND
RAIN CHANCES, WITH MOST LOCATIONS SEEING DRY CONDITIONS BY 7-8PM.
HOWEVER, NORTHWEST FLOW RAIN SHOWERS WILL LINGER THROUGH TONIGHT
ALONG THE NC/TN BORDER. TEMPS WILL REMAIN ABOVE FREEZING OVERNIGHT
WHERE NW FLOW SHOWERS OCCUR SO NO WINTRY PRECIP IS EXPECTED. LOWS
TONIGHT WILL END UP A FEW DEGREES ABOVE CLIMO EAST OF THE MOUNTAINS
AS SOME CLOUD COVER WILL LINGER THROUGH DAYBREAK FRIDAY. LOWS ACROSS
THE MOUNTAINS WILL END UP SEVERAL DEGREES ABOVE CLIMO THANKS TO
THICKER CLOUD COVER, ESPECIALLY ACROSS THE WESTERN NORTH CAROLINA
MOUNTAINS. BREEZY WINDS, THIS TIME OUT OF THE NW, WILL DEVELOP
AGAIN THIS EVENING INTO TONIGHT BEHIND THE COLD FRONT BUT WILL
REMAIN WELL BELOW ADVISORY CRITERIA.
SHORT TERM /FRIDAY THROUGH SUNDAY/
AS OF 200 AM THU: NORTHWEST FLOW WILL CONTINUE ACROSS THE MOUNTAINS
FRIDAY, WITH PROG SOUNDINGS REVEALING PERSISTENT MOISTURE IN THE
UPSLOPE LAYER, AND VERY SMALL INSTABILITY WHICH SHOULD BE ENOUGH TO
PRODUCE CLOUD COVER IF NOT A FEW SPITS OF PRECIP. TEMPS SHOULD REMAIN
ABOVE FREEZING THERE UNTIL PRECIP ENDS, WITH MOISTURE TOO SHALLOW FOR
ICE NUCLEATION; WE THUS ADVERTISE ALL RAIN. OTHERWISE, SUNSHINE AND
(IN THE PIEDMONT) DOWNSLOPE FLOW STILL SHOULD RESULT IN MAX TEMPS
REBOUNDING A LITTLE ABOVE NORMAL. GUSTS OF 30-35 MPH WILL CONTINUE
IN HIGH ELEVATIONS DURING THE DAY; LOWER ELEVATIONS AND THE PIEDMONT
WILL EXPERIENCE BREEZY CONDITIONS, WITH GUSTS MOSTLY AROUND 20 MPH,
ALTHOUGH A FEW GUSTS CLOSER TO 30 COULD MIX DOWN BRIEFLY IN THE
AFTERNOON.
HEIGHT GRADIENT WILL FURTHER RELAX FRI NIGHT AND THE HIGH ELEVATION
WINDS SHOULD TAPER OFF. MINS WILL RETURN TO ABOUT NORMAL; FRI NIGHT
IS LIKELY TO BE THE COLDEST NIGHT OF THE NEXT FEW FOR THE MOUNTAINS.
DRY CONTINENTAL HIGH PRESSURE WILL BUILD INTO THE AREA FROM THE WEST
ON SATURDAY, AS ATTENDANT UPPER RIDGE AXIS MOVES EAST OF THE
MISSISSIPPI. THAT AXIS WILL PUSH EAST OF THE APPALACHIANS BY SUNDAY.
POP WILL REMAIN NEAR ZERO AND SKIES MOSTLY CLEAR. MAX TEMPS WILL
TREND SLIGHTLY WARMER EACH DAY. SATURDAY NIGHT APPEARS LIKELY TO BE
COOLER THAN FRIDAY NIGHT IN OUR EAST, WHEREAS THE MOUNTAINS WILL
ALREADY BE SEEING THE EFFECT OF THE INCREASED THICKNESSES AT THAT
TIME AND LIKELY END UP A LITTLE WARMER.
LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/
AS OF 230 AM THU: THERE REMAINS CONSENSUS AMONG GUIDANCE THAT AN
UPPER LOW WILL MOVE FROM ONTARIO TO NEAR MAINE SUNDAY NIGHT AND
MONDAY, SUPPRESSING THE RIDGE OVER THE EASTERN SEABOARD TEMPORARILY,
WITH AXIS BEING FORCED OUT TO SEA. HEIGHT RISES WILL CONCURRENTLY
DEVELOP IN THE CENTRAL MISSISSIPPI VALLEY AS ANOTHER UPPER LOW SWINGS
ACROSS THE SOUTHERN ROCKIES AND INDUCES CYCLOGENESIS OVER WEST TX.
THE "NEW" RIDGE IS SHOWN TO SHIFT EAST TO THE APPALACHIANS BY EARLY
TUE, FOLLOWED BY THE COLD FRONT AHEAD OF THE OCCLUDING LOW IN THE
CENTRAL CONUS. ALTOGETHER, TEMPS SHOULD CONTINUE ON A GRADUAL TREND
FURTHER ABOVE NORMAL, WITH OVERNIGHT LOWS REMAINING ABOVE FREEZING,
AND MAX TEMPS IN THE LOWER 70S IN MOST LOWER ELEVATIONS BY MONDAY.
OUR NEXT CHANCE FOR PRECIP STILL LOOKS TO RESULT FROM THAT FRONT
REACHING THE AREA LATE TUE OR EARLY WED.
THERE APPEARS REASONABLY GOOD CONSENSUS AMONG THE MAJOR ENSEMBLES
THAT BY THAT TIME, THE DISTURBANCE NOW KNOWN AS PTC 19--OR ITS
REMNANT--WILL BE IN THE CENTRAL GULF OF MEXICO. ONCE AGAIN THE
CANADIAN GDPS DEPICTS THE REMNANT MORE OR LESS MERGING WITH THE COLD
FRONT IN THE LOWER MS VALLEY AND A BROAD RAIN SHIELD EXPANDING ACROSS
MUCH OF THE SOUTHEAST. IT CURRENTLY APPEARS AN OUTLIER IN THAT; EVEN
INCORPORATING ALL THE GEPS MEMBERS, PROBABILITY OF MORE THAN 1" OF
RAIN IN 24 HOURS IS SMALL IN OUR CWA, WITH HIGHEST PROBS ACROSS
NORTHERN FL AND SOUTH GA. CONFIDENCE IS UNDERSTANDABLY ON THE LOW
END GIVEN THE LONG RANGE, BUT AS OF NOW IT DOES NOT LOOK LIKE PTC 19
WILL POSE A SIGNIFICANT THREAT TO OUR CWA.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
AT KCLT AND ELSEWHERE: RAIN IS ALREADY BEGINNING TO TAPER OFF TO THE
WEST, AND SHOULD END AT ALL SITES BY AROUND 00Z THIS EVENING. CIGS
LOOK TO STABILIZE IN THE LIFR TO IFR RANGE UNTIL A COLD FRONT
PUSHES THRU THIS EVENING. THIS WILL HELP CLEAR OUT A LOT OF THE
CLOUD COVER, BUT MAY ALLOW FOG AND LOW STRATUS TO QUICKLY FORM
LATE EVENING THRU THE OVERNIGHT. GUIDANCE IS MIXED ON THE EXTENT
OF THE LIFR CIGS, BUT COULD BE ACROSS MOST OF THE PIEDMONT SITES
THRU DAYBREAK FRIDAY. SO WILL TREND TOWARD SOME SCT-BKN 400 FT
CIGS WITH THE 18Z TAFS. THE LOW CLOUDS AND FOG SHOULD SCATTER OUT
FAIRLY QUICKLY FRIDAY MORNING, AS A DRY NW FLOW PICKS UP BEHIND
THE FRONT. WIND WILL TOGGLE TO NNW TONIGHT AND INCREASE TO AROUND
8-10 KT. IT WILL BE BREEZY AT KAVL STARTING BEFORE DAYBREAK, GUSTS
SHOULD BE LIMITED EAST OF THE MOUNTAINS. A STRATOCU DECK AROUND
3500-5000 FT IS EXPECTED TO DEVELOP, ESPECIALLY ACROSS THE NC TAF
SITES, GENERALLY SCATTERED, BUT MAY PRODUCE A CIG BY MID-AFTN.
OUTLOOK: HIGH PRESSURE BRINGS DRY AND VFR CONDITIONS BACK FRIDAY
INTO EARLY NEXT WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...WIMBERLEY
NEAR TERM...AR/ARK
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...ARK
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