284
FXUS62 KGSP 140810
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
310 AM 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 245 AM 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
LIGHT RAIN CONTINUES LIFTING NORTHEAST ACROSS THE FORECAST AREA THIS
MORNING AHEAD OF A COLD FRONT, WITH MOSTLY CLOUDY SKIES IN PLACE.
WITH RAIN COVERAGE EXPECTED TO EXPAND THROUGH DAYBREAK, AND CLOUD
COVER LIMITING RADIATIONAL COOLING, LOWS THIS MORNING WILL END UP ~4-
7 DEGREES ABOVE NORMAL. COULD NOT ENTIRELY RULE OUT THE POTENTIAL
FOR SOME BRIEF SLEET TO MIX IN WITH RAIN AT TIMES, MAINLY OVER THE
HIGHER ELEVATIONS OF THE NC MOUNTAINS, THROUGH DAYBREAK. HOWEVER,
SLEET IS NOT EXPECTED TO ACCUMULATE SO NO MAJOR IMPACTS ARE
EXPECTED.
COLD AIR DAMMING (CAD) WILL REMAIN IN FULL FORCE TODAY AHEAD OF THE
COLD FRONT. THE ENTIRE FORECAST AREA WILL SEE OVERCAST SKIES AND
WIDESPREAD RAIN THIS MORNING THROUGH LATE THIS AFTERNOON AHEAD OF
THE FRONT. 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 AFTERNOON BEFORE TAPERING OFF BRIEFLY LATE
THIS 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 IN BEHIND THE FRONT. 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 /08Z THURSDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: A COLD FRONT APPROACHING OUT OF THE WEST
IS LEADING TO BKN TO OVC VFR CLOUD COVER ACROSS THE TERMINALS AND
RAIN ACROSS THE WESTERN HALF OF THE FORECAST AREA AS OF 06Z. LLWS
CANNOT BE ENTIRELY RULED OUT, ESPECIALLY AT KAVL, THROUGH THE
MORNING HOURS BUT THE LLWS POTENTIAL LOOKS MARGINAL AT BEST SO DID
NOT MENTION IN THE TAFS AT THIS TIME. RAIN WILL CONTINUE TO EXPAND
NORTHEASTWARD AND CIGS WILL GRADUALLY LOWER THROUGH LATE THIS
MORNING INTO EARLY THIS AFTERNOON. CIGS SHOULD MAINLY DROP TO IFR
LEVELS WITH THE POTENTIAL FOR HIGH-END LIFR CIGS IN THE HEAVIEST
SHOWERS. STARTED WITH TEMPOS FOR RA TOWARDS THE BEGINNING OF THE TAF
PERIOD, WITH PREVAILING RA AFTER THE TEMPOS END. RA SHOULD STICK
AROUND THROUGH THE LATE AFTERNOON/EARLY EVENING HOURS BEFORE
GRADUALLY TAPERING OFF FROM WEST TO EAST. VSBYS WILL DECREASE AS
WELL WITH THE RAIN SHIELD, RANGING MOSTLY FROM MVFR TO IFR. PATCHY
FOG LOOKS TO STICK AROUND/REDEVELOP TONIGHT INTO DAYBREAK FRIDAY
EAST OF THE MOUNTAINS SO HAVE THIS ACCOUNTED FOR TOWARDS THE END OF
THE TAF PERIOD. CLOUD COVER WILL GRADUALLY THIN OUT LATE THIS
AFTERNOON INTO THIS EVENING BECOMING SCT TO BKN. CIGS WILL GRADUALLY
LIFT TO MVFR LEVELS LATE THIS AFTERNOON INTO THIS EVENING. WINDS
WILL REMAIN SE AT KAVL AND NE EAST OF THE MOUNTAINS THROUGH THE
MORNING HOURS. WINDS WILL THEN GRADUALLY TURN N/NW ACROSS THE
TERMINALS BEHIND THE COLD FRONT THIS AFTERNOON INTO THIS EVENING.
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
SHORT TERM...WIMBERLEY
LONG TERM...WIMBERLEY
AVIATION...AR
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