780
FXUS62 KGSP 141121
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
621 AM EST SAT FEB 14 2026
WHAT HAS CHANGED
THE AVIATION FORECAST WAS UPDATED TO REFLECT THE IMPENDING 12Z
TAF ISSUANCE.
KEY MESSAGES
1. DRY CONDITIONS CONTINUE TODAY, AND ISOLATED CRITICAL RH SUPPORT
ANOTHER AFTERNOON OF MARGINAL FIRE WEATHER ISSUES.
2. WIDESPREAD RAINFALL IS STILL EXPECTED ON SUNDAY, BUT HYDRO
CONCERNS ESSENTIALLY NONEXISTENT GIVEN ONGOING DROUGHT CONDITIONS
ACROSS THE REGION.
3. A TREND TOWARD A DRY AND VERY WARM PATTERN IS EXPECTED NEXT
WEEK.
DISCUSSION
KEY MESSAGE 1: DRY CONDITIONS CONTINUE TODAY, AND ISOLATED CRITICAL
RH SUPPORT ANOTHER AFTERNOON OF MARGINAL FIRE WEATHER ISSUES.
SPRAWLING 1024MB SURFACE HIGH CENTERED NORTH OF CAPE HATTERAS
CONTINUES TO DOMINATE THE PATTERN THIS MORNING, MAINTAINING DRY
AND QUIET CONDITIONS ACROSS THE ENTIRETY OF THE WESTERN CAROLINAS
AND NORTHEAST GEORGIA. DESPITE THE HIGH'S LOCATION TO OUR EAST,
BASICALLY NO DISCERNIBLE MOISTURE RETURN HAS DEVELOPED. RATHER, ANY
MOISTURE APPEARS TO STILL BE LOCATED WELL UPSTREAM, WITH WIDESPREAD
CIRRUS LOCATED OVER WEST-CENTRAL TENNESSEE AND THE MISSISSIPPI
VALLEY, AND SLOWLY EXPANDING EASTWARD PER RECENT SATELLITE IMAGERY.
MARGINALLY-LOW RELATIVE HUMIDITY IS EXPECTED TO DEVELOP AGAIN
SATURDAY AFTERNOON AS A SHALLOW MIXED LAYER DEVELOPS BY LATE
MORNING, TAPPING INTO DRY AIR ALOFT. WERE FLOW ALOFT A BIT
STRONGER, ONE MIGHT EXPECT DEWPOINTS TO CRATER DURING PEAK HEATING,
BUT WITH LIGHT FLOW THROUGH THE DEPTH OF THE TROPOSPHERE, THERE
WON'T BE MUCH TO INCITE BETTER MIXING AT THE TOP OF A WEAKLY-CAPPED
PBL. SO, MOST LOCATIONS EAST OF THE MOUNTAINS CAN EXPECT AFTERNOON
RH TO DROP INTO THE 25-30% RANGE, BUT THE LIKELIHOOD OF RH <25% IS
FAIRLY LOW OUTSIDE THE I-77 CORRIDOR. FIRE DANGER WILL BE NONZERO,
BUT LIMITED BY LIGHT WINDS OF ONLY 3-6KTS ACROSS THE REGION.
RH WILL REBOUND BY LATE EVENING, AS DAYTIME MIXING ABATES AND WE
START TO GET BETTER MOISTURE RETURN AHEAD OF THE NEXT ACTIVE SYSTEM.
KEY MESSAGE 2: WIDESPREAD RAINFALL IS STILL EXPECTED ON SUNDAY,
BUT HYDRO CONCERNS ESSENTIALLY NONEXISTENT GIVEN ONGOING DROUGHT
CONDITIONS ACROSS THE REGION.
GUIDANCE IS IN GOOD AGREEMENT THAT A PROGRESSIVE SHORTWAVE TROUGH
WILL MAKE TRACKS OUT OF THE DESERT SOUTHWEST SATURDAY AND QUICKLY
TRAVERSE THE SOUTHERN CONUS...DRIVING A MATURE SURFACE LOW INTO
THE LOWER MISSISSIPPI VALLEY BY LATE TONIGHT. ALL INDICATIONS
ARE THAT THE LOW WILL ALREADY BE IN THE PROCESS OF OCCLUDING
BY SUNDAY MORNING, BUT A VERY STRONG WAA REGIME ON THE LEADING
EDGE OF THIS SYSTEM WILL NONETHELESS PUMP AMPLE MOISTURE INTO
THE AREA...RESULTING IN THE ONSET OF RAINFALL AROUND OR SHORTLY
AFTER DAWN SUNDAY FOR THE WESTERN CAROLINAS. GFS, NAM, AND HREF
PROFILES ARE SUPPORTIVE OF IN SITU COLD-AIR DAMMING EAST OF THE NC
MOUNTAINS...BUT THE SYSTEM'S OVERALL TRACK IS FAR ENOUGH SOUTH, AND
THE COOL-SECTOR AIR MASS MODIFIED ENOUGH BY THE TIME OF ONSET, THAT
EVEN WITHIN THE WEDGE TEMPERATURES WILL ONLY BE IN THE 40S. SO,
AN ALL-RAIN FORECAST REMAINS A NEAR CERTAINTY, WITH THE EXCEPTIONS
OF VERY HIGH RIDGETOPS IN THE SMOKIES AND BALSAMS, WHICH COULD
FEASIBLY WET-BULB DOWN COLD ENOUGH TO SEE BRIEF FLURRIES AT THE
ONSET SUNDAY MORNING.
PWS RANGING FROM 1-1.5" ACROSS THE AREA AND DECENT SYNOPTIC FORCING
DURING THE DAY SUNDAY WILL SUPPORT EFFICIENT PRECIPITATION,
RESULTING IN RAINFALL TOTALS OF 1-1.25 INCHES FOR MUCH OF THE
AREA...LIKELY EVEN MORE IN FAVORED UPSLOPE ZONES ACROSS THE BLUE
RIDGE ESCARPMENT. THE 00Z HREF DOESN'T QUITE EXTEND OUT FAR ENOUGH
TO CAPTURE THE ENTIRE EVENT, BUT THE IMPENDING 12Z CYCLE WILL,
AND WILL PROVIDE MORE INSIGHT INTO HIGH-END TOTALS. IN GENERAL,
THOUGH, HYDRO ISSUES APPEAR UNLIKELY GIVEN MOST OF THE FORECAST AREA
IS CURRENTLY UNDER D2-D3 DROUGHT CONDITIONS. ENSEMBLE HYDROGRAPHS
FURTHER SUPPORT THIS ASSESSMENT. BOTH THE 00Z REFS AND HREF SUPPORT
~25% CHANCES OF MARGINAL 100-150 J/KG SBCAPE ACROSS THE EXTREME
SOUTHERN TIER OF THE FORECAST AREA - LIKELY TOO LITTLE INSTABILITY
IF IT EVEN MATERIALIZES FOR A SEVERE RISK, BUT PERHAPS ENOUGH FOR
A RUMBLE OF THUNDER AND BRIEF, LOCALIZED CONVECTIVE RAIN RATES.
ELSEWHERE, GUIDANCE IS IN GOOD AGREEMENT THAT THE WEDGE WILL REMAIN
TOO ENTRENCHED FOR ANY SURFACE-BASED INSTABILITY.
OPERATIONAL MODELS REMAIN IN GOOD AGREEMENT THAT AS THE Z500
TROUGH AXIS SHIFTS TO OUR EAST SUNDAY NIGHT, COASTAL CYCLOGENESIS
WILL OCCUR OVER THE NC OUTER BANKS. THIS WILL HAVE THE IMPACT
OF HELPING USHER IN A POSTFRONTAL CAA REGIME THAT MUCH QUICKER,
ERODING THE IN SITU WEDGE IN SHORT ORDER AND BRINGING A SWIFT END
TO RAINFALL THROUGH EARLY MONDAY MORNING.
KEY MESSAGE 3: A TREND TOWARD A DRY AND VERY WARM PATTERN IS
EXPECTED NEXT WEEK.
COLD AIR DAMMING WEDGE QUICKLY BREAKS DOWN MONDAY AS THE PARENT
SURFACE HIGH SHIFTS OFF THE NEW ENGLAND COAST AND THE PASSING UPPER
SHORTWAVE AND ATTENDANT SURFACE LOW SLIDE OFF THE CAROLINA COAST.
THEREAFTER, BROAD AND FLAT UPPER RIDGING BECOMES ESTABLISHED FROM
MEXICO INTO THE GULF WITH AN ELONGATED BELT OF WESTERLIES EXTENDING
FROM THE DESERT SOUTHWEST TO THE APPALACHIANS. RISING HEIGHTS ALONG
WITH A NORTHWARD DEVELOPING WARM SECTOR WILL FOSTER A RETURN TO WELL
ABOVE AVERAGE TEMPERATURES WITH AFTERNOON HIGHS CLIMBING INTO THE
MID TO UPPER 60S BY MID WEEK FOLLOWED BY LOW TO MID 70S BY THURSDAY
AND FRIDAY. A FRONTAL BOUNDARY MAY SLOWLY DROP THROUGH THE OHIO
VALLEY AND TOWARDS THE AREA, BUT WILL BE ORIENTED PARALLEL TO THE
ENTRENCHED WESTERLIES. THUS, CONFIDENCE IS LOW AS TO HOW CLOSE TO
THE AREA THE BOUNDARY WILL MAKE IT. NONETHELESS, A FEW STRAY WARM
ADVECTION SHOWERS CANNOT BE DISCOUNTED BY LATE WEEK, BUT THIS WILL
BE THE EXCEPTION AND NOT THE RULE WITH MOST LOCATIONS REMAINING DRY.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: VFR CONTINUES INTO TODAY AS HIGH PRESSURE
DOMINATES THE PATTERN. SATELLITE IMAGERY DEPICTS EXTENSIVE
CIRRUS SHIELD OVER THE TENNESSEE VALLEY, AND IT'S EXPECTED TO
CONTINUE MARCHING EAST, GRADUALLY THICKENING CIRRUS ACROSS THE
WESTERN CAROLINAS THROUGH THE DAY TODAY. LINGERING CALM WINDS
THIS MORNING WILL BECOME A LIGHT S/SW WIND DURING THE DAY.
HIGH VFR CEILINGS SHOULD DEVELOP THIS AFTERNOON INTO TONIGHT,
BUT NO PREVAILING RESTRICTIONS ARE EXPECTED TO DEVELOP UNTIL THE
PREDAWN HOURS SUNDAY MORNING, WHEN MVFR CEILINGS WILL BEGIN TO
EXPAND EASTWARD OUT OF THE SAVANNAH RIVER VALLEY. ALL THE 12Z
TAFS NOW FEATURE PROB30S FOR ONSET OF LIGHT RAIN BEFORE DAWN.
MORE APPRECIABLE, PREVAILING RAIN WILL DEVELOP AFTER 12Z SUNDAY -
BEYOND THE END OF THE PERIOD FOR ALL TERMINALS EXCEPT KCLT, WHICH
NOW FEATURES PREVAILING -RA AND ASSOCIATED MVFR RESTRICTIONS DURING
THE FINAL HOURS OF THE 12Z TAF PERIOD.
OUTLOOK: PRECIPITATION WILL RAMP UP DURING THE FIRST PART OF SUNDAY
AND CONTINUE INTO THE AFTERNOON. WIDESPREAD RAIN WILL RESULT IN
LOW CEILINGS - PROBABLY IFR OR WORSE - WELL INTO SUNDAY NIGHT.
DRY CONDITIONS SHOULD RETURN MONDAY AND PERSIST THROUGH THE FIRST
PART OF THE WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
MPR/TW
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