974
FXUS62 KGSP 021837
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
237 PM EDT SUN AUG 2 2026
WHAT HAS CHANGED
UPDATED THE AVIATION DISCUSSION FOR THE 18Z TAFS.
KEY MESSAGES
1. SUCCESSIVE ROUNDS OF RAINFALL WILL DEVELOP AGAIN TODAY. CAN'T
RULE OUT AN ISOLATED STRONG TO SEVERE STORM, OR ISOLATED FLASH
FLOOD ISSUES THIS EVENING.
2. TYPICAL AUGUST WEATHER RETURNS FOR THE NEW WORKWEEK. ISOLATED
HYDRO ISSUES CANNOT BE RULED OUT, MAINLY THE FIRST HALF OF
THE WEEK.
DISCUSSION
KEY MESSAGE 1: SUCCESSIVE ROUNDS OF RAINFALL WILL DEVELOP AGAIN TODAY.
CAN'T RULE OUT AN ISOLATED STRONG TO SEVERE STORM, OR ISOLATED
FLASH FLOOD ISSUES THIS EVENING.
SHOWERS HAVE BEGUN TO BLOSSOM ACROSS THE LOW TERRAIN, LARGELY ALONG
AN AREA OF DIFFERENTIAL HEATING FOLLOWING THIS MORNING'S THICK CLOUD
COVER, AND BOLSTERED BY A STAGNANT FRONTAL BOUNDARY NEAR THE NC-TN
BORDER. RECENT SATELLITE IMAGERY DEPICTS A Z500 TROUGH AXIS
EXTENDING FROM NORTHERN MISSISSIPPI AND INTO INDIANA AND WESTERN
OHIO, STILL SANDWICHED BETWEEN BROAD RIDGING OVER THE WESTERN
ATLANTIC AND THE CENTRAL CONUS HEAT DOME. THE LATEST RAP ANALYSIS
THAT ANY LINGERING CLOSED LOW IS BECOMING LESS PRONOUNCED, FAVORING
MORE OF AN OPEN WAVE. THIS EXPOSES US TO SOME RIPPLES OF SHORTWAVE
ENERGY ALOFT, AS THE TROUGH ITSELF BECOMES ESSENTIALLY ANCHORED IN
ITS CURRENT LOCATION. MESOANALYSIS CONTINUES TO DEPICT PWS AS HIGH
AS 2.2" EAST OF THE MOUNTAINS, AND EXTREMELY WARM, MOIST PROFILES
ACROSS MOST OF THE AREA.
EXPECTATIONS FOR TODAY HAVEN'T CHANGED MUCH SINCE THE PREVIOUS
FORECAST; THE 12Z SUITE OF GUIDANCE CAME IN WITH GOOD CONSISTENCY
ON THE DEVELOPMENT OF SCATTERED SHOWERS AGAIN TODAY EAST OF A
STALLING FRONTAL BOUNDARY PROGGED TO REMAIN JUST OVER THE WESTERN
TIER OF THE FORECAST AREA. THE ENVIRONMENT WILL BE A JUICY ONE,
FEATURING 2-2.25" PWS, EXTREMELY WARM PROFILES WITH ANEMIC MID-LEVEL
LAPSE RATES, AND TALL, SKINNY UNSTABLE LAYERS. SBCAPE WILL SURGE
TO 1500-2000 J/KG, BUT STRUGGLE TO PRODUCE MUCH ACTUAL BUOYANCY.
ABOUT THE ONLY THING TODAY'S ENVIRONMENT WILL HAVE GOING FOR IT IS
15-25KTS OF DEEP LAYER SHEAR, ENOUGH FOR SOME DEGREE OF ORGANIZATION
AND A RESULTANT LOW-END DAMAGING WIND THREAT...POSSIBLY AUGMENTED
BY HYDROMETEOR LOADING GIVEN THE EXEPCTATION FOR EFFICIENT RAINFALL-
PRODUCERS TODAY. A LAYER OF DRY AIR ALOFT ALSO LOOKS TO PUSH INTO
THE AREA LATER THIS AFTERNOON, WHICH SHOULD RAISE DCAPE VALUES GOING
INTO THE EVENING. GUIDANCE SUGGESTS THAT AT LEAST ONE ROUND OF
RAINFALL WILL DEVELOP DURING THE AFTERNOON, AND POSSIBLY A SECOND
ROUND GOING INTO LATE EVENING OR THE FIRST HALF OF TONIGHT.
THE CAMS ARE IN DECENT AGREEMENT THAT FOR MOST OF THE AREA,
QPF WILL FALL BELOW ANY THRESHOLD OF CONCERN. WIDESPREAD HYDRO
ISSUES AREN'T LIKELY. HOWEVER, SUCCESSIVE RUNS OF THE HRRR AND
RRFS HAVE COME IN WITH A RIBBON OR TWO OF 2-4" RAINFALL TOTALS,
MAINLY FALLING THIS EVENING WHERE STRONGER CELLS TRAIN. THERE'S NO
CONSISTENCY IN *WHERE* THIS SETS UP, THOUGH, WITH SOME HRRR RUNS
KEEPING HIGHER QPF CONFINED TO THE MOUNTAINS, AND A COUPLE RRFS
RUNS PRODUCING HIGHER TOTALS AS FAR EAST AS THE I-77 CORRIDOR.
IF SUCH A CORRIDOR OF HIGHER RAINFALL THIS EVENING WERE TO SET
UP ACROSS AN AREA ALREADY SATURATED BY PREVIOUS RAINFALL (MAINLY
THE NC AND SC BLUE RIDGE ESCARPMENT) THEN A FLASH FLOOD WARNING
OR TWO COULD BE IN ORDER.
THE FRONT WILL STRUGGLE TO MAKE ANY FURTHER EASTWARD PROGRESS GOING
INTO THE NEW WORKWEEK, AS THE UPPER PATTERN BECOMES STAGNANT IN
RESPONSE TO A COMPLEX BLOCKING PATTERN THAT'LL PERSIST WELL INTO
THE WEEK.
KEY MESSAGE 2: TYPICAL AUGUST WEATHER RETURNS FOR THE NEW WORKWEEK.
ISOLATED HYDRO ISSUES CANNOT BE RULED OUT, MAINLY THE FIRST HALF
OF THE WEEK.
MOST OF THE UPCOMING WEEK STILL LOOKS LIKE IT'LL BE DRIVEN BY
A PERSISTENT UPPER PATTERN CONSISTING OF AN ATLANTIC RIDGE, A
CENTRAL CONUS RIDGE, AND A TROUGH TRAPPED BETWEEN THEM, OVER THE
TENNESSEE VALLEY AND WESTERN CAROLINAS. THE ENSEMBLES ARE COMING
INTO INCREASINGLY GOOD AGREEMENT THAT FOR AT LEAST THE MIDDLE OF
THE WEEK, WE'LL HAVE A CLOSED CUTOFF LOW SITTING IN PLACE ACROSS
AREA, AS A RESULT OF WHICH WE CAN EXPECT MORE WIDESPREAD RAINFALL
ON TUESDAY AND WEDNESDAY, POTENTIALLY LINGERING PAST THE TYPICAL
DIURNAL MAX. SO, ESPECIALLY DURING THE FIRST HALF OF THE WEEK,
ISOLATED HYDRO/FLASH FLOOD ISSUES AREN'T OUT OF THE QUESTION IF
TRAINING CELL SET UP IN THE RIGHT SPOTS.
BY THURSDAY, THE MAJORITY OF LREF MEMBERS FEATURE THE UPPER LOW
OPENING BACK UP INTO THE MEAN FLOW AS A LONGWAVE TROUGH SLIDES
ACROSS THE NORTHERN US AND CANADA. WE'LL REMAIN WITHIN A RELATIVE
WEAKNESS IN THE SUBTROPICAL RIDGE, AND THAT WILL CONTINUE TO
DRIVE DAILY SHOWERS AND THUNDERSTORMS, BUT THE DEEPER MOISTURE
AND ASSOCIATED HIGH PWS AND PATHETIC LAPSE RATES WILL HAVE EXITED
THE AREA BY THEN, SO WE'LL BE TRENDING BACK TOWARD SEASONALLY
NORMAL WEATHER.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: WIDESPREAD SHRA CONTINUES ACROSS MOST OF THE
TERMINAL FORECAST AREA, WITH SHOWERS AND EMBEDDED THUNDER ONGOING.
MANY SITES REMAIN MVFR AFTER STRUGGLING TO FULLY SCATTER OUT MORNING
STRATUS DECKS, AND INCREASINGLY WIDESPREAD RAINFALL WILL RESULT
IN VARYING CONDITIONS THROUGH THE REMAINDER OF THE AFTERNOON.
EXPECT THIS FIRST ROUND TO PERSIST INTO EARLY EVENING BEFORE
TRANSLATING EAST...AND THEN A SECOND ROUND ALONG AN ADVANCING
FRONTAL BOUNDARY LATER ON THIS EVENING. CONFIDENCE IS LOW ON
HOW FAR EAST THIS SECOND ROUND WILL MAKE IT BEFORE DISSIPATING.
ANOTHER NIGHT OF AT LEAST MVFR TO IFR CEILINGS, AND PERHAPS SOME
PATCHY FOG, WILL DEVELOP OVERNIGHT, BUT GUIDANCE SUGGESTS IT WILL
SCATTER OUT A LITTLE FASTER THAN IT DID TODAY AND YESTERDAY.
OUTLOOK: DAILY SHOWERS AND THUNDERSTORMS, ALONG WITH ASSOCIATED
FLIGHT RESTRICTIONS, ARE EXPECTED TO LINGER THROUGH AT LEAST THE
MIDDLE OF NEXT WEEK. PATCHY FOG AND LOW STRATUS WILL BE POSSIBLE
IN THE MOUNTAIN VALLEYS EACH MORNING, AND WHEREVER HEAVIER RAINFALL
FELL THE PREVIOUS EVENING.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
MPR
CLICK HERE TO GO TO PREVIOUS BULLETINS.
Main Text Page