006
FXUS62 KGSP 291805
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
205 PM EDT SUN JUN 29 2025
SYNOPSIS
A TYPICAL SUMMER PATTERN CONTINUES MONDAY WITH SEASONABLE
TEMPERATURES AND CHANCES FOR AFTERNOON AND EARLY EVENING
THUNDERSTORMS. A COLD FRONT APPROACHES THE AREA ON TUESDAY BRINGING
GREATER COVERAGE OF THUNDERSTORMS. DRIER WEATHER LOOKS TO RETURN FOR
THE HOLIDAY WEEKEND BEHIND THE FRONT.
NEAR TERM /THROUGH MONDAY/
AS OF 150 PM EDT SUNDAY: CONVECTION TAKING ON A FAMILIAR PATTERN
THIS AFTERNOON WITH GOOD COVERAGE ALREADY ACROSS THE MOUNTAINS AND
FOOTHILLS AND ISOLATED COVERAGE ELSEWHERE. EXPECT THE BEST COVERAGE
TO REMAIN ACROSS THE MOUNTAINS, FOOTHILLS AND NC NW PIEDMONT WITH
LOW END SCATTERED COVERAGE ELSEWHERE. MESOANALYSIS SHOWS A VERY
UNSTABLE AIR MASS WITH MODERATE DCAPE AND VERY LOW BULK SHEAR.
EXPECT THE STRONGEST STORMS TO HAVE THE POTENTIAL TO PRODUCE A
DAMAGING DOWNBURST WITH NO SIGNIFICANT ORGANIZATION. A FEW AREAS OF
HEAVY RAINFALL WITH THE VERY HIGH PW VALUES AND SLOW MOVING STORMS.
ISOLATED FLOODING IS POSSIBLE AS WELL.
CONVECTIVE COVERAGE SHOULD DIMINISH WITH LOSS OF HEATING BUT
ISOLATED CONVECTION COULD LINGER UNTIL MIDNIGHT. EXPECT CLEARING
SKIES AND LIGHT WINDS OVERNIGHT. MOUNTAIN VALLEY FOG IS LIKELY WITH
PATCHY FOG ELSEWHERE, ESPECIALLY NEAR BODIES OF WATER OR LOCATIONS
THAT HAD HEAVIER RAINFALL. LOWS NEAR NORMAL MOUNTAINS AND A FEW
DEGREES ABOVE NORMAL ELSEWHERE.
MONDAY LOOKS TO BE A NEAR CARBON COPY WITH GOOD COVERAGE OF
CONVECTION DEVELOPING ACROSS THE MOUNTAINS AROUND NOON AND SCATTERED
CONVECTION ELSEWHERE. EXPECT A NEAR CARBON COPY WITH THE SEVERE
DOWNBURST AND HEAVY RAIN POTENTIAL WITH A VERY UNSTABLE AIR MASS,
LIGHT BULK SHEAR, MODERATE DCAPE, AND HIGH PW VALUES. HIGHS ACROSS
THE MOUNTAINS WILL BE NEAR NORMAL AND A FEW DEGREES ABOVE NORMAL
ELSEWHERE.
SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/
AS OF 1225 PM SUNDAY: A NORTHERN STREAM TROUGH WILL SWING ACROSS THE
GREAT LAKES REGION AND INTO NEW ENGLAND ON TUESDAY WHILE ANOTHER
UPPER LOW ASSOCIATED WITH A TROPICAL UPPER TROPOSPHERIC TROUGH
DRIFTS ALONG THE SOUTHEAST COAST. BROAD BERMUDA RIDGE WILL ALSO
EXTEND INTO THE COASTAL PLAIN WHICH WILL FURTHER PROMOTE DEEP-LAYER
SOUTHWEST FLOW ACROSS THE REGION. PLENTIFUL DEEP MOISTURE WILL BE
PRESENT WITHIN THIS REGIME WITH A SURFACE COLD FRONT APPROACHING THE
AREA FROM THE NORTHWEST WITHIN THE TROUGH AXIS. MOISTURE POOLING
AHEAD OF THE FRONTAL BOUNDARY IN CONCERT WITH WEAK, BUT NON-ZERO,
FORCING WILL PROMOTE NUMEROUS TO WIDESPREAD MAINLY DIURNAL
THUNDERSTORMS ACROSS THE AREA ON TUESDAY. WEAK TROUGHING AND THE
NEARBY POSITION OF THE FRONT MAY EVEN SUPPORT SEVERAL STORMS
CONTINUING INTO THE OVERNIGHT BEYOND THE TRADITIONAL DIURNAL
PATTERN. FORECAST SOUNDINGS REVEAL TRADITIONAL SUMMER PROFILES IN
THE SOUTHEAST WITH VERY TALL/SKINNY CAPE AND A LACK OF DRIER AIR.
THE RESULT IS POOR LAPSE RATES, WEAK DCAPE AND A LOWER SURFACE DELTA
THETAE. CLUSTERS OF STORMS AND/OR LINEAR SEGMENTS WILL LIKELY
ORGANIZE ALONG COMPOSITE COLD POOLS AND A COUPLE STRONG TO ISOLATED
SEVERE STORMS CANNOT BE RULED OUT WITH THE MAIN THREAT BEING
ISOLATED WET MICROBURSTS. THE BOUNDARY ITSELF SLOWLY DROPS INTO THE
AREA TUESDAY NIGHT INTO WEDNESDAY WITH ANOTHER ROUND OF DIURNAL
SHOWERS AND STORMS WEDNESDAY AFTERNOON AND EARLY EVENING.
LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/
AS OF 1245 PM SUNDAY: A SECOND SHORTWAVE TROUGH DROPS ACROSS THE
GREAT LAKES THURSDAY WITH WEAK NORTHWEST FLOW SETTING UP OVER THE
SOUTHERN APPALACHIANS IN THE WAKE OF THE FIRST TROUGH AXIS. THIS
SHOULD HELP TO SLOWLY PUSH THE FRONTAL BOUNDARY ACROSS AND
EVENTUALLY SOUTH OF THE AREA. HOW LONG THIS TAKES AND EXACTLY HOW
FAR SOUTH IT ENDS UP REMAINS TO BE SEEN. IF PROGRESS IS SLOWER AT
LEAST ISOLATED TO WIDELY SCATTERED DIURNAL STORMS WILL REMAIN
POSSIBLE ACROSS SOUTHERN PORTIONS OF THE AREA ON THURSDAY AND
POTENTIALLY FRIDAY. MOST OF THE AREA SHOULD SEE THE ARRIVAL OF DRIER
AIR, HOWEVER, WITH PWATS FALLING TO 1-1.25" WITHIN LOWER THETAE AIR.
HISTORICALLY, PWATS THIS LOW ARE UNFAVORABLE FOR SUMMER DIURNAL
PULSE CONVECTION ALTHOUGH AN ISOLATED STORM OR TWO CAN NEVER BE
RULED OUT ACROSS THE MOUNTAINS. RELATIVELY DRY WEATHER MAY CONTINUE
THROUGH THE HOLIDAY WEEKEND, BUT DEEPER MOISTURE WILL EVENTUALLY
RETURN AND IT'S ARRIVAL WILL BE TIED TO AN INCREASE IN RAIN CHANCES -
WHENEVER THAT ENDS UP OCCURRING.
AVIATION /18Z SUNDAY THROUGH FRIDAY/
AT KCLT AND ELSEWHERE: SIMILAR PATTERN TO THE LAST FEW DAYS TODAY.
CONVECTION ONGOING ACROSS THE MOUNTAINS WILL DEVELOP ACROSS THE AREA
DURING THE AFTERNOON. CONFIDENCE HAS INCREASED ENOUGH TO ADD TEMPOS
FOR MOST LOCATIONS, STILL PROB30 FOR KAND. ISOLATED CONVECTION MAY
LINGER LATER INTO THE EVENING, BUT CHANCE TOO LOW FOR THE TAFS AT
THIS TIME. MOSTLY CLEAR SKIES AND LIGHT AND VARIABLE WIND OVERNIGHT.
MOUNTAIN VALLEY FOG IS A NEAR CERTAINTY, BUT GIVEN THE LACK OF
RESTRICTIONS AT KAVL THE PAST 2 MORNINGS, WILL HOLD OFF ON ANY FOR
NOW AND LET LATER SHIFTS ADD IF IT BECOMES MORE CERTAIN. DIURNAL
CONVECTION SHOULD FOLLOW A SIMILAR PATTERN ON MONDAY.
OUTLOOK: DAILY CHANCES FOR AFTERNOON AND EVENING SHOWERS AND
THUNDERSTORMS THROUGH WED. FOG AND/OR LOW STRATUS POSSIBLE EACH
MORNING IN THE USUAL MOUNTAIN VALLEYS AS WELL AS NEAR LAKES AND
RIVERS. DRIER AIR MAY MOVE IN THU ENDING CONVECTIVE CHANCES.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
SYNOPSIS...TW
NEAR TERM...RWH
SHORT TERM...TW
LONG TERM...TW
AVIATION...RWH
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