683
FXUS62 KGSP 010529
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
129 AM EDT SAT AUG 1 2026
WHAT HAS CHANGED
NO SIGNIFICANT CHANGES FOR THIS FORECAST UPDATE.
AVIATION DISCUSSION WAS UPDATED FOR THE 06Z TAFS.
KEY MESSAGES
1. ANOTHER FRONTAL SYSTEM ARRIVES FROM THE WEST THIS LATER TODAY
THROUGH SUNDAY. THE FRONT MAY BRIEFLY STALL ACROSS OUR AREA
EARLY NEXT WEEK, BRINGING BACK HIGH RAIN CHANCES, BELOW-NORMAL
TEMPERATURES, AND SOME POTENTIAL FOR LOCALLY HEAVY RAINFALL.
2. A RETURN TO TYPICAL MID-SUMMER WEATHER IS EXPECTED NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: ANOTHER FRONTAL SYSTEM ARRIVES FROM THE WEST THIS
LATER TODAY THROUGH SUNDAY. THE FRONT MAY BRIEFLY STALL ACROSS OUR
AREA EARLY NEXT WEEK, BRINGING BACK HIGH RAIN CHANCES, BELOW-NORMAL
TEMPERATURES, AND SOME POTENTIAL FOR LOCALLY HEAVY RAINFALL.
STOUT UPPER RIDGING REMAINS ENTRENCHED OVER THE DESERT SOUTHWEST
WITH ACTIVE NORTHERN STREAM FLOW EXTENDING FROM THE PACIFIC
NORTHWEST INTO THE MISSISSIPPI VALLEY. A LARGE UPPER LOW IS PUSHING
ONSHORE OVER THE PACIFIC NORTHWEST WITH A LEAD WAVE DROPPING OUT OF
THE MIDWEST INTO THE MISSISSIPPI VALLEY. THIS WILL BE THE MAIN
FEATURE OF INTEREST THROUGH THE WEEKEND AS IT SLOWLY SLIDES ACROSS
THE OHIO VALLEY AND INTO THE APPALACHIANS. AN ATTENDANT SURFACE
REFLECTION WILL ACCOMPANY THE WAVE WITH A FRONTAL BOUNDARY DRAPED
FROM CENTRAL KENTUCKY INTO TENNESSEE. LOW-LEVEL MASS RESPONSE WILL
STRENGTHEN A 20-35KT LOW-LEVEL JET THAT IS FORECAST TO TRANSLATE
ACROSS THE REGION LATE THIS AFTERNOON THROUGH SUNDAY. THIS WILL
FOSTER THE ADVECTION OF A DEEP PLUME OF ANOMALOUS MOISTURE WITH
PWATS SURGING TO 2-2.4", WHICH WILL CHALLENGE DAILY RECORDS AT
PEACHTREE CITY, GA AND GREENSBORO, NC UPPER AIR SITES.
THE 00Z SUITE OF CAMS IS IN GENERALLY GOOD AGREEMENT THAT A BAND OF
CONVECTION ON THE LEADING EDGE OF THE MOISTURE PLUME WILL PUSH INTO
THE MOUNTAINS AND NORTHEAST GEORGIA LATE MORNING INTO EARLY
AFTERNOON AND THROUGH THE UPSTATE AND FOOTHILLS/PIEDMONT THROUGH
PEAK HEATING. ADDITIONAL CLUSTERS OF UPSTREAM CONVECTION ARE ALSO
PROGGED TO DEVELOP FROM ALABAMA INTO EASTERN TENNESSEE AND GEORGIA.
THIS ACTIVITY WILL ACCOMPANY THE LOW-LEVEL JET AND AT LEAST SOME
EXTENT WILL PERSIST INTO THE FORECAST AREA OVERNIGHT INTO EARLY
SUNDAY MORNING OUTSIDE OF THE TRADITIONAL DIURNAL WINDOW. THE MAIN
CONCERN WILL BE THE POTENTIAL FOR SEVERAL INSTANCES OF LOCALLY HEAVY
RAINFALL AND FLASH FLOODING FROM TRAINING AND SLOW MOVING STORMS,
ESPECIALLY ALONG THE SOUTHERN ESCARPMENT. CAMS DIVERGE, HOWEVER,
WITH HOW THIS ACTIVITY EVOLVES OVERNIGHT AND THE EXTENT OF COVERAGE.
THE HRRR SOLUTION IS THE MOST AGGRESSIVE WITH A NOTABLE CLUSTER OF
STORMS OVER THE UPSTATE AND SOUTHERN ESCARPMENT AND HIGHLIGHTS THE
POTENTIAL FOR ISOLATED RAINFALL TOTALS OF 3-6" OVER A SHORT SEVERAL
HOUR WINDOW. SHOULD THIS MATERIALIZE, ISOLATED FLASH FLOODING WOULD
DEFINITELY BE POSSIBLE OWING TO VERY MOIST PROFILES AND MODEST
MOISTURE TRANSPORT WITHIN THE CLOUD-BEARING LAYER.
HEADING INTO SUNDAY, THE DEEP MOISTURE PLUME WILL BE PREDOMINATELY
SITUATED FROM ALONG AND EAST OF I-85 AS THE UPPER TROUGH AXIS AND
FRONTAL BOUNDARY APPROACHES. EXTENSIVE CLOUD COVER AND ONGOING
CONVECTION DURING THE MORNING HOURS CASTS UNCERTAINTY AS TO THE
EXTENT OF DESTABILIZATION AND DEVELOPMENT OF ADDITIONAL SHOWERS AND
STORMS BY THE AFTERNOON AND EVENING. GIVEN THE ABUNDANCE OF DEEP
MOISTURE AND FORCING FROM THE WAVE IT WOULD APPEAR LIKELY THAT AT
LEAST SCATTERED TO NUMEROUS SHOWERS AND STORMS SHOULD REDEVELOP IN A
MODESTLY UNSTABLE AIRMASS PENDING AT LEAST A FEW HOURS OF DAYTIME
HEATING. ONCE AGAIN, ANY ADDITIONAL ACTIVITY WILL POSE A RISK FOR
ISOLATED FLASH FLOODING, ESPECIALLY FOR ANY STORMS THAT TRAIN OVER
AREAS THAT HAVE ALREADY SEEN HIGHER RAINFALL TOTALS. A SECONDARY
THREAT WILL EXIST FOR AN ISOLATED STRONG TO MARGINALLY SEVERE STORM
OR TWO BOTH SATURDAY AND SUNDAY. DEEP-LAYER SHEAR INCREASES ON
SUNDAY WITH THE APPROACH OF THE WAVE, BUT THERMODYNAMIC PARAMETERS
WILL BE LACKLUSTER OTHERWISE. NEAR MOIST ADIABATIC LAPSE RATES AND A
DEARTH OF DCAPE WITHIN A VERY MOIST PROFILE AND TALL/SKINNY CAPE
PROFILES WILL GENERALLY PRECLUDE A THREAT FOR DAMAGING WINDS.
NONETHELESS A FEW ISOLATED WATER LOADED DOWNBURST WILL REMAIN
POSSIBLE.
KEY MESSAGE 2: A RETURN TO TYPICAL MID-SUMMER WEATHER IS EXPECTED NEXT
WEEK.
GUIDANCE BEGINS TO DIVERGE REGARDING THE EVOLUTION OF THE SYNOPTIC
PATTERN AS WE HEAD INTO EARLY NEXT WEEK. SOME GUIDANCE KEEPS SOME
SEMBLANCE OF A CLOSED UPPER LOW OVER THE SOUTHERN APPALACHIANS WHILE
OTHERS SHIFT THE WAVE NORTHEAST OF THE AREA. AT THE SAME TIME, A
SUBTROPICAL RIDGE WILL BUILD OFFSHORE. AT THE VERY LEAST, THE REGION
WILL RESIDE WITHIN A RELATIVE WEAKNESS BETWEEN TWO UPPER RIDGES,
WHICH WILL FAVOR AT LEAST TRADITIONAL DIURNAL CONVECTION EACH DAY.
SHOULD A WEAK UPPER LOW LINGER ACROSS THE REGION WE COULD SEE HIGHER
THAN CLIMO POPS HANG ON LONGER INTO THE WEEK.
AVIATION /06Z SATURDAY THROUGH WEDNESDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS PREVAIL AT THE START OF THE
TAF PERIOD, BUT A MYRIAD OF RESTRICTIONS WILL PLAGUE THE FORECAST AT
ALL TERMINALS STARTING LATER THIS MORNING AROUND DAYBREAK. LOW-LEVEL
MOISTURE IS PUSHING TOWARDS THE AREA FROM THE SOUTHEAST AND COULD
BRING A BRIEF PERIOD OF MVFR CEILINGS WITH PERHAPS AN INSTANCE OR
TWO OF IFR BETWEEN ROUGHLY 10-15Z THIS MORNING. THEREAFTER, A BAND
OF SHOWERS AND THUNDERSTORMS WILL MOVE INTO THE AREA FROM THE WEST
LATE THIS MORNING THROUGH THE AFTERNOON. ADDITIONAL SHOWERS AND
PERHAPS A COUPLE STORMS MAY PERSIST THROUGH THE OVERNIGHT INTO EARLY
SUNDAY MORNING. ASSOCIATED RESTRICTIONS CAN BE EXPECTED WITH ANY OF
THIS ACTIVITY. A LOW STRATUS DECK MAY ALSO DEVELOP OVERNIGHT INTO
EARLY SUNDAY MORNING WITH THE POTENTIAL FOR WIDESPREAD IFR PENDING
HOW ANY SHOWERS AND STORMS EVOLVE. WINDS WILL BE LIGHT AND VARIABLE
OVERNIGHT SHIFTING TO OUT OF THE SOUTH/SOUTHEAST DURING THE DAY.
OUTLOOK: SHOWER AND THUNDERSTORM CHANCES AND ASSOCIATED RESTRICTIONS
EXPECTED TO CONTINUE THROUGH AT LEAST THE MIDDLE OF NEXT WEEK.
WHILE CONVECTION WILL BE MOST ACTIVE DURING THE AFTERNOON/EVENING,
SOME DEGREE OF OVERNIGHT AND EARLY MORNING COVERAGE IS ANTICIPATED
TONIGHT INTO EARLY SUNDAY. WIDESPREAD LOW CLOUDS AND FOG ARE
POSSIBLE SUNDAY MORNING AND AGAIN MONDAY MORNING. A RETURN TO MOSTLY
DIURNAL CONVECTION AND EARLY MORNING MOUNTAIN VALLEY FOG/STRATUS IS
EXPECTED DURING THE NEW WORK WEEK.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
TW
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