213
FXUS62 KGSP 201800
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
200 PM EDT WED MAY 20 2026
WHAT HAS CHANGED
THE FORECAST CONTINUES TO TREND WET AND COOL, ESPECIALLY THROUGH THE
MEMORIAL DAY HOLIDAY WEEKEND.
THE AVIATION DISCUSSION WAS UPDATED TO REFLECT THE 18Z TAF ISSUANCE.
KEY MESSAGES
1. A COLD FRONT APPROACHES THE AREA TOMORROW AND THEN STALLS
THROUGH THE WEEKEND INTO EARLY NEXT WEEK BRINGING A NOTICEABLY
WETTER AND COOLER FORECAST.
DISCUSSION
KEY MESSAGE 1: A COLD FRONT APPROACHES THE AREA TOMORROW AND THEN
STALLS THROUGH THE WEEKEND INTO EARLY NEXT WEEK BRINGING A
NOTICEABLY WETTER AND COOLER FORECAST.
AN UPPER LOW ASSOCIATED WITH A TROPICAL UPPER TROPOSPHERIC TROUGH
(TUTT) CONTINUES TO SPIN JUST OFF THE CAROLINA COAST WHILE UPPER
RIDGING BREAKS DOWN AND GETS SHUNTED EAST AND OFFSHORE. THIS IS
OCCURRING AS BROAD TROUGHING BECOMES ESTABLISHED FROM THE ROCKIES
THROUGH THE GREAT PLAINS. THIS IN TURN PLACES THE SOUTHEAST STATES
WITH A MOIST SOUTHWEST FLOW REGIME WITH MULTIPLE SHORTWAVES AND
PERTURBATIONS EMBEDDED WITHIN THE BACKGROUND FLOW REGIME. A SURFACE
COLD FRONT IS ALSO DROPPING ACROSS THE OHIO VALLEY AND TOWARDS THE
APPALACHIANS. ANOTHER WARM SUMMER-LIKE DAY CONTINUES THIS AFTERNOON
WITH TEMPERATURES WELL INTO THE UPPER 80S TO LOW 90S. ISOLATED TO
WIDELY SCATTERED SHOWERS AND A FEW THUNDERSTORMS WILL BE POSSIBLE
MAINLY ACROSS THE MOUNTAINS LATER THIS AFTERNOON THROUGH THE
EVENING. BY TOMORROW, THE FRONTAL BOUNDARY FINALLY PUSHES INTO THE
AREA AND WILL WORK IN CONJUNCTION WITH PEAK HEATING TO INSTIGATE
MUCH GREATER COVERAGE OF CONVECTION ACROSS MUCH OF THE AREA.
CONVECTIVE INITIATION WILL OCCUR LATE ENOUGH IN THE DAY THAT
TEMPERATURES WILL STILL BE WARM, BUT A FEW DEGREES BELOW TODAY.
MODEST INSTABILITY WILL BE IN PLACE ALONG WITH AT LEAST SOME FLOW
THROUGH THE COLUMN. CAMS DO INDICATE THE POTENTIAL FOR A COUPLE
LOOSELY ORGANIZED MULTICELL CLUSTERS AND PERHAPS LINEAR SEGMENTS
WHICH COULD TAKE ADVANTAGE OF THE ENVIRONMENT AND PRODUCE LOCALLY
GUSTY WINDS AND PERHAPS AN ISOLATED DAMAGING WIND GUST OR TWO.
MEAGER LAPSE RATES AND A LACK OF MORE DOWNDRAFT CAPE WILL LIKELY
LIMIT ANY SEVERE THREAT, HOWEVER.
THE MOST NOTICEABLE CHANGES WILL OCCUR FRIDAY INTO THE WEEKEND AS A
STOUT SURFACE HIGH MIGRATES FROM THE GREAT LAKES INTO NEW ENGLAND.
THIS WILL ALLOW FOR A RATHER IMPRESSIVE LATE SEASON COLD AIR DAMMING
WEDGE TO DEVELOP ACROSS THE AREA. AFTERNOON HIGHS MAY REMAIN BELOW
80 AND SOME LOCATIONS ALONG AND NORTH OF THE I-40 CORRIDOR MAY
STRUGGLE TO REACH 70. THE WEDGE LIKELY PERSISTS INTO SATURDAY BEFORE
FACING ITS DEMISE BY THE END OF THE WEEKEND INTO EARLY NEXT WEEK.
ISENTROPIC ASCENT ATOP THE WEDGE IN CONCERT WITH CONTINUED MOIST
SOUTHWEST FLOW AND A PASSING UPPER IMPULSE WILL FOSTER THE
DEVELOPMENT OF WIDESPREAD SHOWERS AND THUNDERSTORMS. SURFACE-BASED
INSTABILITY WILL BE LIMITED WITHIN THE WEDGE, BUT ELEVATED CAPE ABOVE
THE INVERSION LAYER SHOULD BE SUFFICIENT TO SUPPORT AT LEAST
ISOLATED TO SCATTERED THUNDER EVEN WITHIN THE COOLER AIR. GUIDANCE
CONTINUES TO PAINT A WET PATTERN INTO NEXT WEEK AS WELL, EVEN AS THE
CAD ERODES. ANOTHER FRONTAL BOUNDARY DROPS DOWN FROM THE NORTH AND
MAY STALL NEAR THE AREA KEEPING CONTINUED RAIN CHANCES AROUND.
AVIATION /18Z WEDNESDAY THROUGH MONDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS ARE EXPECTED TO PREVAIL AT
MOST TERMINALS THROUGH THE PERIOD. AN AFTERNOON CUMULUS FIELD IS IN
THE PROCESS OF DEVELOPING ACROSS THE AREA ALONG WITH HIGH CLOUDS
STREAMING OVERHEAD. COVERAGE OF AFTERNOON SHOWERS AND STORMS SHOULD
REMAIN LIMITED TO THE MOUNTAINS THIS AFTERNOON AND EVENING WHERE A
PROB30 HAS BEEN CARRIED AT KAVL. A GENERALLY QUIET OVERNIGHT PERIOD
IS EXPECTED, BUT A FEW INSTANCES OF MOUNTAIN VALLEY FOG CANNOT BE
DISCOUNTED, ESPECIALLY WHERE RAINFALL OCCURS TODAY. A FRONT
APPROACHES THE AREA TOMORROW AND WILL BRING GREATER COVERAGE OF
AFTERNOON/EVENING SHOWERS AND THUNDERSTORMS. MOST OF THIS ACTIVITY
WILL OCCUR AFTER THE CURRENT 18Z END TIME OF THE TAF, BUT WENT AHEAD
AND INCLUDED MENTION AT KCLT FOR THE END OF THE 30 HOUR TAF PERIOD.
OUTLOOK: AN APPROACHING FRONT AND INCREASING MOISTURE WILL BRING
A MORE ACTIVE PATTERN FOR MAINLY AFTERNOON AND EVENING SHOWERS
AND THUNDERSTORMS BEGINNING THURSDAY AFTERNOON AND THEN CONTINUING
THROUGH THE END OF THE WEEK. COLD-AIR DAMMING MAY PRODUCE WIDESPREAD
MVFR TO IFR CEILINGS THROUGH THE DAY FRIDAY. THE POTENTIAL FOR
OVERNIGHT FOG/LOW CLOUDS WILL INCREASE THROUGH THE PERIOD AS WELL.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
TW
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