928
FXUS62 KGSP 181742
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
142 PM EDT MON MAY 18 2026
WHAT HAS CHANGED
RAINFALL TOTALS HAVE TRENDED DOWN THURSDAY THROUGH SUNDAY.
KEY MESSAGES
1. A SUMMER-LIKE PATTERN WILL CONTINUE THROUGH MID-WEEK, WITH
ABOVE NORMAL TEMPERATURES. CHANCES FOR MOUNTAIN DIURNAL CONVECTION
INCREASE WEDNESDAY AS A FRONT APPROACHES.
2. A COLD FRONT WILL BRING BETTER RAIN CHANCES THURSDAY INTO
THE WEEKEND BUT WITH ONLY LIGHT RAINFALL AMOUNTS EXPECTED, ANY
DROUGHT RELIEF WILL BE LIMITED.
DISCUSSION
KEY MESSAGE 1: A SUMMER-LIKE PATTERN WILL CONTINUE THROUGH MID-WEEK,
WITH ABOVE NORMAL TEMPERATURES. CHANCES FOR MOUNTAIN DIURNAL
CONVECTION INCREASE WEDNESDAY AS A FRONT APPROACHES.
AN UPPER LEVEL RIDGE WILL PERSIST ALONG THE EAST COAST, WITH A
BERMUDA HIGH SUPPORTING PERSISTENT SOUTHERLY LOW LEVEL FLOW THROUGH
MID-WEEK. DESPITE THE SOUTHERLY FLOW, PROFILES WILL REMAIN SOMEWHAT
DRY UNTIL LATER WEDNESDAY, WITH SURFACE DEWPOINTS FORECAST TO MIX
OUT INTO THE 50S THIS AFTERNOON AND AGAIN TUE AFTERNOON. AS SUCH,
DIURNAL INSTABILITY WILL BE MUTED, AND VERY LITTLE-TO-NO DIURNAL
CONVECTION IS ANTICIPATED THROUGH TUE EVENING. TEMPERATURES WILL
OTHERWISE REMAIN 6-8 DEGREES ABOVE CLIMO THROUGH WED.
BY LATE WEDNESDAY, THE RIDGE WILL BEGIN TO WEAKEN AS A STRONG
SHORT WAVE TROUGH PASSES THROUGH EASTERN CANADA AND NEW
ENGLAND. THE LEADING EDGE OF AN ATTENDANT/WEAK FRONTAL ZONE
IS FORECAST TO APPROACH THE SOUTHERN APPALACHIANS BY LATE WED
AFTERNOON...INTRODUCING SUFFICIENT CONVERGENCE AND POOLING MOISTURE
TO ENHANCE DIURNAL CONVECTIVE CHANCES ACROSS THE MOUNTAINS. IN
FACT...LIKELY POPS ARE FORECAST FOR MUCH OF THE NC MOUNTAINS BY
00Z THU. SHEAR PARAMETERS WILL REMAIN QUITE WEAK ACROSS OUR AREA,
AND INSTABILITY IS FORECAST TO BE FAIRLY MODEST, SO THE THREAT
FOR SEVERE STORMS WILL BE VERY LOW.
KEY MESSAGE 2: A COLD FRONT WILL BRING BETTER RAIN CHANCES THURSDAY
INTO THE WEEKEND BUT WITH ONLY LIGHT RAINFALL AMOUNTS EXPECTED, ANY
DROUGHT RELIEF WILL BE LIMITED.
A COLD FRONT WILL TRACK ACROSS THE FORECAST AREA WEDNESDAY EVENING
INTO EARLY THURSDAY MORNING BEFORE STALLING OVER THE CAROLINAS ON
FRIDAY. THE FRONT WILL THEN REACTIVATE AS A WARM FRONT AND LIFT
NORTHWARD OVER THE WEEKEND, STALLING OVER THE OHIO VALLEY/MID-
ATLANTIC THROUGH EARLY NEXT WEEK. THIS FRONT WILL BRING BETTER RAIN
CHANCES THAN WE HAVE SEEN IN A WHILE BUT IT APPEARS THAT AN UPPER
RIDGE COULD BUILD BACK OVER THE SOUTHEAST FASTER THAN ANTICIPATED
THIS WEEKEND INTO EARLY NEXT WEEK WHICH COULD ACT TO SUPPRESS SHOWER
AND THUNDERSTORM ACTIVITY. THUS, CONFIDENCE ON POPS THIS WEEKEND
REMAINS LOW. WE SHOULD GET A BETTER IDEA ON POPS ONCE HIGH-RES
GUIDANCE BECOMES AVAILABLE LATER IN THE WEEK. THE MAIN CHANGE FROM
THE PREVIOUS FORECAST IS THAT QPF HAS TRENDED LOWER THIS FORECAST
CYCLE, WITH THE NBM NOW SHOWING MOST LOCATIONS SEEING 1" OR LESS OF
RAINFALL THURSDAY INTO THE WEEKEND. THERE STILL REMAINS THE
POTENTIAL FOR SOME LOCALLY HIGHER RAINFALL AMOUNTS >1" ALONG THE
NC/TN BORDER AND ALONG THE BLUE RIDGE ESCARPMENT. ALTHOUGH ANY RAIN
WILL BE BENEFICIAL, THESE AMOUNTS WILL NOT DO MUCH TO IMPROVE THE
ONGOING DROUGHT. ANY SEVERE POTENTIAL CONTINUES TO LOOK LOW THROUGH
THE PERIOD. ABOVE NORMAL HIGHS STICK AROUND ON THURSDAY BEFORE BELOW
NORMAL HIGHS RETURN BRIEFLY ON FRIDAY AS COLD AIR DAMMING DEVELOPS
BEHIND THE FRONT. THE 06Z GFS IS TRENDING A BIT STRONGER REGARDING
THE WEDGE SO AFTERNOON TEMPS ON FRIDAY MAY TREND COOLER IF THIS
TREND CONTINUES. CAD LINGERS THROUGH THE FIRST HALF OF SATURDAY
BEFORE ERODING (PER THE 06Z GFS) SO HIGHS ON SATURDAY SHOULD END UP
NEAR NORMAL TO JUST ABOVE NORMAL. HIGHS WILL END UP A FEW DEGREES
ABOVE NORMAL ON BOTH SUNDAY AND MONDAY. LOWS EACH NIGHT WILL REMAIN
A FEW TO SEVERAL DEGREES ABOVE NORMAL.
AVIATION /18Z MONDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: WHILE LOW LEVEL MOISTURE CONTINUES TO SLOWLY
INCREASE, CONDITIONS REMAIN FAIRLY DRY IN THE RELATIVE SENSE, AND
CONVECTIVE-FREE WEATHER AND VFR CONDITIONS ARE FORECAST TO PERSIST
AT THE TAF SITES THROUGH THE PERIOD. OTHERWISE, FEW/SCT CUMULUS,
MAINLY IN THE 035-050 RANGE ARE EXPECTED THIS AFTERNOON. WINDS
WILL REMAIN S/SW AT 5-10 KTS THROUGH MUCH OF THE PERIOD.
OUTLOOK: VFR TO PERSIST THROUGH MID-WEEK, EXCEPT PERHAPS IN MOUNTAIN
VALLEYS, WHERE PATCHY MORNING FOG/LOW STRATUS MAY DEVELOP EACH
MORNING. INCREASING MOISTURE WILL BRING A MORE ACTIVE PATTERN FOR
MAINLY DIURNAL CONVECTION BEGINNING LATE WEDNESDAY, CONTINUING
THROUGH THE END OF THE WEEK. THE POTENTIAL FOR OVERNIGHT FOG/LOW
CLOUDS WILL INCREASE AS WELL.
GSP WATCHES/WARNINGS/ADVISORIES
GA...NONE.
NC...NONE.
SC...NONE.
AR/JDL
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