298
FXUS62 KGSP 191046
AFDGSP
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE GREENVILLE-SPARTANBURG SC
646 AM EDT TUE MAY 19 2026
WHAT HAS CHANGED
THE AVIATION DISCUSSION WAS UPDATED TO REFLECT THE 12Z TAF ISSUANCE.
KEY MESSAGES
1. A SUMMER-LIKE PATTERN WILL CONTINUE THROUGH WEDNESDAY, WITH
ABOVE NORMAL TEMPERATURES AND INCREASING HUMIDITY. CHANCES FOR
MOUNTAIN DIURNAL CONVECTION INCREASE WEDNESDAY AFTERNOON AS A
FRONT APPROACHES.
2. A COLD FRONT WILL BRING BETTER RAIN CHANCES THURSDAY INTO THE
WEEKEND, BUT ANY DROUGHT RELIEF WILL BE LIMITED.
DISCUSSION
KEY MESSAGE 1: A SUMMER-LIKE PATTERN WILL CONTINUE THROUGH WEDNESDAY,
WITH ABOVE NORMAL TEMPERATURES AND INCREASING HUMIDITY. CHANCES
FOR MOUNTAIN DIURNAL CONVECTION INCREASE WEDNESDAY AFTERNOON AS
A FRONT APPROACHES.
WE SEEM TO BE ON TRACK WITH FLATTENING THE MID/UPPER RIDGE ON THE
EAST COAST THROUGH MID-WEEK AS A POWERFUL SYSTEM LIFTS NORTHEAST
FROM THE PLAINS TO EASTERN CANADA. HOWEVER, A NEW WRINKLE HAS
APPEARED IN THE GUIDANCE TODAY IN THE FORM OF A CURIOUS WEAK UPPER
LOW DRIFTING NORTHWESTWARD TO THE NORTH OF THE BAHAMAS. THIS DOESN'T
REALLY APPEAR TO HAVE MUCH POTENTIAL TO DEVELOP INTO ANYTHING, BUT
IT WOULD INTRODUCE A WEAKNESS IN WHAT WOULD HAVE OTHERWISE BEEN A
MORE PERSISTENT SOUTHWESTERLY FLOW ALOFT THAT WOULD HAVE BEEN MORE
EFFICIENT IN MOVING MOISTURE NORTHEASTWARD FROM THE GULF. INSTEAD,
IT SPLITS THE RIDGE BETWEEN THE OLD ANTICYCLONE MOVING EASTWARD
AWAY FROM THE EAST COAST, AND A REMNANT RIDGE OVER THE EASTERN
GULF. THIS WILL NOT DO ANYTHING TO IMPROVE OUR CHANCES FOR RAIN
OR THE RAINFALL AMOUNTS SHOULD SHOWERS DEVELOP. FOR TODAY, THE
CAMS KEEP US DRY, AS EXPECTED, BUT THIS WOULD HAVE RAMIFICATIONS
STARTING WEDNESDAY AFTERNOON. THE NEW GUIDANCE KEEPS A COLD FRONT
STRUNG OUT ACROSS THE TN VALLEY TO MID-ATLANTIC REGION THROUGH
WEDNESDAY NIGHT, WHICH IS TO SAY, TO OUR WEST AND NORTH. THE CAMS
GO OUT FAR ENOUGH WITH THIS CYCLE TO SHED SOME LIGHT ON COVERAGE
FOR WEDNESDAY AFTERNOON AND THERE ARE SOME DIFFERENCES, WITH THE
HRRR BEING THE MOST SPARSE. PRECIP PROBS HAVE BEEN TEMPERED BY
THE HRRR AND LOWERED A BIT FROM WHAT THE NBM INDICATES FOR NOW,
AND GENERALLY KEPT OVER THE MOUNTAINS. THE THREAT FOR SEVERE STORMS
APPEARS TO BE LOW BECAUSE OF A LACK OF BUOYANCY AND SHEAR IN THE
LATEST RAP. PRECIP AMOUNTS WOULD ALSO BE MODEST.
AS FOR TEMPS, THEY CONTINUE TO LOOK SUMMERY, WITH HIGHS RUNNING
7-12 DEGREES ABOVE NORMAL, WHICH SHOULD RESULT IN SEASONALLY
MILD OVERNIGHT LOWS AND THEN HIGHS GENERALLY IN THE LOWER 90S BY
WEDNESDAY AFTERNOON. THIS WOULD STILL BE SEVERAL DEGREES BELOW
RECORDS AND NOT PROBLEMATIC WITH REGARD TO THE HEAT INDEX AS THE
AIR MASS WILL REMAIN TOO DRY.
KEY MESSAGE 2: A COLD FRONT WILL BRING BETTER RAIN CHANCES THURSDAY
INTO THE WEEKEND, BUT ANY DROUGHT RELIEF WILL BE LIMITED.
OUR WEATHER SITUATION LOOKS UNSETTLED BEGINNING ON THURSDAY AND
CONTINUING PERHAPS THROUGH THE END OF THE FORECAST PERIOD AS THE
UPPER PATTERN KEEPS A MEAN TROF TO OUR WEST AND RIDGE OVER THE
EAST COAST THAT MAINTAINS A SOUTHWESTERLY FLOW ALOFT AND THE GULF
OPEN. DETAILS ARE SKETCHY OF COURSE, BUT THE COLD FRONT SHOULD
MOVE INTO THE AREA ON THURSDAY AND PROVIDE THE FOCUS FOR NUMEROUS
SHOWERS AND STORMS. THE BOUNDARY WILL DROP SOUTH OF THE FORECAST
AREA AT SOME POINT THURSDAY OR THURSDAY NIGHT EITHER AS OUTFLOW
FROM CONVECTION OR AS A WEAK COLD AIR DAMMING HIGH WEDGES DOWN FROM
THE GREAT LAKES. THIS MAKES THE FORECAST FOR THURSDAY UNCERTAIN,
PARTICULARLY IN TERMS OF HIGH TEMPS WHICH ARE STILL FORECAST TO BE
WARM FOR THE TIME BEING. IT COULD EASILY END UP TEN DEGREES LESS
THAN FORECAST, BUT THE 10-15 DEGREE DROP ON FRIDAY LOOKS LIKE THE
BETTER BET AS THE SIGNAL FOR COLD AIR DAMMING LOOKS A LITTLE BIT
STRONGER. THE WEEKEND IS ALSO MORE UP IN THE AIR BECAUSE THE NEW
GFS SUGGESTS THE WEAK WEDGE MAY PERSIST THROUGH SATURDAY AND INTO
SUNDAY, SO PRECIP CHANCES REMAIN HIGH AND TEMPS MIGHT NOT RETURN
TO NORMAL AS FAST AS THOUGHT. BY THE TIME WE GET INTO THE EARLY
PART OF NEXT WEEK, THE GUIDANCE SHOWS A SOUTHERN STREAM SYSTEM
LIFTING OUT OF THE SOUTHERN PLAINS TOWARD THE TN VALLEY REGION,
WHICH WOULD KEEP SOME PERIODIC FORCING/FOCUS FOR ABOVE NORMAL
CHANCES OF RAIN EACH DAY. ON THE ONE HAND, THERE ISN'T MUCH OF
A SIGNAL FOR HEAVY RAIN IN ANY OF THIS, SO NO MEANINGFUL DROUGHT
RELIEF IS SUGGESTED. ON THE OTHER HAND, THIS PATTERN WOULD, AT A
MINIMUM, KEEP THE SITUATION FROM GETTING ANY WORSE.
AVIATION /12Z TUESDAY THROUGH SATURDAY/
AT KCLT AND ELSEWHERE: VFR CONDITIONS WILL PREVAIL AT ALL TERMINALS
THROUGH THE PERIOD. SATELLITE IMAGERY SHOWS AN EXTENSIVE AREA
OF FOG AND LOW STRATUS OVER THE COASTAL PLAIN, BUT IT HAS MADE
LITTLE PROGRESS AND HAS YET TO REACH THE FALL LINE, SO IT LOOKS
LIKE KCLT WILL BE SPARED. HOWEVER, THERE ARE SOME LOW CLOUDS
TO THE SOUTHEAST, SO A FEW035 WILL BE CARRIED FIRST THING THIS
MORNING. OTHERWISE, WIND WILL BE LIGHT FROM THE S TO SW AGAIN TODAY,
WITH A FEW HIGH-BASED STRATOCU. PERSISTENCE LOOKS GOOD FOR TONIGHT,
MEANING MORE LIGHT/VARIABLE WINDS AND SCATTERED CIRRUS.
OUTLOOK: INCREASING MOISTURE WILL BRING A MORE ACTIVE PATTERN FOR
MAINLY DIURNAL CONVECTION BEGINNING WEDNESDAY AFTERNOON AND THEN
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.
PM
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