787
FXUS62 KCAE 121021
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
621 AM EDT SAT SEP 12 2026
WHAT HAS CHANGED
SEPARATED KEY MESSAGES TO REFLECT ON TODAY'S CONVECTIVE
POTENTIAL AND A PATTERN SHIFT INTO EARLY NEXT WEEK.
KEY MESSAGES
- 1. ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS EXPECTED TODAY.
- 2. ABOVE NORMAL TEMPERATURES LAST INTO NEXT WEEK WITH DRIER
CONDITIONS RETURNING.
DISCUSSION
KEY MESSAGE 1: ANOTHER ROUND OF SHOWERS AND THUNDERSTORMS EXPECTED
TODAY.
UPPER TROUGHING CONTINUES TO MOVE ACROSS THE SOUTHERN TIER OVER THE
NEXT 24-36 HOURS, WITH RICH MOISTURE CONTINUING TO ADVECT INTO THE
AREA. PW WILL CONTINUE TO INCREASE ABOVE 1.8" AND EVENTUALLY SURPASS
2" IN THE NEXT FEW HOURS. CONVECTIVE TEMPS ARE FORECAST IN THE UPPER
80S AND LOWER 90S AGAIN THIS AFTERNOON, AND COMBINED WITH A WEAK
SHORTWAVE PASSING THROUGH THE REGION, THERE SHOULD BE ENOUGH
INSTABILITY FOR SHOWERS AND THUNDERSTORMS TO GO ANOTHER ROUND. THAT
SAID, DCAPE VALUES ARE LARGELY UNIMPRESSIVE AND ANY DOWNBURSTS WILL
LIKELY BE FORCED MAINLY BY PRECIP LOADING. CAMS DEPICT MORE OF A
LINEAR SEGMENT MOVING THROUGH THE FA THIS AFTERNOON AND EVENING, BUT
SHEAR APPEARS TO BE MINIMAL. GIVEN THE HIGH MOISTURE IN PLACE,
EXPECT FAIRLY DECENT COVERAGE OF PRECIP ACROSS THE REGION WITH THE
POTENTIAL FOR SOME HEAVIER RAINFALL TOTALS. ADDITIONAL UNCERTAINTY
LIES IN HOW LONG IT TAKES TO REACH CONVECTIVE TEMPERATURES GIVEN THE
REMAINING DEBRIS CLOUDS FROM FRIDAY'S CONVECTION, AND WHETHER
STRATUS IS ABLE TO DEVELOP IN THE PRE-DAWN HOURS THIS MORNING. THIS
COULD PUSH BACK TIMING OF CONVECTIVE INITIATION.
KEY MESSAGE 2: ABOVE NORMAL TEMPERATURES LAST INTO NEXT WEEK WITH
DRIER CONDITIONS RETURNING.
SUNDAY INTO EARLY NEXT WEEK, THE TROUGH MOVES OFFSHORE AND STRONG
RIDGING BUILDS OVER THE EASTERN CONUS. PRECIP CHANCES ARE EXPECTED
TO DIMINISH AS A RESULT, AND PW VALUES FALL BELOW 1.6". THE RIDGE IS
THEN FORECAST TO REMAIN IN CONTROL MUCH OF NEXT WEEK, AND
TEMPERATURES SHOULD REMAIN ABOVE NORMAL WITH DECENT CONFIDENCE AND
SMALL IQR'S. MONDAY SHOULD BE THE WARMEST DAY WITH A NOTABLE DROP
SEVERAL DEGREES BY TUESDAY DUE TO A GENERALLY DRY BACKDOOR FRONT
CROSSING THE REGION. SURFACE DEWPOINTS ALSO LOOK TO DROP FURTHER,
HELPING MAKE THE AIRMASS MORE FALL-LIKE. STILL, HIGHS REMAIN ABOVE
TYPICAL MID-SEPTEMBER VALUES. WE'LL CONTINUE TO WATCH FOR SOME
WEAKNESS ON THE EASTERN SIDE OF THE RIDGE. MODELS ARE DEPICTING AN
INTERESTING FEATURE MID TO LATE NEXT WEEK REGARDING AN UPPER LOW
ROTATING AROUND THE HIGH FROM NEW ENGLAND SOUTH ALONG THE ATLANTIC
COAST AND EVENTUALLY RETROGRADING INTO THE GULF. THERE IS STILL
PLENTY OF UNCERTAINTY REGARDING THIS LOW'S EVOLUTION IN THE
EXTENDED, INCLUDING IF OR WHEN IT MAY INFLUENCE OUR SENSIBLE
WEATHER.
AVIATION /12Z SATURDAY THROUGH WEDNESDAY/
RESTRICTIONS WILL CONTINUE THIS MORNING THROUGH 15Z. ADDITIONAL
FOG/STRATUS POSSIBLE TONIGHT.
WIDESPREAD RAIN YESTERDAY HAS LED TO INCREASED LOW LEVEL
MOISTURE OVER THE REGION. WEAK WINDS EARLY THIS MORNING HAVE
PROMOTED CEILING AND VISIBILITY RESTRICTIONS AT ALL TAF SITES.
CONVECTIVE DEBRIS CLOUDS SEEM TO BE PLAYING A ROLE IN LIMITING
THE EXTENT OF FOG/STRATUS AND CAUSING RESTRICTIONS TO
PERIODICALLY LIFT. AS THE DEBRIS CLOUDINESS CONTINUES TO CLEAR
WE SHOULD SEE RESTRICTIONS BECOME MORE SUSTAINED.
NUMEROUS THUNDERSTORMS ARE EXPECTED AGAIN TODAY WITH DEEP
MOISTURE OVER THE REGION. CONFIDENCE IN THUNDERSTORM
RESTRICTIONS HAS INCREASED AND ALLOWED US TO PUT VCTS IN THE
TAFS AFTER 18Z FOR ALL SITES. THESE STORMS SHOULD BE EFFICIENT
RAIN PRODUCERS AND WOULD LEAD TO BRIEF VISIBILITY RESTRICTIONS.
STORMS WILL LIKELY CONTINUE INTO THE EARLY EVENING BUT DIMINISH
OVERNIGHT. RAINFALL MAY LEAD TO A SIMILAR OUTLOOK FOR
RESTRICTIONS TONIGHT WITH PATCHY FOG EXPECTED, AT LEAST IN
LOCATIONS THAT RECEIVE HEAVY RAIN.
EXTENDED AVIATION OUTLOOK...LOWER RAIN CHANCES SUNDAY BUT THE
POTENTIAL FOR EARLY MORNING FOG/STRATUS PERSISTS INTO EARLY
NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...EC
AVIATION...CJR
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