087
FXUS62 KCAE 291640
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
1240 PM EDT THU MAY 29 2025
SYNOPSIS
TEMPERATURES RETURNING TO MORE SEASONAL VALUES FOR REST OF THE WEEK.
SHOWERS AND STRONGER STORMS POSSIBLE THIS AFTERNOON AND AGAIN
FRIDAY, FOLLOWED BY A RETURN TO DRIER WEATHER THROUGH THE
WEEKEND.
NEAR TERM /THROUGH TONIGHT/
KEY MESSAGE(S):
- SCATTERED STRONG TO SEVERE THUNDERSTORMS THIS AFTERNOON AND
EVENING, PARTICULARLY IN THE SOUTHERN/EASTERN MIDLANDS AND
CSRA.
AN ACTIVE AFTERNOON AND EVENING LOOKS TO BE ON TAP ACROSS A GOOD
PORTION OF THE FORECAST AREA. A PERIOD OF STRONG TO SEVERE
THUNDERSTORMS, ALONG WITH A HEAVY RAINFALL THREAT, IS POISED TO
MOVE THROUGH THE CSRA AND THE SOUTHERN/EASTERN MIDLANDS THIS
AFTERNOON AND INTO THE EVENING HOURS. SOME BREAKS IN THE CLOUD
COVER ACROSS THOSE AREAS HAVE ALLOW INSTABILITY TO INCREASE
EARLY THIS AFTERNOON. REGIONAL RADARS SHOWING A MCV MOVING UP
THROUGH SOUTH-CENTRAL GA, WITH MOST GUIDANCE SHOWING ACTIVITY
AHEAD OF IT INCREASING IN COVERAGE AND INTENSIFYING AS IT MOVES
INTO THE CSRA. ADDITIONAL DEVELOPMENT ACROSS THE EASTERN
MIDLANDS AND INTO THE COASTAL PLAINS WILL ALSO OCCUR IN ADVANCE
OF THIS MCV. STRONG TO DAMAGING WINDS, AND EVEN AN ISOLATED
TORNADO, WILL BECOME POSSIBLE AS THE AFTERNOON PROGRESSES. SPC
MAINTAINS A SLIGHT RISK IN THAT AREA, WITH THE REMAINDER OF THE
FORECAST AREA IN A MARGINAL RISK. IN ADDITION, WITH HIGH PWAT
VALUES, THESE STORMS WILL BE CAPABLE OF PRODUCING PERIODS OF
HEAVY RAINFALL AS THEY MOVE THROUGH, SO THERE WILL BE A THREAT
OF FLOODING. AREAS THAT ARE NORTH OF I-20 WILL HAVE A LOWER
THREAT OF SEEING ANY SEVERE STORMS, BUT PERIODS OF RAINFALL WILL
STILL OCCUR THROUGH THIS EVENING AT THE VERY LEAST.
LATER TONIGHT AS THE SHORTWAVE TROUGH MOVES EAST, ACTIVITY WILL
DIMINISH, ESPECIALLY AFTER MIDNIGHT. CAN NOT COMPLETELY RULE
OUT AN ISOLATED SHOWER OVERNIGHT, BUT MAJORITY OF THE PERIOD
AFTER MIDNIGHT SHOULD BE DRY. OVERNIGHT LOWS ONLY FALL INTO THE
MID TO UPPER 60S AGAIN.
SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/
KEY MESSAGE(S):
- A LINE OF STRONG-SEVERE STORMS AHEAD OF A COLD FRONT IS
EXPECTED FRIDAY AFTERNOON INTO THE EARLY EVENING.
- PRIMARY THREATS APPEAR TO BE DAMAGING WIND GUSTS, HEAVY RAIN,
AND SOME HAIL.
- DRIER CONDITIONS BEGIN TO TAKE GRIP LATE FRIDAY INTO
SATURDAY.
FRIDAY'S SEVERE ENVIRONMENT: THE DEEPENING UPPER TROUGH NOW
IMPINGES ON THE REGION FRIDAY AS 90KTS OF SOUTHWESTERLY FLOW
ALOFT AND UPPER DIVERGENCE OVERSPREAD THE FA BY THE AFTERNOON
HOURS WITH A PREFRONTAL TROUGH MOVING IN AHEAD OF THE SURFACE
COLD FRONT. MAINLY UNIDIRECTIONAL SOUTHWESTERLY FLOW IS SEEN
ACROSS ALL LEVELS OF THE ATMOSPHERE, WITH A 35-40 KT LLJ LIKELY
DEVELOPING BY THE MID AFTERNOON. THIS ENHANCED SOUTHWESTERLY
FLOW BRINGS STRONG MOISTURE TRANSPORT INTO THE FA WITH PWAT'S
SURGING NEAR 1.70-1.80" AND TEMPERATURES INTO THE MID 80S.
STRONG 500 MB HEIGHT FALLS ASSOCIATED WITH THE DEEPENING TROUGH,
BRING ADDITIONAL FORCING FOR ASCENT AS WELL AS STEEPENING MID-
LEVEL LAPSE RATES. WITH STRONG FLOW THROUGHOUT MOST OF THE
ATMOSPHERE (NEAR THE NAEFS 99TH PERCENTILE FROM 200MB TO 850MB),
SHEAR WILL PLENTIFUL IN THIS ENVIRONMENT AS NEARLY 50 KTS OF
0-6KM BULK SHEAR IS EXPECTED AND BETWEEN 25-40 KTS OF 0-3KM
SHEAR. THIS FAVORABLE ENVIRONMENT ALSO LOOKS TO YIELD IN EXCESS
OF 1500 J/KG OF MLCAPE AND STRONG LOW LEVEL INSTABILITY WITH
3KM CAPE UP TO 100 J/KG POSSIBLE.
TIMING/POTENTIAL HAZARDS: AS MORE HIGH RES GUIDANCE HAS REACHED
FRIDAY, THE OVERALL TIMING AND MODE OF CONVECTION IS IN DECENT
AGREEMENT. THE MAIN OUTLIER IN THE MODEL SUITE IN TERMS OF
TIMING IS THE RAP, WHICH BRINGS AN ORGANIZED LINE OF CONVECTION
CLOSER TO THE LATE AFTERNOON, BUT THE BULK OF HIGH-RES GUIDANCE
HAS THE LINE ENTERING THE NORTHERN FA FROM THE WEST CLOSER TO
THE EARLY AFTERNOON WITH THE PREFRONTAL TROUGH. IN TERMS OF
STORM ORGANIZATION, THE EXPERIMENTAL RRFS DEPICTS A BIT MORE OF
A BROKEN/SEGMENTED LINE OF CONVECTION WHILE THE HRRR, NSSL'S WRF
MODEL SUITE, RAP, AND THE MEAN HREF SOLUTION DEPICT AN ORGANIZED
CONVECTIVE LINE ACROSS THE BULK OF THE CWA WITH MINIMAL
CONVECTION AHEAD OF IT TO HINDER IT'S POTENTIAL INTENSITY. NOW
FOR POTENTIAL HAZARDS. LUCKILY, THE LINE OF STORMS SHOULD BE
FAIRLY QUICK MOVING AND THUS WIDESPREAD FLASH FLOODING IS NOT
EXPECTED, BUT WITH PARTS OF THE CSRA AND THE EASTERN MIDLANDS
SEEING BETWEEN 5-10" OF RAINFALL OVER THE PAST 3 WEEKS,
LOCALIZED FLOODING CANNOT BE RULED OUT HERE. ALL SEVERE HAZARDS
APPEAR POSSIBLE, WITH A NON-ZERO TORNADO RISK AS FIXED LAYER STP
VALUES BETWEEN 0.5-1.0 ARE SEEN, THOUGH 0-1KM HELICITY IS ON
THE LOWER END DUE TO THE MINIMAL VEERING OF WINDS IN THE LOW
LEVELS. DAMAGING WIND GUSTS AND POSSIBLE SEVERE HAIL WOULD BE
THE MAIN HAZARDS EXPECTED WITH THE LIKELY STRONG COLD POOL
ASSOCIATED WITH THE LINE AND STEEPER MID-LEVEL LAPSE
RATES/COOLER TEMPERATURES ALOFT. DUE TO THESE THREATS, THE SPC
HAS MAINTAINED THE CWA IN ITS SLIGHT RISK (LEVEL 2 OUT OF 5) FOR
SEVERE WEATHER AT THIS TIME.
THIS LINE IS EXPECTED TO CLEAR THE FA BY THE EARLY EVENING WITH
DRIER AIR AND CONDITIONS BEING USHERED IN BEHIND THE SURFACE
COLD FRONT WITH PWAT'S QUICKLY FALLING TO NEAR 1".
LONG TERM /SATURDAY THROUGH THURSDAY/
KEY MESSAGE(S):
- DRIER CONDITIONS CONTINUE TO BE EXPECTED IN THE EXTENDED WITH
NEAR AVERAGE TEMPERATURES, THAT POSSIBLY BECOME SLIGHTLY
ABOVE AVERAGE EARLY NEXT WEEK.
ENSEMBLE GUIDANCE IS IN GOOD AGREEMENT THAT THE TROUGHING OVER
THE EASTERN CONUS IS SLOWLY REPLACED BY UPPER RIDING INTO NEXT
WEEK. PWAT'S GENERALLY LOOK TO BE NEAR OR UNDER 1" FOR MUCH OF
THE PERIOD AND THUS MOSTLY DRY CONDITIONS ARE EXPECTED EACH DAY
IN THE EXTENDED. THE MAIN CHANCE FOR LOW END POPS APPEAR TO BE
LATE SUNDAY AND INTO MONDAY AS GUIDANCE HAS PICKED UP ON A
POTENTIAL SHORTWAVE ROUNDING THE BASE OF THE UPPER TROUGH BEFORE
IT DEPARTS. AFTER THIS, STRONG RIDGING AND SURFACE HIGH
PRESSURE SLIDE INTO THE REGION, MAINTAINING THE EXPECTED MOSTLY
DRY CONDITIONS. TEMPERATURES OVER THE WEEKEND STICK TO NEAR
AVERAGE, BUT MAY RISE TO JUST ABOVE AVERAGE INTO EARLY NEXT
WEEK.
AVIATION /18Z THURSDAY THROUGH TUESDAY/
A MIXTURE OF MID AND UPPER LEVEL CLOUDINESS WILL CONTINUE
THROUGH MUCH OF THE TAF PERIOD AT ALL LOCATIONS. A STRONG
SHORTWAVE WILL MOVE INTO THE FORECAST REGION THIS AFTERNOON,
WITH PERIODS OF RAINFALL AND STRONG TO POSSIBLY SEVERE
THUNDERSTORMS POSSIBLE AT ALL LOCATIONS. MOST AREAS WILL SEE
VCTS AROUND THE START OF THE 18Z TAF PERIOD, WITH SEVERAL HOURS
OF NEEDING A TEMPO GROUP FOR PERIODS OF TSRA IMPACTING EACH
TERMINAL THROUGH THE EARLY EVENING HOURS AT THE VERY LEAST.
OUTSIDE OF ANY STORMS, VFR CONDITIONS EXPECTED INTO THIS
EVENING, WITH MVFR OR LOWER CONDITIONS POSSIBLE IN
THUNDERSTORMS. BY 04Z ALL ACTIVITY SHOULD BE EAST OF ALL TAF
LOCATIONS, SO WILL REMOVE MENTION OF VCTS/VCSH BY THEN. A
RETURN OF MVFR/IFR CONDITIONS THEN POSSIBLE AS THE RAINFALL
EXITS, WITH CEILINGS LOWERING TO MVFR AROUND 02Z, THEN INTO IFR
AFTER 04Z AT MANY LOCATIONS. IMPROVEMENT BACK TO VFR AFTER 15Z
ON FRIDAY AHEAD OF THE NEXT LINE OF CONVECTION THAT WILL BE
POSSIBLE BY FRIDAY AFTERNOON.
EXTENDED AVIATION OUTLOOK...CHANCES OF DIURNAL SHOWERS AND
THUNDERSTORMS THROUGH FRIDAY WITH THE POTENTIAL FOR PERIODIC
RESTRICTIONS. VFR EXPECTED THIS WEEKEND INTO EARLY NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
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