995
FXUS62 KCAE 131020
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
620 AM EDT MON JUL 13 2026
WHAT HAS CHANGED
INCREASED HEAVY RAINFALL THREAT WITH TODAY'S ACTIVITY. AVIATION
DISCUSSION UPDATED FOR 12Z TAF.
KEY MESSAGES
- 1. SCATTERED TO WIDESPREAD SHOWERS AND STORMS EXPECTED THIS
AFTERNOON, CONTINUING INTO THE EARLY OVERNIGHT. A COUPLE
STRONG TO MARGINALLY SEVERE STORMS WILL BE POSSIBLE ALONG WITH
ISOLATED SPOTS OF FLASH FLOODING. LINGERING MOISTURE LEADING
TO SCATTERED TO WIDESPREAD AFTERNOON STORMS TUESDAY AND
WEDNESDAY.
DISCUSSION
KEY MESSAGE 1: SCATTERED TO WIDESPREAD SHOWERS AND STORMS
EXPECTED THIS AFTERNOON, CONTINUING INTO THE EARLY OVERNIGHT. A
COUPLE STRONG TO MARGINALLY SEVERE STORMS WILL BE POSSIBLE ALONG
WITH ISOLATED SPOTS OF FLASH FLOODING. LINGERING MOISTURE
LEADING TO SCATTERED TO WIDESPREAD AFTERNOON STORMS TUESDAY AND
WEDNESDAY.
OVERALL, THERE HAS NOT BEEN MUCH CHANGE IN THE OUTLOOK FOR
TODAY. A SLOW MOVING SURFACE FRONT SHOULD GRADUALLY WORK SOUTH
THROUGH THE FA BEFORE STALLING NEAR THE CSRA AS A MID-LEVEL LOW
WORKS INTO NORTHERN AL/GA. MEAN SFC-400MB FLOW OUT OF THE
SOUTHWEST SHOULD ADVECT PWAT'S 1.5-2 STANDARD DEVIATIONS ABOVE
NORMAL (~2.20-2.40"), CREATING VERY MOIST PROFILES. WITH SURFACE
DEWPOINTS REMAINING IN THE LOW TO MID 70S, MEAN HREF SOUNDINGS
INDICATE SBCAPE VALUES BETWEEN 1500-2000 J/KG SHOULD DEVELOP
THROUGH THE DAY, LESS THAN PREVIOUS DAYS MOSTLY DUE TO COOLER
SURFACE TEMPERATURES RANGING FROM THE LOW 80S NORTH TO THE MID
TO UPPER 80S SOUTH. WITH MORE MOIST ADIABATIC PROFILES, DCAPE IS
PROGGED TO BE LESS THAN PREVIOUS DAY'S AS WELL. AN UPTICK IN
KINEMATICS FROM THE MID LEVEL LOW SHOULD BRING INCREASED SHEAR
(EBWD ~20-25 KTS) THOUGH, SO A FEW STRONG TO MARGINALLY SEVERE
STORMS REMAIN POSSIBLE DURING THE AFTERNOON/EARLY EVENING WITH
THE MAIN HAZARD BEING DAMAGING WIND GUSTS FROM PRECIP- LOADED
DOWNDRAFTS. ACTIVITY LIKELY CARRIES INTO THE OVERNIGHT, BUT THE
SEVERE RISK IS EXPECTED TO DIMINISH DURING THIS PERIOD.
THE BIGGER TALKING POINT IS THE HEAVY RAINFALL POTENTIAL
THROUGH THE DAY. AS 00Z GUIDANCE HAS FILTERED IN, THERE IS AN
INCREASED SIGNAL FOR LOCALLY HIGH RAINFALL AMOUNTS. THESE MOIST
ADIABATIC PROFILES, LONG/SKINNY CAPE, A NEARLY STATIONARY FRONT,
AND THE AFOREMENTIONED PWAT'S SHOULD ACT TO BRING QUITE
EFFICIENT RAINFALL RATES AND THE POTENTIAL FOR TRAINING
CONVECTION. THE HREF 24HR QPF LPMM PRODUCT INDICATES A FAIRLY
WIDESPREAD 0.50-1.0" IS A REASONABLE EXPECTATION, BUT IT DOES
INDICATE SPOTS OF 2-5" BEING POSSIBLE, WHICH IS FURTHER
SUPPORTED IN DETERMINISTIC CAMS AND THE 00Z REFS LPMM. THERE IS
LESSER CONFIDENCE IN THE EXACT PLACEMENT OF HIGHER QPF AMOUNTS
WITH SOME SPATIAL VARIABILITY AMONGST DETERMINISTIC CAMS, BUT
WITH THE FRONTAL BOUNDARY EXPECTED TO NEARLY STALL IN THE
SOUTHERN FA, THIS COULD BE AN AREA TO WATCH MORE CLOSELY. AREAS
IN THE SOUTHEASTERN MIDLANDS NEAR EASTERN BAMBERG COUNTY INTO
ORANGEBURG AND SOUTHERN CALHOUN COUNTIES SAW 1-3" OF RAINFALL
FROM SUNDAY'S ACTIVITY SO THESE SPOTS WOULD BE THE MOST
SENSITIVE TO ADDITIONAL HIGHER AMOUNTS. OVERALL, ISOLATED
INSTANCES OF FLASH FLOODING WILL BE POSSIBLE IF THESE HIGHER
AMOUNTS ARE REALIZED.
SCATTERED SHOWER AND THUNDERSTORM CHANCES WILL LIKELY CONTINUE
TUESDAY AND WEDNESDAY AS ENSEMBLE METEOGRAMS INDICATE PWAT'S
NEAR TO OVER 2" REMAIN IN PLACE THROUGH AT LEAST THE FIRST HALF
OF WEDNESDAY. AS THE MID LEVEL LOW SLOWLY RETROGRADES, DRIER AIR
MAY BEGIN PUSHING INTO THE PEE DEE AND NORTHERN MIDLANDS
WEDNESDAY, BRINGING LOWER RAIN CHANCES HERE. COOLER THAN NORMAL
TEMPERATURES ARE ALSO EXPECTED TO PERSIST THROUGH WEDNESDAY
BEFORE GRADUALLY WARMING DURING THE SECOND HALF OF THE WEEK BACK
TO NEAR NORMAL. TYPICAL DIURNAL RAIN CHANCES COULD MAKE AN
APPEARANCE LATE IN THE WEEK INTO NEXT WEEKEND, BUT THERE IS
GENEROUS SPREAD IN LREF CLUSTER ANALYSIS AT THIS POINT.
AVIATION /10Z MONDAY THROUGH FRIDAY/
LOW CEILINGS POSSIBLE THIS MORNING....
AT DAYBREAK, MVFR CEILINGS ARE BEING REPORTED AT CAE/CUB, WITH
LIFR CEILINGS AT OGB. GUIDANCE HAS BACKED OFF ON THE THREAT FOR
LOW CEILINGS AT THE REMAINING TERMINALS SO OPTED TO MOVE THE
POTENTIAL INTO A TEMPO AND AMEND AS NEEDED. ANY LOW STRATUS
SHOULD LIFT AND SCOUR OUT BY MIDDAY, GIVING WAY TO SCATTERED
CUMULUS. ANOTHER ROUND OF AFTERNOON AND EVENING CONVECTION IS
EXPECTED, POTENTIALLY RESULTING IN BRIEF RESTRICTIONS AT THE
TERMINALS. PROB30 REMAINS IN PLACE FROM 18Z TO 00Z TUESDAY FOR
THIS POTENTIAL. CONFIDENCE IN MVFR-IFR CEILINGS APPEARS TO BE
HIGHER MONDAY NIGHT ONCE THE CONVECTION DISSIPATES THEREFORE NEW
LINES WERE ADDED TO THIS UPDATE TO REFLECT DECREASING CLOUD
BASES.
EXTENDED AVIATION OUTLOOK...A GOOD CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS WITH ASSOCIATED RESTRICTIONS IS EXPECTED
THROUGH AT LEAST TUESDAY.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...7/DH
AVIATION...7
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