370
FXUS62 KCAE 121039
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
639 AM EDT SUN JUL 12 2026
WHAT HAS CHANGED
SHOWERS AND A FEW THUNDERSTORMS MOVE THROUGH EARLY THIS MORNING
WITH ADDITIONAL CONVECTION EXPECTED BY THE AFTERNOON. AVIATION
DISCUSSION UPDATED FOR 12Z TAFS.
KEY MESSAGES
- 1. SCATTERED STORMS EXPECTED AGAIN THIS AFTERNOON AND MONDAY.
LOCALLY HEAVY RAINFALL AND FREQUENT LIGHTNING CAN BE EXPECTED
BUT DAMAGING WIND GUSTS WILL BE POSSIBLE IN STRONGEST STORMS
EACH DAY, ESPECIALLY TODAY.
- 2. ONE MORE HOT/HUMID DAY TODAY BEFORE COOLER TEMPERATURES
ARE EXPECTED DURING THE FIRST HALF OF NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: SCATTERED STORMS EXPECTED AGAIN THIS AFTERNOON
AND MONDAY. LOCALLY HEAVY RAINFALL AND FREQUENT LIGHTNING CAN BE
EXPECTED BUT DAMAGING WIND GUSTS WILL BE POSSIBLE IN STRONGEST
STORMS EACH DAY, ESPECIALLY TODAY.
12Z UPDATE: RADAR IMAGERY AT DAYBREAK IS PICKING UP ON MAINLY
LIGHT SHOWERS IN THE CENTRAL MIDLANDS WITH ONE DISSIPATING
THUNDERSTORM MOVING ACROSS AIKEN COUNTY. OTHERWISE, THE PREVIOUS
FORECAST IS ON TRACK WITH THE MAIN WINDOW FOR SEVERE WEATHER
EXPECTED FROM ROUGHLY 4PM TO 10PM TODAY.
PREVIOUS DISCUSSION: AS OF WRITING THIS, THE SLOW MOVING
FRONTAL BOUNDARY IS APPROACHING NORTHERN NC/TN WITH THE MID
LEVEL LOW SLOWLY DRIFTING INTO THE NORTHERN TENNESSEE VALLEY. A
RATHER MOIST AIRMASS REMAINS IN PLACE WITH PWAT'S ABOVE 1.70"
AND SURFACE DEWPOINTS IN THE LOW TO MID 70S. DUE TO THIS, A
COUPLE SHOWERS AND EVEN A WEAK STORM ARE MOVING INTO THE WESTERN
CSRA. THIS ISOLATED ACTIVITY COULD CONTINUE INTO THE EARLY
MORNING HOURS, BUT MESOANALYSIS SHOWS INCREASED CIN OVER THE FA,
THUS NO STRONG STORMS ARE EXPECTED. IF THIS ACTIVITY PERSISTS
INTO THE EARLY TO MID MORNING HOURS, INCREASED DEBRIS CLOUD
COVER MAY ACT TO LIMIT DESTABILIZATION A BIT FOR THE MAIN ROUND
OF CONVECTION LATER IN THE DAY. AT THIS TIME, THIS IS NOT
EXPECTED TO BE THE CASE WITH LITTLE CAM SUPPORT FOR THIS
SOLUTION, BUT IT IS WORTH MONITORING.
THE AFOREMENTIONED MID LEVEL LOW AND SURFACE FRONT ARE EXPECTED
TO NEAR THE FA THROUGH THE DAY TODAY BUT AHEAD OF THESE
FEATURES ANOTHER ROUND OF SCATTERED CONVECTION IS ANTICIPATED
THIS AFTERNOON INTO THE EVENING. THE ENVIRONMENT IS EXPECTED TO
BE CHARACTERIZED BY SBCAPE VALUES BETWEEN 2500-3000 J/KG, DECENT
MIXING THAT YIELDS DCAPE VALUES BETWEEN 600-800 J/KG, PWAT'S
NEAR 2", AND TEI VALUES BETWEEN 25-28. DEEP LAYER SHEAR IS
EXPECTED TO BE MARGINAL, BUT FORECAST SOUNDINGS DEPICT BOTH THIS
AND CLOUD LAYER SHEAR CLOSER TO 20-30 KTS NEAR THE PEE DEE AS
THE FRONT NEARS. OVERALL, THIS YIELDS A SIMILAR ENVIRONMENT TO
YESTERDAY, THOUGH WITH SLIGHTLY MORE SYNOPTIC FORCING AND
ENHANCED CONVERGENCE ALONG THE FRONT. SCATTERED STRONG TO SEVERE
THUNDERSTORMS ARE EXPECTED BY THE EARLY AFTERNOON WITH
CONVECTIVE TEMPS BETWEEN 90-92F AND WITH THE STRONGER FORCING,
MORE CELL/COLD POOL INTERACTIONS COULD BRING A COUPLE ROBUST
CLUSTERS ACROSS THE FA AS DEPICTED IN THE LATEST HREF AND HRRR
RUNS. OVERALL, WET MICROBURSTS BRINGING A DAMAGING WIND RISK
WILL BE THE MAIN HAZARD, BUT IF AN APPRECIABLY DEEP CORE IS SEEN
WITH FAVORABLE INTERACTIONS, CANNOT RULE OUT SOME SUB-SEVERE
HAIL. FREQUENT LIGHTNING AND HEAVY RAINFALL ARE ALSO EXPECTED
WITH THIS ACTIVITY. IT IS WORTH NOTING THAT ISOLATED INSTANCES
OF FLASH FLOODING WILL BE POSSIBLE WITH THE INCREASED COVERAGE
TODAY AS ONE LOCATION COULD HAVE CONVECTION TRAIN AND BRINGING
EFFICIENT RAINFALL. AT THIS TIME THE HREF LPMM SHOWS A COUPLE
SPOTS OF 2-4" COULD BE POSSIBLE, BUT CONFIDENCE IN THE EXACT
PLACEMENT OF THESE SPOTS IS LOW. SCATTERED SHOWERS AND STORMS
ARE EXPECTED TO CARRY INTO THE OVERNIGHT WITH THE FRONT MOVING
IN, BUT THE OVERALL SEVERE RISK SHOULD DIMINISH WITH INSTABILITY
BECOMING A BIT MORE ELEVATED. THE WHOLE CWA IS OUTLINED IN
SPC'S SLIGHT RISK (LEVEL 2 OUT OF 5) FOR SEVERE WEATHER AND IS
ALSO OUTLINED IN WPC'S MARGINAL RISK FOR EXCESSIVE RAINFALL
(LEVEL 1 OUT OF 4), THOUGH PARTS OF THE PEE DEE AND NORTHERN
MIDLANDS ARE IN THE SLIGHT RISK (LEVEL 2 OUT OF 4) FOR EXCESSIVE
RAINFALL.
ON MONDAY, THE FRONT IS EXPECTED TO MOVE THROUGH AND THE MID
LEVEL LOW SHOULD DROP INTO THE REGION AS PWAT'S INCREASE TOWARD
2.10-2.20". LOW LEVEL FLOW BECOMES INCREASINGLY NORTHERLY TO
NORTHEASTERLY, KEEPING TEMPERATURES A BIT COOLER AND INCREASED
CLOUD COVER IS EXPECTED TO LIMIT DESTABILIZATION. THIS BRINGS A
LOWER RISK FOR SEVERE WEATHER WITH MORE MARGINAL THERMODYNAMICS,
BUT A COUPLE STRONG TO MARGINALLY SEVERE STORMS CANNOT BE RULED
OUT DURING THE AFTERNOON/EVENING AS DEEP LAYER SHEAR IS
SLIGHTLY INCREASED. THE BIGGER RISK MONDAY MAY BE THE HEAVY
RAINFALL RISK AS SCATTERED TO WIDESPREAD SHOWERS AND STORMS MOVE
THROUGH THE AREA DURING THE DAY WITH EFFICIENT RAIN RATES
LIKELY IN THIS MOIST AIRMASS. BOTH HREF AND REFS PROBABILITIES
FOR GREATER THAN 1" OF QPF MONDAY APPROACH 50-70% ACROSS THE CWA
AND WHERE TRAINING OF CONVECTION OCCURS, ISOLATED FLASH
FLOODING WILL ONCE AGAIN BE POSSIBLE, ESPECIALLY ANYWHERE THAT
SEES HEAVY RAINFALL TODAY.
KEY MESSAGE 2: ONE MORE HOT/HUMID DAY TODAY BEFORE COOLER
TEMPERATURES ARE EXPECTED DURING THE FIRST HALF OF NEXT WEEK.
THERE HAS NOT BEEN A SIGNIFICANT CHANGE IN THE TEMPERATURE
OUTLOOK FOR THE COMING DAYS. WITH THE EXPECTATION OF LITTLE IN
WAY OF MORNING SHOWERS/WEAK STORMS AND THUS DEBRIS CLOUDINESS,
ROBUST HEATING IS EXPECTED TODAY WITH TEMPERATURES WARMING BACK
INTO THE MID 90S RATHER QUICKLY. DEWPOINTS REMAINING IN THE LOW
TO MID 70S COULD BRING HEAT INDICES BACK BETWEEN 100-105F BEFORE
CONVECTION COOLS THINGS OFF A BIT. LOW LEVEL FLOW THAT BECOMES
A BIT MORE NORTHERLY TO NORTHEASTERLY MONDAY IS EXPECTED TO
BRING THE FIRST DAY OF RELIEF AS TEMPERATURES LIKELY STICK TO
LOW TO UPPER 80S, THOUGH THINGS COULD TREND A BIT LOWER
DEPENDING ON HOW WIDESPREAD SHOWERS AND STORMS ARE. THE NORTH TO
SOUTH GRADIENT COULD ALSO END UP BEING A BIT TIGHT DEPENDING
WHERE THE FRONTAL BOUNDARY STALLS OUT. THIS COOLER AIRMASS IS
EXPECTED TO STICK AROUND TUESDAY, BEFORE WARMING TO NEAR NORMAL
ON WEDNESDAY AS SOUTHWESTERLY LOW LEVEL FLOW MOVES BACK IN.
HEADING INTO THE SECOND HALF OF THE WEEK, UPPER HEIGHT RISES
MOVE BACK IN WITH WARMING 850MB TEMPERATURES TOWARD THE NAEFS
90TH PERCENTILE. THIS MEANS A RETURN TO NORMAL TO ABOVE NORMAL
TEMPERATURES CAN BE EXPECTED IN THIS WINDOW WITH MORE DIURNALLY
DRIVEN SHOWERS/STORMS POSSIBLE.
AVIATION /10Z SUNDAY THROUGH THURSDAY/
THUNDERSTORM THREAT INCREASES THIS AFTERNOON....
RADAR IMAGERY AT DAYBREAK IS PICKING UP ON SHOWERS IN THE
CENTRAL MIDLANDS BRINGING LIGHT RAINFALL TO CAE/CUB. THE
THUNDERSTORM THAT MOVED OVER AIK HAS MOVED TO THE EAST, WITH
LINGERING SHOWERS IN THE AREA. SHOWER ACTIVITY SHOULD CONTINUE
TO DIMINISH DURING THE NEXT HOUR. SCATTERED CUMULUS SHOULD
DEVELOP AROUND MIDDAY, WITH THE THREAT FOR SHOWERS AND
THUNDERSTORM INCREASING IN THE AFTERNOON. RESTRICTIONS FROM
SHOWERS AND THUNDERSTORMS ARE MOST LIKELY BETWEEN 20Z AND 02Z
WHERE A PROB30 HAS BEEN PLACED FOR ALL TERMINALS. RAIN SHOULD
TAPER OFF TONIGHT, THOUGH THE CLOUDS MAY LINGER. MODEL GUIDANCE
CONTINUES TO SHOW THE POTENTIAL FOR POST-FRONTAL LOW CLOUDS
AND/OR FOG NEAR THE END OF THE CURRENT TAF PERIOD.
EXTENDED AVIATION OUTLOOK...A GOOD CHANCE FOR AFTERNOON SHOWERS
AND THUNDERSTORMS WITH ASSOCIATED RESTRICTIONS IS EXPECTED INTO
EARLY NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...7/DH
AVIATION...7
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