700
FXUS62 KCAE 271901
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
301 PM EDT MON JUL 27 2026
WHAT HAS CHANGED
HEAT ADVISORY WILL BE IN EFFECT FROM NOON
TO 8 PM TUESDAY ALONG/SOUTH OF I-20. CONDITIONAL RISK FOR SEVERE
WEATHER EXISTS TUESDAY EVENING. AVIATION DISCUSSION UPDATED FOR
18Z TAF.
KEY MESSAGES
- 1. HOT/HUMID CONDITIONS TUESDAY WITH A HEAT ADVISORY IN
EFFECT FROM NOON TO 8PM ALONG AND SOUTH OF I-20 WITH HEAT
INDICES UP TO 108F POSSIBLE.
- 2. ISOLATED STORMS POSSIBLE TODAY BEFORE A COLD FRONT BRINGS
ISOLATED TO SCATTERED CHANCES TUESDAY EVENING. SEVERE WEATHER
IS POSSIBLE WITH THIS ACTIVITY. DRIER CONDITIONS THEN MOVE IN
FOR THE LATE WEEK.
DISCUSSION
- 1. HOT/HUMID CONDITIONS TUESDAY WITH A HEAT ADVISORY IN
EFFECT FROM NOON TO 8PM ALONG AND SOUTH OF I-20 WITH HEAT
INDICES UP TO 108F POSSIBLE.
AS SOUTHWESTERLY FLOW STRENGTHENS AHEAD OF THE INCOMING FRONT
TUESDAY, TEMPERATURES ARE PROGGED TO REACH THE MID TO UPPER 90S
DURING THE AFTERNOON. A FAIRLY MOIST AIR MASS SHOULD REMAIN IN
PLACE AS WELL WITH SURFACE DEWPOINTS STICKING TO THE LOW TO MID
70S. THERE IS A BIT OF UNCERTAINTY IN TERMS OF HOW DEEP OF
MIXING WILL OCCUR AND THUS THE MIXING OUT OF SURFACE DEWPOINTS.
MODEL GUIDANCE INDICATES 925 MB DEWPOINTS SHOULD REMAIN NEAR
68-72F, SO I AM LEANING TOWARDS SURFACE DEWPOINTS WILL NOT MIX
OUT ALL TOO MUCH. THE AFOREMENTIONED AFTERNOON HIGHS COUPLED
WITH THE MOIST AIRMASS SHOULD BRING HEAT INDICES BETWEEN
105-108F ACROSS THE FA TOMORROW AFTERNOON, HIGHEST ALONG/SOUTH
OF THE I-20 CORRIDOR. DUE TO THIS, A HEAT ADVISORY WILL BE IN
EFFECT FROM NOON TO 8 PM HERE. BE SURE TO TAKE HEAT SAFETY
PRECAUTIONS TOMORROW.
- 2. ISOLATED STORMS POSSIBLE TODAY BEFORE A COLD FRONT BRINGS
ISOLATED TO SCATTERED CHANCES TUESDAY EVENING. SEVERE WEATHER
IS POSSIBLE WITH THIS ACTIVITY. DRIER CONDITIONS THEN MOVE IN
FOR THE LATE WEEK.
ISOLATED CONVECTION IS SEEN DEVELOPING ACROSS THE AREA THIS
AFTERNOON AS MLCAPE VALUES APPROACH 2000-2500 J/KG WITH FAIRLY
WEAK DEEP LAYER SHEAR. THE SLIGHTLY "DRIER" AIRMASS AND DEEPER
MIXING HAVE BROUGHT DCAPE VALUES TOWARD 800-1000 J/KG HOWEVER,
SO A STRONGER STORM WITH STRONG DOWNBURST WINDS CANNOT BE RULED
OUT OVER THE COMING HOURS BEFORE MOSTLY DRY CONDITIONS SET UP
OVERNIGHT.
THE MAIN CHANGE IN THE OUTLOOK COMES TUESDAY WITH A SLIGHTLY
GREATER RISK FOR SEVERE WEATHER, ESPECIALLY TOWARD THE PEE DEE
REGION. GUIDANCE IS INSISTENT THAT A SHORTWAVE CURRENTLY MOVING
OVER THE APEX OF THE LARGE RIDGE CENTERED A BIT WEST OF THE
NORTHERN PLAINS WILL AID IN AMPLIFYING TROUGHING OVER THE
EASTERN CONUS. THIS SHOULD LEAD TO A CLOSED MID-LEVEL LOW
DEVELOPING OVER THE NORTHEAST DURING THE DAY TUESDAY WITH THE
OVERALL TROUGHING PATTERN BECOMING MORE AMPLIFIED. THIS COULD
BRING ENHANCED MID-LEVEL FLOW AND DEEP LAYER SHEAR DOWN TOWARD
THE FA AS SHOWN IN THE 12Z HREF AND REFS. THE ADVERTISED FRONTAL
BOUNDARY SHOULD BEGIN NEARING THE PEE DEE TOWARD LATE TUESDAY
EVENING, BUT AHEAD OF THIS, A BROKEN LINE OF CONVECTION IS SHOWN
DEVELOPING ACROSS SOUTHERN VA AND NORTH CENTRAL NC DURING THE
AFTERNOON IN CAMS. THIS AREA OF CONVECTION IS EXPECTED TO MOVE
IN BY THE LATE AFTERNOON TO EARLY EVENING HOURS FROM THE
NORTHWEST, BUT THE POTENTIAL SEVERE RISK IS A BIT CONDITIONAL.
CONSIDERABLE UNCERTAINTY REMAINS IN THE OVERALL ORGANIZATION OF
CONVECTION ACROSS CAMS, WITH RUNS LIKE THE HRRR, AND HRW'S BEING
A BIT MORE ISOLATED TO SCATTERED WHILE THE 12Z NAM3KM, PREVIOUS
RRFS RUNS, AND THE EXPERIMENTAL RRFS-MPAS FAVOR A QUASAI-LINEAR
MCS MOVING THROUGH THE PEE DEE AND POSSIBLY DOWN INTO THE
CENTRAL MIDLANDS. WITH TIMING FAVORING THE EVENING HOURS, WANING
SURFACE BASED INSTABILITY SHOULD LIMIT A GREATER SEVERE RISK,
BUT THE POTENTIAL TO TAP INTO ~1500 J/KG OF MLCAPE EXISTS AS
STRONGER KINEMATICS MOVE INTO PLACE.
OVERALL, THIS SET UP BRINGS THE CONDITIONAL RISK FOR DAMAGING
COLD POOL DRIVEN WIND GUSTS, AND A NON-ZERO WEAK TORNADO RISK.
THIS NON- ZERO TORNADO RISK MAINLY STEMS FROM A DEVELOPING LLJ
INTO THE EVENING WITH MODELED SOUNDINGS INDICATING AROUND
100-150 M^2/S^2 OF 0-1KM SRH DEVELOPING, ESPECIALLY TOWARD THE
PEE DEE WHERE EFFECTIVE SHEAR VALUES ARE GREATEST AS WELL
(AROUND 40-45 KTS). AS MENTIONED ABOVE, GENEROUS UNCERTAINTY
REMAINS IN STORM ORGANIZATION LATE TUESDAY AFTERNOON INTO THE
EVENING REMAINS AND ANY SHIFT TIMING WISE COULD BRING CHANGES TO
THE OVERALL THERMODYNAMIC/KINEMATIC BALANCE SO CONFIDENCE IN
REALIZING THESE RISKS IS RATHER LOW, ESPECIALLY WITH SOUTHWARD
EXTENT. BE SURE TO STAY TUNED TO FUTURE FORECASTS AS BETTER
CONSENSUS IS LIKELY REACHED.
ENSEMBLE GUIDANCE THEN IS IN GOOD AGREEMENT THAT THE FRONT WILL
PUSH THROUGH THE FA ON WEDNESDAY WITH MUCH DRIER AIR MOVING IN
DURING THE LATE WEEK. THIS IS EXPECTED TO POSSIBLY DRIVE PWATS
UNDER 1" BY THURSDAY AND INTO FRIDAY AS SHOWN IN DETERMINISTIC
GLOBAL MODELS. MOISTURE SHOULD GRADUALLY RETURN DURING THE
WEEKEND WITH POSSIBLE RAIN CHANCES.
AVIATION /18Z MONDAY THROUGH SATURDAY/
OUTSIDE OF MORNING MVFR RESTRICTIONS, MAINLY VFR EXPECTED TO
OCCUR.
WEAK TROUGH STILL REMAINS ACROSS THE REGION AGAIN TODAY.
ISOLATED SHOWER OR STORMS WILL REMAIN POSSIBLE THROUGH THE
AFTERNOON, BUT LIMITED COVERAGE WILL MEAN POTENTIAL AMENDMENTS
AS ACTIVITY NEARS ANY TAF LOCATIONS. BRIEF MVFR RESTRICTIONS
COULD OCCUR IN ANY RAIN ACTIVITY. OUTSIDE OF THAT THIS AFTERNOON
AND INTO THE OVERNIGHT HOURS, THERE WILL BE SOME SCATTERED TO
BROKEN MID-LEVEL VFR CLOUDINESS. MAIN RESTRICTIONS ARE EXPECTED
TOWARDS SUNRISE AGAIN TUESDAY MORNING, WITH MVFR/IFR CONDITIONS
POSSIBLE AS MORNING FOG FORMS ACROSS THE AREA. WINDS GENERALLY
LIGHT AND VARIABLE, FAVORING A WESTERLY DIRECTION ON TUESDAY.
EXTENDED AVIATION OUTLOOK...RAIN CHANCES INCREASE MID-WEEK WITH
RESTRICTIONS POSSIBLE AS A FRONT PUSHES INTO THE SOUTHEAST.
DRIER AIR MOVES IN FOR THE SECOND HALF OF THE WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...HEAT ADVISORY FROM NOON TO 8 PM EDT TUESDAY FOR SCZ016-022-
027>031-035-037-038-041-135>137.
GA...HEAT ADVISORY FROM NOON TO 8 PM EDT TUESDAY FOR GAZ063>065-077.
DISCUSSION...DH
AVIATION...73
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