424
FXUS62 KCAE 090628
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
228 AM EDT SUN AUG 9 2026
WHAT HAS CHANGED
COVERAGE OF DIURNAL CONVECTION EACH DAY HAS TRENDED MORE
SPOTTY/ISOLATED. AVIATION DISCUSSION UPDATED FOR 06Z TAFS.
KEY MESSAGES
- 1. ISOLATED DIURNAL STORMS POSSIBLE EACH DAY THIS WEEK. A
STRONG STORM CANNOT BE RULED OUT.
- 2. INCREASING HEAT AND HUMIDITY IS EXPECTED NEXT WEEK.
DISCUSSION
- 1. ISOLATED DIURNAL STORMS POSSIBLE EACH DAY THIS WEEK. A
STRONG STORM CANNOT BE RULED OUT.
SOUTHERLY TO SOUTHEASTERLY NEAR SURFACE FLOW IS EXPECTED TO
CONTINUE TODAY AND INTO EARLY NEXT WEEK, BEFORE BECOMING A BIT
MORE SOUTHWESTERLY TO WESTERLY LATE IN THE WEEK. OVERALL, WITH
THE REGION REMAINING BETWEEN THE UPPER RIDGE OVER THE WESTERN US
AND THE STRONG AREA OF HIGH PRESSURE OFF THE EAST COAST,
SEASONABLE MOISTURE SHOULD PERSIST THROUGH THE FORECAST PERIOD
WITH SURFACE DEWPOINTS LIKELY REMAINING IN THE LOW TO MID 70S
MUCH OF THE FORECAST PERIOD (AS WELL AS PWAT'S NEAR TO JUST
BELOW 2"). THIS MOISTURE COMBINED WITH STRONG HEATING SHOULD
BRING SBCAPE VALUES GREATER THAN 2000 J/KG MOST DAYS BUT WITH
LACKING UPPER KINEMATICS, CREATING AN ENVIRONMENT CONDUCIVE FOR
SPOTTY TO ISOLATED PULSE CONVECTION EACH AFTERNOON THROUGH THE
MID TO LATE WEEK, THOUGH THE LATEST NBM HAS COME IN A BIT DRIER.
AS IS TYPICAL THIS TIME OF THE YEAR, A STRONG STORM OR TWO
CANNOT BE RULED OUT WITH THE RISK OF STRONG DOWNBURST WINDS, BUT
WIDESPREAD SEVERE WEATHER IS UNLIKELY. A BIT MORE UNCERTAINTY
IN TERMS OF PRECIP CHANCES ENTERS LATE THIS WEEK INTO THE
WEEKEND. THIS IS DRIVEN BY GREATER SPREAD AMONGST GLOBAL
DETERMINISTIC AND ENSEMBLE GUIDANCE WITH THE STRENGTH OF A
SHORTWAVE MOVING OUT OF THE NORTHERN GREAT LAKES AND THUS IT'S
ABILITY TO PUSH A SURFACE FRONT NEAR THE REGION. A MORE
AMPLIFIED SOLUTION COULD BRING INCREASED RAIN CHANCES/COVERAGE,
BUT DETAILS STILL NEED TO BE SORTED OUT.
- 2. INCREASING HEAT AND HUMIDITY IS EXPECTED NEXT WEEK.
AS PREVIOUSLY DISCUSSED, 500MB HEIGHTS ARE EXPECTED TO
GRADUALLY RISE THROUGH THE WEEK, PEAKING NEAR THE NAEFS 90TH
PERCENTILE BY THE LATE WEEK. AS THIS OCCURS, 850MB TEMPERATURES
CURRENTLY NEAR 18C SHOULD RISE TO BETWEEN 20-23C BY THE MID
WEEK. WITH THESE WARMING LOW LEVEL TEMPERATURES, RISING MID
LEVEL HEIGHTS, AND THE EXPECTED SPOTTY NATURE OF AFTERNOON
CONVECTION, HIGH TEMPERATURES ARE PROGGED TO PEAK IN THE MID TO
UPPER 90S TUESDAY ONWARD. DUE TO THE UNCERTAINTY IN POTENTIAL
TROUGHING BY THIS WEEKEND DISCUSSED IN KEY MESSAGE #1, LARGER
NBM IQR SPREADS EXIST, BUT NEAR NORMAL TO JUST ABOVE NORMAL
TEMPERATURES STILL SEEM LIKELY. SURFACE DEWPOINTS REMAINING IN
THE LOW TO MID 70S THROUGH THE PERIOD BRING INCREASED CONFIDENCE
IN HEAT INDICES RISING BACK ABOVE 100F WITH LREF PROBABILITIES
REACHING ABOVE 70% BY TUESDAY WITH PROBABILITIES FOR INDICES
ABOVE 105F BETWEEN 30-50% THURSDAY AND FRIDAY. OVERALL,
CONFIDENCE IN REACHING HEAT ADVISORY CRITERIA IS LOW, BUT SPOTS
OF 105-108F COULD BE POSSIBLE MAINLY BETWEEN WEDNESDAY AND
FRIDAY SO BE PREPARED FOR RETURNING HOT/HUMID CONDITIONS THIS
WEEK.
AVIATION /06Z SUNDAY THROUGH THURSDAY/
OUTSIDE OF SOME PREDAWN FOG/STRATUS RESTRICTIONS THIS MORNING, THE
REMAINDER OF THE TAF PERIOD SHOULD FEATURE VFR CONDITIONS.
LITTLE CHANGE IN THE ENVIRONMENT OVERALL WITH PLENTY OF LOW LEVEL
MOISTURE IN PLACE. OVERALL SOUTH TO SOUTHEASTERLY SURFACE FLOW
SHOULD PERSIST THROUGH THE PERIOD ONCE AGAIN, THOUGH NEAR CALM WINDS
ARE EXPECTED THROUGH THE NIGHT AND ONLY ABOUT 5-8 KTS DURING THE
DAY. GUIDANCE IS MIXED, THOUGH SLIGHTLY MORE AGGRESSIVE MOST
RECENTLY WITH STRATUS/FOG FORMATION. THIS MAKES CONCEPTUAL SENSE
GIVEN LITTLE CHANGE IN ENVIRONMENT, SO WENT WITH A PERSISTENCE
FORECAST WITH A TEMPO GROUP FOR RESTRICTIONS. VFR THEN RETURNS AFTER
13Z. ISOLATED CONVECTION EXPECTED AGAIN THIS AFTERNOON BUT
CONFIDENCE IN COVERAGE IS TOO LIMITED FOR ANY MENTION IN THE TAFS AT
THIS TIME.
EXTENDED AVIATION OUTLOOK...A SEASONAL PATTERN OF EARLY MORNING
RESTRICTIONS AND DIURNAL THUNDERSTORMS IS LIKELY THROUGH MUCH
OF THE EXTENDED.
CAE WATCHES/WARNINGS/ADVISORIES
SC...NONE.
GA...NONE.
DISCUSSION...DH
AVIATION...EC
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