576
FXUS62 KCAE 030557
AFDCAE
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE COLUMBIA SC
157 AM EDT FRI JUL 3 2026
WHAT HAS CHANGED
ONLY MINOR FORECAST UPDATES WITH THIS PACKAGE. AVIATION
DISCUSSION UPDATED FOR 06Z TAF'S.
KEY MESSAGES
- 1. ABOVE NORMAL TEMPERATURES CONTINUE, PEAKING DURING THE
INDEPENDENCE DAY WEEKEND. A HEAT ADVISORY WILL BE IN EFFECT
ALONG AND NORTH OF I-20 FROM 12PM-8PM FRIDAY WITH HEAT INDICES
BETWEEN 104-108F POSSIBLE.
- 2. INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS LATE THIS
WEEKEND INTO NEXT WEEK.
DISCUSSION
KEY MESSAGE 1: ABOVE NORMAL TEMPERATURES CONTINUE, PEAKING
DURING THE INDEPENDENCE DAY WEEKEND. A HEAT ADVISORY WILL BE IN
EFFECT ALONG AND NORTH OF I-20 FROM 12PM-8PM FRIDAY WITH HEAT
INDICES BETWEEN 104-108F POSSIBLE.
AN INTENSE PERIOD OF HEAT IS FORECAST TO CONTINUE AS WE HEAD
INTO THE JULY 4TH HOLIDAY WEEKEND. A STRONG RIDGE OF HIGH
PRESSURE, ANALYZED AT ~597DM 500 HPA HEIGHTS, IS CENTERED TO OUR
NORTH ACROSS THE MID-ATLANTIC. NORTHERLY AND NORTHEASTERLY FLOW
ON THE EASTERN SIDE OF THIS RIDGE IS FORECAST TO CONTINUE
ADVECTING A VERY WARM AIRMASS ATOP THE CAROLINAS OVER THE NEXT
SEVERAL DAYS, WITH 850 HPA TEMPS FORECAST TO WARM TO 21C-23C
FRI-SUN OF THIS PERIOD. WHILE THE RIDGE IS FORECAST TO BEGIN
BREAKING DOWN BY SUNDAY, THIS ANOMALOUSLY WARM LOW-LEVEL AIRMASS
IS FORECAST TO YIELD HOT TEMPS CENTERED ON THE JULY 4TH HOLIDAY.
GUIDANCE SHOWS NEAR TO BELOW NORMAL 0-3KM MIXING RATIOS FOR
EARLY JULY, WHICH IS EXPECTED TO YIELD DEEPLY MIXED BOUNDARY
LAYERS EACH AFTERNOON THIS WEEKEND. THIS SHOULD RESULT IN HIGHS
NEAR 100F EACH AFTERNOON, PARTICULARLY ACROSS THE
CENTRAL/NORTHERN MIDLANDS AND PEE DEE REGION OF OUR FORECAST
AREA. NBM/LREF PROBABILITIES OF MAXT >100F PEAKS SAT/SUN WITH
FORECAST SOUNDINGS SUPPORTING THIS POSSIBILITY.
WHILE TEMPS WILL BE HOT, THE DEEP MIXING IS PROMOTED BY A
SLIGHTLY "DRIER" THAN NORMAL AIRMASS THAT IS IN PLACE ACROSS THE
AREA. DEWPOINTS ARE FORECAST TO DIP INTO THE MID TO UPPER 60S
EACH AFTERNOON BEFORE THEY BEGIN REBOUNDING EARLY NEXT WEEK.
THIS CREATES AN ODD CIRCUMSTANCE WHERE WE ARE IN JULY AND DON'T
QUITE HAVE THE HUMIDITY TO GET EXACTLY TO OUR HEAT ADVISORY
CRITERIA. HOWEVER, GIVEN THIS IS A PROLONGED PERIOD OF HEAT
OVERLAPPING WITH THE INDEPENDENCE DAY HOLIDAY, HEAT ADVISORIES
LOOK LIKELY ON SATURDAY AND SUNDAY AS WELL. HEAT INDEX VALUES
WILL LIKELY PEAK TODAY IN THE 104F-108F RANGE, WITH ACTUAL HIGH
TEMPS IN THE 99F-102F RANGE SAT/SUN. THE COMBINATION OF THESE
TWO, PLUS OVERNIGHT LOWS ONLY RECOVERING INTO THE MID/UPPER 70S,
SHOULD YIELD A PROLONGED PERIOD OF HEAT STRESS THAT THE HEAT
INDEX REALLY DOESN'T CAPTURE. SO WITH THIS EXPECTED, EXERCISE
CAUTION THIS HOLIDAY WEEKEND WHEN SPENDING AN EXTENDED PERIOD OF
TIME OUTDOORS. MAKE SURE TO REVIEW AND TAKE APPROPRIATE HEAT
SAFETY MEASURES! THE ELDERLY, YOUNG CHILDREN, PETS, AND THOSE
WITHOUT INDOOR COOLING WILL BE AT PARTICULAR RISK THIS WEEKEND
AND OVER THE COMING WEEK. HEAT INDEX VALUES MAY ACTUALLY RISE
AGAIN EARLY NEXT WEEK WHILE REMAINING BELOW ADVISORY CRITERIA AS
DEWPOINTS INCREASE THROUGH THE MIDDLE OF NEXT WEEK. DAILY
SHOWER AND STORM CHANCES MAKE CONFIDENCE IN THE OVERALL HEAT
RISK A BIT HAZY BEYOND SUNDAY.
KEY MESSAGE 2: INCREASING CHANCES FOR SHOWERS AND THUNDERSTORMS
LATE THIS WEEKEND INTO NEXT WEEK.
THE SIGNAL PERSISTS ACROSS ENSEMBLE AND GLOBAL MODELS THAT THE
UPPER RIDGE WILL BECOME INCREASINGLY SUPPRESSED SUNDAY INTO NEXT
WEEK AS A SHORTWAVE TROUGH WORKS INTO THE GREAT LAKES REGION.
THIS WILL ALLOW FOR SOME WEAK HEIGHT FALLS AND SHORTWAVE ENERGY
TO MOVE INTO THE REGION EARLY IN THE WEEK WITH PWAT'S TICKING
BACK UP NEAR 2". WITH THE CONTINUED HEAT AND NOW INCREASED
MOISTURE EARLY NEXT WEEK, SEASONABLE TO STRONG DIURNAL
INSTABILITY COULD DEVELOP WITH DAILY SHOWERS AND STORMS
POSSIBLE. SOME STRONG TO SEVERE STORMS ARE EXPECTED EACH
AFTERNOON WITHIN THIS REGIME AS HIGH CAPE AND LOW SHEAR SHOULD
LEAD TO DOWNBURSTS ACROSS THE AREA. DETAILS OF THIS WILL BECOME
CLEARER OVER THE NEXT FEW DAYS.
AVIATION /06Z FRIDAY THROUGH TUESDAY/
VFR CONDITIONS GENERALLY EXPECTED THROUGH THE TAF PERIOD.
UPPER RIDGING WILL CONTINUE TO LIMIT POTENTIAL FOR ANY SHOWERS
OR THUNDERSTORMS TODAY. OVERALL, EXPECT VFR CONDITIONS,
ALTHOUGH BRIEF MVFR VISIBILITIES ARE POSSIBLE AROUND SUNRISE AT
FOG PRONE AGS/OGB, BUT CONFIDENCE TOO LOW FOR TAF INCLUSION.
LIGHT WINDS THIS MORNING BECOMING EAST TO SOUTHEAST ONCE AGAIN,
5-10 KTS UNDER CLEAR OR MOSTLY CLEAR SKIES. SKIES THEN CLEAR
TONIGHT WITH LIGHT SOUTH WINDS.
EXTENDED AVIATION OUTLOOK...RAINFALL UNLIKELY THROUGH SATURDAY
AS RIDGING BUILDS OVERHEAD. BRIEF EARLY MORNING VSBY
RESTRICTIONS POSSIBLE. RAIN CHANCES AND POSSIBLE RESTRICTIONS
START TO INCREASE SUNDAY INTO EARLY NEXT WEEK.
CAE WATCHES/WARNINGS/ADVISORIES
SC...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
SCZ016-018-020>022-025>028-030-115-116.
GA...HEAT ADVISORY FROM NOON TODAY TO 8 PM EDT THIS EVENING FOR
GAZ040-063>065.
DISCUSSION...PL
AVIATION...EC
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