809
FXUS64 KHUN 041123
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
623 AM CDT FRI SEP 4 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 931 PM CDT THU SEP 3 2026
- A HEAT ADVISORY REMAINS IN EFFECT THROUGH 8 PM SATURDAY DUE TO
MAJOR TO EXTREME HEATRISK, ALONG WITH AFTERNOON HEAT INDICES
RISING UP TO 105-109 DEGREES IN PORTIONS OF THE FORECAST AREA.
- VERY LOW CHANCES (10-20%) FOR SHOWERS AND THUNDERSTORMS WILL
CONTINUE THROUGH THE WEEK. ONE OR TWO STRONG MAY BECOME STRONG
FRIDAY AFTERNOON AND SATURDAY AFTERNOON.
NEAR TERM
(TODAY)
ISSUED AT 152 AM CDT FRI SEP 4 2026
EARLY MORNING TEMPS CURRENTLY RANGE FROM THE LOW TO MID 70S UNDER
CLEAR SKIES AND CALM WINDS. WILL BE WATCHING FOR PATCHY FOG
FORMATION THIS MORNING ESPECIALLY FOR LOCATIONS THAT SAW RAINFALL
YESTERDAY AFTERNOON, BUT SO FAR THIS MORNING THERE IS NO EVIDENCE
OF FOG ACROSS THE TN VALLEY. DANGEROUS HEAT WILL CONTINUE TO BE
THE FOCUS TODAY WITH AFTERNOON HEAT INDICES FORECAST TO EXCEED 105
DEGREES ACROSS A LARGE PORTION OF THE TN VALLEY. NO MAJOR CHANGES
WERE MADE TO THE FORECAST DURING THE EARLY MORNING UPDATE.
PREVIOUS DISCUSSION:
MAJOR (LEVEL 3 OF 4) TO EXTREME (LEVEL 4/4) HEAT IMPACTS WILL
CONTINUE ON FRIDAY WITH A STRONG AREA OF HIGH PRESSURE (AND ITS
SUBSEQUENT HEAT DOME UNDERNEATH IT) REMAINING DIRECTLY OVER THE
TENNESSEE VALLEY. AMPLE SUNSHINE AND SOUTHERLY FLOW WILL AGAIN
WARM HIGHS INTO THE 95 TO 100 DEGREE RANGE IN MOST LOCATIONS BY
THE AFTERNOON. THE COMBINATION OF THESE HOT TEMPERATURES AND
DEWPOINTS IN THE 70S WILL ONCE AGAIN LEAD TO PEAK HEAT INDEX
VALUES IN THE 105-110 RANGE. A HEAT ADVISORY REMAINS IN EFFECT
UNTIL 8 PM SATURDAY. ADDITIONALLY, VERY LOW (10-20%) CHANCES FOR
SHOWERS AND THUNDERSTORMS WILL EXIST DURING THE AFTERNOON HOURS.
THIS ACTIVITY WILL BE TIED TO DIURNAL HEATING AND DISSIPATE AFTER
SUNSET. A VAST MAJORITY OF LOCATIONS WILL REMAIN DRY.
SHORT TERM
(FRIDAY NIGHT THROUGH SUNDAY)
ISSUED AT 931 PM CDT THU SEP 3 2026
SIMILAR HEAT IMPACTS WILL CONTINUE ON THIS WEEKEND EVEN AS A WEAK
SHORTWAVE/FRONT APPROACHES THE REGION FROM THE NORTH. HIGHS AGAIN
IN THE MID/UPPER 90S WITH HEAT INDEX VALUES BETWEEN 105-110 WILL
CREATE MAJOR (LEVEL 3/4) TO EXTREME (LEVEL 4/4) IMPACTS AND
EXTREME CAUTION IS URGED FOR THOSE WITH OUTDOOR PLANS. AS ALLUDED
TO, A WEAK SHORTWAVE WILL FORCE A FRONT SOUTH THROUGH THE REGION
LATE SATURDAY AFTERNOON/EVENING. THIS FEATURE WILL SERVE AS A
FOCUS FOR A FEW SHOWERS AND THUNDERSTORMS ONCE AGAIN.
UNFORTUNATELY THIS INITIAL SHORTWAVE WILL DO LITTLE TO MODIFY
THIS AIR MASS ON SUNDAY AS HIGHS IN THE UPPER 90S AND HEAT INDEX
VALUES AROUND 105 DEGREES WILL BE COMMON ONCE AGAIN. THE HEAT
ADVISORY MAY NEED TO BE EXTENDED THROUGH SUNDAY.
LONG TERM
(SUNDAY NIGHT THROUGH THURSDAY)
ISSUED AT 931 PM CDT THU SEP 3 2026
THE UPPER LEVEL RIDGE IS FORECAST TO SLIGHT SHIFT TO THE WEST THE
BEGIN THE WEEK, ALLOWING RELATIVELY (KEY WORD HERE) COOLER
TEMPERATURES TO SETTLE OVER THE TN VALLEY. HIGH TEMPERATURES WILL
STILL BE IN THE LOW 90S WITH OVERNIGHT LOWS IN THE MID 60S TO LOW 70S
AS MODERATE (LEVEL 2 OF 4) HEAT IMPACTS CONTINUE THROUGH THE WEEK. AS
THE RIDGE SHIFTS BACK EASTWARD, TEMPERATURES WILL GRADUALLY CLIMB
BACK INTO THE MID 90S BY THE END OF THE WEEK WITH DIURNAL HEATING
CONTRIBUTING TO LOW CHANCES (20% OR LESS) OF THUNDERSTORM DEVELOPMENT
EACH DAY. ONE THING TO WATCH WILL BE WHERE SFC HIGH PRESSURE SETS UP
ALONG THE APPALACHIANS AND WHETHER OR NOT NE AL AND SOUTHERN MIDDLE
TN EXPERIENCE CAD (COLD USED LOOSELY). IF THIS IS THE CASE, INCREASED
POPS MAY BE NECESSARY AS DIFFERENTIAL HEATING BOUNDARIES BEGIN TO SET
UP ALONG NORTH CENTRAL AL. AS FAR AS HEAT HEADLINES GO, WILL LIKELY
NOT NEED ANYTHING PAST SUNDAY AS HEAT INDICES DROP TO AROUND 100
DEGREES.
AVIATION
(12Z TAFS)
ISSUED AT 623 AM CDT FRI SEP 4 2026
VFR CONDITIONS ARE FORECAST THROUGH THE END OF THE TAF PERIOD WITH
FEW TO SCT CU THIS AFTERNOON AND LIGHT/VAR WINDS. THERE IS A VERY
LOW CHANCE FOR SHOWERS AND STORMS THIS AFTERNOON BUT CONFIDENCE
WAS NOT HIGH ENOUGH TO INCLUDE IN TAFS AT THIS TIME.
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 8 PM CDT SATURDAY FOR ALZ001>010-016.
TN...HEAT ADVISORY UNTIL 8 PM CDT SATURDAY FOR TNZ076-096-097.
NEAR TERM...25
SHORT TERM....AMP
LONG TERM....AMP
AVIATION...25
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