060
FXUS64 KHUN 031113
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
613 AM CDT THU SEP 3 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 852 PM CDT WED SEP 2 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.
- A LOW CHANCE OF STORMS (DOWNBURSTS) IS FORECAST ON SATURDAY
WITH THE POTENTIAL FOR DAMAGING WINDS, HEAVY RAIN, AND FREQUENT
LIGHTNING.
NEAR TERM
(TODAY)
ISSUED AT 210 AM CDT THU SEP 3 2026
EARLY MORNING TEMPERATURES HAVE FALLEN TO THE LOW TO MID 70S AREA
WIDE UNDER CLEAR SKIES AND LIGHT WINDS. NIGHTTIME RGB SATELLITE
SHOWS NO EVIDENCE OF ANY FOG FORMATION DESPITE RH VALUES NEAR 100%
IN SOME LOCATIONS. THE MAIN FOCUS FOR TODAY WILL CONTINUE TO BE
THE DANGEROUS HEAT AND A HEAT ADVISORY REMAINS IN EFFECT FOR THE
ENTIRE AREA. NO MAJOR CHANGES WERE NEEDED DURING THE OVERNIGHT
UPDATE.
PREVIOUS DISCUSSION:
UPPER LEVEL RIDGING WILL PERSIST THROUGH TODAY, BUT THE MAIN AXIS
OF THE RIDGE IS EXPECTED TO SHIFT EASTWARD OVER THE APPALACHIANS
THROUGH THE DAY. SURFACE HIGH PRESSURE WILL CONTINUE ITS HOLD OVER
THE APPALACHIANS AS WELL. THIS MEANS ANOTHER HOT AND HUMID DAY
FOR THE TENNESSEE VALLEY. THERE IS A VERY LOW CHANCE OF A FEW
SHOWERS/STORMS TOMORROW AFTERNOON, ESPECIALLY OVER NE AL. BUT,
CONFIDENCE IN THEIR OCCURRENCE IS LOW AT THE MOMENT. HIGHS ARE
FORECAST TO REACH THE MID TO UPPER 90S WITH DEW POINTS IN THE
LOWER 70S. THIS LEADS TO FORECAST HEAT INDICES IN THE 100-109
DEGREE RANGE ALONG WITH MAJOR HEATRISK (LEVEL 3 OF 4) FOR THE
ENTIRE LOCAL AREA AND WBGTS IN THE UPPER 80S TO AROUND 90 DEGREES.
WE COULD MIX OUT A BIT TOMORROW AFTERNOON LIKE WE DID TODAY,
CAUSING DEW POINTS TO BE LOWER (UPPER 60S); BUT, IT WILL STILL BE
HOT AREA-WIDE. THEREFORE, THE HEAT ADVISORY REMAINS IN EFFECT
THROUGH SATURDAY EVENING FOR ALL OF NORTH ALABAMA AND SOUTHERN
MIDDLE TENNESSEE.
PLEASE REMEMBER HEAT SAFETY, ESPECIALLY IF YOU WORK OUTSIDE OR
HAVE OUTDOOR ACTIVITIES! STAY HYDRATED, TAKE PLENTY OF BREAKS IN
THE SHADE, AND NEVER LEAVE PEOPLE OR PETS IN VEHICLES!
SHORT TERM
(THURSDAY NIGHT THROUGH SATURDAY)
ISSUED AT 852 PM CDT WED SEP 2 2026
HOT AND HUMID CONDITIONS WILL CONTINUE THROUGH THE END OF THE
WEEK (AS WILL THE HEAT ADVISORY), WITH HIGHS IN THE MID TO UPPER
90S, LOWS IN THE LOWER TO MID 70S, AND ELEVATED DEW POINTS (LOWER
TO MID 70S). IN TERMS OF OUR HEAT PARAMETERS, THEY REMAIN FAIRLY
CONSTANT, WITH HEAT INDICES BETWEEN 102-108 DEGREES, MAJOR
HEATRISK (LEVEL 3 OF 4) AREA-WIDE, AND WBGTS IN THE UPPER 80S TO
AROUND 90 DEGREES.
HOWEVER, THE UPPER RIDGE IS SHOWN TO BEGIN TO BREAK DOWN AS AN
UPPER TROUGH OVER THE NORTHEAST DIGS SOUTHWARD FRIDAY NIGHT
THROUGH SATURDAY. THIS, IN ADDITION TO A BACKDOOR SURFACE COLD
FRONT SLATED TO SWEEP ACROSS THE TENNESSEE VALLEY
SATURDAY/SATURDAY NIGHT, INCREASED SHOWER AND STORM CHANCES ARE
FORECAST BY LATE WEEK (ALBEIT LOW AT PRESENT). WITH HIGHS IN THE
MID TO UPPER 90S, INSTABILITY WILL BE ABUNDANT. GUIDANCE INDICATES
THAT BULK SHEAR WILL BE LOW, BUT DCAPE WILL BE WELL ABOVE 1000
J/KG (CLOSER TO 1500 J/KG). IN ADDITION, MODEL SOUNDINGS SHOW
QUITE THE "INVERTED V" SIGNATURE SATURDAY AFTERNOON. OTHER VARIOUS
DOWNBURST PARAMETERS SUCH AS WINDEX, THETA-E DIFFERENCE, AND
LAPSE RATES ARE ALSO WELL WITHIN OR EXCEEDING THRESHOLDS FOR A
CONDUCIVE DOWNBURST ENVIRONMENT. THEREFORE, SATURDAY LOOKS TO BE A
DAY WHERE DOWNBURSTS WILL BE THE MAIN STORM MODE WITH DAMAGING
WINDS, FREQUENT LIGHTNING, AND HEAVY RAIN THE MAIN THREATS. NOT
EXPECTING MUCH IN THE WAY OF HAIL WITH MODEL FREEZING LEVELS NEAR
16KFT, BUT THIS WILL BE MONITORED. WE ARE NOT OUTLOOKED BY SPC FOR
SEVERE STORMS YET; HOWEVER, IF THESE TRENDS HOLD, IT IS ENTIRELY
PLAUSIBLE THAT ALL OR A PORTION OF THE REGION WILL HAVE AT LEAST A
LOW CHANCE OF STRONG TO SEVERE STORMS. STAY TUNED!
OVERALL, CONTINUE TO PRACTICE HEAT SAFETY AND STAY WEATHER AWARE!
LONG TERM
(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 852 PM CDT WED SEP 2 2026
THE UPPER-RIDGE LOOKS AS IF IT MAY TEMPORARILY SHIFT BACK TO THE
WEST EARLY NEXT WEEK. HOWEVER, THIS COMES WITH A WORD OF CAUTION.
AT LEAST MODERATE (LEVEL 2/4) HEAT IMPACTS WILL CONTINUE THROUGH
THE MIDDLE OF NEXT WEEK AS HIGHS IN THE LOW TO MID 90S ARE STILL
FORECAST EACH DAY. THE MAIN DIFFERENCE WILL BE DEWPOINTS WHICH
WILL BE MODIFIED IN WAKE OF A SHORTWAVE PASSAGE SATURDAY NIGHT,
DROPPING THE FROM THE MID 70S INTO THE UPPER 60S. THIS WILL KEEP
OUR PEAK HEAT INDEX VALUES AROUND 100 DEGREES EACH DAY AS OPPOSED
TO 105-110. WITH RIDGING STILL THE DOMINANT FEATURE OVER
CENTRAL/SOUTHERN PORTIONS OF THE CONUS, AN OVERALL DRY FORECAST
WILL STILL REMAIN INTACT. HOWEVER, WITH THE TENNESSEE VALLEY BEING
ON THE EDGE OF THE RIDGE, LOW CHANCES (20%) OF DIURNALLY DRIVEN
SHOWERS AND THUNDERSTORMS WILL EXIST EACH AFTERNOON SUNDAY THROUGH
WEDNESDAY.
AVIATION
(12Z TAFS)
ISSUED AT 613 AM CDT THU SEP 3 2026
VFR CONDITIONS WILL CONTINUE THROUGH THE TAF PERIOD WITH CLEAR
SKIES AND LIGHT/VAR WINDS.
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....26
LONG TERM....AMP
AVIATION...25
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