398
FXUS64 KHUN 151127
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
627 AM CDT SAT AUG 15 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 323 AM CDT SAT AUG 14 2026
- DANGEROUS HEAT WILL IMPACT THE TENNESSEE VALLEY THROUGH THE
MIDDLE OF NEXT WEEK, WITH MAJOR (LEVEL 3/4) TO EXTREME (LEVEL
4/4) HEAT IMPACTS FORECAST.
- A HEAT ADVISORY IS IN EFFECT FOR ALL OF NORTHERN ALABAMA AND
SOUTHERN MIDDLE TENNESSEE THROUGH 7 PM MONDAY, WITH EXTENSIONS
POTENTIALLY INTO THE MIDDLE OF NEXT WEEK.
- A MARGINAL (1 OUT OF 5) RISK FOR SEVERE THUNDERSTORMS IS
FORECAST ACROSS NORTHERN ALABAMA NEAR AND EAST OF I-65 MONDAY
AFTERNOON.
NEAR TERM
(TODAY)
ISSUED AT 323 AM CDT SAT AUG 15 2026
STRONG UPPER LEVEL RIDGING SITUATED OVER THE DEEP SOUTH WAS A MAIN
FEATURE CONTROLLING WEATHER ACROSS THE TENNESSEE VALLEY. THIS
UPPER HIGH FEATURING HEIGHTS IN THE UPPER 590S DECAMETERS SHOULD
REMAIN ACROSS THE SOUTHERN LOWER-48 INTO THE FIRST HALF OF NEXT
WEEK. THUS VERY WARM TO HOT CONDITIONS WILL CONTINUE FOR THE
PERIOD. ADDING TO THIS IS MOISTURE, WITH AREA DEWPOINTS MAINLY IN
THE LOW/MID 70S FORECAST FOR MUCH OF THE DAY. A GRADIENT OF
DEWPOINTS SHOULD SETUP DURING THE DAY, WITH HIGHER VALUES TO THE
EAST. SLIGHTLY DRIER VALUES MOVING ACROSS OUR WESTERN AREAS WILL
ACTUALLY HELP TEMPER HEAT INDEXES THERE. THUS WITH LESSER CLOUD
COVER AND MORE OPPORTUNITY FOR DAYTIME HEATING, HIGH TEMPERATURES
OVER NW ALABAMA SHOULD SOAR INTO THE UPPER 90S PER THE NBM AND THE
GFS LAMP. OLDER NAM/GFS MOS WERE HINTING AT 100/102 RESPECTIVELY
FOR MUSCLE SHOALS, THAT CANNOT BE RULED OUT. THE REST OF THE AREA
SHOULD EXPERIENCE HIGH TEMPERATURES IN THE MID/UPPER 90S.
WITH SLIGHTLY HIGHER MOISTURE VALUES TO THE EAST, STRONG DAYTIME
HEATING COULD RESULT IN AN ISOLATED SHOWER OR THUNDERSTORM FORMING
THIS AFTERNOON. STAYING WITH THE NBM, ONLY FAR NE ALABAMA ARE
PAINTED WITH LOWER END 15-20 PERCENT CONVECTION CHANCES THIS
AFTERNOON.
SHORT TERM
(SATURDAY NIGHT THROUGH MONDAY)
ISSUED AT 929 PM CDT FRI AUG 14 2026
THE HIGH PRESSURE RIDGE WILL AMPLIFY AND MOVE EASTWARD OVER THE
MID SOUTH AND LOWER MISSISSIPPI VALLEY SUNDAY INTO MONDAY, WITH A
HEAT DOME UNDERNEATH THIS RIDGE SUBSEQUENTLY SHIFTING EAST INTO
THE REGION. DAYTIME HIGHS IN THE 95 TO 100 DEGREE RANGE WILL BE
COMMON BOTH DAYS. WITH DEWPOINTS IN THE MID TO UPPER 70S, HEAT
INDEX VALUES REACH THE 105-110 DEGREE RANGE, WITH SOME LOCATIONS
PEAKING BETWEEN 110-114 DEGREES. AS A RESULT, NWS HEAT RISK
HIGHLIGHTS A MAJOR (LEVEL 3/4) THREAT TO EXTREME (LEVEL 4/4)
THREAT FOR HEAT IMPACTS BOTH DAYS. A HEAT ADVISORY IS IN EFFECT
UNTIL 7 PM MONDAY, BUT WE WILL NEED TO MONITOR FORECAST TRENDS
ACROSS PORTIONS OF NORTHWEST AND NORTH CENTRAL ALABAMA AND
SOUTHERN MIDDLE TENNESSEE WHERE AN UPGRADE TO AN EXTREME HEAT
WARNING MAY BE NEEDED IN LATER FORECAST UPDATES.
* UPDATED AT 323 AM CDT FRI AUG 14 2026
A RETURN OF DEEPER MOISTURE OVER OUR MORE EASTERN AREAS IS
FORECAST ON MON. THIS INCREASE IN MOISTURE PLUS CONTINUED STRONG
HEATING WILL RESULT IN A MORE UNSTABLE ENVIRONMENT. THIS HIGHER
INSTABILITY, ALONG WITH THE APPROACH OF A COLD FRONT WILL BRING A
LOWER END RISK OF THUNDERSTORM DEVELOPMENT MON AFTERNOON. FORECAST
SOUNDINGS INDICATE A POTENTIAL OF STRONG OUTFLOW WIND GUSTS, AKA
MICROBURST LIKE IN THE STRONGEST STORMS. PRECIPITABLE WATER
AMOUNTS IN THE 1.8" TO 2" WILL BRING A RISK OF LOCALLY HEAVY
DOWNPOURS AS WELL.
LONG TERM
(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 929 PM CDT FRI AUG 14 2026
THE CENTER OF THE RIDGE WILL BEGIN TO GRADUALLY FLATTEN THROUGH
THE WEEK, BUT MAJOR (LEVEL 3/4) HEAT IMPACTS WILL CONTINUE
THROUGH THE WORK WEEK. THIS IS DUE TO HIGHS IN THE MID 90S AND
DEWPOINTS IN THE MID TO UPPER 70S CREATING HEAT INDEX VALUES IN
EXCESS OF 105 DEGREES EACH DAY. IN ADDITION TO THE HEAT, LOW
CHANCES (20-30%) OF DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS
WILL RETURN TO THE FORECAST EACH AFTERNOON TUESDAY THROUGH FRIDAY,
THANKS TO THE DEEP MOISTURE IN PLACE. THE ONE CAVEAT WOULD BE IF
THE RIDGE SHIFTS A LITTLE FURTHER TO THE WEST, PLACING THE AREA
UNDER NORTHWEST FLOW ALOFT. SHOULD THIS PLAY OUT, WE MAY BE MORE
UNDER THE THREAT FOR MCS ACTIVITY THAT RIDES ALONG THE EDGE OF THE
RIDGE. WE'LL HAVE TO WATCH THIS IN THE DAYS TO COME. OVERALL, HOT
AND HUMID WEATHER FOR THE FORESEEABLE FUTURE.
AVIATION
(12Z TAFS)
ISSUED AT 627 AM CDT SAT AUG 15 2026
UNDER MOSTLY CLEAR SKIES, PATCHY FOG HAS FORMED ACROSS PORTIONS OF
THE TN VALLEY. SOME OF THIS FOG WAS IMPACTING KMSL, WITH LOCAL
VSBY REDUCTIONS TO 1SM. THIS FOG SHOULD DISSIPATE IN THE NEXT HOUR
OR SO AS THE SUN RISES. STRONG DAYTIME HEATING SHOULD PRODUCE FEW
TO SCATTERED CUMULUS WITH CLOUD BASES ABOVE 5KT FT. THE HEATING
OF A MORE MOIST AIRMASS OVER FAR NE AL COULD LEAD TO ISOLATED
SHOWER AND THUNDERSTORM DEVELOPMENT MAINLY THIS AFTERNOON. LIGHT
WINDS EARLY IN THE PERIOD WILL BECOME WESTERLY 5-7KT IN THE LATE
MORNING AND AFTERNOON, WITH WINDS BECOMING LIGHT AFTER DUSK.
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR ALZ001>010-016.
TN...HEAT ADVISORY UNTIL 7 PM CDT MONDAY FOR TNZ076-096-097.
NEAR TERM...RSB
SHORT TERM....AMP.24
LONG TERM....AMP.24
AVIATION...RSB
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