836
FXUS64 KHUN 180230
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
930 PM CDT THU SEP 17 2026
..NEW NEAR TERM, SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 930 PM CDT THU SEP 17 2026
- A HEAT ADVISORY IS IN EFFECT THROUGH 8 PM SATURDAY ACROSS ALL
OF SOUTHERN MIDDLE TENNESSEE AND NORTHERN ALABAMA.
- NWS HEAT RISK HIGHLIGHTS MODERATE (LEVEL 2/4) TO MAJOR (LEVEL
3/4) HEAT IMPACTS THROUGH THE WEEKEND ACROSS THE TENNESSEE
VALLEY. LOCALIZED EXTREME (LEVEL 4/4) IMPACTS MAY OCCUR IN
URBANIZED AREAS.
NEAR TERM
(REST OF TONIGHT AND FRIDAY)
ISSUED AT 930 PM CDT THU SEP 17 2026
A TRANQUIL EVENING IS IN STORE ACROSS THE TENNESSEE VALLEY AS THE
AREA SITS UNDERNEATH A LARGE AMPLITUDE MID AND UPPER LEVEL RIDGE.
SFC HIGH PRESSURE REMAINS CENTERED OVER THE SOUTHEAST AND AS A
RESULT, LIGHT WINDS AND CLEAR SKIES ARE FORECAST TONIGHT.
TEMPERATURES THIS EVENING HAVE FALLEN QUICKLY AFTER SUNSET THANKS
TO THE RELATIVELY DRIER AIR WITH OVERNIGHT LOWS EXPECTED TO DROP INTO
THE LOWER 70S.
ANOTHER RINSE AND REPEAT DAY IS FORECAST ON FRIDAY WITH
VERY HOT TEMPERATURES EXPECTED AS AFTERNOON HIGHS RISE INTO THE
MID TO UPPER 90S. THE GOOD NEWS IS THAT DEWPOINTS WILL ONCE AGAIN
MIX OUT DURING THE PEAK HEATING HOURS AND DROP DOWN INTO THE MID
TO UPPER 60S. THIS KEEPS MAX HEAT INDEX VALUES BETWEEN 100F-107F.
HOWEVER, WITH WET BULB GLOBE TEMPERATURES IN THE UPPER 80S TO
AROUND 90F AND NWS HEAT RISK AT MODERATE (LEVEL 3 OUT OF 4) TO
EXTREME (LEVEL 4 OUT OF 4) IN THE METRO AREA, DANGEROUS HEAT WILL
ONCE AGAIN BE THE MAIN CONCERN OF FRIDAY. THEREFORE THE HEAT
ADVISORY WILL CONTINUE THROUGH SATURDAY. MAKE SURE TO PRACTICE
GOOD HEAT SAFETY BY STAYING HYDRATED AND AVOIDING LONG AMOUNTS OF
TIME IN DIRECT SUNLIGHT. WHILE THERE IS A VERY LOW CHANCE OF A
STRAY SHOWER ACROSS PORTIONS OF NE AL TOMORROW, THE LATEST CAMS
SUGGEST THE BULK OF THE PRECIP SHOULD REMAIN TO THE NORTHEAST OF
THE LOCAL FORECAST AREA.
SHORT TERM
(FRIDAY NIGHT THROUGH SUNDAY NIGHT)
ISSUED AT 930 PM CDT THU SEP 17 2026
AS WE HEAD INTO THE WEEKEND THE UPPER LEVEL RIDGE BEGINS TO BREAK
DOWN AND RECEDE A BIT TO THE WEST. AT THE SAME TIME, A WEAK LOW
PRESSURE SYSTEM OFF THE EAST COAST OF FLORIDA BEGINS TO DRIFT TO
THE WEST. THIS WILL PRODUCE MORE FAVORABLE CONDITIONS FOR
AFTERNOON CONVECTION, ESPECIALLY EAST OF I-65. AT THIS TIME, NO
SEVERE STORMS ARE EXPECTED GIVEN THE WEAK SHEAR PROFILES. HOWEVER,
CANNOT RULE OUT A STRONG STORM OR TWO CAPABLE OF GUSTY WINDS AS
DCAPE VALUES RISE ABOVE 1000 J/KG. PRIOR TO ANY PRECIP,
TEMPERATURES WILL ONCE AGAIN WARM INTO THE MID TO UPPER 90S BOTH
SATURDAY AND SUNDAY. SHOWERS AND STORMS WILL DISSIPATE AFTER
SUNSET WITH THE LOSS OF DAYTIME HEATING RESULTING IN CALM
CONDITIONS OVERNIGHT. SOMETHING TO KEEP AN EYE ON IS THE LOW
CHANCES FOR EARLY MORNING FOG IN AREAS THAT RECEIVE RAINFALL
DURING THE DAY. OTHERWISE, MILD AND HUMID NIGHTS CONTINUE WITH
OVERNIGHT LOWS IN THE UPPER 60S TO LOWER 70S.
LONG TERM
(MONDAY THROUGH THURSDAY)
ISSUED AT 930 PM CDT THU SEP 17 2026
EXTENDED RANGE MODEL SOLUTIONS SUGGEST THAT A 500-MB RIDGE WILL
REMAIN POSITIONED ACROSS THE FORECAST AREA ON MONDAY. HOWEVER, AS WE
PROGRESS THROUGH THE REST OF THE PERIOD, IT IS BECOMING INCREASINGLY
LIKELY THE THE SOUTHERN EDGE OF THE MID-LATITUDE WESTERLIES WILL
DEVELOP SOUTHWARD INTO OUR REGION, WITH INDICATIONS OF A FLAT
SUBTROPICAL RIDGE LYING ACROSS THE NORTHERN GULF AND DEVELOPMENT OF
AN UPPER LOW (FROM PHASING OF 2-3 DISTINCT NORTHERN STREAM
SHORTWAVES) OVER THE GREAT LAKES. IN THE LOW-LEVELS, A WEAK AREA OF
LOW PRESSURE IS PREDICTED TO MIGRATE FROM THE MID-SOUTH INTO THE TN
VALLEY ON MONDAY, BEFORE DEGENERATING INTO A FRONTAL WAVE AS IT LIFTS
NORTHEASTWARD INTO THE UPPER OH VALLEY MONDAY NIGHT. ALTHOUGH THE
TRAILING COLD FRONT WILL MAKE ONLY GRADUAL SOUTHEASTWARD PROGRESSION
INTO THE OZARKS AND OH VALLEY BY EARLY TUESDAY MORNING, MESOSCALE
BOUNDARIES ORIGINATING FROM EXTENSIVE CONVECTION TO OUR NORTHWEST
SHOULD CONTRIBUTE TO A HIGHER COVERAGE OF THUNDERSTORMS ACROSS OUR
CWFA MONDAY AFTERNOON AND EVENING. AS SURFACE PRESSURES BEGIN TO RISE
WITHIN A HIGH MIGRATING EASTWARD ACROSS SOUTHERN ONTARIO/QUEBEC (AND
RENEWED CYCLOGENESIS TAKES PLACE OVER THE EASTERN GREAT LAKES), THE
COLD FRONT WILL ADVANCE FURTHER SOUTHEASTWARD ON TUESDAY, RESULTING
IN ANOTHER EPISODE OF CONVECTION DURING THE AFTERNOON/EVENING HOURS.
SUFFICIENT CAPE WILL EXIST TO SUPPORT A RISK FOR STRONG-LOCALLY
SEVERE THUNDERSTORMS BOTH PERIODS, ESPECIALLY GIVEN AN INCREASE IN
MID-LEVEL FLOW TO 15-25 KNOTS. AS THE COLD FRONT SHIFTS FURTHER
SOUTHEASTWARD THROUGH THE REGION WEDNESDAY, LIGHT-MODERATE NORTHERLY
FLOW WILL BEGIN TO ADVECT A SLIGHTLY COOLER/DRIER AIRMASS INTO THE
REGION, WITH HIGHS ON WEDNESDAY AND THURSDAY DROPPING BACK INTO THE
85-90F RANGE AND LOWS FALLING INTO THE L-M 60S.
AVIATION
(00Z TAFS)
ISSUED AT 544 PM CDT THU SEP 17 2026
VFR CONDITIONS WITH LIGHT WINDS WILL CONTINUE THROUGH THE TAF
PERIOD. THERE IS A VERY LOW CHANCE OF AN AFTERNOON THUNDERSTORM
TOMORROW, ESPECIALLY OVER NE AL, BUT CONFIDENCE IS TOO LOW TO
INCLUDE IN THE FORECAST.
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...GH
SHORT TERM....GH
LONG TERM....70/DD
AVIATION...GH
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