469
FXUS64 KHUN 050238
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
938 PM CDT FRI SEP 4 2026
..NEW NEAR TERM, SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 937 PM CDT FRI SEP 4 2026
- A HEAT ADVISORY REMAINS IN EFFECT THROUGH 8 PM SUNDAY 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 (30% OR LESS) OF THUNDERSTORMS ARE FORECAST
SATURDAY AFTERNOON INTO THE LATE EVENING, WITH A LOW CHANCE OF
SOME BECOMING SEVERE. DAMAGING WINDS WILL BE THE PRIMARY THREAT
IS ANY STRONG TO SEVERE STORMS.
NEAR TERM
(REST OF TONIGHT AND SATURDAY)
ISSUED AT 937 PM CDT FRI SEP 4 2026
SHOWERS AND THUNDERSTORMS THAT FORMED EARLIER THIS EVENING HAVE
SINCE SUBSIDED AND DRY CONDITIONS ARE FORECAST OVERNIGHT. MOSTLY
CLEAR SKIES COUPLED WITH LIGHT WINDS WILL SUPPORT A PATCHY FOG
RISK OVER AREAS WITH SMALLER DEW POINT DEPRESSIONS AND AREAS THAT
SAW RAIN EARLIER. RECENT MODEL RUNS KEEP SMALLER DEW POINT
DEPRESSIONS ALONG AND WEST OF I-65, SO CONFIDENCE IS HIGHER IN AT
LEAST PATCHY FOG FORMING THERE OVERNIGHT INTO EARLY SATURDAY. IF
ANY FOG IS REALIZED, IT WILL DISSIPATE SHORTLY AFTER SUNRISE.
OVERNIGHT LOWS ARE FORECAST TO DROP INTO THE MID 70S, PROVIDING
LITTLE RELIEF FROM THE ONGOING HEAT.
SATURDAY AFTERNOON INTO THE EVENING, LOW CHANCES (30% OR LESS) OF
THUNDERSTORMS RETURN TO THE FORECAST AS A RESULT OF A SHORTWAVE
AHEAD OF THE LOOMING UPPER LEVEL RIDGE IN ADDITION TO DIURNAL
HEATING SUPPORT. HIGHS ARE FORECAST TO QUICKLY RISE INTO THE UPPER
90S ONCE AGAIN BEFORE CONVECTION MATERIALIZES, WITH A LOW CHANCE
(25% OR LESS) OF SOME AREAS IN NW AL HITTING 100 DEGREES. A HEAT
ADVISORY REMAINS IN EFFECT THROUGH SATURDAY. MODEL SOUNDINGS SHOW
THE TYPICAL INVERTED V PROFILE FOR DOWNBURSTS, WITH 1.9" PWAT
VALUES (NEAR 90TH PERCENTILE PER BMX SOUNDING CLIMATOLOGY) AS WELL
AS STRONG MLCAPE (1300 J/KG) AND DCAPE (900-1000 J/KG). STOUT LOW
LEVEL LAPSE RATES (9-10 C/KM) ARE ALSO WORTH NOTING TO SUPPORT
DOWNBURSTS AND SUBSEQUENT DAMAGING WINDS. IN ADDITION TO PWATS, A
LOW FLOODING THREAT WILL ALSO BE SUPPORTED BY SLOW STORM MOTION AS
CORFIDI UPSHEAR VALUES ARE LESS THAN 5 KTS. WHILE WE ARE
CURRENTLY BARELY CLIPPED BY A MARGINAL RISK (LEVEL 1 OF 5), WE
WOULD NOT BE SURPRISED IF THE MARGINAL RISK WAS STRETCHED
SOUTHWESTWARD INTO PORTIONS OF NORTHEASTERN AL AND SOUTHERN MIDDLE
TN. BE SURE TO HAVE MULTIPLE WAYS TO GET WARNINGS TOMORROW
AFTERNOON AND KEEP UP TO DATE WITH THE LATEST FORECAST.
SHORT TERM
(SATURDAY NIGHT THROUGH MONDAY)
ISSUED AT 937 PM CDT FRI SEP 4 2026
THUNDERSTORMS SHOULD GRADUALLY COME TO AN END BY THE LATE EVENING
HOURS SATURDAY WITH THE LOSS OF DIURNAL SUPPORT. HOWEVER, SUB-
SEVERE THUNDERSTORMS WILL LIKELY REMAIN IN THE AREA THROUGH THE
EARLY MORNING HOURS- BRINGING ADDITIONAL HEAVY RAINFALL AS WELL AS
LIGHTNING WITH A LOW CHANCE OF GUSTY WINDS. WHILE OUR HEAT
ADVISORY WAS SLATED TO END SATURDAY NIGHT, IT HAS NOW BEEN
EXTENDED TO SUNDAY NIGHT AS THE TENNESSEE VALLEY REMAINS UNDER THE
INFLUENCE OF AN UPPER LEVEL RIDGE AND SUBSEQUENT ABOVE NORMAL
TEMPERATURES. HIGH TEMPERATURES ON SUNDAY ARE FORECAST TO REACH
THE UPPER 90S WITH HEAT INDICES UP TO 109 DEGREES. A COLD FRONT
SHOULD PUSH THROUGH THE AREA SUNDAY AFTERNOON, BRINGING SLIGHT RELIEF
FROM THE HEAT BY SUNDAY NIGHT AS LOW TEMPERATURES DROP INTO THE
UPPER 60S TO LOWER 70S (AS OPPOSED TO MID 70S THE PAST SEVERAL
NIGHTS). HIGHS ON MONDAY ARE STILL FORECAST TO REACH THE 90S,
HOWEVER, HEAT INDICES SHOULD BE CAPPED NEAR 100 DEGREES AS A
RELATIVELY DRIER AIRMASS SHIFTS SOUTHWARD INTO THE AREA. LOW
CHANCES (30% OR LESS) OF THUNDERSTORMS REMAIN IN RESPONSE TO
DIURNAL HEATING MONDAY AFTERNOON.
LONG TERM
(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 937 PM CDT FRI SEP 4 2026
HEAT WILL PERSIST THROUGH THE LONG TERM AS WELL. THE VAST RIDGE OF
HIGH PRESSURE THAT IS CENTERED OVER THE SOUTHERN PLAINS AND MID MS
VALLEY WILL EXPAND EASTWARD TO ENCOMPASS THE REST OF THE SOUTHEAST
EARLY THIS WEEK. MID WEEK, A TROUGH WILL SWING THROUGH THE SOUTHERN
CANADIAN PRAIRIE PROVINCES DAMPENING THE RIDGE, AND SFC HIGH
PRESSURE WILL SET UP ALONG THE APPALACHIANS. THIS SET UP COULD CREATE
A CAD EXPANDING INTO NE AL AND PORTIONS OF SOUTHERN MIDDLE TN. IF
THIS COMES TO FRUITION, ADJUSTMENTS TO POPS (SLIGHT INCREASE) AND
TEMPS (SLIGHT DECREASE) WOULD BE NEEDED. REGARDLESS, IT LOOKS LIKE
TEMPS WILL REMAIN IN THE 90S THROUGHOUT THE WEEK, WHICH IS PAR FOR
THE COURSE THIS MONTH, BUT RUNNING A TAD HIGHER THAN SEASONAL NORMS
WHICH IS 87-88 DEGREES. HEAT INDEX VALUES WILL HOVER AROUND 100
DEGREES AND THE NWS HEAT RISK WILL BE A LEVEL 2 (MODERATE LEVEL) FOR
THE LARGE MAJORITY OF US. REMAIN HEAT SMART:
SLOW DOWN, COOL DOWN, STAY HYDRATED AND NEVER LEAVE PEOPLE OR PETS
IN VEHICLES.
AVIATION
(00Z TAFS)
ISSUED AT 617 PM CDT FRI SEP 4 2026
VFR CONDITIONS ARE FORECAST OVERNIGHT INTO SATURDAY MORNING.
SATURDAY AFTERNOON INTO THE EVENING, A PROB30 GROUP WAS ADDED AT
BOTH SITES INTO MVFR DUE TO LOW THUNDERSTORM CHANCES POTENTIALLY
CAUSING LOWERED VISIBILITIES AND CEILINGS.
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 8 PM CDT SUNDAY FOR ALZ001>010-016.
TN...HEAT ADVISORY UNTIL 8 PM CDT SUNDAY FOR TNZ076-096-097.
NEAR TERM...HC
SHORT TERM....HC
LONG TERM....JMS
AVIATION...HC
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