719
FXUS64 KHUN 032242
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
542 PM CDT THU SEP 3 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1016 AM 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.
- A FEW THUNDERSTORMS MAY OCCUR BOTH THIS AFTERNOON AND FRIDAY
AFTERNOON, WITH A SLIGHT INCREASE IN COVERAGE EXPECTED ON
SATURDAY. REGARDLESS OF THE NUMBER OF STORMS, CONDITIONS WILL
BE FAVORABLE FOR LOCALLY DAMAGING WINDS, HEAVY RAIN, AND
FREQUENT LIGHTNING ON A DAILY BASIS.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 158 PM CDT THU SEP 3 2026
THERE HAVE BEEN NO MAJOR CHANGES TO PREVIOUS NEAR TERM FORECAST
REASONING SINCE THE UPDATE EARLIER THIS MORNING, WITH CURRENT
TEMPERATURES ON TRACK TO PEAK IN THE M-U 90S. ALTHOUGH MIXING HAS
RESULTED IN GRADUAL REDUCTION OF DEWPOINTS IN PARTS OF THE CWFA
OVER THE LAST COUPLE OF HOURS, APPARENT TEMPS ARE STILL EXPECTED
TO SOLIDLY REACH THE 100-105F RANGE (WITH MANY LOCATIONS INSIDE
URBAN HEAT ISLANDS REACHING 105-107F). THE GENERAL COVERAGE OF
SHOWERS (AND PERHAPS A FEW THUNDERSTORMS) IS EXPECTED TO SLOWLY
INCREASE THROUGH 21-23Z AS A SUBTLE LOW-LEVEL CONVERGENCE AXIS
LIFTS NORTHWARD INTO THE REGION, BUT CELLS WILL LIKELY NEED TO
SUSTAIN A 45-50 DBZ ECHO IN THE 19-21 KFT LAYER IN ORDER TO
PRODUCE LIGHTNING (AND THIS MAY BE DIFFICULT TO ACHIEVE DUE TO THE
PRESENCE OF A WEAK SUBSIDENCE INVERSION AROUND THIS LEVEL). AFTER
EARLY EVENING CONVECTION DISSIPATES, MOSTLY CLEAR SKIES AND DRY
CONDITIONS WILL PREVAIL OVERNIGHT, WITH LOWS IN THE L-M 70S.
PREVIOUS DISCUSSION:
A MID-LEVEL HIGH WILL REMAIN CENTERED ACROSS WESTERN PORTIONS OF
NC/SC THROUGHOUT THE NEAR TERM PERIOD, AS A BROAD BUT GRADUALLY
STRENGTHENING TROUGH RETROGRADES ACROSS THE EASTERN/CENTRAL GULF.
TO THE EAST OF THE TROUGH, A LOWER-AMPLITUDE EASTERLY WAVE
(CURRENTLY SITUATED OFF THE ATLANTIC COAST OF FL) WILL PROGRESS
NORTHWESTWARD INTO SOUTHERN GA/NORTH FL BUT SHOULD WEAKEN WITH
TIME AS IT ENCOUNTERS A REGION OF INCREASINGLY CONFLUENT FLOW.
AT THE SURFACE, OUR FORECAST AREA WILL LARGELY REMAIN UNDER THE
INFLUENCE OF A HIGH ACROSS THE SOUTHERN APPALACHIANS, WITH LIGHT
SE WINDS DURING THE DAYLIGHT HOURS TRANSITIONING TO CALM FLOW AT
NIGHT. HOWEVER, A SUBTLE PRESSURE TROUGH/STREAMLINE CONFLUENCE
AXIS (RELATED TO THE RETROGRADING TROUGH TO OUR SOUTH) IS
PREDICTED TO LIFT NORTHWESTWARD THROUGH THE CWFA LATE THIS
AFTERNOON/EARLY THIS EVENING AND MAY PROVIDE SUFFICIENT LOW-LEVEL
ASCENT FOR THE DEVELOPMENT OF A FEW SHOWERS AND THUNDERSTORMS
(BEGINNING IN THE 18-20Z TIMEFRAME). ALTHOUGH OZ CAMS INDICATE
THAT STORM COVERAGE WILL BE COMPARATIVELY LOWER IN THE VICINITY OF
THE BOUNDARY ACROSS OUR REGION (AND MUCH HIGHER FROM SOUTHWESTERN
AL INTO THE ARKLAMISS), STEEP LOW-LEVEL LAPSE RATES, MLCAPE IN
THE 2000-2500 J/KG RANGE AND PWAT VALUES IN THE 1.7-1.9" RANGE
SUGGEST THAT LOCALLY DAMAGING DOWNBURST WINDS AND FREQUENT
LIGHTNING MAY ACCOMPANY THE STRONGEST CELLS. IN THE ABSENCE OF
CONVECTIVE INFLUENCES, IT WILL BE ANOTHER HOT/HUMID DAY FEATURING
HIGHS IN THE M-U 90S. SIMILAR TO YESTERDAY, EFFICIENT MIXING WILL
LIKELY LOWER DEWPOINTS INTO THE M60S FOR MANY LOCATIONS (PERHAPS
KEEPING HI IN THE 100-105F RANGE AWAY FROM URBAN HEAT ISLANDS).
HOWEVER, WE HAVE NO PLANS TO ALTER THE ONGOING HEAT ADVISORY AT
THIS POINT.
CURRENT THINKING IS THAT ANY LINGERING SHOWERS/THUNDERSTORMS THIS
EVENING WILL DISSIPATE BETWEEN 0-2Z, BUT WITH THE POTENTIAL FOR A
LOW-LEVEL CONVERGENCE AXIS IN OUR GENERAL REGION, IT WOULD NOT BE
OUT OF THE REALM OF POSSIBILITY FOR ISOLATED CONVECTIVE CELLS TO
PERSIST A BIT LATER INTO THE EVENING. OVERNIGHT LOWS WILL ONCE
AGAIN BE IN THE M60S (WITH A FEW L60S IN THE EAST), WITH BRIEF
DEVELOPMENT OF PATCHY FOG AROUND SUNRISE IN VALLEYS AND NEAR LARGE
BODIES OF WATER.
SHORT TERM
(FRIDAY THROUGH SATURDAY NIGHT)
ISSUED AT 1016 AM CDT THU SEP 3 2026
DURING THE PERIOD FROM FRIDAY INTO FRIDAY NIGHT, THE MID-LEVEL
HIGH TO OUR NORTHEAST IS PREDICTED TO WEAKEN AS A DEEPENING
NORTHERN STREAM TROUGH DIGS SOUTHEASTWARD INTO THE CANADIAN
MARITIME PROVINCES. HOWEVER, A NEW ANTICYCLONE ALOFT WILL BECOME
ESTABLISHED OVER THE SOUTHERN PLAINS, AND THE UPPER TROUGH OVER
THE CENTRAL GULF WILL CONTINUE TO ADVANCE SLOWLY WESTWARD AS ITS
RELATED SURFACE WAVE DRIFTS VERY SLOWLY NORTHWESTWARD IN THE
VICINITY OF THE LA COAST. ALTHOUGH SOME AFTERNOON/EARLY EVENING
SHOWERS AND THUNDERSTORMS MAY CERTAINLY OCCUR IN OUR CWFA ONCE
AGAIN, CONCENTRATION APPEARS AS IF IT WILL BE HIGHEST IN THE
VICINITY OF A LOW-LEVEL CONVERGENCE AXIS (LIKELY SITUATED TO OUR
NORTHWEST) AND ACROSS SOUTHERN PORTIONS OF THE GULF COAST STATES,
WHERE RICH TROPICAL MOISTURE WILL SPREAD INLAND WITHIN A DEEP
SOUTH-SOUTHEAST FLOW REGIME. THUS, WE WILL KEEP POPS IN THE 10-20%
RANGE BUT SHOULD EMPHASIZE THAT THERMODYNAMIC PARAMETERS WILL
REMAIN SUFFICIENT FOR LOCALLY DAMAGING DOWNBURST WINDS.
NORTHERLY FLOW ALOFT WILL QUICKLY BECOME ESTABLISHED AND
STRENGTHEN FROM SATURDAY INTO SATURDAY NIGHT, WITHIN THE GRADIENT
BETWEEN A HIGH OVER THE SOUTHERN PLAINS AND AN AMPLIFYING TROUGH
TO OUR NORTHEAST. ALTHOUGH THIS WILL ADVECT DRIER AIR SOUTHWARD
(RESULTING IN A MINOR REDUCTION IN ATMOSPHERIC MOISTURE CONTENT),
THE ENVIRONMENT WILL BECOME MORE CONDUCIVE FOR THUNDERSTORMS
DURING THIS TIMEFRAME, ESPECIALLY AS A LENGTHY OUTFLOW BOUNDARY
(ORIGINATING FROM A NOCTURNAL MCS OVER THE LOWER GREAT LAKES/OH
VALLEY FRIDAY NIGHT) APPROACHES THE REGION FROM THE NORTHEAST
SATURDAY AFTERNOON. AS A RESULT, POPS HAVE BEEN INCREASED INTO THE
10-30% RANGE, AND THIS ACTIVITY COULD LINGER WELL INTO THE
EVENING HOURS (ESPECIALLY IF THE OUTFLOW BOUNDARY ACTUALLY ENTERS
OUR FORECAST AREA). IN SPITE OF LOWER PWAT VALUES, CONDITIONS WILL
REMAIN FAVORABLE FOR DAMAGING WIND AND FREQUENT LIGHTNING.
REGARDING TEMPERATURES, VERY LITTLE FLUCTUATION IS EXPECTED OVER
THE COURSE OF THE SHORT TERM PERIOD, WITH AFTERNOON HIGHS IN THE
M-U 90S AND OVERNIGHT LOWS IN THE L-M 70S. ALTHOUGH MIXING MAY
LOWER DEWPOINTS ON A DAILY BASIS, HI SHOULD REMAIN SUFFICIENTLY
HIGH TO WARRANT CONTINUATION OF THE CURRENT HEAT ADVISORY THROUGH
SATURDAY EVENING.
LONG TERM
(SUNDAY 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
(00Z TAFS)
ISSUED AT 542 PM CDT THU SEP 3 2026
THE VERY FEW SHRA OUT THERE WILL QUICKLY DIMINISH IN THE NEXT HOUR
OR TWO WITH THE LOSS OF HEATING. AS A RESULT, CLEAR AND CALM
CONDITIONS WILL OCCUR OVERNIGHT AND THROUGH THE DAY ON FRIDAY,
WITH VFR CONDITIONS PREVAILING.
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...70
SHORT TERM....70
LONG TERM....AMP
AVIATION...AMP.24
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