605
FXUS64 KHUN 192309
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
609 PM CDT SAT SEP 19 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 142 PM CDT SAT SEP 19 2026
- CONDITIONS WILL BE FAVORABLE FOR STRONG-SEVERE THUNDERSTORMS
EACH AFTERNOON INTO TUESDAY, WITH THE GREATEST SPATIAL COVERAGE
OF STORMS EXPECTED MONDAY AND TUESDAY. LOCALLY DAMAGING
DOWNBURST WINDS, FREQUENT LIGHTNING AND HEAVY RAINFALL WILL
BE THE MAIN STORM IMPACTS.
- HOT TEMPERATURES WILL CONTINUE INTO MONDAY, WITH HIGHS IN THE
MID-UPPER 90S IN THE VALLEY. A HEAT ADVISORY REMAINS IN EFFECT
THROUGH 8 PM CDT THIS EVENING.
- A SLIGHTLY COOLER AND DRIER AIRMASS WILL ARRIVE LATE IN THE
FORECAST PERIOD, WITH HIGHS DROPPING BACK INTO THE 80S ON
THURSDAY/FRIDAY.
NEAR TERM
(TONIGHT)
ISSUED AT 142 PM CDT SAT SEP 19 2026
AS OF THE EARLY AFTERNOON, STRONG HEATING AND STEEPER MID-LEVEL
LAPSE RATES HAVE RESULTED IN SCATTERED SHOWER AND THUNDERSTORM
DEVELOPMENT OVER AND AROUND THE TENNESSEE VALLEY. MOVEMENT OF THE
ACTIVITY IS SSE AROUND 5 MPH. THERE SHOULD BE A SOMEWHAT HIGHER
COVERAGE OF SHOWERS, WITH SOME OF THE STORMS ESPECIALLY EAST OF
I-65 COULD BECOME STRONG TO SEVERE. DOWNBURST/MICROBURST TYPE
OUTFLOW WIND GUSTS AND HEAVY DOWNPOURS ARE THE MAIN THREATS.
MIXING NOW OCCURRING WAS REDUCING MOST AREA DEWPOINTS INTO THE
MID/UPPER 60S. THIS HAS HELPED RELIEVE MOST OF THE AREA FROM
EXPERIENCING HEAT INDEXES AT OR ABOVE 105. THUS WE WILL LET THE
ON-GOING HEAT ADVISORY EXPIRE AT 8 PM THIS EVENING.
OTHERWISE, SHOWER ACTIVITY SHOULD END AS WE GO INTO THE EARLY
EVENING. DEPENDING UPON WHERE AND HOW MUCH RAIN FALLS, PATCHY LATE
NIGHT FOG DEVELOPMENT COULD OCCUR. AREAS THAT RECEIVE A "WETTING"
RAIN OF OVER 1/10 OF AN INCH, AS WELL AS THOSE MORE SHELTERED
VALLEY LOCATIONS WOULD HAVE THE BEST ODDS OF EXPERIENCING FOG. LOW
TEMPERATURES SHOULD COOL FROM THE UPPER 60S NE ALABAMA TO THE
LOW/MID 70S URBAN AREAS AND LOCATIONS NEAR LARGE BODIES OF WATER.
SHORT TERM
(SUNDAY THROUGH TUESDAY)
ISSUED AT 1045 AM CDT SAT SEP 19 2026
THE UPPER DISTURBANCE TO OUR NE WILL MOVE FURTHER TO THE EAST ON
SUN, WHILE THE UPPER RIDGE TO OUR WEST AND LOW OVER THE NE GULF
REMAINS. THUS ANOTHER HOT DAY EXPECTED. HIGHS SHOULD RISE INTO THE
LOW 90S EAST TO MID/UPPER 90S WEST. DEWPOINTS IN THE 70S AGAIN
SHOULD MIX DOWN INTO THE 60S, THUS ARE EXPECTING HEAT INDEXES TO
REMAIN LESS THAN 105 DEGREES. DESPITE NO ADVISORY, AREA RESIDENTS
SHOULD MAINTAIN AWARENESS FOR THE HEAT. THE MIXING SHOULD ALSO
LOWER SHOWER/THUNDERSTORM CHANCES IN THE AFTERNOON. WILL KEEP LOW
CHANCES OF AFTERNOON CONVECTION FOR OUR MORE EASTERN AREAS, THAT
WILL BE HELPED BY MORE RUGGED TERRAIN. SIMILARLY MILD/WARM SUN
NIGHT WITH LOWS IN THE LOW/MID 70S.
A SYNOPTIC SCALE SYSTEM FORMING TO OUR WEST WILL APPROACH THE
TENNESSEE VALLEY ON MONDAY. THIS SYSTEM WILL BRING LOW/MEDIUM
CHANCES OF SHOWERS/THUNDERSTORMS. WITH BETTER FORCING FROM THIS
SYSTEM, STORMS THAT FORM COULD BECOME STRONG TO SEVERE, WITH MORE
DOWNBURST-TYPE OUTFLOW WIND GUSTS THE MAIN THREAT. THIS RISK HAS
BEEN NOTED BY THE SPC, WITH MOST OF THE AREA IN A MARGINAL (1 OUT
OF 5) RISK FOR SEVERE STORMS. BEFORE SHOWERS BEGIN, EXPECT
SIMILARLY HOT CONDITIONS WITH HIGHS MAINLY IN THE 90S (LOWER 90S
EAST TO MID/UPPER 90S WEST). IT SHOULD BE BIT COOLER MON NIGHT
WITH LOWS FROM THE MID 60S EAST TO LOWER 70S NEAR LARGE BODIES OF
WATER. SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS ARE
FORECAST TUESDAY, WITH HIGHS FROM THE UPPER 80S EAST TO MID 90S
WEST. CONFIDENCE IS TOO LOW THIS FAR OUT TO EXACTLY DISCERN STORM
STRENGTH; CANNOT RULE OUT STRONGER STORM CHANCES TUE. LASTLY, THE
AUTUMN 2026 SEASON BEGINS TUE EVENING AROUND 704 PM CDT.
LONG TERM
(TUESDAY NIGHT THROUGH FRIDAY)
ISSUED AT 1057 PM CDT FRI SEP 18 2026
LATEST EXTENDED RANGE FORECAST DATA SUGGEST THAT A WEAK NORTHERN
STREAM TROUGH WILL ADVANCE SLOWLY EASTWARD FROM THE MID-MS VALLEY
INTO THE NORTHERN MID-ATLANTIC STATES NEXT WEEK, AS IT WILL LIKELY
BE BLOCKED BY RIDGING TO ITS NORTH. AT THE SURFACE, A TROUGH
(INITIALLY EXTENDING FROM CENTRAL PARTS OF MS/AL NORTH-
NORTHEASTWARD INTO THE UPPER OH VALLEY) IS PREDICTED TO REMAIN
NEARLY STATIONARY ON TUESDAY, AND WILL LIKELY FOCUS DEVELOPMENT OF
ADDITIONAL SHOWERS AND THUNDERSTORMS ACROSS OUR REGION BOTH
DURING THE DAY AND AT NIGHT. IN SIMILAR FASHION TO MONDAY, A FEW
STRONG-SEVERE THUNDERSTORMS MAY OCCUR DURING THE AFTERNOON AND
EVENING HOURS, AIDED BY HIGH CAPE AND INCREASING W-NW FLOW ALOFT.
ALTHOUGH THERE IS SOME UNCERTAINTY REGARDING PRECISELY WHEN THIS
WILL OCCUR, THE SURFACE TROUGH IS EXPECTED TO SHIFT SLOWLY
SOUTHEASTWARD AT SOME POINT WEDNESDAY/THURSDAY, ALLOWING A
COOLER/DRIER AIRMASS (ORIGINATING FROM AN ANTICYCLONE ACROSS
SOUTHERN QC) TO SPREAD SOUTHEASTWARD INTO THE REGION. THIS COUPLED
WITH 20-30 KNOT W-NW FLOW ALOFT AND DRY ADVECTION THROUGH THE
DEPTH OF THE TROPOSPHERIC COLUMN WILL ALLOW RAIN CHANCES TO
DECREASE CONSIDERABLY ON THURSDAY/FRIDAY. AFTERNOON HIGHS WILL
FALL BACK INTO THE L-M 80S BY THE END OF THE WORK WEEK, WITH
OVERNIGHT LOWS THURSDAY NIGHT/FRIDAY MORNING IN THE U50S-L60S.
AVIATION
(00Z TAFS)
ISSUED AT 609 PM CDT SAT SEP 19 2026
VFR CONDITIONS ARE FORECAST THROUGH THE TAF PERIOD. HOWEVER, A LOW
CHANCE OF PATCHY FOG EXISTS LATE TONIGHT INTO SUNDAY.
HUN WATCHES/WARNINGS/ADVISORIES
AL...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR ALZ001>010-016.
TN...HEAT ADVISORY UNTIL 8 PM CDT THIS EVENING FOR TNZ076-096-097.
NEAR TERM...RSB
SHORT TERM....RSB
LONG TERM....70
AVIATION...HC
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