247
FXUS64 KHUN 060919
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
419 AM CDT SUN SEP 6 2026
..NEW NEAR TERM
KEY MESSAGES
UPDATED AT 419 AM CDT SUN SEP 6 2026
- A HEAT ADVISORY REMAINS IN EFFECT THROUGH 8 PM THIS EVENING DUE
TO A MAJOR HEAT RISK, AND AFTERNOON HEAT INDICES RISING UP TO
105-109 DEGREES IN PORTIONS OF THE FORECAST AREA.
- A RISK OF STRONG TO SEVERE THUNDERSTORMS IS FORECAST FOR MUCH
OF THE TENNESSEE VALLEY TODAY. STRONG TO DAMAGING WIND GUSTS
ARE THE MAIN THREATS POSED BY THE STRONGER STORMS.
- NOT AS HOT HIGH TEMPERATURES CONTINUE FROM LABOR DAY INTO THE
LATE WEEK.
NEAR TERM
(TODAY)
ISSUED AT 419 AM CDT SUN SEP 6 2026
A SOMEWHAT OF BUSY OVERNIGHT CONTINUED, AS ISOLATED TO SCATTERED
SHOWERS AND THUNDERSTORMS IMPACT PORTIONS OF THE TENNESSEE VALLEY.
THIS CONVECTION WAS FORMING IN AN UNSTABLE REGION ALOFT, AND FROM
INTERACTION OF NUMEROUS REMAINING OUTFLOW BOUNDARIES FROM PREVIOUS
CONVECTION. THIS ELEVATED INSTABILITY WAS PRODUCING MODERATE MID-
LEVEL LAPSE RATES OF NEAR 6C/KM ESPECIALLY OVER MIDDLE TENNESSEE,
ALONG WITH MIX LAYER CAPES OF 1500-2000 J/KG. THIS ACTIVITY WAS
HEADING SOUTHWARD AROUND 10 MPH. IN A VERY MOISTURE ENVIRONMENT
WITH PRECIPITABLE WATER AMOUNTS OF 1.8 TO 2", SOME LOCALLY HEAVY
AMOUNTS OF RAINFALL HAVE OCCURRED (INCLUDING FROM SAT). A FEW
MESONET SITES HAVE RECORDED LOCAL TOTALS OVER 1.5" IN SPOTS FROM
WEST OF WINCHESTER AND AROUND HUNTSVILLE. MRMS WAS SHOWING SPOTTY
MAXIMA IN THOSE LOCATIONS ABOVE, AND SE OF DECATUR AND WEST OF
CULLMAN. MOST MODEL GUIDANCE HAS THE CONVECTION WINDING DOWN AS WE
NEAR DAYBREAK. MUGGY CONDITIONS WILL CONTINUE, WITH LOWS ONLY
FALLING INTO THE LOW/MID 70S. GIVEN HUMID CONDITIONS, SOME PATCHY
LATE NIGHT FOG COULD OCCUR, ESPECIALLY IN THOSE NORMALLY FOG PRONE
LOCATIONS, AS WELL AS PLACES THAT RECEIVED RECENT RAINFALL.
ONE MORE HOT DAY IS FORECAST TO START OUT A NEW WEEK. HIGH
TEMPERATURES SHOULD SOAR BACK INTO THE MID/UPPER 90S (CANNOT RULE
OUT AN ISOLATED 100F HIGH IN THE HOTTEST SPOTS). DEWPOINTS STAYING
IN THE LOW/MID 70S WILL PRODUCE HEAT INDEX VALUES FROM 105-109F,
THUS THE HEAT ADVISORY CONTINUES THROUGH 8 PM THIS EVENING.
A FRONTAL BOUNDARY LOCATED FROM THE NORTHERN HIGH PLAINS, ACROSS
MISSOURI AND KENTUCKY, AND THE CAROLINAS WILL MOVE SOUTHWARD
ACROSS THE REGION TODAY. AS A SLIGHTLY MILDER AIRMASS FILTERS IN,
STRONG DAYTIME HEATING AND RESULTANT INSTABILITY WILL RESULT IN
THE DEVELOPMENT OF ADDITIONAL SHOWERS AND THUNDERSTORMS. WITH A
MOISTURE LADEN ENVIRONMENT IN PLACE, DAYTIME HEATING WILL PRODUCE
HIGHER INSTABILITY, ALONG WITH AN AIRMASS CHANGE AS SLIGHTLY DRIER
AIR FILTERS IN. THUS SOME OF THE STORMS COULD BECOME STRONG TO
SEVERE IN INTENSITY, WITH DAMAGING OUTFLOW WIND GUSTS THE MAIN
THREAT. FREQUENT LIGHTNING AND HEAVY DOWNPOURS ARE EXPECTED AS
WELL. FLASH FLOODING IS MINIMAL, ESPECIALLY IF HEAVY RAIN IMPACTS
AN AREA THAT ALREADY RECEIVED RECENT HEAVY RAINFALL.
SHORT TERM
(TONIGHT THROUGH TUESDAY)
ISSUED AT 955 PM CDT SAT SEP 5 2026
THE SHORT TERM PERIOD WILL BE DRIVEN BY THE UPPER LEVEL RIDGE AS
IT SHIFTS SLIGHTLY WESTWARD TO BEGIN THE WORK WEEK THEN QUICKLY
RETURNS EASTWARD, BRINGING CONTINUED ABOVE NORMAL TEMPERATURES TO
THE TENNESSEE VALLEY. DURING THIS TIME, HIGH TEMPERATURES ARE
FORECAST TO REACH THE UPPER 80S TO MID 90S (WITH WARMER
TEMPERATURES REMAINING IN NW AL) AND HEAT INDICES UP TO NEAR 100
DEGREES. THESE RELATIVELY COOLER (THAN THE PAST WEEK) TEMPERATURES
WILL KEEP HEAT PRODUCTS OFF THE TABLE SINCE WE WILL BE BELOW
CRITERIA, HOWEVER, BE SURE TO CONTINUE PRACTICING HEAT SAFETY TO
AVOID HEAT ILLNESS IF SPENDING TIME OUTDOORS.
LONG TERM
(TUESDAY NIGHT THROUGH SATURDAY)
ISSUED AT 955 PM CDT SAT SEP 5 2026
AS THE UPPER LEVEL RIDGE REMAINS THE MAIN INFLUENCE OVER THE AREA
THROUGH THE LONG TERM, THERE WILL ALSO BE ANOTHER FEATURE TO
WATCH. AS AN UPPER LEVEL SHORTWAVE AND SUBSEQUENT LOW PRESSURE
SYSTEM SHIFT EASTWARD NORTH OF THE GREAT LAKES, A WEAK RIDGE WILL
DEVELOP AHEAD OF THIS IN THE NORTHERN APPALACHIAN REGION AND BRING
SUBSEQUENT SFC HIGH PRESSURE. IN TURN, WEAK CAD WILL ADVECT INTO
THE EASTERN PORTIONS OF THE AREA, WHICH WILL LIKELY SET UP A
DIFFERENTIAL HEATING BOUNDARY BY EARLY TO MID WEEK AND ALLOW LOW
CHANCES OF THUNDERSTORMS (30% OR LESS) EACH AFTERNOON. THIS WILL
BE DEPENDENT ON WHERE THE SFC HIGH OFFICIALLY SETS UP. OTHERWISE,
MOSTLY DRY CONDITIONS ARE FORECAST WITH CONTINUED HIGH
TEMPERATURES IN THE LOW TO MID 90S. BEYOND THE LONG TERM, THE
CLIMATE PREDICTION CENTER KEEPS US IN AN AREA FOR LIKELY ABOVE
NORMAL TEMPERATURES FOR THE 8-14 DAY PERIOD. THEREFORE, RELIEF
FROM THIS HEAT IS NOT CURRENTLY IN SIGHT.
AVIATION
(06Z TAFS)
ISSUED AT 1135 PM CDT SAT SEP 5 2026
VFR CONDITIONS CONTINUE THROUGH THE TAF PERIOD AT BOTH SITES WITH
A LOW CHANCE (15%) OF SHOWER OR THUNDERSTORM DEVELOPMENT AT KHSV
OVER THE NEXT 1-2 HOURS. THIS HAS NOT BEEN ADDED TO THE OFFICIAL
TAF DUE TO VERY LOW CONFIDENCE IN THIS AFFECTING THE TERMINAL.
OTHERWISE, A LOW CHANCE OF PATCHY FOG EXISTS DURING THE EARLY
MORNING HOURS ON SUNDAY. CONFIDENCE REMAINS LOW IN THIS AFFECTING
THE TERMINAL.
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....HC
LONG TERM....HC
AVIATION...HC
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