813
FXUS64 KHUN 231104
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
604 AM CDT THU JUL 23 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 403 AM CDT WED JUL 23 2026
- FLOOD WATCH IN EFFECT FOR AREAS EAST OF I-65 THROUGH 7 PM
FRIDAY.
- LOW TO MEDIUM CHANCES OF SHOWERS AND STORMS TODAY; WILL
INCREASE TO MEDIUM TO HIGH CHANCES BY FRIDAY AND SATURDAY.
- THROUGH THE END OF THE WEEK, LOCALLY HEAVY RAINFALL AND A LOW-
MEDIUM FLASH FLOODING THREAT MAY EVOLVE DUE TO SEVERAL DAYS OF
SHOWERS AND THUNDERSTORMS AND AN EXTREMELY MOIST, TROPICAL-LIKE
AIR MASS.
NEAR TERM
(TODAY)
ISSUED AT 403 AM CDT THU JUL 23 2026
BASED ON AREA OBSERVATIONS AND RADAR TRENDS, THE FRONTAL BOUNDARY
CURRENTLY STRETCHES FROM NEAR COLUMBUS, MS ENE THROUGH OUR
SOUTHERN MIDDLE TENNESSEE COUNTIES INTO SOUTHEASTERN TENNESSEE AT
THIS HOUR. FAIRLY WIDESPREAD LIGHT TO MODERATE RAINFALL HAS
DEVELOPED NEAR AND SOUTH OF IT OVER AREAS NORTH OF THE TENNESSEE
RIVER AND INTO SOUTHERN MIDDLE TENNESSEE. A FEW HEAVIER DOWNPOURS
ALSO ARE LIKELY EMBEDDED, BUT THESE POCKETS OF HEAVIER DOWNPOURS
LOOK TO BE VERY ISOLATED AT THIS TIME AND SHOWERS ARE MOVING ENE
FAIRLY QUICKLY.
EXPECT THESE AREAS OF RAIN TO SHIFT SLOWLY SOUTHWARD AND EXPAND
IN COVERAGE DURING THE DAY TODAY. EXPECT SOME THUNDERSTORMS TO
DEVELOP PRODUCING HEAVIER AMOUNTS OF RAINFALL GIVEN PWATS OF 2.0
TO 2.2 INCHES FORECAST. SOME AREAS OF FLASH FLOODING (ESPECIALLY
EAST OF THE I-65 CORRIDOR) COULD DEVELOP AS THE FOCUSING MECHANISM
(FRONTAL BOUNDARY) SLOWLY MOVES SOUTH THROUGH THE AFTERNOON
HOURS. EXPECT HIGHS TO STRUGGLE TO REACH THE 80 TO 85 DEGREE RANGE
IN MANY LOCATIONS NEAR AND NORTH OF THE TENNESSEE RIVER. SOME
LOCATIONS FURTHER SOUTH SHOULD BE A TAD WARMER WITH HIGHS CLIMBING
INTO THE MID/UPPER 80S.
SHORT TERM
(THURSDAY NIGHT THROUGH SATURDAY)
ISSUED AT 923 PM CDT WED JUL 22 2026
THE SHORT TERM PATTERN WILL BE LARGELY DOMINATED BY AN UPPER LEVEL
RIDGE AND SUBSEQUENT SFC HIGH IN THE SOUTHERN PLAINS/DEEP SOUTH-
KEEPING THE TENNESSEE VALLEY IN A NW FLOW PATTERN. ADDITIONALLY,
REMNANTS FROM TROPICAL STORM BERTHA WILL BE SHIFTING NORTHWARD
INTO THE AREA TO MEET A STALLED FRONTAL BOUNDARY, WHICH SHOULD
PROVIDE ENOUGH FORCING/MOISTURE FOR A PROLONGED PERIOD OF
INTERMITTENT HEAVY RAINFALL. THE GRADIENT IN RAINFALL AMOUNTS WILL
LIKELY BE SHARP, WITH GREATER RAINFALL AMOUNTS ALONG AND EAST OF
I-65, WHERE A FLASH FLOOD WATCH IS IN EFFECT THROUGH 7 PM FRIDAY.
THE WEATHER PREDICTION CENTER HAS CONTINUED A SLIGHT RISK (LEVEL 2
OF 4) FOR FLASH FLOODING THROUGH MOST OF THE AREA ON FRIDAY AND A
MARGINAL RISK (LEVEL 1 OF 4) FOR FLASH FLOODING ON SATURDAY AS THE
FRONT BEGINS TO RETREAT OUT OF OUR AREA. THE FLASH FLOOD THREAT IS
SUPPORTED BY PWATS IN THE 2-2.25" RANGE, WHICH IS ABOVE THE 90TH
PERCENTILE PER BMX SOUNDING CLIMATOLOGY. AREAS ALONG AND EAST OF
I-65 WILL LIKELY RECEIVE AT LEAST 1-2 INCHES OF RAIN WITH ISOLATED
HIGHER AMOUNTS (UP TO 4-5") IN AREAS WHERE STRONGER STORMS OCCUR.
HEAVY RAINFALL WILL LIKELY CAUSE PONDING OF WATER ON ROADWAYS AND
IN AREAS OF POOR DRAINAGE AS WELL AS RISES ON RIVERS/CREEKS IN THE
AREA. A LOW TO MEDIUM RISK OF FLASH FLOODING EXISTS THROUGH THE
WEEKEND. BE SURE TO PAY ATTENTION TO THE LATEST FORECAST AND HAVE
MULTIPLE WAYS TO GET WARNINGS, ESPECIALLY IF YOU HAVE OUTDOOR
PLANS. OTHERWISE, TEMPERATURES WILL BE CAPPED IN THE MID TO UPPER
80S UNDER CLOUD COVER THROUGH THE AREA. HOWEVER, A WARM UP IS ON
THE WAY NEXT WEEK (MORE ON THIS IN THE LONG TERM BELOW).
LONG TERM
(SATURDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 923 PM CDT WED JUL 22 2026
A RIDGE DOMINATED UPPER LEVEL PATTERN WILL PREVAIL ACROSS MUCH OF
THE LOWER-48 AS WE HEAD INTO NEXT WEEK. FORECASTS OF 500MB HEIGHTS
LATE SAT INDICATED STRONG UPPER RIDGING SPRAWLED FROM THE DESERT SW,
SOUTHERN ROCKIES, AND THE HIGH PLAINS FROM WYOMING TO THE BIG BEND. A
DEEP UPPER LOW OVER THE HUDSON BAY WAS PRODUCING TROUGHING WHICH
EXTENDED SOUTHWARD ALONG THE EAST COAST. THIS FIRMLY PLACES THE
GREATER TENNESSEE VALLEY IN A NW FLOW ALOFT, WHICH APPEARS WILL
CONTINUE INTO THE MIDDLE OF NEXT WEEK. A NUMBER OF PASSING UPPER
LEVEL DISTURBANCE WITHIN THIS STREAM WILL HELP CONTRIBUTE TO
CONVECTION IMPACTING THE AREA EARLY IN THE PERIOD. EXACT TIMING AND
PLACEMENT OF THEM IS RATHER DIFFICULT, SO AM DEPENDING UPON ENSEMBLE
AND BLEND GUIDANCE VERSUS DETERMINISTIC OUTPUT.
AT THE SURFACE, A FRONTAL BOUNDARY NOW MOVING IN A NW-SE MANNER
ACROSS THE AREA SHOULD RETURN AS A WARM FRONT LATE FRI INTO SAT. THIS
WILL BRING ADDITIONAL LOWER LEVEL MOISTURE FROM THE GULF OF AMERICA
FURTHER INLAND. OUTPUT FROM THE NBM HAS PRECIPITABLE WATER AMOUNTS OF
OVER 2" ACROSS THE FORECAST FROM SAT EVENING INTO SUN MORNING. WITH
PASSING UPPER LEVEL SUPPORT, THERE WILL BE GOOD CHANCES FOR NUMEROUS
SHOWERS AND THUNDERSTORMS TO IMPACT THE TENNESSEE VALLEY. SOME OF THE
STORMS COULD BECOME STRONG. OF GREATER WORRY IS RAINFALL OUTPUT IN
SUCH A HUMID ENVIRONMENT. EXCESSIVE RAINFALL AND A POTENTIAL OF
FLOODING CANNOT BE RULED OUT; WHICH WILL BE DEPENDENT UPON HOW MUCH
RAINFALL OCCURS BEFOREHAND. THE FRONTAL BOUNDARY PER DESI AND NBM
GUIDANCE SHOULD MOVE SOUTHWARD AGAIN LATE SUN INTO MON, WITH SHOWER
ACTIVITY ENDING FOR THE START OF A NEW WORK WEEK.
DAILY TEMPERATURES INTO THE MIDDLE OF NEXT WEEK APPEAR WILL BE ON THE
RISE, IN PART THANKS TO THE STRONG UPPER RIDGE JUST TO OUR WEST. AS
SHOWER ACTIVITY ENDS ON SUN, THE HEAT WILL RETURN. HIGHS TO START A
NEW WEEK SHOULD RANGE FROM THE MID/UPPER 80S TO THE LOWER 90S WEST.
EVEN WARMER CONDITIONS ARE EXPECTED FOR THE MON-WED TIMEFRAME, WITH
HIGHS ALL THREE DAYS MAINLY IN THE LOW/MID 90S, AND LOWS IN THE
LOW/MID 70S. HEAT INDEX VALUES ON SUN SHOULD RANGE FROM THE MID/UPPER
90S EAST TO 107 IN THE MORE URBANIZED SPOTS. ANOTHER NEED FOR HEAT
ADVISORIES MAYBE NEEDED SUN, BUT APPEAR MORE LIKELY NEXT MON/TUE,
WITH VALUES RANGING FROM THE UPPER 90S TO 109 IN THE HOTTEST SPOTS.
THEY COULD BE SOME RELIEF BY THE MIDWEEK, AS ANOTHER FRONTAL BOUNDARY
MOVES ACROSS THE AREA FROM THE NORTH. THIS BOUNDARY WILL ALSO BRING
LOWER END RAIN CHANCES BACK TO PARTS OF THE VALLEY.
AVIATION
(12Z TAFS)
ISSUED AT 604 AM CDT THU JUL 23 2026
CIGS ARE PRIMARILY MVFR AROUND BOTH TERMINALS WITH A MORE
CONCENTRATED AREA OF -RA AND RA NEAR THE KHSV TERMINAL AND FURTHER
ENE. THROUGH 15Z, THINKING -RA MAY BE MORE PREDOMINANT AT KHSV
AND LESS SO AT KMSL. THEREFORE, KEPT PREDOMINANT CONDITIONS AT
KMSL AS VCSH WITH A TEMPO BETWEEN 12Z AND 15Z FOR -RA. RAIN/STORM
CHANCES SHOULD DIMINISH BETWEEN 15Z AND 18Z AT BOTH TERMINALS.
THUS PREDOMINANT VCSH AS INCLUDED FOR BOTH TERMINALS AFTER 15Z. A
PROB30 GROUP WAS THEN INCLUDED AS RAIN/STORM CHANCES DECREASE FROM
15Z TO 20Z AT KMSL AND FROM 15Z TO 21Z AT KHSV. NOT SURE WE WILL
SEE VFR CIGS RETURN PREDOMINANTLY UNTIL AFTER 20Z OR 21Z AT EITHER
TERMINAL.
HUN WATCHES/WARNINGS/ADVISORIES
AL...FLOOD WATCH THROUGH FRIDAY EVENING FOR ALZ006>010-016.
TN...FLOOD WATCH THROUGH FRIDAY EVENING FOR TNZ076-096-097.
NEAR TERM...KTW
SHORT TERM....HC
LONG TERM....RSB
AVIATION...KTW
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