688
FXUS64 KHUN 230546
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1246 AM CDT THU JUL 23 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 923 PM CDT WED JUL 22 2026
- FLOOD WATCH IN EFFECT FOR AREAS EAST OF I-65 THROUGH 7 PM
FRIDAY.
- LOW TO MEDIUM CHANCES OF SHOWERS AND STORMS THURSDAY; 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
(REST OF TONIGHT AND THURSDAY)
ISSUED AT 923 PM CDT WED JUL 22 2026
A COLD FRONT IS SLOWLY SHIFTING SOUTHEASTWARD THROUGH THE
TENNESSEE VALLEY AS A FEW SCATTERED SHOWERS IMPACT THE AREA ALONG
THE BOUNDARY. ADDITIONALLY, ADDITIONAL SHOWERS ARE IN CENTRAL
ALABAMA SHIFTING NORTHWARD WHICH HAVE BEEN FUELED BY SOUTHERLY
FLOW AS TROPICAL STORM BERTHA MOVES INTO LOUISIANA. AS THE COLD
FRONT CONTINUES SOUTHWARD, IT WILL LIKELY STALL OVER THE TN VALLEY
INTO THE APPALACHIAN REGION OVER THE NEXT COUPLE OF DAYS (MORE ON
THIS IN THE SHORT TERM) WHICH WILL CAUSE A HEIGHTENED CONCERN FOR
FLASH FLOODING- ESPECIALLY IN NE AL AND PORTIONS OF SOUTHERN
MIDDLE TN. CAMS CONTINUE TO KEEP CONVECTION SCATTERED IN NATURE
THROUGH THURSDAY AFTERNOON INTO THE EVENING. WITH MINIMAL SHEAR,
INSTABILITY WILL SUPPORT LOCALLY GUSTY WINDS IN ADDITION TO
LIGHTNING. HOWEVER, NO SEVERE THREAT IS PRESENT AT THIS TIME. THE
WEATHER PREDICTION CENTER HAS OUTLOOKED MOST OF OUR COVERAGE AREA
IN A SLIGHT RISK (LEVEL 2 OF 4) FOR FLASH FLOODING, WHICH IS
SUPPORTED BY PWATS IN THE 2-2.2" RANGE (ABOVE 90TH PERCENTILE PER
BMX SOUNDING CLIMATOLOGY). PONDING OF WATER ON ROADWAYS IS LIKELY
AND A LOW-MEDIUM CHANCE OF ISOLATED FLASH FLOODING EXISTS. A FLOOD
WATCH IS IN EFFECT THROUGH 7 PM CDT FRIDAY PRIMARILY ALONG AND
EAST OF I-65.
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
(06Z TAFS)
ISSUED AT 1246 AM CDT THU JUL 23 2026
AN OUTFLOW BOUNDARY MOVING NORTHWARD TOWARDS THE TERMINALS IS
HELPING TO PRODUCE SHOWERS (30-50% COVERAGE) NEAR THEM. MVFR CIGS
ARE IN PLACE CURRENTLY AND EXPECT THAT TO CONTINUE INTO THE EARLY
MORNING HOURS AT BOTH TERMINALS. A TEMPO GROUP FOR -TSRA AND MVFR
VSBYS WAS INCLUDED BETWEEN 06Z AND 10Z TO ACCOUNT FOR THAT
POSSIBILITY. MODELS ARE HINTING THAT THE -TSRA COVERAGE WILL
INCREASE AFTER 10Z AT BOTH TERMINALS AND BECOME PREDOMINANT. MVFR
CIGS/VSBYS AND THIS ACTIVITY WILL LIKELY CONTINUE THROUGH 15Z.
THEN EXPECT VCSH TO BE PREDOMINANT, BUT MVFR CIGS WILL CONTINUE.
ANOTHER ROUND OF MORE SCATTERED (20-40% COVERAGE) -TSRA ARE
EXPECTED, THUS ONLY INCLUDED A PROB30 BETWEEN 15Z AND 18Z AT BOTH
TERMINALS. WIND SHOULD BECOME MORE NORTHERLY AFTER 18Z OR 19Z WITH
VFR CONDITIONS RETURNING.
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...HC
SHORT TERM....HC
LONG TERM....RSB
AVIATION...KTW
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