817
FXUS64 KHUN 261657
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1157 AM CDT TUE MAY 26 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 904 AM CDT TUE MAY 26 2026
- A FLOOD WATCH FOR FLASH FLOODING IS IN EFFECT THROUGH 10 PM
TUESDAY FOR CULLMAN, MORGAN, MADISON, JACKSON, MARSHALL AND
DEKALB COUNTIES.
- MEDIUM TO HIGH CHANCES FOR SHOWERS AND THUNDERSTORMS CONTINUE
ACROSS THE TENNESSEE VALLEY INTO THE WEEKEND.
NEAR TERM
(TODAY AND TONIGHT)
ISSUED AT 904 AM CDT TUE MAY 26 2026
DENSE CLOUD COVER PERSISTS ACROSS THE TENNESSEE VALLEY THIS
MORNING, BUT SATELLITE IMAGERY ALREADY SHOWS SOME ISOLATED SPOTS
OF PARTIAL CLEARING. THIS, COMBINED WITH SOUTHERLY WINDS SHOULD
ALLOW TEMPERATURES TO MAKE IT INTO THE LOWER 80S BY THIS AFTERNOON
IN MOST LOCATIONS. A MESO LOW WILL DEVELOP OVER WESTERN KENTUCKY
LATER TODAY NEAR A STALLED FRONTAL BOUNDARY NEAR THE OHIO RIVER.
WINDS IN THE MID TO UPPER-LEVELS WILL BE OUT OF THE SW/WSW, BUT AT
THE SURFACE A BROAD AREA OF LOCALLY BACKED WINDS WILL EXIST FROM
NORTHERN/CENTRAL ALABAMA INTO EASTERN TENNESSEE AND KENTUCKY INTO
THE EARLY AFTERNOON. WITH EFFECTIVE SHEAR AROUND 20-30 KTS AND
MLCAPE VALUES AROUND 500-1000 J/KG, THIS MAY ALLOW FOR SOME
MODESTLY ORGANIZED DIURNALLY DRIVEN SHOWERS AND THUNDERSTORMS
DURING THE AFTERNOON.
WITH THE AFOREMENTIONED LOW MOVING NORTHWARD THIS AFTERNOON/EVENING,
SURFACE WINDS SHOULD VEER TO THE SW, BUT WE STILL NEED TO WATCH
FOR A FEW LOCALLY STRONG STORMS AND EVEN AN ELEVATED MESO OR TWO
IN THE STRONGEST CONVECTION. THE PRIMARY RISK, BY FAR, CONTINUES
TO BE LOCALLY HEAVY RAINFALL AND A LOW CHANCE FOR FLASH FLOODING.
FORECASTED PWATS BETWEEN 1.5"-1.7" ARE BETWEEN THE 90TH-99TH
PERCENTILE PER BMX/OHX SOUNDING CLIMATOLOGY. IN PARTICULAR,
LOCATIONS IN THE FLOOD WATCH (AREAS IN ALABAMA ALONG AND EAST OF
I-65) WILL BE MOST FAVORED FOR LOCALIZED FLOODING IN SLOWER MOVING
CONVECTION WHERE TRAINING OCCUR. THUS, WE WILL KEEP THE FLOOD
WATCH IN EFFECT UNTIL 10 PM WHEN THESE SHOWERS AND STORMS WILL
GENERALLY WANE OVERNIGHT. WITH DENSE CLOUD COVER IN PLACE, IT WILL
AGAIN BE A VERY WARM/HUMID NIGHT, WITH LOWS IN THE UPPER 60S.
SHORT TERM
(WEDNESDAY THROUGH THURSDAY)
ISSUED AT 904 AM CDT TUE MAY 26 2026
A PRETTY SIMILAR PATTERN WILL PERSIST WEDNESDAY AND THURSDAY
ACROSS THE TENNESSEE VALLEY, THOUGH WIND SHEAR VALUES WILL BE A
BIT LOWER BOTH DAYS. CONVECTION WILL AGAIN BE DIURNALLY DRIVEN AND
FAVORED TO DEVELOP ALONG ANY LINGERING MESOSCALE BOUNDARIES FROM
THE PREVIOUS DAY'S CONVECTION. HEATING SHOULD BE SUFFICIENT ENOUGH
(WITH THE SOUTHWESTERLY SURFACE FLOW AND ENOUGH BREAKS IN THE
CLOUDS) TO PUSH TEMPERATURES INTO THE LOW TO MID 80S EACH
AFTERNOON. MLCAPE VALUES AROUND 1000 J/KG WILL SUPPORT A FEW
LOCALLY STRONG PULSE THUNDERSTORMS DURING PEAK HEATING IN THE
AFTERNOON AND EVENING HOURS. HOWEVER, THE PRIMARY THREAT BY FAR
AGAIN WILL BE LOCALLY HEAVY RAINFALL AND A LOW CHANCE OF FLASH
FLOODING GIVEN THE VERY MOIST, TROPICAL AIR MASS IN PLACE.
LONG TERM
(THURSDAY NIGHT THROUGH MONDAY)
ISSUED AT 1120 PM CDT MON MAY 25 2026
MOST GUIDANCE SHOWS THE SURFACE FRONT PUSHING SOUTH OF THE AREA BY
THURSDAY EVENING. CLOUD COVER SHOULD LINGER THOUGH BEHIND THE FRONT
OVER THE AREA. NOT MUCH APPRECIABLE COLD AIR ADVECTION OR DRIER AIR
SHOWN RIGHT BEHIND THE FRONT. THIS COMBINATION SHOULD KEEP OVERNIGHT
LOWS ON THE WARM SIDE IN THE LOWER TO MID 60S. THIS SHOULD ALSO
PROVIDE A BRIEF BREAK FROM RAINFALL ACTIVITY.
MOST GUIDANCE MOVES THE FRONT NORTHWARD AROUND DAYBREAK ON FRIDAY
INTO NORTHWESTERN ALABAMA AND POSSIBLY SOME OF OUR SOUTHEASTERN
COUNTIES IN AL. FORCING IS NOT VERY STRONG, BUT DOES MOVE BACK OVER
THE AREA. INSTABILITY BETWEEN 1000 AND 1600 J/KG (SOME GUIDANCE A BIT
MORE) DOES DEVELOP BY THE AFTERNOON HOURS. SHEAR THOUGH IS VERY WEAK
(~10 TO 15 KNOTS). PWATS REMAIN HIGH BETWEEN 1.6 TO 1.8 INCHES. SO A
VERY SATURATED ATMOSPHERIC COLUMN WILL NOT TAKE MUCH FORCING TO
PRODUCE HEAVY RAINFALL RATES. A CONTINUE THREAT FOR A PERIOD OF RAIN
AND THUNDERSTORMS DEVELOPING DURING THE AFTERNOON AND EARLY EVENING
IS EXPECTED. A FLOODING RISK WILL LIKELY EXTEND INTO FRIDAY.
MUCH DEEPER AND STRONGER FORCING SEEMS TO DEVELOP IN MANY MODELS
SATURDAY OVERNIGHT AS THE MAIN UPPER LEVEL TROUGH AXIS MOVES EAST
ALOFT. THIS COULD PRODUCE A CONCENTRATION OF HEAVIER RAINFALL AND
SOME STORMS MORE SO OVER GEORGIA AND MAYBE EXTENDING WEST INTO NE
ALABAMA. A RISK FOR SOME FLASH FLOODING WILL LIKELY CONTINUE ON
FRIDAY AFTERNOON INTO FRIDAY NIGHT.
MODELS DIVERGE ON HOW AMPLIFIED THE UPPER LEVEL TROUGH AXIS IS FRIDAY
NIGHT INTO SATURDAY AND INTO THE WEEKEND, WHICH WILL HAVE A BIG
IMPACT ON WHETHER THE FRONT SHIFTS SOUTH OF THE AREA OR NOT.
MODEL CONVERGE A BIT MORE ON STRONGER FORCING AND SHEAR DEVELOPING
OVER THE AREA ON MONDAY. SHEAR IS BETTER WITH THIS SYSTEM AND
INSTABILITY IS NOT BAD. THERE MAY BE SOME STRONG TO SEVERE
THUNDERSTORM THREAT WITH THAT SYSTEM, BUT THIS IS TOO FAR OUT IN
THE EXTENDED TO HAVE MUCH CONFIDENCE WITH IT.
AVIATION
(18Z TAFS)
ISSUED AT 1157 AM CDT TUE MAY 26 2026
LIGHT RAIN SHOWERS WILL GRADUALLY INCREASE IN COVERAGE THROUGH THE
AFTERNOON AND INTO THE EVENING, WITH THE POTENTIAL FOR TSRA DURING
THE 20-00Z WINDOW. HAVE ADDED A TEMPO AT BOTH TERMINALS TO REFLECT
THIS HIGHER CONFIDENCE ABOUT TSRA AND AWWS AND/OR AMENDMENTS MAY
BE NEEDED DURING THIS TIMEFRAME. PRECIPITATION WILL WANE THIS
EVENING, BUT CEILINGS WILL DROP TO MVFR LEVELS TONIGHT AND INTO
WEDNESDAY MORNING AS LOW STRATUS BUILDS BACK INTO THE AREA.
HUN WATCHES/WARNINGS/ADVISORIES
AL...FLOOD WATCH UNTIL 10 PM CDT THIS EVENING FOR ALZ006>010-016.
TN...NONE.
NEAR TERM...AMP.24
SHORT TERM....AMP
LONG TERM....KTW
AVIATION...AMP.24
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