618
FXUS64 KHUN 260420
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1120 PM CDT MON MAY 25 2026
..NEW NEAR TERM, SHORT TERM, LONG TERM
KEY MESSAGES
UPDATED AT 1120 PM CDT MON MAY 25 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
(REST OF TONIGHT AND TUESDAY)
ISSUED AT 1120 PM CDT MON MAY 25 2026
WET AND UNSETTLED WEATHER WILL CONTINUE ACROSS THE TENNESSEE
VALLEY INTO THE UPCOMING WEEKEND. A GENERAL TROUGHING WEST AND
RIDGING WEST SETUP WILL BECOME ESTABLISHED AS WE GO FURTHER INTO
THE WEEK. THAT, ALONG WITH RIDGING OVER THE NW ATLANTIC WILL KEEP
A DEEP SOUTHERLY FLOW FROM THE GULF CONTINUING ACROSS MUCH OF THE
SOUTHEASTERN CONUS. THIS MOISTURE, ALONG WITH PASSING UPPER LEVEL
SUPPORT AND DAYTIME HEATING PRODUCED INSTABILITY, WILL KEEP MEDIUM
TO HIGH CHANCES OF SHOWERS AND SOME THUNDERSTORMS IN THE FORECAST.
INTO THE OVERNIGHT, ADDITIONAL MOISTURE AND CONVECTION IN PROGRESS
FROM SOUTH OF THE FLORIDA PANHANDLE TO ALONG THE AL/GA BORDER WILL
GENERALLY HEAD SLIGHT TO THE EAST OF DUE NORTH MORE INTO GEORGIA
IN THE LATE NIGHT. ANOTHER AREA OF CONVECTION A BIT SEPARATE FROM
THE PREVIOUSLY MENTIONED SHOWERS, SHOULD MOVE MORE TO THE NNW
ACROSS NW ALABAMA. AN INTERESTING FEATURE WITH THIS CONSISTED OF
A HEIGHTENED AREA OF SHEAR MOVING OVER THE EASTERN HALF OF OUR
AREA IN THE OVERNIGHT. SO FAR, SHORT-TERM MODELS WERE IN AGREEMENT
KEEPING SHOWER DEVELOPMENT SUPPRESSED OVER OUR EASTERN AREAS. BUT
IN A MARGINALLY UNSTABLE ATMOSPHERE, ESPECIALLY WITH AN AREA OF
HIGHER SHEAR (0-1KM HELICITY IN THE 200-300 M/S RANGE) MOVING
NORTHWARD ACROSS THE EASTERN HALF OF OUR AREA IN THE OVERNIGHT IS
AN ATTENTION GETTER. WEAK CAPPING ~850MB ALOFT SHOULD HELP KEEP
CONVECTION SUPPRESSED IN THE OVERNIGHT.
BUT OVER NW ALABAMA, AN AREA OF CONVECTION MOVING NNW WEST OF I-65
WILL BRING LOCALLY HEAVY RAINFALL OVER THAT AREA. 1-HOUR FLASH
FLOOD GUIDANCE OVER NW ALABAMA IS GENERALLY OVER 2" WHICH WILL
PROVIDE SOME SAVING GRACE FAR AS EXCESSIVE RAINFALL PRODUCING
FLOODING. THESE SHOWERS SHOULD SLOWLY WIND DOWN AS WE GO INTO THE
LATE NIGHT. THAT SAID, WE'RE BE MONITORING THIS SITUATION FOR LATE
NIGHT FLOODING. OTHERWISE MUGGY CONDITIONS ARE EXPECTED WITH LOWS
IN THE MID 60S. AWAY FROM AREAS RECEIVING SHOWERS, PATCHY FOG
DEVELOPMENT CANNOT BE RULED OUT IN THE LATE NIGHT AND TUESDAY
MORNING.
OTHERWISE WITH DEEP MOISTURE PRESENT, ADDITIONAL SHOWERS AND A FEW
THUNDERSTORMS ARE IN THE FORECAST FOR TUESDAY. WITH MORE CLOUDS
THAN SUN AND MEDIUM TO HIGH RAIN CHANCES (~40% WEST TO ~80% EAST),
HIGH TEMPERATURES SHOULD ONLY RISE INTO THE LOWER 80S. PRECIPITABLE
WATER (PW) AMOUNTS IN 1.5" TO 1.7" WILL SUPPORT SHOWERS CAPABLE OF
PRODUCING LOCALLY HEAVY RAINFALL.
SHORT TERM
(TUESDAY NIGHT THROUGH THURSDAY)
ISSUED AT 1120 PM CDT MON MAY 25 2026
THE FORECAST SHOULD TAKE ON MORE OF A DIURNAL TREND (THIS ONE WITH
HIGHER RAIN CHANCES AFTERNOON/EVENING) AS WE GO INTO THROUGH THE
MIDWEEK. ANOTHER MUGGY NIGHT IS EXPECTED TUESDAY NIGHT, WITH LOWS
IN THE MID 60S. PW MOISTURE OF 1.6" TO 1.7" IS EXPECTED WEDNESDAY,
BRINGING MORE POTENTIALLY HEAVY DOWNPOURS. WITH MORE CLOUDS AND
DECENT RAIN CHANCES OF 60-80%, HIGH TEMPERATURES SHOULD RANGE IN
THE LOW/MID 80S. LOWS WILL COOL INTO THE MID/UPPER 60S. SIMILAR
CONDITIONS ARE FORECAST ON THURSDAY. A COLD FRONT LOCATED TO OUR
NORTH, WILL APPROACH THE FORECAST AREA LATER IN THE DAY. DEPENDING
UPON TIMING, IT COULD BRING HIGHER RAIN CHANCES AS WELL AS
STRONGER STORMS.
THE WEATHER PREDICTION CENTER HAS MOST, IF NOT ALL OF THE AREA IN
A MARGINAL RISK FOR EXCESSIVE RAINFALL THIS WEEK. THUS DEPENDING
UPON WHEN AND WHERE RAINFALL OCCURS, IF IT IS HEAVY AND FALLS ON
AN AREA THAT IS VERY WET TO SATURATED FROM RECENT RAINS, RUNOFF
WILL OCCUR AND BRING RISKS OF FLASH FLOODING AND FLOODING ACROSS
THE TENNESSEE VALLEY THROUGH THURSDAY. THUNDERSTORM CHANCES WILL
REMAIN IN THE FORECAST AS WELL, EXCEPT "GENERAL" INTENSITY
CONVECTION IS ANTICIPATED WITH THE USUAL GUSTY OUTFLOW WINDS AND
HEAVY DOWNPOURS. STORMS IN HIGH PW REGIMES CAN BECOME ELECTRICALLY
ACTIVE AS WELL.
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
(00Z TAFS)
ISSUED AT 643 PM CDT MON MAY 25 2026
GENERALLY INCLEMENT FLYING WEATHER WILL PERSIST ACROSS MUCH OF THE
TN VALLEY FOR THE TAF. A BROAD AREA OF SHOWERS WITH A FEW EMBEDDED
THUNDERSTORMS WAS MOVING NORTHWARD AROUND 10KT FROM EASTERN MS,
ACROSS N/AL AND N/GA AND E/TN. SHOWERS SHOULD TEMPORARILY END OVER
N/AL EAST OF I-65 THIS EVENING, BUT ARE EXPECTED TO CONTINUE ACROSS
NW ALABAMA INTO THE LATE EVENING BEFORE GRADUALLY ENDING. WITH THE
SHOWERS, CIG/VSBY REDUCTION TO MVFR (AT TIMES IFR) ARE EXPECTED.
CONDITIONS SHOULD IMPROVE INTO THE MVFR/VFR RANGE AFTER THE
SHOWERS CEASE. THERE IS A RISK FOR FOG IF CLOUDS SCATTER OUT
BEFORE DAYBREAK TUE. MORE SHOWERS ARE EXPECTED TO IMPACT THE AREA
TUE AFTERNOON.
HUN WATCHES/WARNINGS/ADVISORIES
AL...FLOOD WATCH THROUGH TUESDAY EVENING FOR ALZ006>010-016.
TN...NONE.
NEAR TERM...RSB
SHORT TERM....RSB
LONG TERM....RSB
AVIATION...RSB
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