990
FXUS64 KHUN 011733
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1233 PM CDT FRI MAY 1 2026
..NEW AVIATION
KEY MESSAGES
UPDATED AT 1053 PM CDT WED APR 30 2026
- MEDIUM TO HIGH CHANCES OF RAIN TONIGHT. RAINFALL TOTALS
BETWEEN 0.25" TO 0.5" ARE FORECAST.
- A MUCH COOLER AIR MASS WILL ARRIVE THIS WEEKEND, WITH DAYTIME
HIGHS IN THE MID TO UPPER 60S AND OVERNIGHT LOWS IN THE UPPER
30S/40S.
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1053 AM CDT FRI MAY 1 2026
FAIRLY WIDESPREAD CLOUD COVER ABOVE 15,000 FEET HAS PUSHED NORTH
OVER MUCH OF NORTHERN ALABAMA AND INTO PORTIONS OF SOUTHERN MIDDLE
TENNESSEE. THE BELOW NORMAL TEMPERATURES CONTINUE THIS MORNING
WITH TEMPERATURES CURRENTLY IN THE MID TO UPPER 50S. MOST GUIDANCE
SHOWS (INCLUDING MESO-SCALE MODELS) CLOUD COVER HOLDING ON NEAR
AND SOUTH OF THE TENNESSEE RIVER FOR SURE.
A PRE-FRONTAL TROUGH AXIS CAN BE SEEN IN SURFACE ANALYSIS
EXTENDING SOUTHWEST THROUGH THE WESTERN PORTIONS OF THE OHIO
VALLEY. OVERUNNING FROM THE STALLED FRONTAL BOUNDARY EXTENDING
WEST TO EAST THROUGH THE NORTHERN GULF OF AMERICA IS PRODUCING THE
CLOUD COVER OVER THE AREA.
THE PRE-FRONTAL TROUGH AXIS PUSHES EAST THROUGH THE DAY. AT THE
SAME TIME, A SURFACE LOW DEVELOPS ALONG THE WESTERN EDGE OF THE
STALLED FRONT OVER THE NORTHERN GULF OF AMERICA. AS THIS MOVES ENE
ALONG THE FRONT, THE FRONT BEGINS TO MOVE TO THE NORTH THIS
AFTERNOON INTO TONIGHT. HOWEVER, HOW FAR NORTH THIS GOES WILL BE
LIMITED BY THE PROGRESSION OF THE DRIER AIR BEHIND THIS PRE-
FRONTAL TROUGH AXIS AS IT MOVES EAST. NEWEST GUIDANCE SEEMS TO
FURTHER LIMIT THE NORTHWARD PROGRESSION FROM PREVIOUS RUNS.
EITHER WAY, NOT EXPECTING RAIN TO PUSH INTO NORTHERN ALABAMA UNTIL
THIS EVENING AT THE EARLIEST (LIKELY LATER IN THE EVENING). THERE
MAY BE SOME BREAKS IN CLOUD COVER NORTH OF THE TENNESSEE RIVER
INTO SOUTHERN MIDDLE TENNESSEE, AS THE DRIER AIR ALOFT ALONG AND
BEHIND THE PREF-RONTAL TROUGH AXIS PUSH INTO THOSE AREAS. THIS
COULD PUSH HIGHS A TAD HIGHER THERE INTO THE 71 TO 74 DEGREE
RANGE. FURTHER SOUTH, IN MORE PERSISTENT CLOUD COVER, HIGHS WILL
LIKELY BE MORE IN THE UPPER 60S TO AROUND 70 DEGREES.
TIMING AND AMOUNT OF RAINFALL EXPECTED SOUTH OF THE TENNESSEE
RIVER TONIGHT HAS DROPPED WITH NEW GUIDANCE AS WELL. NEWEST
GUIDANCE SHOWS ONLY UP TO 0.3 INCHES OF RAIN IN MAINLY CULLMAN
COUNTY, AL (HEAVIEST AMOUNTS FURTHER SOUTH).
SHORT TERM
(SATURDAY THROUGH MONDAY)
ISSUED AT 1053 AM CDT FRI MAY 1 2026
TRENDING TOWARDS NEW GUIDANCE IN THIS FORECAST UPDATE. MODELS PUSH
THIS RAIN EAST OF THE AREA BETWEEN 3 AND 5 AM, ALSO A BIT EARLIER
EXITING THE AREA. EVEN STRONGER COLD AIR ADVECTION IS SHOWN
BEHIND THIS FRONT ON SATURDAY. EXPECT CLEARING BEHIND THE FRONT
BETWEEN 7 AM AND 10 AM MOSTLY ON SATURDAY MORNING. SOUTHERN MIDDLE
TENNESSEE MAY SEE SOME AFTERNOON REDEVELOPMENT OF CLOUD COVER AND
MAYBE ISOLATED SHOWERS WITH THE SOUTHWESTERN EDGE OF AN UPPER LOW
TRAILING BEHIND THE FRONT. WITH DOMINANT COLD AIR ADVECTION,
DESPITE SUNSHINE RETURNING, HIGHS WILL BE WELL BELOW NORMAL, ONLY
REACHING THE 65 TO 68 DEGREE RANGE MOSTLY. SOUTHERN TENNESSEE MAY
BE A BIT COOLER DUE TO CLOUD COVER, ONLY CLIMBING INTO THE LOWER
TO MID 60S.
WINDS SHOULD DROP OFF SATURDAY NIGHT AND BECOME LIGHT AND
VARIABLE AS A LARGE AREA OF HIGH PRESSURE BUILDS INTO THE AREA.
THIS WILL BE A GOOD RADIATIONAL COOLING SETUP. HOWEVER, AT THIS
TIME, MODELS DON'T SHOW REALLY LOW DEWPOINTS ADVECTING INTO THE
AREA. THIS LOOKS REASONABLE BASED ON UPSTREAM DEWPOINTS (BUT WILL
NEED TO MONITOR FOR LOWER DEWPOINT ADVECTION). THE MAIN REASON TO
WATCH THIS IS FOR LOWS ON SATURDAY NIGHT. IF WE HAVE ADVECTION OF
DEWPOINTS IN THE 33 TO 38 DEGREE RANGE OVER MORE OF THE AREA INTO
NORTHERN ALABAMA, FROST POTENTIAL MAY BE A CONCERN. HOWEVER,
RIGHT NOW, TOO MUCH GUIDANCE DOES NOT SHOW THIS OCCURRING. IT WILL
BE VERY COOL FOR THIS TIME OF YEAR REGARDLESS. IT LOOKS LIKE LOWS
SHOULD DROP INTO THE 38 TO 43 DEGREE RANGE MAINLY, KEEPING FROST
CONCERNS AT BAY.
HIGH PRESSURE WILL REMAIN IN CONTROL OF SENSIBLE WEATHER ON
SUNDAY. WE WILL STILL BE IN FAIRLY AMPLIFIED NW FLOW ALOFT ON
SUNDAY. SO, WEAKER BUT STILL STRONG COLD AIR ADVECTION WILL
CONTINUE. WITH A BIT MORE SUNSHINE, EXPECT HIGHS TO REACH THE
UPPER 60S TO LOWER 70S ACROSS NORTHERN ALABAMA AND SOUTHERN MIDDLE
TENNESSEE.
FROM SUNDAY NIGHT INTO MONDAY MORNING NOT MUCH CHANGES, EXCEPT
UPPER LEVEL FLOW BECOMES ZONAL AGAIN. WE SHOULD SEE MORE MOISTURE
ADVECTION AND WARMER RETURN FLOW AROUND THE BACKSIDE OF THE
SURFACE HIGH BEGIN RETURNING TO THE AREA. EAST OF I-65,
TEMPERATURES WILL STILL DROP INTO THE 40 TO 45 DEGREE RANGE ONE
MORE NIGHT. FURTHER WEST, LOWS SHOULD ONLY DROP INTO THE LOWER
50S.
ON MONDAY, SOUTHWESTERLY LOW LEVEL FLOW RE-ESTABLISHES ITSELF.
ABUNDANT SUNSHINE IS EXPECTED THOUGH SOME PARTLY CLOUDY CONDITIONS
MAY OCCUR. THIS COMBINATION SHOULD ALLOW HIGHS TO CLIMB BACK TO
NEAR NORMAL VALUES INTO THE 75 TO 80 DEGREE RANGE.
LONG TERM
(MONDAY NIGHT THROUGH FRIDAY)
ISSUED AT 1053 AM CDT FRI MAY 1 2026
BY MONDAY NIGHT INTO TUESDAY MORNING, A VERY STRONG AND LARGE
UPPER LOW AND ITS ASSOCIATED LONGWAVE TROUGH AXIS DIGS SOUTHEAST
FROM CENTRAL CANADA INTO THE EASTERN GREAT LAKES AND OHIO VALLEY
REGIONS. THIS EXTENDS WSW INTO THE CENTRAL PLAINS AS WELL. STRONG
WARM AIR ADVECTION IS EXPECTED AHEAD OF THIS, BUT CLOUD COVER WILL
INCREASE SIGNIFICANTLY TUESDAY LATE MORNING AND INTO THE AFTERNOON
HOURS. DESPITE STRONGER WARM AIR ADVECTION, HIGHS WILL LIKELY REMAIN
ABOUT THE SAME OR SLIGHTLY LOWER DUE TO THE REDUCTION IN INSOLATION.
FOR NOW, HAVE KEPT NBM HIGHS IN THE MID TO UPPER 70S.
ENOUGH FORCING AND DEEP ENOUGH MOISTURE MAY SINK FAR ENOUGH SOUTH
BY LATE TUESDAY AFTERNOON FOR A FEW SHOWERS TO DEVELOP IN NW
ALABAMA. THE MORE PERSISTENT AND BETTER COVERAGE OF RAIN LOOKS TO
OCCUR TUESDAY NIGHT AS THE FRONT MOVES CLOSER TO THE AREA. 30 TO
40 KNOTS OF SHEAR DOES DEVELOP AHEAD OF THE FRONT. HOWEVER, SBCAPE
IS NOT REALLY SHOWN IN MOST GUIDANCE.
THIS FRONT SEEMS TO SLOW DOWN AND STALL OVER CENTRAL AND NORTHERN
ALABAMA DURING THE DAY ON WEDNESDAY. AS ANOTHER LONGWAVE TROUGH
AXIS ROTATES AROUND THE PARENT UPPER LOW NOW OVER SE CANADA, A
STRONGER LOW AND MID LEVEL JET DEVELOPS THAT PUSHES SOUTHEAST
WEDNESDAY AFTERNOON INTO WEDNESDAY EVENING AND PUSHES EAST THROUGH
THE OHIO VALLEY.
THIS SHOULD RE-ENVIGORATE THE FRONTAL BOUNDARY OVER THE AREA. MUCH
STRONGER SHEAR IS SHOWN IN MOST GUIDANCE OVER THE SOUTHEAST AS
THIS OCCURS. SBCAPE VALUES CLIMB TO BETWEEN 500 AND 1200 J/KG.
LAPSE RATES ARE FAIRLY STEEP AS WELL, MORE THEN 6.5 DEGREES/KM.
THUS, WE MAY SEE SOME STRONG TO SEVERE THUNDERSTORM ACTIVITY
DEVELOP ON WEDNESDAY INTO WEDNESDAY EVENING.
AVIATION
(18Z TAFS)
ISSUED AT 1230 PM CDT FRI MAY 1 2026
VFR CONDITIONS ARE EXPECTED THROUGH MUCH OF THE TAF PERIOD. A
PROB30 BETWEEN 5Z AND 8Z WAS INCLUDED AT THE TERMINALS FOR THE LOW
POSSIBILITY OF -SHRA DROPPING CIGS OR VSBYS TO MVFR LEVEL LATER
TONIGHT. OTHERWISE, NORTHERLY WINDS BETWEEN 5 AND 10 KNOTS ARE
EXPECTED.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...KTW
SHORT TERM....KTW
LONG TERM....KTW
AVIATION...KTW
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