509
FXUS64 KHUN 081754
AFDHUN
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE HUNTSVILLE AL
1254 PM CDT THU MAY 8 2025
..NEW AVIATION
NEAR TERM
(REST OF TODAY AND TONIGHT)
ISSUED AT 1039 AM CDT THU MAY 8 2025
DENSE FOG THAT IMPACTED PARTS OF THE TENNESSEE VALLEY IN THE LATE
NIGHT AND EARLIER THIS MORNING HAS DISSIPATED, THANKS TO DAYTIME
HEATING AND MIXING. AN OTHERWISE MOIST LOWER ATMOSPHERE PERSISTS,
WITH MORE CLOUD BASES IN THE IFR-MVFR (600-2500 FT AGL) RANGE.
AREA TEMPERATURES HAVE SLOWLY RISEN INTO THE UPPER 60S AND LOWER
70S WITH LIGHT S-SW WINDS. A BIT MORE LOWER LEVEL MIXING AND SOME
ADDITIONAL SUN SHOULD HELP HIGH TEMPERATURES LATER TODAY RISE INTO
THE MID 70S TO LOWER 80S.
THIS HEATING WILL RESULT IN A MORE UNSTABLE ENVIRONMENT AS WE GO
INTO THE AFTERNOON. THIS AND THE APPROACH OF AN UPPER LEVEL SYSTEM
WILL BRING GOOD CHANCES OF SHOWERS AND THUNDERSTORMS DEVELOPING.
THE LATEST TIMING HAS STORMS FORMING IN THE EARLY AFTERNOON, AND
PROGRESSING IN WSN-ESE MANNER. OVERALL CONVECTION SHOULD WANE AS
WE GO INTO THE EVENING, AS THEY WILL BE DRIVEN BY DAYTIME HEATING.
SURFACE BASED CAPES IN THE 1500-2000 J/KG RANGE AND HELICITY OF
50-150 M/S RANGE WILL SUPPORT STRONG TO SEVERE THUNDERSTORMS. THE
MAIN THREAT WILL BE DAMAGING WIND GUSTS OVER 60 MPH, AND LARGE
HAIL (+2"!). A DEEP SHEAR OF 35-40 KT IS NOT TOO FAVORABLE FOR
TORNADO DEVELOPMENT, HOWEVER THOSE CANNOT BE RULED OUT.
SHORT TERM
(FRIDAY THROUGH SUNDAY)
ISSUED AT 1039 AM CDT THU MAY 8 2025
SHOWER ACTIVITY SHOULD WANE AS WE GO INTO TONIGHT WITH A LOSS OF
DAYTIME HEATING. MODEL OUTPUT AND MOS WERE HINTING THAT FOG COULD
BECOME AN ISSUE AGAIN IN THE OVERNIGHT. IT IS UNCERTAIN IF WE WILL
NEED ANOTHER DENSE FOG ADVISORY AT THIS TIME.
A GENERALLY UNSETTLED PATTERN WILL TAKE PLACE AS MEAN TROUGHING
PERSISTS ACROSS THE EASTERN CONUS. ANOTHER UPPER LEVEL LOW IS
FORECAST TO FORM OVER THE DEEP SOUTH LATE FRIDAY INTO SATURDAY.
THE PRESENCE OF THIS FEATURE AND SUFFICIENT RESIDUAL MOISTURE WILL
KEEP A THREAT OF SHOWERS AND THUNDERSTORMS INTO SUNDAY. COOLER
THAN NORMAL CONDITIONS ARE FORECAST FOR THE FRI-SUN PERIOD, WITH
HIGHS ONLY IN THE 70S EXPECTED. NORMAL HIGHS THIS TIME OF YEAR ARE
IN THE LOWER 80S FOR REFERENCE.
LONG TERM
(SUNDAY NIGHT THROUGH WEDNESDAY)
ISSUED AT 1135 PM CDT WED MAY 7 2025
AS AN UPPER LEVEL LOW SHIFTS SOUTHEASTWARD AND THEN MOVES BACK TO
THE NORTHEAST EARLY NEXT WEEK, WE WILL REMAIN IN A PATTERN
FAVORABLE FOR DAILY SHOWER/THUNDERSTORM CHANCES THROUGH THE LONG
TERM PERIOD. RAINFALL MAY BE HEAVY AT TIMES, HOWEVER, PWATS ARE
FORECAST TO BE IN THE 1.1-1.2" RANGE PER THE LREF 50TH
PERCENTILE-- WHICH FALLS JUST ABOVE THE DAILY MEAN PER BMX
SOUNDING CLIMATOLOGY FOR MOST OF THIS TIME PERIOD. WHILE FLASH
FLOODING IS NOT FORECAST, THERE COULD BE PONDING OF WATER IN AREAS
OF POOR DRAINAGE AND/OR LOW LYING AREAS DUE TO RUNOFF. HIGH
TEMPERATURES DURING THIS TIME ARE FORECAST TO REFLECT A WARMING
PATTERN AS THEY TRANSITION FROM THE 70S ON SUNDAY TO THE 80S ON
WEDNESDAY. LOWS ARE FORECAST TO DROP INTO THE 50S-60S DURING THIS
TIME PERIOD.
AVIATION
(18Z TAFS)
ISSUED AT 1254 PM CDT THU MAY 8 2025
WITH DAYTIME HEATING AND GREATER INSTABILITY, CONVECTION HAS BEGUN
DEVELOPING FROM THE KY/TN BORDER NEAR I-65, TO MIDDLE TN N, AND
NW OF NW AL. AN UPPER LEVEL SYSTEM APPROACHING FROM THE WNW WILL
HELP PRODUCE MORE SHOWERS AND THUNDERSTORMS. SOME STORMS COULD
BECOME SEVERE, WITH WIND GUSTS OVER 50KT AND HAIL OF 2", POSSIBLY
LARGER. PARTIALLY ADDRESSED THIS WITH VARIABLE WINDS GUSTING TO
30KT AND REDUCED VISIBILITIES IN A TEMPO GROUP. SHOWER ACTIVITY
SHOULD END FROM WEST TO EAST AS WE GO INTO THE EVENING. MORE FOG
IS EXPECTED TO DEVELOP IN THE LATE NIGHT AND EARLY FRI. DEPENDING
UPON HOW MUCH RAINFALL IS REALIZED AND WHERE IT FELL, SOME OF THE
FOG COULD BECOME LOCALLY DENSE WITH VISIBILITY REDUCTIONS TO 1/4
OF MILE. FOG THAT FORMS SHOULD DISSIPATE SHORTLY AFTER DAYBREAK
WITH VFR CONDITIONS LATE FRI MORNING.
HUN WATCHES/WARNINGS/ADVISORIES
AL...NONE.
TN...NONE.
NEAR TERM...RSB
SHORT TERM....RSB
LONG TERM....KTW
AVIATION...RSB
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