950
FXUS63 KLMK 161251
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
851 AM EDT FRI MAY 16 2025
KEY MESSAGES
* SIGNIFICANT SEVERE WEATHER OUTBREAK POSSIBLE LATE THIS AFTERNOON
INTO THIS EVENING.
* ALL SEVERE WEATHER HAZARDS ARE ON THE TABLE, INCLUDING DAMAGING
WINDS, LARGE HAIL, TORNADOES, AND TORRENTIAL RAINFALL. A FEW
STRONG TORNADOES AND INSTANCES OF VERY LARGE HAIL ARE POSSIBLE.
* STRONG TO SEVERE THUNDERSTORMS ARE ALSO POSSIBLE THIS MORNING
WEST OF INTERSTATE 65, WITH LARGE HAIL AS THE MAIN HAZARD.
MESOSCALE
ISSUED AT 851 AM EDT FRI MAY 16 2025
A SW-NE ORIENTED LINE OF STRONG TO SEVERE CONVECTION EXTENDS FROM
SOUTHWEST KY INTO THE SOUTHERN BLUEGRASS REGION. ACTIVITY HAS BEEN
LOCALLY SEVERE IN SPOTS, WITH HAIL BEING THE PRIMARY WEATHER
HAZARDS. WE'VE HAD QUITE A FEW REPORTS OF NICKELS, DIMES, AND A FEW
QUARTERS.
THIS ACTIVITY IS BEING FORCED WITHIN A WARM ADVECTIVE SCHEME AND THE
NOCTURNAL LOW-LEVEL JET AXIS COMING IN FROM THE SOUTHWEST. MODEL
PROXIMITY SOUNDINGS SHOW THE BOUNDARY LAYER BEING IN A COOL STATE
DUE TO NOCTURNAL EFFECTS. HOWEVER, ALOFT, STEEP LAPSE RATES ATOP A
MOIST AIRMASS RESULT IN MUCAPE VALUES OF 1000-1800 J/KG. CELLS HAVE
BEEN EXHIBITING A SUPERCELLULAR TYPE STRUCTURE TO THEM AT TIMES.
MODEL PROXIMITY HODOGRAPHS FROM THE RAP AND HRRR SHOW STRAIGHT, BUT
ELONGATED HODOGRAPHS SUPPORTING THIS CONVECTIVE MODE. THE ACTIVITY
HAS BEEN TRAINING ALONG AND JUST NORTH OF THE WK PARKWAY AND THEN
EAST-NORTHEAST ALONG THE BLUEGRASS PARKWAY. LOW-MID LEVEL LAPSE
RATES ARE A BIT LESS STEEP OUT EAST OF I-65 RESULTING IN A MARKED
WEAKENING TREND OF CONVECTION AS IT HEADS EAST OF THE I-65 CORRIDOR.
RECENT RADAR IMAGERY FROM PAH/HPX SHOW THE SCATTERED CELLS STARTING
TO FORM A LINE. THIS AGREES WELL WITH RECENT HRRR GUIDANCE
SUGGESTING THAT A SMALL SCALE MCS MAY END UP FORMING AND MOVING
ACROSS SOUTHERN KY THIS MORNING RESULTING IN A CONTINUED WIND/HAIL
THREAT. WW259 REMAINS IN EFFECT UNTIL 10 AM EDT. AS OF THIS
WRITING, THE MAIN SEVERE WEATHER THREAT LOOKS TO REMAIN ALONG AND
SOUTH OF THE WK/BG PARKWAYS THROUGH LUNCHTIME.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 407 AM EDT FRI MAY 16 2025
A SIGNIFICANT SEVERE WEATHER OUTBREAK IS POSSIBLE LATER THIS
AFTERNOON AND THIS EVENING ACROSS THE OHIO VALLEY. STORMS DEVELOPING
AHEAD OF AN INCOMING COLD FRONT WILL QUICKLY BECOME SEVERE IN A VERY
UNSTABLE AND STRONGLY SHEARED ENVIRONMENT. ALL SEVERE WEATHER
HAZARDS, INCLUDING WIDESPREAD DAMAGING WINDS, VERY LARGE HAIL, AND
STRONG TORNADOES ARE POSSIBLE, AS WELL AS LOCALIZED FLASH FLOODING.
MAIN BUST POTENTIAL HINGES ON THE EVOLUTION OF STORMS THIS MORNING,
WHICH HAVE DEVELOPED OVER WESTERN KENTUCKY. THESE STORMS WILL HAVE A
LARGE HAIL THREAT OF THEIR OWN, ESPECIALLY WEST OF INTERSTATE 65.
WHILE THEY WILL AT LEAST TEMPORARILY STABILIZE THE ATMOSPHERE,
STRONG WARM ADVECTION IS LIKELY TO WIN OUT, ALLOWING A FAIRLY QUICK
RECOVERY THIS AFTERNOON.
WITH AROUND 3000 J/KG OF MIXED-LAYER CAPE, 1000 J/KG OF DOWNDRAFT
CAPE, AND 60 KT OF EFFECTIVE SHEAR, INITIALLY DISCRETE STORMS WILL
ORGANIZE INTO AT LEAST BOWING SEGMENTS. A FEW OF THE DISCRETE CELLS
COULD PRODUCE VERY LARGE HAIL AND/OR STRONG TORNADOES, AND LINE
SEGMENTS COULD PRODUCE HURRICANE-FORCE WIND GUSTS. SPIN-UP TORNADOES
WILL ALSO BE IN PLAY WITH ANY OF THE BOWING STRUCTURES AS WELL.
THE PEAK SEVERE THREAT COULD BE SLIGHTLY DELAYED DEPENDING ON HOW
QUICKLY THE ATMOSPHERE CAN RELOAD AFTER MORNING CONVECTION, BUT THE
THREAT WILL MAINLY BE FOCUSED ON THE EVENING HOURS. INITIAL DISCRETE
CELLS COULD DEVELOP IN THE LATE AFTERNOON.
IT'S ALSO WORTH NOTING THAT IN THE LATE EVENING, THE LINE WILL
BECOME MORE EAST-WEST ORIENTED, OPENING THE DOOR FOR EXCESSIVE
RAINFALL ESPECIALLY OVER SOUTH-CENTRAL KENTUCKY. CONFIDENCE IN THE
EXACT PLACEMENT IS LOW AT THIS TIME, BUT IT BEARS WATCHING AS THE
EVENT UNFOLDS.
BOTTOM LINE, SIGNIFICANT SEVERE WEATHER IS POSSIBLE LATE THIS
AFTERNOON AND THIS EVENING. MAKE SURE YOU HAVE MULTIPLE WAYS TO
RECEIVE WARNINGS AND A PLAN IN PLACE SHOULD A WARNING BE ISSUED!
LONG TERM /SATURDAY THROUGH THURSDAY/
ISSUED AT 352 PM EDT THU MAY 15 2025
BY SATURDAY MORNING, THE ACTUAL COLD FRONT WILL BE PUSHING THROUGH
THE AREA WITH MOST OF THE SHOWERS AND STORMS EXITING TO OUR EAST.
THE ASSOCIATED UPPER LOW WILL BE OVER THE GREAT LAKES WITH THE
LONGWAVE TROUGH AXIS EXTENDING SOUTH OVER THE OH AND TN VALLEYS
BEFORE FLATTENING OUT AGAINST THE SUBTROPICAL RIDGE OVER THE GULF.
WEAK CAA BEHIND THE FRONT WILL RESULT IN CLIMATOLOGICAL NORMAL
TEMPERATURES FOR THE WEEKEND WITH HIGHS IN THE MID TO UPPER 70S TO
LOWER 80S ACCOMPANIED BY BREEZY WSW WINDS ON SATURDAY. OVERALL, MOST
WILL EXPERIENCE A FAIR WEATHER WEEKEND.
SOUTHERN KY WILL SEE A SLIGHT CHANCE OF SHOWERS ON SUNDAY AS THE
SOUTHERN EDGE OF THE NEW AIRMASS BEGINS TO LIFT NORTHWARD DUE TO THE
NEXT LOW PRESSURE SYSTEM STRENGTHENING OVER THE CENTRAL PLAINS. THIS
WILL BEGIN ANOTHER PERIOD OF UNSETTLED WEATHER AS WE ENTER THE
BEGINNING OF THE NEW WORK WEEK.
BY MONDAY, A WARM FRONT WILL BEGIN LIFTING ACROSS THE REGION
RESULTING IN WARM AND MOIST AIR ADVECTION, AS PWATS SURGE INTO THE
UPPER PERCENTILES OF SPC'S SOUNDING CLIMATOLOGY. MODELS TEND TO
AGREE ON CONVECTION FROM OUR WEST MOVING INTO OUR AREA BY MONDAY
MORNING WITH ANOTHER ROUND MONDAY EVENING. THE WARM FRONT APPEARS TO
STALL OVER THE REGION, PROLONGING OUR SHOWER AND STORM CHANCES INTO
TUESDAY AND WEDNESDAY BEFORE THE OCCLUDED LOW PUSHES THROUGH ON
WEDNESDAY. WITH MODEL SOUNDINGS ADVERTISING SUFFICIENT INSTABILITY
AND ML GUIDANCE ALSO SHOWING ENHANCED SEVERE PROBABILITIES, SEVERE
WEATHER CAN NOT BE RULED OUT. DETAILS REMAIN HAZY THIS FAR OUT, BUT
WILL CONTINUE TO MONITOR CLOSELY WITH SUBSEQUENT FORECAST PACKAGES.
STAY TUNED.
AVIATION /12Z TAFS THROUGH 18Z SATURDAY/
ISSUED AT 712 AM EDT FRI MAY 16 2025
MAIN CHALLENGE IN THIS TAF SET IS TIMING AND IMPACTS OF TWO
DIFFERENT WAVES OF CONVECTION. ONGOING CONVECTION THIS MORNING WILL
MAINLY PRODUCE BRIEF IFR VIS IN THE HEAVIEST RAIN, BUT CIGS SHOULD
REMAIN VFR WITH THE EXCEPTION OF LEX AND PERHAPS RGA. FIRST WAVE OF
STORMS WILL PUSH EAST OF THE TERMINALS BY 15-17Z, GIVING WAY TO
MAINLY MID-LEVEL CIGS THIS AFTERNOON WITH GUSTY SSW WINDS.
NEXT WAVE OF MORE VIGOROUS STORMS IS EXPECTED EARLY THIS EVENING.
GIVEN THE WIND THREAT, OPTED TO INCLUDE A TEMPO WITH CONVECTIVE
WINDS STARTING AROUND 23Z IN HNB/BWG, CLOSER TO 00Z AT SDF, AND 01-
02Z IN LEX AND RGA. THIS WILL ALSO BE THE BETTER SHOT AT MVFR CIGS
AND IFR VIS, AND COULD WARRANT A PREVAILING MENTION IN LATER TAF
ISSUANCES. SOME UNCERTAINTY BETWEEN WAVES AT BWG AND RGA AS WE COULD
HAVE A LINGERING BOUNDARY DRAPED ACROSS TO FOCUS CONVECTION SOONER.
SHOULD BE A FAIRLY SHARP CUTOFF AND CLEARING OUT OF LOWER CLOUDS
AFTER THE STORMS PASS AROUND MIDNIGHT. LIGHT SW WINDS AND CIRRUS
CEILINGS HEADING INTO SAT MORNING.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
MESOSCALE....MJ
SHORT TERM...RAS
LONG TERM....CG
AVIATION.....RAS
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