826
FXUS63 KLMK 150528
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
128 AM EDT THU MAY 15 2025
KEY MESSAGES
* A FEW STRONG TO SEVERE STORMS ARE POSSIBLE THIS EVENING AND
TONIGHT, WITH LARGE HAIL BEING THE MAIN SEVERE THREAT.
* MULTIPLE WAVES OF STRONG TO SEVERE STORMS ARE POSSIBLE THURSDAY
NIGHT THROUGH FRIDAY NIGHT. THURSDAY NIGHT, OVERALL CONFIDENCE IN
STORMS IS FAIRLY LOW, THOUGH ANY STORMS WHICH DO DEVELOP COULD
BRING LARGE HAIL AND DAMAGING WINDS.
* ALL SEVERE HAZARDS ARE IN PLAY FRIDAY EVENING INTO FRIDAY NIGHT,
INCLUDING LARGE HAIL, DAMAGING WINDS, AND TORNADOES. A FEW STRONG
TORNADOES AND INSTANCES OF VERY LARGE HAIL ARE POSSIBLE.
CONFIDENCE IN SEVERE HAZARDS AND TIMING IS STILL FAIRLY LOW AND
WILL DEPEND ON ANY STORMS THURSDAY NIGHT.
UPDATE
ISSUED AT 847 PM EDT WED MAY 14 2025
THINGS REMAIN QUIET ACROSS THE CWA AT THE MOMENT, AND AT LEAST FOR
NOW, INITIATION OF ANY CONVECTION SEEMS TO BE RUNNING A BIT BEHIND
SCHEDULE. WE'LL STEADILY SEE AN UPTICK IN THE LOW LEVEL JET FROM SW
TO TO NE OVER THE NEXT 3 TO 6 HOURS, AND MODELS CONTINUE TO INDICATE
THAT ISOLATED TO WIDELY SCATTERED SHOWERS AND A FEW STORMS COULD
INITIATE. THE BIG QUESTION IS WHETHER ANY TRIGGERED UPDRAFTS WILL BE
ABLE TO OVERCOME THE SUBTLE INVERSION AROUND H7? IF SO, THEN THERE
IS MODEST MUCAPE VALUES AROUND 1000 J/KG TO TAP INTO. IF NOT, THEN
WE'LL JUST SEE SHALLOW SHOWERS TRAPPED BELOW THE SUBSIDENCE
INVERSION. WE'LL CONTINUE TO MONITOR THROUGH THE LATE EVENING,
KEEPING ISOLATED TO SCATTERED POPS IN THE FORECAST, BUT OVERALL
CONFIDENCE IS LOW ON HOW MUCH, IF ANY, COVERAGE WE ARE GOING TO SEE.
IF A FEW STORMS DO GET GOING, THEN HAIL WOULD BE THE PRIMARY SEVERE
HAZARD AS STORM ACTIVITY SHOULD BE ELEVATED IN NATURE.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 154 PM EDT WED MAY 14 2025
ACROSS THE REGION SO FAR TODAY, MOSTLY SUNNY SKIES HAVE BEEN
OBSERVED ACROSS MUCH OF NORTH CENTRAL KY AND SOUTH CENTRAL IN, WHILE
LOW STRATUS AND FOG HAS BEEN PRESENT FARTHER TO THE SOUTH,
ESPECIALLY SOUTH OF THE WK/BG PARKWAYS. LOW-LEVEL MOISTURE IS NOW
BEGINNING TO MIX INTO A STRATOCUMULUS FIELD ACROSS THE AREA, WITH
THE GREATEST CLOUD COVER OCCURRING WHERE THE STRATUS LAYER WAS THIS
MORNING. A BAND OF LIGHT RAIN SHOWERS IS ALSO NOTED EXTENDING FROM
EASTERN IN INTO FAR NORTHERN KY; THIS IS LIKELY ASSOCIATED WITH THE
UPPER LOW WHICH IS JUST NORTHEAST OF THE AREA THIS MORNING.
AS WE HEAD THROUGH THE AFTERNOON HOURS, SINCE WE ARE ON THE
ANTICYCLONIC SIDE OF THE UPPER LOW AND DRIER AIR ALOFT IS FILTERING
INTO THE REGION, WOULD EXPECT MUCH LESS COVERAGE IN SHOWERS AND
STORMS. STILL CAN'T RULE OUT AN ISOLATED CELL GIVEN RESIDUAL LOW-
LEVEL MOISTURE; HOWEVER, MOST SHOULD REMAIN DRY THIS AFTERNOON.
TEMPERATURES ARE ALREADY IN THE MID 70S WHERE WE HAVE HAD MORE
SUNSHINE THIS MORNING, AND HIGHS SHOULD REACH THE UPPER 70S AND LOW
80S THIS AFTERNOON.
THERE IS INCREASING POTENTIAL FOR SCATTERED SHOWERS AND
THUNDERSTORMS TO DEVELOP ALONG THE LEADING EDGE OF A WARM FRONT LATE
THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS. WHILE THE NEAR-SFC
LAYER SHOULD BEGIN TO STABILIZE AROUND SUNSET, SHORT RANGE MODEL
GUIDANCE HAS A LOW-LEVEL THETA-E RIDGE SURGING IN FROM THE SOUTHWEST
TONIGHT, RESULTING IN STEEPENING MID-LEVEL LAPSE RATES AND
INCREASING MU CAPE VALUES. WHILE INCREASING ZONAL FLOW ALOFT WILL
LEAD TO STRONGER DEEP-LAYER SHEAR COMPARED TO THE PAST FEW DAYS,
EFFECTIVE BULK SHEAR VALUES ARE STILL PROGGED TO BE AROUND 25-30 KT,
INCREASING THE POTENTIAL FOR A FEW ORGANIZED CELLS. WOULD EXPECT THE
MAIN THREAT WITH STORMS TONIGHT TO BE LARGE HAIL; HOWEVER, DAMAGING
WINDS EXIST AS A SECONDARY THREAT IF ANY CONVECTION CAN GET GOING
EARLIER IN THE EVENING WHEN THE NEAR-SFC STABLE LAYER WILL BE
SHALLOWER. THE MAIN TIME FRAME FOR STORMS TONIGHT LOOKS TO BE
BETWEEN 00-06Z, LIFTING FROM SW TO NE AS THE WARM FRONT CROSSES THE
AREA. OTHERWISE, TEMPERATURES SHOULD BE MILD, WITH LOWS ONLY FALLING
INTO THE MID-TO-UPPER 60S.
ON THURSDAY, THE MID-LEVEL RIDGE AXIS WILL EXTEND FROM SOUTHWEST TO
NORTHEAST ACROSS THE MID-MISSISSIPPI AND LOWER OHIO VALLEYS AS
TROUGHING OVER THE CENTRAL PLAINS EVOLVES INTO A CLOSED LOW OVER THE
NORTHERN PLAINS BY THURSDAY EVENING. 850 MB TEMPERATURES BETWEEN 23-
25 DEGREES CELSIUS WILL SUPPORT UNSEASONABLY WARM TEMPERATURES
ACROSS THE AREA. THIS WARM AIR IN THE MID-LEVELS WILL ALSO HELP TO
SUPPRESS CONVECTION DURING THE DAYTIME ON THURSDAY. WHILE SOME OF
THE HIGH-RESOLUTION CAM GUIDANCE TRIES TO DEVELOP SHOWERS AND STORMS
DURING THE DAY ON THURSDAY, THE EXPECTATION IS THAT THIS EITHER WILL
NOT OCCUR, OR WOULD BE WEAK SHOWERS WITHIN THE WARM ADVECTION REGIME
BELOW THE MID-LEVEL CAP. SIMPLY PUT, THE POTENTIAL FOR STRONG TO
SEVERE STORMS DURING THE DAYTIME HOURS ON THURSDAY LOOKS TO BE
FAIRLY LOW AT THIS TIME. THE TEMPERATURE FORECAST FOR THE DAY ON
THURSDAY IS ALSO A BIT TRICKY AS ANY LOW-LEVEL CLOUDS AND SHOWERS
WHICH TRY TO DEVELOP WOULD LIMIT HEATING. WHILE THERE IS A
SIGNIFICANT POTENTIAL FOR TEMPERATURES TO REACH 90 DEGREES IN THE
URBAN HEAT CENTERS, WILL ADVERTISE MID-TO-UPPER 80S AT THIS TIME
GIVEN CONTINUED UNCERTAINTY IN CLOUD COVERAGE.
LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/
ISSUED AT 351 PM EDT WED MAY 14 2025
THURSDAY NIGHT THROUGH FRIDAY NIGHT...
A CLOSED UPPER LOW WILL BE SPINNING OVER THE NORTHERN PLAINS
THURSDAY EVENING AS AN ATTENDANT SFC LOW BECOMES OCCLUDED NEAR THE
ND/MN BORDER. EXTENDING TO THE SOUTHEAST OF THE OCCLUDING SFC LOW
WILL BE A COLD FRONT WHICH WILL GRADUALLY LOSE DEFINITION AS IT
APPROACHES THE CONFLUENCE OF THE MISSISSIPPI AND OHIO RIVERS. AS THE
LOW PRESSURE SYSTEM BECOMES VERTICALLY STACKED, ITS EASTWARD
PROGRESSION WILL SLOW, RESULTING IN SOUTHEASTERN U.S. RIDGING
REMAINING IN PLACE INTO THE DAY ON FRIDAY. AS A RESULT, MID-LEVEL
WARM AIR WILL KEEP A PRETTY STOUT CAPPING INVERSION OVER CENTRAL KY
AND SOUTHERN IN THURSDAY NIGHT, WITH LFCS EXPECTED TO BE AROUND 700
MB. HOWEVER, TO THE NORTHWEST OF THE AREA, WHERE THERE WILL BE
GREATER MID-LEVEL HEIGHT FALLS AND BETTER FORCING WITHIN THE LEFT
EXIT REGION OF THE JET, CONVECTION IS EXPECTED TO DEVELOP ALONG THE
FRONTAL BOUNDARY.
THE QUESTION FOR SEVERE STORM POTENTIAL ACROSS OUR AREA THURSDAY
NIGHT INTO FRIDAY MORNING WILL BE WHETHER UPSTREAM CONVECTION CAN
SURVIVE AN INCREASINGLY HOSTILE LOW-MID LEVEL THERMODYNAMIC PROFILE
AS IT MOVES OFF TO THE SOUTHEAST. IF STORMS CAN SURVIVE INTO
SOUTHERN IN AND CENTRAL KY, 1500-2000 J/KG MUCAPE AND 45-50 KT OF
EFFECTIVE BULK SHEAR WILL SUPPORT STRONG TO SEVERE CONVECTION;
HOWEVER, CONFIDENCE IS PRETTY LOW THAT WE WILL BE ABLE TO GET STORMS
INTO OUR AREA. THE LATER INTO THE NIGHT THAT STORMS SURVIVE, THE
MORE LIKELY IT BECOMES THAT CONVECTION WILL BE ELEVATED; AS A
RESULT, WHILE TORNADOES AND DAMAGING WINDS ARE CERTAINLY WITHIN THE
REALM OF POSSIBILITY, THINK THAT LARGE HAIL MAY BE THE MAIN THREAT
IN OUR AREA THURSDAY NIGHT.
DURING THE DAY ON FRIDAY, THE UPPER LOW TO OUR NORTHWEST WILL PIVOT
AND GRADUALLY SHIFT EASTWARD, SENDING A STRENGTHENING UPPER-LEVEL
JET ACROSS THE OHIO VALLEY. DEPENDING ON THE COVERAGE AND INTENSITY
OF STORMS THURSDAY NIGHT, WE MAY NEED SOME TIME FOR THE ATMOSPHERE
TO RECOVER ON FRIDAY, WHICH WOULD HAVE A SUBSTANTIAL IMPACT ON
SEVERE STORM POTENTIAL AND TIMING FRIDAY AFTERNOON INTO FRIDAY
NIGHT. IF THERE IS LIMITED CONVECTION THURSDAY NIGHT, THE PARAMETER
SPACE FRIDAY AFTERNOON AND FRIDAY NIGHT WILL BE VERY CONCERNING.
MLCAPE OF 2500-3500 J/KG AND DEEP-LAYER SHEAR ON THE ORDER OF 55-60
KT WILL SUPPORT EXPLOSIVE ORGANIZED CONVECTION. THERE SHOULD BE
ENOUGH DIRECTIONAL DIFFERENCE BETWEEN THE LOW-LEVEL AND UPPER-LEVEL
WINDS FOR CONVECTION TO REMAIN DISCRETE, AT LEAST INITIALLY, AND
MODELED SUPERCELL COMPOSITE PARAMETER VALUES OF 6 OR GREATER SHOW
THE POTENTIAL FOR LONG-LASTING SUPERCELLS ACROSS THE OHIO VALLEY.
WITHIN THESE CELLS, ALL SEVERE HAZARDS, INCLUDING LARGE HAIL,
DAMAGING STRAIGHT-LINE WINDS, AND TORNADOES, SOME OF WHICH COULD BE
STRONG, WILL BE IN PLAY. LATER IN THE EVENING, WOULD EXPECT
CONVECTION TO GROW UPSCALE INTO LARGE BOWING SEGMENTS/MCSS,
INCREASING THE DAMAGING WIND POTENTIAL.
STORMS SHOULD HELP TO PUSH THE COLD FRONT THROUGH THE REGION BY
SATURDAY MORNING, BRINGING AN END TO THE STRONG-SEVERE STORM
POTENTIAL. OVERALL CONFIDENCE IS STILL LOW GIVEN THE AMOUNT OF
UNKNOWNS RELATED TO ANTECEDENT CONVECTION WHICH STILL REMAINS. WITH
THAT BEING SAID, THE INSTABILITY/SHEAR PARAMETERS ARE CONCERNING TO
SAY THE LEAST, WITH SIGNIFICANT SEVERE WEATHER LOOKING INCREASINGLY
LIKELY ACROSS THE REGION FRIDAY EVENING.
SATURDAY INTO EARLY NEXT WEEK...
THE WEEKEND IS LOOKING FAIRLY QUIET AS THE COLD FRONT PUSHES INTO
THE TENNESSEE VALLEY ON SATURDAY, BRINGING DRIER AIR ACROSS OUR
REGION. WHILE THERE LIKELY WON'T BE SUPER STRONG COLD ADVECTION WITH
A WSW WIND BEHIND THE FRONT, FAIRLY SEASONABLE TEMPERATURES AND
BREEZY CONDITIONS ARE EXPECTED ON SATURDAY. ON SUNDAY, RIDGING WILL
BEGIN TO BUILD IN FROM THE SOUTHWEST AS SFC HIGH PRESSURE MOVES
ACROSS THE GREAT LAKES. THIS WILL CAUSE THE SFC FRONT TO BEGIN TO
TRY TO LIFT BACK TO THE NORTH, INCREASING MOISTURE AND PRECIPITATION
CHANCES FROM THE SOUTH. THE MOST LIKELY SOLUTION AT THIS TIME WOULD
KEEP THINGS DRY ACROSS THE AREA ON SUNDAY WITH THE POSSIBLE
EXCEPTION OF AREAS ALONG THE TN BORDER. TEMPERATURES SHOULD BE
FAIRLY SIMILAR TO SATURDAY (UPPER 70S/LOW 80S), WITH MUCH LIGHTER
WINDS EXPECTED.
EARLY NEXT WEEK, A GRADUAL RETURN TO MORE ACTIVE WEATHER IS EXPECTED
AS ANOTHER UPPER-LEVEL TROUGH EJECTS FROM THE WESTERN CONUS INTO THE
CENTRAL PLAINS. RIDGING SHOULD MOVE ACROSS THE AREA ON MONDAY, WITH
A GRADUAL WARMUP EXPECTED INTO THE MIDDLE OF NEXT WEEK. TUESDAY INTO
WEDNESDAY, A RETURN OF MORE ACTIVE WEATHER IS EXPECTED AS ANOTHER
COLD FRONT PUSHES ACROSS THE REGION. CONFIDENCE IN TIMING AND
SPECIFIC THREATS IS FAIRLY LOW, THOUGH IT IS WORTH NOTING THAT LONG
RANGE AI/ML GUIDANCE IS INDICATING A RETURN OF A SEVERE THREAT NEXT
TUESDAY NIGHT INTO WEDNESDAY.
AVIATION /06Z TAFS THROUGH 12Z FRIDAY/
ISSUED AT 113 AM EDT THU MAY 15 2025
WINDOW FOR PRECIP HAS CLOSED AS THE EFFECTIVE BOUNDARY HAS LIFTED
NORTH OF THE TERMINALS. SCT-BKN HIGH-BASED STRATUS INITIALLY ACROSS
SDF AND LEX, WITH A MORE SOLID BUT STILL HIGH-BASED DECK SPREADING
NE FROM BWG. WE'LL REMAIN VFR THROUGH THE NIGHT WITH LIGHT S-SE
WINDS.
MID-LATE MORNING SDF AND LEX COULD AGAIN SEE LOW STRATO-CU AS LOW-
LEVEL MOISTURE IS TRAPPED UNDER A STRONG INVERSION AT THE TOP OF THE
GROWING BOUNDARY LAYER. COULD BE JUST ENOUGH COVERAGE FOR A MVFR CIG
BUT WILL REMAIN ABOVE 2000 FEET.
VERY WARM AND STRONGLY CAPPED BOUNDARY LAYER IN THE AFTERNOON WILL
SUPPORT GENERALLY SCATTERED FLAT CU, WITH SSW WINDS GUSTING JUST
OVER 20 KT. GUSTS WILL PERSIST WELL INTO THE EVENING AHEAD OF AN
APPROACHING COLD FRONT. STORMS THAT DEVELOP UPSTREAM WILL BE FACING
AN INCRESASINGLY HOSTILE ENVIRONMENT AS THEY PUSH SOUTH AND EAST
TOWARD HNB AND SDF, SO CONFIDENCE IS TOO LOW TO INCLUDE IN THE TAFS
LATE IN THE EVENING.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
UPDATE...BJS
SHORT TERM...CSG
LONG TERM...CSG
AVIATION...RAS
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