277
FXUS63 KLMK 051915
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
315 PM EDT FRI SEP 5 2025
KEY MESSAGES
* COLD FRONT TO PUSH THROUGH THE REGION TONIGHT INTO SATURDAY.
STRONG TO SEVERE STORMS WILL BE POSSIBLE OUT AHEAD OF THIS FRONT
THIS EVENING AND INTO THE EARLY OVERNIGHT HOURS. SCATTERED SHOWERS
WILL LINGER SATURDAY MORNING.
* COOLER AND DRIER AIR WILL RETURN TO THE REGION LATE SATURDAY AND
INTO SUNDAY. OVERNIGHT LOWS SUNDAY AND MONDAY MORNING MAY BREAK
RECORD LOW TEMPS. PLEASANT WEATHER IS EXPECTED FOR NEXT WEEK.
SHORT TERM /THROUGH SATURDAY/
ISSUED AT 314 PM EDT FRI SEP 5 2025
AT THIS HOUR, A SURFACE COLD FRONT BISECTS THE AREA, WITH SFC WINDS
VEERING FROM SW TO W/NW FROM EAST TO WEST ACROSS CENTRAL KY AND
SOUTHERN IN. AHEAD OF THE FRONT, TEMPERATURES IN THE MID-TO-UPPER
80S AND LOWER 90S COMBINED WITH DEWPOINT TEMPERATURES IN THE UPPER
60S AND LOWER 70S SUPPORT A MODESTLY UNSTABLE ENVIRONMENT, WITH
AROUND 2000-2500 J/KG MLCAPE ALONG AND SOUTH OF THE KY PARKWAYS AS
OF 18Z. TO THE NORTH AND WEST OF THE FRONT, A SHARP GRADIENT IN NEAR-
SFC MOISTURE LEADS TO AN ENVIRONMENT WHICH IS NOT SUPPORTIVE FOR
DEEP CONVECTION. EVIDENCE OF THIS CAN BE SEEN ON SATELLITE VIA THE
DIFFERENCE BETWEEN A ROBUST CU FIELD OVER KY VERSUS MUCH MORE STABLE
STRATIFORM CLOUDS OVER IN.
LONGWAVE MID- AND UPPER-LEVEL TROUGHING EXTENDS ACROSS THE UPPER
MIDWEST AND GREAT LAKES REGION, WITH A SUBTLE SHORTWAVE AND
ASSOCIATED SPEED MAX NOTED ON LATEST ANALYSIS OVER THE OZARKS,
EJECTING TOWARD THE LOWER OHIO VALLEY LATER THIS AFTERNOON. THIS
SHORTWAVE, ALONG WITH SOME ASSISTANCE FROM LOW-LEVEL CONVERGENCE
ALONG THE FRONT, SHOULD BE THE FORCING MECHANISM WHICH SUPPORTS
CONVECTIVE INITIATION. AREAS WHICH WILL HAVE A CHANCE AT STRONG TO
SEVERE STORMS THIS EVENING WILL DEPEND ON HOW MUCH SOUTHEASTWARD
PROGRESSION THE DRIER/MORE STABLE AIR MASS CAN MAKE BEFORE STORMS
INITIATE. OVER THE PAST 24 HOURS, HI-RES GUIDANCE HAS CONTINUED TO
TREND LATER AND FARTHER SOUTHEAST WITH THE SEVERE RISK THIS EVENING.
FOLLOWING THIS TREND, THE LATEST SPC DAY 1 SLIGHT RISK HAS SHIFTED
TO AREAS MAINLY ALONG AND SOUTH OF THE KENTUCKY PARKWAYS, WITH THE
EDGE OF THE MARGINAL RISK NOW SOUTH OF THE OHIO RIVER.
FOR STORMS WHICH DEVELOP THIS AFTERNOON AND EVENING, DEEP-LAYER
SHEAR IS EXPECTED TO BE ON THE ORDER OF 35-40 KT, WHICH WILL SUPPORT
MULTICELL AND SOME SUPERCELLULAR STRUCTURES, AT LEAST INITIALLY. IT
WOULD BE DURING THIS INITIAL PERIOD THAT ANY SEVERE HAIL WOULD BE
MOST LIKELY. IF THERE WAS TO BE ANY SPIN-UP TORNADOES, IT WOULD ALSO
BE SHORTLY AFTER STORMS FIRE, THOUGH UNIDIRECTIONAL WIND PROFILES
WILL GENERALLY BE UNSUPPORTIVE FOR SRH/MESOCYCLONE DEVELOPMENT. WITH
CURRENT SPC MESOANALYSIS SHOWING 1100+ J/KG OF DCAPE AND STEEP LLVL
LAPSE RATES, STORMS SHOULD GUST OUT, AND THE PRIMARY SEVERE THREAT
WILL BE DAMAGING WINDS. THE MAIN TIMING FOR ANY STRONG TO SEVERE
STORMS WOULD BE BETWEEN 21-03Z.
AS WE HEAD LATER INTO THE EVENING, THE CONTINUED SOUTHWARD PUSH OF
THE COLD FRONT ALONG WITH TYPICAL NIGHTTIME TRENDS WILL LEAD TO
INCREASING LLVL STABILITY, LIMITING THE SEVERE WIND GUST POTENTIAL.
ADDITIONALLY, AFTER THE FIRST ROUND OF CONVECTION MOVES OFF TO THE
EAST, THERE SHOULD BE A 3-6 HOUR LULL IN PRECIPITATION COVERAGE
BEFORE A SECOND ROUND OF SHOWERS AND SUB-SEVERE STORMS MOVES ACROSS
THE REGION EARLY SATURDAY MORNING. THIS APPEARS TO BE ASSOCIATED
WITH THE MID-LEVEL TROUGH AXIS CROSSING THE REGION ALONG WITH SOME
RESIDUAL INSTABILITY ALOFT. THIS ROUND OF MOSTLY SHOWERS AND A FEW
STORMS SHOULD CONTINUE THROUGH THE MORNING ON SATURDAY BEFORE
EXITING AROUND EARLY AFTERNOON.
RAINFALL AMOUNTS SHOULD GENERALLY INCREASE THE FARTHER SOUTHEAST YOU
GO, WITH SOUTHERN AND SOUTHEASTERN KY EXPECTED TO SEE THE MOST RAIN
TONIGHT INTO TOMORROW. 12Z HREF SHOWS A FEW SWATHS OF 2-4" OF QPF IN
LOCALIZED PROBABILITY-MATCHED MEAN ANALYSIS, PRIMARILY ACROSS THE
LAKE CUMBERLAND REGION AND THE SOUTHERN BLUEGRASS. IN THESE HIGHER
SWATHS, LOCALIZED FLASH FLOODING WILL BE POSSIBLE, MAINLY DUE TO
HIGH RATES OVERWHELMING DRY SOILS.
OTHERWISE, CONDITIONS WILL IMPROVE FROM NW TO SE DURING THE
AFTERNOON ON SATURDAY AS DRIER AIR WORKS IN BEHIND THE COLD FRONT.
TEMPERATURES WILL BE CONSIDERABLY COOLER, ESPECIALLY WHERE CLOUDS
ARE SLOW TO CLEAR. HIGHS ON SATURDAY SHOULD RANGE FROM THE UPPER 60S
TO THE MID 70S.
LONG TERM /SATURDAY NIGHT THROUGH FRIDAY/
ISSUED AT 314 PM EDT FRI SEP 5 2025
BY SATURDAY NIGHT, SKIES SHOULD BEGIN CLEARING AS THE COLD FRONT
PUSHES WELL EAST OF THE REGION. LONGWAVE TROUGHING ALOFT WILL REMAIN
IN PLACE FOR MUCH OF THE REMAINDER OF THE FORECAST PERIOD WITH HIGH
PRESSURE BUILDING IN FROM THE NW IN THE LOWER LEVELS. THIS WILL
RESULT IN DRY WEATHER FOR NEXT WEEK.
COLD AIR ADVECTION FROM A MODIFIED CP AIRMASS WILL SETTLE OVER THE
REGION, WITH SUNDAY AND MONDAY MORNING LOWS POSSIBLY SETTING RECORDS
(SEE CLIMATE SECTION BELOW). EXPECT TO SEE TEMPERATURES FALL INTO
THE MID TO UPPER 40S BY SUNDAY MORNING, WARMING INTO THE LOW TO MID
70S SUNDAY AFTERNOON, AND THEN FALLING TO THE COLDEST OF THE
FORECAST PERIOD MONDAY MORNING WITH LOWS BOTTOMING OUT IN THE LOW TO
MID 40S.
BY MONDAY, THE UPPER LOW OVER QUEBEC WILL CONTINUE TO RETREAT TO THE
NE CREATING BAGGY TROUGHING OVER THE OH VALLEY. AT THE SURFACE, HIGH
PRESSURE WILL ALSO ADVANCE TO THE NE US, ALLOWING SURFACE WINDS TO
GRADUALLY VEER FROM NW TO N TO E. BY TUESDAY, WAA SETS UP AS WINDS
VEER TO THE SOUTH, AND WE'LL BEGIN TO SEE A GRADUAL WARM UP
THROUGHOUT THE REST OF THE WORK WEEK AS AFTERNOON MAX TEMPERATURES
REACH BACK INTO THE LOW TO MID 80S TUESDAY AND THE MID TO UPPER 80S
THE FOLLOWING DAYS. LOTS OF SUNSHINE IN STORE FOR NEXT WEEK!
AVIATION /18Z TAFS THROUGH 00Z SUNDAY/
ISSUED AT 147 PM EDT FRI SEP 5 2025
A COLD FRONT IS LOCATED OVER THE REGION THIS AFTERNOON, WITH WINDS
VEERING FROM SW TO NW ACROSS THE FRONT. A SCT-BKN CU FIELD HAS
DEVELOPED OVER THE PAST HOUR OR SO AND IS EXPECTED TO CONTINUE
THROUGH THE DAYTIME HOURS, WITH COVERAGE DECREASING BEHIND THE COLD
FRONT. LATE THIS AFTERNOON INTO THIS EVENING, SCATTERED SHOWERS AND
THUNDERSTORMS ARE EXPECTED TO DEVELOP MAINLY SOUTHEAST OF A LINE
FROM BWG TO LEX, WITH SDF AND HNB LIKELY REMAINING DRY INTO THE
EARLY NIGHTTIME HOURS. GUSTY WINDS AND VISIBILITY DROPS WOULD BE
EXPECTED WITH ANY STRONGER SHOWER OR STORM THIS EVENING. TONIGHT,
WINDS SHOULD BE FAIRLY LIGHT, GENERALLY 5 KT OR LESS, WITH ISOLATED
TO SCATTERED SHOWERS CONTINUING INTO SATURDAY MORNING. CEILINGS AND
VIS MAY BOUNCE TO MVFR/IFR LEVELS IN ANY HEAVIER SHOWERS; HOWEVER,
CONFIDENCE IS TOO LOW FOR A PREVAILING/TEMPO MENTION AT THIS TIME.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
SHORT TERM...CSG
LONG TERM...CG
AVIATION...CSG
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