809
FXUS63 KLMK 201121
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
721 AM EDT SUN SEP 20 2026
KEY MESSAGES
* UNSEASONABLY HOT WEATHER WILL CONTINUE AREA-WIDE TODAY AND OVER
SOUTHERN KENTUCKY TOMORROW, WITH AFTERNOON HEAT INDICES NEAR 100
DEGREES.
* MILDER WEATHER WILL GRADUALLY OVERSPREAD THE AREA THIS WEEK, WITH
HIGHS LIKELY (60-80% CHANCE) IN THE 70S NORTH OF AN OWENSBORO TO
BEREA LINE BY TUESDAY, AND AREA-WIDE BY WEDNESDAY.
* WHILE AN ISOLATED STORM CAN'T BE RULED OUT THIS AFTERNOON, THE
BEST CHANCES (30-50%) WILL BE TONIGHT INTO MONDAY MORNING NEAR AND
NORTH OF I-64, AND AGAIN MONDAY AFTERNOON AND EVENING EAST OF THE
I-75 CORRIDOR. DRY WEATHER IS FORECAST TO REST OF THE WEEK.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 138 AM EDT SUN SEP 20 2026
*** HOT AGAIN, FEW PM STORMS TODAY ***
BENEATH A RIDGE OF HIGH PRESSURE, THE AIRMASS OVER CENTRAL KENTUCKY
AND SOUTHERN INDIANA REMAINS UNSEASONABLY WARM AND STILL SOMEWHAT
HUMID. AT 130AM SUNDAY MORNING, TEMPERATURES WERE IN THE LOW TO MID
70S AND DEWPOINTS WERE ANYWHERE FROM THE MID 60S ACROSS WESTERN
KENTUCKY TO LOW 70S OVER THE BLUEGRASS WHERE GENTLE SOUTHERLY FLOW
WAS RESULTING IN MOISTURE POOLING AGAINST A SOUTHWARD-SINKING
OUTFLOW BOUNDARY. IT REMAINS TO BE SEEN HOW FAR SOUTH THIS FEATURE
WILL SETTLE EARLY THIS MORNING, BUT WHEREVER THAT BOUNDARY
"LANDS," POTENTIAL WILL EXIST FOR AT LEAST ISOLATED (20-30%
COVERAGE) AFTERNOON SHOWERS AND STORMS. THE NAMNEST, WHICH, OF
THE CONVECTIVE ALLOWING MODELS (CAMS), LOOKS MOST LIKE CURRENT
RADAR - CAPTURING THE ONGOING STORMS OVER SOUTHERN OHIO AND
WEST VIRGINIA - SUGGESTS THAT OUTFLOW WILL SPARK STORMS MAINLY
OVER AREAS NEAR AND EAST OF THE I-75 CORRIDOR AFTER AROUND 3PM
EDT. HOWEVER, THIS IS JUST ONE OF A MYRIAD OF SOLUTIONS GIVEN BY
HREF MEMBERSHIP, AND IT IS VERY POSSIBLE THAT AT THE CURRENT
TIME IT IS SIMPLY "RIGHT FOR THE WRONG REASON," AND THEREFORE
MAY NOT NECESSARILY HAVE THE BEST FORECAST. I ENDED UP BLENDING
THE NATIONAL BLEND OF MODELS (NBM), HREF, AND NAMNEST FOR POPS
THIS AFTERNOON AND EVENING TO TRY AND CAPTURE THE UNCERTAINTY
WHILE HEDGING SLIGHTLY TO THE CURRENT BEST PERFORMING MODEL;
THIS RESULTS IN 15-20% CHANCES FOR PRECIPITATION OVER EASTERN
PORTIONS OF THE COUNTY WARNING AREA (CWA) THIS AFTERNOON AND
EVENING. ELSEWHERE, IT'LL BE ANOTHER HOT - ALBEIT SLIGHTLY LESS
HUMID - DAY WITH AFTERNOON HIGHS SOLIDLY IN THE 90S. IT'LL BE A
STRUGGLE TO REACH TRADITIONAL HEAT ADVISORY CRITERIA (HEAT
INDICES 105+) DUE TO LOWER DEWPOINTS (FORECAST TO FALL INTO THE
MID 60S) DURING THE AFTERNOON, BUT OPTED TO CONTINUE THE
ADVISORY ACROSS AREAS NEAR AND WEST OF A ROUGHLY FRENCH LICK TO
E-TOWN TO EDMONTON LINE WHERE HEATRISK REMAINS MODERATE TO HIGH
AND WETBULB GLOBE TEMPERATURES ARE FORECAST TO ONCE AGAIN REACH
THE MID-UPPER 80S.
*** FEW STORMS MAINLY NEAR/NORTH OF I-64 TONIGHT ***
THIS EVENING INTO TONIGHT, A PAIR OF SHORTWAVE TROUGHS WILL PASS
ACROSS INDIANA - BRINGING INCREASED CHANCES FOR SHOWERS AND STORMS
ACROSS AREAS MAINLY NEAR AND NORTH OF THE I-64 CORRIDOR. FORTUNATELY
BY THEN, DIURNALLY-DRIVEN INSTABILITY SHOULD BE WANING, BUT
INCREASED SHEAR (20-30KT IN THE 0-6KM LAYER) COULD RESULT IN A
MARGINALLY SEVERE STORM WITH LOCALLY DAMAGING WINDS THE PRIMARY
CONCERN AND A LESSER RISK FOR HAIL. SPC MAINTAINS A LEVEL 1 OF
5 (MARGINAL) RISK ACROSS OUR NORTHERN COUNTIES TO ACCOUNT FOR
THIS POTENTIAL, WHICH WILL BE HIGHEST WITH THE EVENING ROUND
IF WE GET ANYTHING (THE CHANCE IS 20-30%); STORMS MAY STAY JUST
NORTH OF THE CWA UNTIL EARLY MONDAY MORNING WITH THE SECOND
SHORTWAVE.
*** MILDER NORTH, STILL HOT WITH STORM CHANCES SOUTH MONDAY ***
A FRONT IS SLATED TO SINK SOUTHWARD ACROSS OUR AREA ON MONDAY,
PERHAPS (40-60%) TRIGGERING ADDITIONAL STORMS OVER SOUTHERN KENTUCKY
AND THE BLUEGRASS, HOWEVER, AT LEAST ACCORDING TO THE 20.00Z CAMS,
MOST OF THE AREA IS NOW LOOKING TO STAY DRY WITH THAT FRONTAL
PASSAGE. THIS FRONT WILL DRIVE A GRADIENT IN TEMPERATURES ACROSS THE
FORECAST AREA, WITH THE HEAT LIKELY LINGERING ANOTHER DAY OVER
SOUTHERN KENTUCKY BUT MILDER CONDITIONS OVERSPREADING THE I-64
CORRIDOR AND POINTS NORTH WHERE HIGHS MAY STRUGGLE TO REACH 80 IN
SPOTS.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 138 AM EDT SUN SEP 20 2026
*** TURNING GRADUALLY MILDER MIDWEEK ***
AS GENTLE NORTHERLY FLOW CONTINUES, THE LOCAL AREA WILL FEEL
PROGRESSIVELY DRIER AND LESS WARM MONDAY NIGHT INTO TUESDAY, BY
WHICH TIME DEWPOINTS SHOULD DIP INTO THE 50S ACROSS NORTHERN
PORTIONS OF THE AREA. PARTS OF SOUTHERN KENTUCKY MAY STILL WARM INTO
THE 80S TUESDAY AFTERNOON, BUT MOST LOCATIONS WILL SEE HIGHS IN THE
70S AND OVERNIGHT LOWS IN THE UPPER 50S TO LOW 60S. WEDNESDAY AND
ONWARD, THE CONTINUAL NORTHERLY FLOW SHOULD (NBM CHANCES ARE
ROUGHLY 60-80%) MAINTAIN HIGHS IN THE 70S AND LOWS IN THE 50S
EACH DAY AREA WIDE - WHICH, THOUGH MUCH COOLER THAN WHAT WE'VE
BECOME ACCUSTOMED TO AS OF LATE, IS NEAR NORMAL FOR LATE
SEPTEMBER.
AVIATION /12Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 721 AM EDT SUN SEP 20 2026
WINDS WILL BLOW GENTLY FROM THE SOUTH EARLY THIS MORNING, THEN VEER
TO SOUTHWEST AND INCREASE AROUND MIDDAY WITH A FEW GUSTS APPROACHING
20 KT EXPECTED DURING THE AFTERNOON. WHILE WINDS WILL SUBSIDE AFTER
23Z, A COUPLE THUNDERSTORMS MAY THREATEN SDF, LEX, AND RGA THIS
EVENING, THOUGH THE CHANCE (20%) WAS TOO LOW TO WARRANT A PROB30
GROUP AT THIS JUNCTURE; CHANCES WERE SLIGHTLY HIGHER AT HNB, SO A
PROB30 GROUP IS IN EFFECT FROM 03-09Z, AFTER WHICH TIME LOW STRATUS
MAY BRING CEILINGS INTO THE IFR CATEGORY THERE. THIS STRATUS, MOVING
SOUTH BEHIND A COLD FRONT, SHOULD BREAK UP WITH HEATING BEFORE
REACHING THE OTHER AIRFIELDS, WITH HREF CHANCES FOR MVFR/IFR
CEILINGS STAYING BELOW 20%.
LMK WATCHES/WARNINGS/ADVISORIES
KY...HEAT ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
KYZ023>028-053-061>063-070>076.
IN...HEAT ADVISORY UNTIL 8 PM EDT /7 PM CDT/ THIS EVENING FOR
INZ083-089.
SHORT TERM...JRB
LONG TERM...JRB
AVIATION...JRB
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