876
FXUS63 KLMK 171929
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
329 PM EDT WED JUN 17 2026
KEY MESSAGES
* GRADIENT WIND GUSTS INCREASE LATE THIS AFTERNOON AND EVENING AS A
STRONG LOW PRESSURE SYSTEM APPROACHES THE GREAT LAKES. NON-
THUNDERSTORM WIND GUSTS OF 30-40 MPH EXPECTED LATER TODAY AND INTO
TONIGHT. A FEW GUSTS OVER 40 MPH ARE POSSIBLE.
* AN APPROACHING COLD FRONT IS EXPECTED TO BRING A LINE OF STRONG TO
SEVERE THUNDERSTORMS INTO THE AREA LATER TONIGHT. GREATEST SEVERE
THREAT IS NORTH OF THE OHIO RIVER, BUT WE COULD SEE STRONG TO
SEVERE STORMS AS FAR SOUTH AS THE WK/BG PKWYS OVERNIGHT. DAMAGING
WINDS ARE THE MAIN HAZARD POSSIBLE, BUT CAN'T RULE OUT A TORNADO
OR HAIL RISK EITHER. NIGHTTIME TORNADOES ARE NOTABLY MORE
DANGEROUS.
* A FLOOD WATCH IS IN EFFECT FROM 9 PM EDT TONIGHT TO 9 AM EDT
TOMORROW, MAINLY ALONG AND NORTH OF I-64.
* THE COLD FRONT STALLS ACROSS THE REGION, LEADING TO ADDITIONAL
POTENTIAL FOR SCATTERED STRONG TO SEVERE STORMS, EXCESSIVE
RAINFALL, AND ISOLATED FLASH FLOODING ACROSS SOUTH-CENTRAL KY ON
THURSDAY.
* A REPRIEVE FROM RAINFALL COMES FRIDAY AND SATURDAY BEFORE THE NEXT
ROUND OF WIDESPREAD RAIN RETURNS STARTING LATE SATURDAY NIGHT.
SHORT TERM /THROUGH THURSDAY NIGHT/
ISSUED AT 329 PM EDT WED JUN 17 2026
THINGS ARE CURRENTLY WARM, GUSTY, AND DRY ACROSS THE CWA HOWEVER
EXPECTING MORE ACTIVE WEATHER AS WE GO INTO THE EVENING AND
OVERNIGHT. THE FIRST CONCERN TO ADDRESS IS THE GUSTY WIND POTENTIAL
THIS AFTERNOON INTO THE EARLY EVENING AS THE LOW LEVEL JET CORE IS
STARTING TO OVERSPREAD THE AREA. SEEING SOME 40 KNOT OBSERVATIONS
UPSTREAM OF US, HOWEVER WE ARE ALSO SEEING CLOUD COVER FROM THE MCS
OVER IL/IN STARTING TO OVERSPREAD OUR NORTHERN COUNTIES. THIS SHOULD
PROVIDE SOME LOW LEVEL STABILITY AS WE GET INTO THE LATE AFTERNOON
AND EARLY EVENING. STILL LIKE THE MESSAGING OF WIDESPREAD 30 TO 40
MPH, WITH A FEW LOCALIZED GUSTS OF 40+ MPH POSSIBLE, ESPECIALLY
ALONG AND WEST OF I-65. WILL CONTINUE THE SPECIAL WEATHER STATEMENT
TO HANDLE THAT MESSAGING.
THE NEXT ISSUE IS THE UPSTREAM MCS THAT HAS BEEN THREATENING TO
IMPACT OUR NORTHERN TIER OR TWO OF COUNTIES. IT CONTINUES TO LEAK
SOUTHWARD TOWARD A JASPER, IN TO MADISON, IN LINE AND COULD BRING A
ROUND OF TRAINING HEAVY RAINFALL IN THOSE AREAS BEFORE IT PUSHES
EAST. MOST LIKELY TIMING WOULD BE ENTERING OUR NORTHERN TIER AS
EARLY AS 5 OR 6 PM EDT. THIS FEATURE HASN'T BEEN SEVERE WARNED
UPSTREAM, AND FOR NOW, IT ONLY LOOKS LIKE BRIEF HEAVY RAINFALL WOULD
BE THE MAIN THREAT. A QUICK 1 TO 2 INCHES COULD FALL FROM THIS, AND
PRIME THE AREA FOR FLOODING POTENTIAL LATER TONIGHT WHEN THE NEXT
ROUND OF SHOWERS AND STORMS MOVES THROUGH.
ASIDE FROM THOSE TWO EARLY CONCERNS, THE MAIN FOCUS FOR THE FORECAST
CONTINUES TO BE TONIGHT INTO TOMORROW. STRONG SURFACE CYCLOGENESIS
IS EXPECTED TO OCCUR FROM THE UPPER MIDWEST INTO THE GREAT LAKES
REGION THIS EVENING AS THE EXIT REGION OF A STRONG MID TO UPPER
LEVEL JET OVERSPREADS THE AREA. A LOW LEVEL JET MORE CHARACTERISTIC
OF A LATE WINTER OR EARLY SPRING SYSTEM WILL RESPOND OVER OUR AREA
BENEATH THE FAVORABLE MID TO UPPER LEVEL JET DYNAMICS. IT SHOULD
PEAK AROUND 45-55 KNOTS LATER TONIGHT ACROSS THE NORTHERN THIRD OF
THE CWA, AND IT WILL AID IN BOTH ENHANCING THE OVERALL SHEAR PROFILE
SIGNIFICANTLY, AND WILL ADD MOISTURE TRANSPORT FOR TRAINING SHOWERS
AND STORMS. DECIDED TO LIFT A FLOOD WATCH (FLASH FLOODING) FOR THE
NORTHERN THIRD OF THE CWA DUE TO THE THREAT FOR TRAINING HEAVY
RAINFALL. HREF MEAN 24 QPF TOTALS AREN'T OVERLY IMPRESSIVE IN THE
WATCH AREA AND GENERALLY RANGE FROM .75 TO 1.5" FOR MOST AREAS.
HOWEVER, THE PMM/LPMM DATA SUGGESTS LOCALIZED POCKETS OF 3-5+
AMOUNTS COULD DEVELOP WHERE THE STORMS TRAIN. GIVEN THE RESIDENCE
TIME OF THE INTENSE LOW LEVEL JET, 1/3/6 HOUR FFG VALUES STILL
DIMINISHED IN SOME AREAS(FLOYD/HARRISON FOR EXAMPLE) FROM RECENT
HEAVY RAINFALL, AND THE FACT THIS IS A NIGHTTIME EVENT WAS ENOUGH TO
GO WITH THE FLOOD WATCH FOR THE AREA.
WE'VE BECOME MODESTLY UNSTABLE THIS AFTERNOON AND 17/12Z HREF
PROBABILITIES SUGGEST AROUND 1000-1500 J/KG OF INSTABILITY SHOULD BE
AROUND TONIGHT AHEAD OF THE NEXT LINE OF STORMS SET TO MOVE INTO THE
AREA FROM THE NW. SOME SURFACE STABILITY WILL LIKELY SET UP AFTER
SUNSET AS HAS CONSISTENTLY BEEN SUGGESTED BY HI-RES FORECAST
SOUNDINGS, HOWEVER WITH ML CAPE VALUES STILL IN THE MODEST TO
MODERATE RANGE, AND THE ADDED FORCING DO THINK ROBUST AND ROTATING
UPDRAFTS ARE SUSTAINABLE INTO OUR AREA OVERNIGHT. SPC HAS MOVED THE
DAMAGING WIND PROBS AND 2-5% TORNADO PROBS FARTHER SOUTH TO ACCOUNT
FOR THE UPSTREAM MCS IMPACT ON WHERE STORMS SET UP LATER TONIGHT.
GIVEN THE OVERALL SHEAR PROFILE, INCLUDING 0-1KM SRH VALUES OF AT
LEAST 250-300 M2/S2 AND POTENTIAL FOR EMBEDDED SUPERCELLS OR
MESOVORTEX FORMATION THE THREAT FOR A FEW TORNADOES, AND PERHAPS A
STRONGER TORNADO, SEEMS WARRANTED ACROSS OUR NORTHERN CWA. IT HAS
BEEN NOTED THAT THE OVERALL 0-3 KM SHEAR VECTOR SHOULD LINE UP MORE
PARALLEL TO THE LINE OF STORM ORIENTATION, SO THIS COULD LIMIT
MESOVORTEX DAMAGING WIND/TORNADO POTENTIAL FROM THAT MECHANISM, BUT
EMBEDDED SUPERCELL STORM MODE IS STILL IN PLAY. WON'T RULE OUT
MESOVORTICES EITHER AS THE SHEAR MAGNITUDE IS SO STRONG THAT IT
DOESN'T NEED TO BE PERPENDICULAR TO THE LINE FOR RIJ INTRUSION. THE
BEST OVERLAP OF SHEAR AND INSTABILITY DOES DROP OFF WITH SOUTHWARD
EXTENT ACROSS OUR AREA, AND BY THE TIME THE STORMS GET INTO NORTHERN
AND CENTRAL KY, WE WILL BE DEEPER INTO THE NIGHT WHERE A BIT MORE
LOW LEVEL STABILITY CAN HELP MITIGATE A BIGGER SEVERE CONCERN.
THE LOW LEVEL JET WILL STEADILY LET GO OF OUR REGION BETWEEN 09 AND
15Z TOMORROW, WITH CONVECTIVE INTENSITY AND COVERAGE DIMINISHING
ACROSS OUR CENTRAL CWA. THERE WILL LIKELY BE A FEW HOURS OF LULL
FROM MID TO LATE MORNING TO EARLY AFTERNOON BEFORE SHOWERS AND
STORMS REDEVELOP ON THE EXISTING OUTFLOW BOUNDARY AND/OR
DIFFERENTIAL HEATING BOUNDARY. IN ADDITION, A SURFACE COLD FRONT
TRAILING FROM THE EASTERN CANADA SURFACE LOW WILL ALSO START TO
SLIDE INTO THE AREA. AS A RESULT, NUMEROUS TO WIDESPREAD SHOWERS AND
STORMS SHOULD THEN RESUME PROGRESSING W TO E AHEAD OF THE
BOUNDARIES, WHILE THE OVERALL PROGRESS OF THE LINE SHIFTS SLOWLY
SOUTHEASTWARD TOMORROW AFTERNOON AND EVENING. OVERALL SHEAR PROFILES
WILL BE WEAKER TOMORROW, AND MORE UNIDIRECTIONAL, SO EXPECT STORM
MODE WOULD PRIMARILY BE MULTICELL CLUSTERS OR PERHAPS A FEW
SUPERCELLS. PRIMARY HAZARD SHOULD BE DAMAGING WINDS ALONG WITH AN
ISOLATED FLASH FLOODING POTENTIAL FOR ANY AREAS THAT SEE REPEATED
TRAINING. MAY HAVE TO CONSIDER A SEPARATE FLOOD WATCH FOR SOUTHERN
KY TOMORROW, BUT CONFIDENCE ISN'T HIGH ENOUGH JUST YET, AND DIDN'T
WANT TO ADD ANY CONFUSION FOR TONIGHT'S THREAT FARTHER NORTH.
THINGS SHOULD QUIET DOWN LATER THURSDAY EVENING AS THE FRONT
PROGRESSES THROUGH THE AREA, AND SURFACE HIGH PRESSURE BEGINS TO
BUILD IN BEHIND THE FRONT. OVERNIGHT LOWS THURSDAY NIGHT SHOULD
FALL INTO THE 60 TO 65 DEGREE RANGE FOR MOST.
LONG TERM /FRIDAY THROUGH WEDNESDAY/
ISSUED AT 329 PM EDT WED JUN 17 2026
FRIDAY - SATURDAY...
THE COLD FRONT ASSOCIATED WITH WEDNESDAY'S LOW PRESSURE SYSTEM
DEPARTS TO THE SOUTHEAST BY FRIDAY MORNING, SETTING UP A BRIEF
STRETCH OF WARM AND DRY WEATHER TO END THE WORKWEEK AND START THE
WEEKEND. SURFACE HIGH PRESSURE FILLS IN BEHIND THE COLD FRONT, AND
CALM NORTHWESTERLY FLOW WILL KEEP TEMPERATURES JUST BELOW AVERAGE
FOR THIS TIME OF YEAR. HIGHS ON FRIDAY WILL GET INTO THE LOW 80S,
WITH MID 80S CURRENTLY FORECAST FOR SATURDAY. DEW POINTS WILL ONLY
BE IN THE UPPER 50S/LOW 60S BOTH DAYS, SO CONDITIONS WILL BE QUITE
COMFORTABLE AS A RESULT.
SATURDAY NIGHT - MONDAY NIGHT...
THE CALMER STRETCH OF WEATHER WON'T LAST FOR LONG AS OUR NEXT ROUND
FOR RAINFALL BEGINS SATURDAY NIGHT. A SHORTWAVE EJECTS FROM THE
EASTERN ROCKIES ON SATURDAY, WITH A RAPIDLY DEVELOPING SURFACE LOW
FOLLOWING WITH IT TOWARDS THE MISSISSIPPI AND OHIO RIVER VALLEYS.
ONCE IT ARRIVES IN THE REGION SATURDAY NIGHT, LREF IS SHOWING THAT
THE MSLP FROM THIS SYSTEM IS ANOMALOUS FOR THIS TIME OF YEAR (~10TH
PERCENTILE CLIMATOLOGICALLY). NUMEROUS SHOWERS AND SCATTERED
THUNDERSTORMS ARE CURRENTLY FORECAST, THOUGH THE INTENSITY OF THESE
STORMS IS STILL UNCERTAIN. WIND SHEAR APPEARS TO BE DECENT BUT ALSO
SEMI-UNIDERECTIONAL, WITH INSTABILITY ONLY BEING MODEST AT THIS
POINT IN TIME. AS A RESULT, CONFIDENCE IS LOW ON THE EXTENT OF
STRONGER STORMS FOR THIS EVENT. THOUGH THERE WILL BE LIMITED TIME
FOR MOISTURE TO MOVE OVER THE AREA, PW VALUES AHEAD OF THE LOW WILL
QUICKLY SOAR TO THE 1.6-1.8" RANGE, PERSISTING UNTIL THE LOW
DEPARTS. LREF GUIDANCE IS PAINTING A BROAD AREA OF ~1.5" OF STORM
TOTAL RAINFALL FROM THIS EVENT, SO WE'LL CONTINUE TO MONITOR THIS IN
CASE A FLOODING THREAT BECOMES MORE APPARENT.
TUESDAY - MIDWEEK...
THE SURFACE LOW WILL DEPART OFF TO THE EAST MONDAY EVENING, WITH
HIGH PRESSURE AGAIN FILLING IN BEHIND IT. GUIDANCE HAS NUMEROUS
SHORTWAVES MOVING OVER THE AREA, BUT WITH HIGH PRESSURE AND DRIER
AIR IN PLACE, CHANCES FOR SHOWERS TO DEVELOP WILL BE LOW (<15%).
TEMPERATURES WILL AGAIN BE SLIGHTLY BELOW AVERAGE, WITH HIGHS IN THE
LOW 80S FORECAST.
AVIATION /18Z TAFS THROUGH 00Z FRIDAY/
ISSUED AT 141 PM EDT WED JUN 17 2026
THE TAF SITES ARE QUIET AND VFR AT THIS HOUR, AND THIS SHOULD REMAIN
THROUGH THE AFTERNOON. WILL BE WATCHING AN UPSTREAM COMPLEX OF
STORMS MOVING TOWARD HNB/SDF/LEX THIS EVENING INTO THE OVERNIGHT.
LOW CONFIDENCE ON WHEN STORMS WILL ARRIVE DUE TO ITS SLOW
PROGRESSION SOUTHWARD. WHEN STORMS DO ARRIVE EXPECT REDUCTIONS IN
VIS TO MFR OR BRIEF PERIODS OF IFR IN HEAVY RAIN AND TSRA. THE LOW
LEVEL JET WILL BE AROUND 40-50 KNOTS OVERNIGHT, HOWEVER DO STILL
EXPECT PLENTY OF SURFACE GUSTS, SO WILL BE CONSERVATIVE ON LOW LEVEL
WIND SHEAR MENTION. SHOWERS AND STORMS SLOWLY SINK SOUTHWARD THROUGH
THE OVERNIGHT AND MAY CLEAR OUR NORTHERN TAF SITES BY MORNING.
SURFACE WINDS WILL VEER AROUND TO THE SW AND THEN W AS A COLD FRONT
PUSHES THROUGH TOMORROW. SOME GUSTS IN THE 20 TO 25 MPH RANGE WILL
STILL BE POSSIBLE.
LMK WATCHES/WARNINGS/ADVISORIES
KY...FLOOD WATCH FROM 9 PM EDT THIS EVENING THROUGH THURSDAY
MORNING FOR KYZ025-029>043-049.
IN...FLOOD WATCH FROM 9 PM EDT /8 PM CDT/ THIS EVENING THROUGH
THURSDAY MORNING FOR INZ076>079-083-084-089>092.
SHORT TERM...BJS
LONG TERM...BJS
AVIATION...BJS
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