428
FXUS63 KLMK 160721
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
321 AM EDT TUE JUN 16 2026
KEY MESSAGES
* RAIN SHOWERS AND A FEW THUNDERSTORMS POSSIBLE THIS EVENING AS A
WEAK COLD FRONT APPROACHES THE AREA.
* WEDNESDAY NIGHT AND THURSDAY, A STRONG LOW PRESSURE SYSTEM WILL
BRING A CHANCE FOR STRONG TO SEVERE THUNDERSTORMS. THE GREATEST
RISK FOR SEVERE STORMS IS EXPECTED IN SOUTHERN IN. HEAVY RAINFALL
AND GUSTY WINDS (IN AND OUT OF THUNDERSTORMS) ARE EXPECTED.
* EXCESSIVE RAINFALL WILL BE POSSIBLE ACROSS SOUTH-CENTRAL KY ON
THURSDAY AS THE COLD FRONT STALLS ACROSS THE REGION. THERE IS SOME
POTENTIAL FOR FLASH FLOODING.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 321 AM EDT TUE JUN 16 2026
SFC HIGH PRESSURE IS SET UP ACROSS THE REGION THIS MORNING, WHICH
HAS KEPT US MOSTLY CLEAR AND DRY OVERNIGHT. HOWEVER, THIS SFC HIGH
WILL SHIFT OFF TO THE EAST TODAY AS A COLD FRONT SWEEPS THROUGH THE
MID-MISSISSIPPI VALLEY TODAY. AHEAD OF THE FRONT, STEADY SOUTHWEST
WINDS ARE EXPECTED, ALONG WITH SOME AFTERNOON GUSTS UP TO 25MPH AS
LAPSE RATES STEEPEN. THIS WILL PROMOTE A WAA PATTERN THIS AFTERNOON,
WITH HIGH TEMPS TOPPING OUT IN THE LOWER 80S. CLOUDS WILL INCREASE
THROUGH THE DAY AS THE FRONT APPROACHES, AND EVENTUALLY SHOULD SEE A
BROKEN LINE OF DECAYING SHOWERS AND STORMS MOVE INTO OUR SOUTHERN IN
COUNTIES BY THE MID TO LATE AFTERNOON HOURS. LOW LEVEL DRY AIR WILL
HELP ERODE THIS PRECIP LINE, BUT STILL EXPECT TO SEE AT LEAST SOME
ISOLATED TO SCATTERED SHOWERS AND STORMS. BEST CHANCES WILL BE ALONG
AND NORTH OF THE I-64 CORRIDOR IN CLOSER PROXIMITY TO THE FRONT, BUT
EVEN AN ISOLATED CHANCE WILL BE POSSIBLE THROUGH THIS EVENING DOWN
TO THE WK/BG PKWYS.
HOWEVER, THIS SFC BOUNDARY IS EXPECTED TO GET STALLED OUT IN THE
VICINITY OF THE OHIO RIVER AND WILL NOT MAKE A COMPLETE PASSAGE
THROUGH THE AREA TODAY. IT WILL LIKELY LIFT BACK TO THE NORTH AS A
WARM FRONT TOMORROW, OPENING UP THE WARM SECTOR ACROSS THE REGION
BEFORE OUR NEXT SYSTEM. AS SUCH, TEMPS WILL BE MUCH WARMER ON
WEDNESDAY. A FEW PRECIP CHANCES WILL LINGER BEYOND 00Z TONIGHT
ACROSS THE NORTHERN HALF OF THE AREA, BUT GENERALLY EXPECT DRIER
WEATHER AFTER 06Z AS INSTABILITY WANES AND MOISTURE CONVERGENCE
ALONG THE FRONT WEAKENS. LOWS FOR TONIGHT WILL BE SLIGHTLY MORE MILD
SOUTH OF THE BOUNDARY WITH LOW TO MID-60S SOUTH OF I-64, THOUGH TO
THE NORTH OF THE BOUNDARY WE COULD SEE TEMPS DROP INTO THE 50S.
LONG TERM /WEDNESDAY THROUGH MONDAY/
ISSUED AT 321 AM EDT TUE JUN 16 2026
===== WEDNESDAY - FRIDAY =====
A STRONG, DEEPENING LOW PRESSURE SYSTEM IS EXPECTED TO CROSS THE
GREAT LAKES ON WEDNESDAY, DRIVEN BY AN UNSEASONABLY STRONG UPPER
TROUGH OVER CANADA. HREF AND LREF PROBS INDICATE THIS SFC LOW COULD
DEEPEN BELOW 990MB ON WEDNESDAY, WHICH WOULD BE SIGNIFICANT FOR JUNE
ACROSS THE OHIO VALLEY. BASED OFF THE ESAT, THE ECMWF MSLP IS
OUTSIDE THE CLIMATE FORECAST SYSTEM REANALYSIS (CFSR) ACROSS THE
GREAT LAKES REGION. THIS IS CONSIDERED A SIGNIFICANT SIGNAL BECAUSE
THIS INDICATES THAT THERE ARE NO OTHER EVENTS IN THE REANALYSIS
DATABASE WITH A SFC LOW THIS DEEP FOR MID-JUNE BETWEEN 1979 AND
2009. FOR OUR FORECAST AREA, THIS TRANSLATES TO A RETURN INTERVAL OF
LESS THAN 1 DAY EVERY 10 YEARS, SO STILL QUITE A STRONG SFC PRESSURE
GRADIENT FOR OUR AREA AS THE SFC LOW TRACKS TO OUR NORTH. AS A
RESULT OF THIS VERY STRONG SFC LOW, OTHER PARAMETERS ARE PUSHED TO
THE EXTREME ENDS OF THE CFSR IN THE ECMWF/NAEFS PERCENTILES. FOR
EXAMPLE, MEAN INTEGRATED VAPOR TRANSPORT IS MAXED OUT IN THE ESAT,
INDICATING THE ENSEMBLES ARE FORECASTING AN IVT THAT EXCEEDS THE
1979-2009 CLIMATOLOGY FOR THIS TIME OF YEAR. THIS ALSO OCCURS IN THE
ESAT FOR MEAN WIND SPEED AT THE 850 HPA LEVEL.
WHAT DOES THIS TRANSLATE TO? THESE SIGNALS ARE GROWING CONFIDENCE IN
SEEING VERY STRONG MOISTURE ADVECTION INTO THE AREA DUE TO AN
IMPRESSIVE 50-60 KT LLJ OVER THE AREA WEDNESDAY EVENING INTO
THURSDAY MORNING. OUR PWAT VALUES WILL LIKELY SOAR ABOVE 2 INCHES,
WHICH WOULD ALSO BE AMONG THE 99TH PERCENTILE OF CLIMATOLOGY. GUSTY
SFC WINDS WILL MIX DOWN TO THE SFC ON WEDNESDAY, WITH GUSTS UP TO 30-
35MPH POSSIBLE. THE HREF SHOWS HIGH PROBABILITY (>80%) OF WIND GUSTS
GREATER THAN 30 MPH WEDNESDAY AFTERNOON, BUT LESSER CHANCES FOR
GREATER THAN 35MPH. BY WEDNESDAY NIGHT, THERE REMAINS SOME
UNCERTAINTY ON HOW STRONG THE NOCTURNAL INVERSION COULD BE, WHICH
PLAYS INTO IF WE'LL CONTINUE TO SEE NEAR ADVISORY LEVEL WIND GUSTS
LATER INTO THE NIGHT.
MOST, IF NOT ALL, OF WEDNESDAY WILL BE DRY, WITH THE STRONG WAA
REGIME HELPING TO BOOST OUR TEMPS INTO THE UPPER 80S BY AFTERNOON.
THE INCREASING MOISTURE ADVECTION WILL ALSO INCREASE OUR DEWPOINTS,
POTENTIALLY REACHING THE LOW-70S IN SOME AREAS. BY THE WEDNESDAY
NIGHT TIME FRAME, WE'LL SEE A LINE OF STRONG TO SEVERE STORMS ALONG
A COLD FRONT ACROSS PORTIONS OF MO/IL/IN. AS MENTIONED IN THE PRIOR
DISCUSSIONS, THIS COLD FRONT WILL BE SLOW MOVING, AND LIKELY WILL
NOT MAKE IT TO OUR AREA UNTIL DURING THE EARLY MORNING HOURS ON
THURSDAY. IN TERMS OF OVERALL SEVERE RISK THIS WOULD BE GOOD NEWS,
AS OUR INSTABILITY WILL BE AT THE DIURNAL MINIMUM. HOWEVER, GIVEN
THE IMPRESSIVE STRENGTH OF THE LLJ, VERY STRONG SHEAR WILL STILL BE
PRESENT, LEADING TO LARGE CURVED HODOGRAPHS, SRH OVER 300 IN THE
LOWER KILOMETERS, AND THE RISK OF TORNADOES. THE GREATER RISK AREA
IS ACROSS SOUTHERN IN, WITH POTENTIAL FALLING OFF AS THE LINE OF
STORMS MOVES SOUTHEAST THROUGH THE FORECAST AREA. AS SUCH, SPC
MAINTAINS A SLIGHT RISK ACROSS OUR FAR NORTHERN CWA, AND A MARGINAL
RISK PRIMARILY ALONG AND NORTH OF THE WK/BG PKWYS IN THE D2 OUTLOOK.
THE FOCUS THEN TURNS TO THURSDAY WITH THE RISK FOR TRAINING
CONVECTION ALONG THE VERY SLOW MOVING COLD FRONT. WITH SUCH A HIGH
PWAT REGIME IN PLACE, THERE IS A RISK FOR EXCESSIVE RAINFALL AND
POTENTIAL FLASH FLOODING CONCERNS MAINLY ACROSS SOUTH-CENTRAL KY.
THESE AREAS ARE STILL DEALING WITH MODERATE TO SEVERE DROUGHT, SO
THERE REMAINS SOME UNCERTAINTY ON HOW MUCH RAINFALL WILL BE NEEDED
FOR HYDRO ISSUES TO ARISE. MAIN SEVERE THREAT WILL BE EAST OF OUR
AREA DURING THE DAY, BUT A SECONDARY MID-LEVEL DISTURBANCE WILL
EJECT OFF THE GULF COAST AND PROVIDE AN ADDITIONAL SURGE OF MOISTURE
INTO THE TN VALLEY. DEPENDING ON THE INTERACTION BETWEEN THE QUASI-
STATIONARY SFC FRONT AND THE GULF COAST DISTURBANCE, ENHANCED
RAINFALL TOTALS AND A HIGHER FLASH FLOODING THREAT WILL BE POSSIBLE
THURSDAY INTO THURSDAY NIGHT.
===== FRIDAY INTO THE WEEKEND =====
THE SLUGGISH SFC BOUNDARY WILL EVENTUALLY EXIT BY FRIDAY MORNING,
WITH LINGERING POPS SHIFTING OUT OF THE AREA BY THE AFTERNOON. UPPER
RIDGING WILL BE MOVING ACROSS THE COUNTRY, WITH SFC HIGH PRESSURE
BUILDING TO OUR WEST. THIS WILL SUPPORT DRIER WEATHER FOR THE
REMAINDER OF FRIDAY AND FOR SATURDAY.
BY THE SECOND HALF OF THE WEEKEND, A PIECE OF UPPER-LEVEL ENERGY
EJECTING ACROSS THE ROCKIES WILL START TO ERODE THE RIDGE OVER THE
PLAINS, WITH MORE ZONAL FLOW ALOFT ALLOWING FOR MOISTURE TO INCREASE
AGAIN INTO THE OHIO VALLEY. TEMPERATURES SHOULD ALSO INCREASE TOWARD
CLIMO NORMALS BY SUNDAY INTO MONDAY. RAIN CHANCES ARE LIKEWISE
EXPECTED TO INCREASE DURING THE SECOND HALF OF THE WEEKEND, WITH THE
HIGHEST RAIN CHANCES CURRENTLY FAVORED SUNDAY NIGHT INTO MONDAY.
WHILE THUNDERSTORMS WILL BE POSSIBLE, IT IS TOO SOON TO SAY WHAT
KIND OF STRONG/SEVERE STORM RISK WILL EXIST WITH THIS DISTURBANCE.
AVIATION /06Z TAFS THROUGH 12Z WEDNESDAY/
ISSUED AT 115 AM EDT TUE JUN 16 2026
VFR CONDITIONS ARE ONGOING ACROSS ALL TERMINALS THIS MORNING. SOME
PATCHY FOG IS NOTED ON SATELLITE IMAGERY, BUT NOT EXPECTED TO CAUSE
MUCH OF ANY IMPACT. DRY WEATHER CONTINUES FOR MAJORITY OF THE DAY,
WITH SFC WINDS FROM THE SW. SOME AFTERNOON WIND GUSTS UP TO 20 KTS
ARE POSSIBLE. BY LATE AFTERNOON AND EVENING, THERE IS A PROB30 FOR
LIGHT RAIN AT SDF AND LEX. LOWER CONFIDENCE IN PRECIP FOR BWG, SO
THEIR FORECAST REMAINS DRY FOR NOW.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
SHORT TERM...CJP
LONG TERM...CJP
AVIATION...CJP
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