139
FXUS63 KLMK 181103
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
703 AM EDT SUN MAY 18 2025
KEY MESSAGES
* STRONG TO SEVERE THUNDERSTORMS WILL BE POSSIBLE MONDAY AND TUESDAY.
* BELOW NORMAL TEMPERATURES EXPECTED LATE NEXT WEEK AND INTO THE
MEMORIAL DAY WEEKEND.
SHORT TERM /THROUGH MONDAY/
ISSUED AT 327 AM EDT SUN MAY 18 2025
QUIET WEATHER IS EXPECTED TODAY AND INTO THIS EVENING WITH SHORTWAVE
RIDGING ALOFT AND A WEAK SFC PRESSURE GRADIENT. COULD SEE FAIRLY
EXTENSIVE CIRRUS COVER AS THE ANVIL BLOWOFF FROM STORMS OVER
MISSOURI STREAMS OVERHEAD, BUT THAT WON'T MAKE MUCH OF A DENT IN
TEMPS. THICKNESS PROGS SUGGEST AFTERNOON MAX TEMPS CLOSE TO
PERSISTENCE.
LATER TONIGHT WE'LL SEE THICKENING CLOUDS AS ANOTHER VIGOROUS LOW
PRESSURE SYSTEM TAKES SHAPE OVER THE ROCKIES, AND GULF MOISTURE ARCS
NW ALONG A SHARPENING WARM FRONT INTO THE MISSISSIPPI VALLEY. OUR
PRECIP CHANCES START TO RAMP UP PRIOR TO DAYBREAK MONDAY AS WE START
TO SEE ISENTROPIC LIFT DEVELOP. BETTER RAIN CHANCES LATE TONIGHT
WILL BE OVER WESTERN KENTUCKY.
LOW-CONFIDENCE FORECAST FOR MONDAY AS IT DEPENDS ON THE EVOLUTION OF
CONVECTION THAT'S EXPECTED TO DEVELOP BY EARLY THIS EVENING OVER
EASTERN KANSAS AND WESTERN MISSOURI. THIS ACTIVITY WILL INITIALLY
LIFT NE BUT CONGEAL INTO A MCS, AFTER WHICH IT WOULD TRY TO ROUND
THE TOP OF THE UPPER RIDGE. HOW WELL IT HOLDS TOGETHER WILL MAKE THE
DIFFERENCE BETWEEN WEAKENING SHOWERS AND STORMS PUSHING THROUGH ON
MONDAY MORNING, OR A MCV FUELING NEW AND STRONGER CONVECTION LATER
IN THE DAY. IF WE CAN DESTABILIZE, THERE IS JUST ENOUGH DEEP-LAYER
SHEAR TO SUPPORT A FEW STRONG TO SEVERE STORMS.
LONG TERM /MONDAY NIGHT THROUGH SATURDAY/
ISSUED AT 327 AM EDT SUN MAY 18 2025
ON TUESDAY, THE UPPER LEVEL TROUGH AXIS ACROSS THE PLAINS WILL SHIFT
EASTWARD AND THE OHIO VALLEY WILL GET MORE SOLIDLY INTO THE WARM
SECTOR AS THE WARM FRONTAL BOUNDARY LIFTS NORTHEASTWARD. CURRENT
MODEL SOLUTIONS CONTINUE SHOW STRONG BOUNDARY LAYER HEATING ACROSS
THE MID-SOUTH AND INTO THE TN VALLEY. MODEL SOUNDINGS DO SHOW
STEEPENING LOW-MID LEVEL LAPSE RATES ATOP THE STRONGER BOUNDARY
LAYER HEATING. MID-LEVEL FLOW IS LIKELY TO INCREASE AS THE MID-
LEVEL JET ROTATES INTO THE MID-SOUTH AND INTO THE OHIO VALLEY.
WHILE THE OVERALL SETUP UP FAVORS THE POTENTIAL FOR SEVERE WEATHER,
UNCERTAINTY REMAINS ON HOW MUCH INSTABILITY WILL BE SEEN ACROSS THE
REGION. CURRENT MODEL DATA REMAINS SUGGESTIVE THAT EXTENSIVE CLOUD
COVER MAY REMAIN IN PLACE ACROSS THE OHIO VALLEY, WITH MORE
SUBSTANTIAL INSOLATION TAKING PLACE TO OUR SOUTH. BASED ON THIS, I
WOULD CLASSIFY THE TUESDAY SEVERE WEATHER THREAT AS CONDITIONAL AT
THE MOMENT. SHOULD WE HAVE MORE CLEARING THAT ANTICIPATED, THE
OVERALL SYNOPTIC AND THERMAL/KINEMATIC ENVIRONMENTAL PARAMETERS WOULD
BE SUPPORTIVE OF MULTI-CELL AND SUPERCELL TYPE STORMS OFFERING ALL
TYPES OF SEVERE THREATS. HIGHS TUESDAY WILL BE DEPENDENT ON CLOUD
COVER WITH READINGS RANGING FROM THE UPPER 70S TO THE LOWER-MIDDLE
80S. OVERNIGHT LOWS WILL BE IN THE UPPER 50S/LOWER 60S.
THE UPPER TROUGH AXIS IS FORECAST TO WEAKEN A BIT AND SLIDE EASTWARD
ON WEDNESDAY WITH A SURFACE COLD FRONT SETTLING SOUTH OF THE REGION.
WHILE THIS WILL END THE THREAT OF SEVERE WEATHER, A COOL NORTHWEST
FLOW WITH EMBEDDED PERTURBATIONS WILL LIKELY KEEP COOL/SHOWERY
WEATHER ACROSS OUR REGION FOR WEDNESDAY AND THURSDAY. HIGHS DURING
THE PERIOD WILL AVERAGE IN THE UPPER 60S TO THE LOWER 70S WITH
OVERNIGHT LOWS IN THE MID-UPPER 40S.
BY FRIDAY, WE'LL SEE A CONTINUATION OF THE UPPER TROUGH AXIS
CENTERED OVER THE NORTHEASTERN US WITH A CONTINUED NORTHWEST FLOW
REGIME OVER THE OHIO VALLEY. HEIGHTS WILL GRADUALLY BUILD FRIDAY
AND INTO SATURDAY. OVERALL, THE PATTERN HERE ARGUES FOR DRIER
CONDITIONS, BUT THE NORTHWEST FLOW WILL KEEP TEMPERATURES ON THE
COOL SIDE. HIGHS ON FRIDAY LOOK TO WARM INTO THE UPPER 60S TO NEAR
70, WITH HIGHS ON SATURDAY REACHING THE LOWER 70S.
AVIATION /12Z TAFS THROUGH 18Z MONDAY/
ISSUED AT 702 AM EDT SUN MAY 18 2025
MAIN WEATHER PLAYERS TODAY WILL BE THE ANVIL BLOWOFF FROM CONVECTION
TO OUR SOUTH AND WEST, AND WEAK SFC RIDGING, LEAVING US WITH CIRRUS
CEILINGS AND LIGHT WESTERLY WINDS EVENTUALLY GOING VARIABLE.
FORECAST CHALLENGE IS WHETHER ANY MORE DIRECT IMPACT COMES FROM
UPSTREAM CONVECTION OR A DEVELOPING WARM FRONT AS WE APPROACH
DAYBREAK MONDAY. WENT FOR -SHRA AND LOWER CEILINGS IN BWG, BUT NOT
AS PESSIMISTIC AS A SEEMINGLY GFS-HEAVY NBM. MVFR CIGS SHOULD DO IT
FOR BWG THROUGH 12Z, AND BROUGHT A LOWER DECK INTO SDF AND HNB BUT
KEPT THOSE SITES VFR.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
SHORT TERM...RAS
LONG TERM...MJ
AVIATION...RAS
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