420
FXUS63 KLMK 250135
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
935 PM EDT MON MAR 24 2025
..UPDATED AVIATION DISCUSSION
KEY MESSAGES
* LIGHT RAIN CHANCES RETURN FOR LATE TONIGHT, MAINLY FOR SOUTHERN
INDIANA AND NORTH-CENTRAL KENTUCKY.
* NEAR NORMAL TEMPERATURES AND PERIODIC RAIN CHANCES TUESDAY THROUGH
THURSDAY, BUT WITH SUBSTANTIAL DRY PERIODS IN BETWEEN.
* WARMER TEMPERATURES AND INCREASING CHANCES FOR SHOWERS AND STORMS
FRIDAY THROUGH NEXT WEEKEND.
UPDATE
ISSUED AT 934 PM EDT MON MAR 24 2025
DRY WEATHER AND TEMPERATURES IN THE UPPER 40S AND LOW-TO-MID 50S ARE
PRESENT ACROSS THE AREA PER LATEST OBS. NIGHTTIME MICROPHYSICS
SATELLITE IMAGERY SHOWS AN EXTENDED BAND OF MOSTLY MID-LEVEL CLOUDS
EXTENDING FROM THE OHIO VALLEY ALL THE WAY UP INTO THE UPPER
MIDWEST. 700 MB CHART SHOWS THIS AREA OF HIGHER MID-LEVEL MOISTURE
WELL, WITH A BAND OF HIGHER RH STREAMING FROM NW TO SE UPSTREAM OF A
MID-LEVEL TROUGH AXIS CENTERED OVER THE APPALACHIANS THIS EVENING.
LIGHT RADAR RETURNS HAVE BEEN INCREASING OVER WESTERN KY, SOUTHERN
IL, AND EASTERN MO OVER THE PAST FEW HOURS. THIS IS LIKELY IN
ASSOCIATION WITH A SHORTWAVE IN THE 850 MB FLOW CURRENTLY NOTED OVER
WESTERN MO AND EASTERN KS. AHEAD OF THIS WAVE, BACKED SW FLOW HAS
PROMOTED THE DEVELOPMENT OF WARM/MOIST ADVECTION, WITH LOW-MID LEVEL
CONVERGENCE ALSO OCCURRING AHEAD OF THIS WAVE. WHILE SATURATION IS
QUICKLY TAKING PLACE 5-10 KFT ALOFT, PRECIPITATION WILL TAKE A WHILE
TO REACH THE GROUND GIVEN 20-30 DEGREE SFC DEWPOINT DEPRESSIONS
WHICH ARE INDICATIVE OF VERY DRY AIR IN THE LOW LEVELS. HOWEVER,
AFTER MIDNIGHT, ENOUGH MOISTURE ADVECTION SHOULD OCCUR THAT A BAND
OF LIGHT RAIN SHOWERS SHOULD DEVELOP. THIS BAND OF SHOWERS IS
EXPECTED TO IMPACT AREAS PRIMARILY ALONG AND NORTH OF THE WK/BG
PARKWAYS THROUGH MID-MORNING TOMORROW, BRINGING ANYWHERE FROM A FEW
HUNDREDTHS TO AROUND A QUARTER INCH OF RAIN AS IT CROSSES THE AREA.
THE FORECAST IS IN GOOD SHAPE, WITH SMALL CHANGES MADE IN THE NEAR
TERM TO PRECIPITATION ONSET AND DEWPOINTS.
SHORT TERM /THROUGH TUESDAY/
ISSUED AT 258 PM EDT MON MAR 24 2025
THE COMBINATION OF A GOOD BOUNDARY LAYER MIXING AND A TIGHT PRESSURE
GRADIENT BETWEEN A SFC HIGH PRESSURE OVER THE ARK-LA-TEX AND A DEEP
SFC LOW OVER THE GREAT LAKES HAS RESULTED IN GUSTY WINDS OVER THE
AREA, MAINLY ACROSS SOUTHERN IN AND ACROSS THE BLUEGRASS WHERE
GUSTS HAVE BEEN 30-35 MPH WITH A FEW ISOLATED GUSTS OF 40 MPH. AN
SPS HAS BEEN ISSUED TO ACCOUNT FOR THE GUSTY WINDS AS GO TOWARDS
SUNSET. DRY AIR MIX DOWN HAS ALSO RESULTED IN DEW POINTS THIS
AFTERNOON INTO THE 20S AND EVEN A FEW UPPER TEENS. USUALLY THESE
CONDITIONS WOULD LEAD TO AN ELEVATED FIRE DANGER BUT DUE TO RECENT
RAINFALL, WE HAVE GOOD FUEL MOISTURES.
THE EVENING WILL BE DRY AS HIGH PRESSURE PASSING BY TO OUR SOUTH AND
WINDS WILL DIMINISH ONCE THE SUN SETS. CLOUDS WILL BE ON THE
INCREASE AS A WEAK CLIPPER SYSTEM DROPS OUT OF THE UPPER MIDWEST AND
INTO THE OHIO VALLEY FOR THE SECOND HALF OF THE OVERNIGHT.
ISENTROPIC LIFT ASSOCIATED WITH A LLJ JUST AHEAD OF THE SYSTEM WILL
ALLOW FOR ENOUGH LIFT FOR A NARROW AREA OF SHOWERS ACROSS NORTH
CENTRAL KY AND SOUTHERN IN. THESE SHOWERS WILL CONTINUE THROUGH THE
START OF THE DAY TOMORROW INTO THE MORNING RUSH. RAIN SHOULD
GENERALLY BE LIGHT AND LOWS OVERNIGHT WILL BE IN THE LOW TO MID 40S.
WEAK SFC LOW AND ASSOCIATED SHOWERS WILL START TO DIMINISH BY LATE
MORNING TO AROUND MIDDAY BUT COULD LINGER ACROSS NORTHERN KY INTO THE
BLUEGRASS. MODELS INDICATED WE COULD SEE SOME CLEARING TOWARDS THE
AFTERNOON. IF THIS OCCURS, WE WOULD HAVE STEEPENING LAPSE RATE WITH
THE CHANCE OF AN ISOLATED SHOWER OR TWO IN THE AFTERNOON. WE WILL
HAVE A TIGHT TEMPERATURES GRADIENT FROM NORTH TO SOUTH OVER THE AREA
WITH UPPER 60S TO NEAR 70 ACROSS SOUTHERN KY WITH MID/UPPER 50S TO
NEAR 60 ACROSS SOUTHERN IN, ALONG THE OHIO RIVER AND INTO THE
BLUEGRASS.
LONG TERM /TUESDAY NIGHT THROUGH MONDAY/
ISSUED AT 258 PM EDT MON MAR 24 2025
TUESDAY NIGHT - THURSDAY...
WE'LL BE UNDER A RIDGE/WEST AND TROUGH/EAST UPPER PATTERN THROUGH
MID WEEK, WITH NW FLOW PERSISTENT OVER OUR REGION. THERE IS A FAIRLY
CONSISTENT SIGNAL FOR SOME LOW TO MID LEVEL MOISTURE IN THE PRESENCE
OF A FRONTOGENETICAL COMPONENT BENEATH THE LEFT EXIT REGION OF AN
UPPER LEVEL JET. THIS LOOKS TO BE ENOUGH TO SQUEEZE OUT SOME LIGHT
QPF OUR OUR AREA TUESDAY NIGHT INTO WEDNESDAY MORNING. RIGHT NOW,
THE NE HALF OF THE CWA STILL LOOKS TO BE THE MOST LIKELY AREA FOR A
FEW HUNDREDTHS TO AROUND A TENTH OF AN INCH OF ADDITIONAL QPF. GIVEN
THE LIGHT QPF, AND A LITTLE BIT OF UNCERTAINTY ON THE EXACT
PLACEMENT, WILL LEAVE POPS IN THE CHANCE RANGE FOR NOW. AFTER COOL
OVERNIGHT LOWS IN THE UPPER 30S AND LOW 40S, WEDNESDAY HIGHS RECOVER
TO THE MID 50S AND LOW 60S.
SURFACE HIGH PRESSURE AND DRY NW FLOW ALOFT LOOK TO BRIEFLY HOLD
OVER OUR AREA WEDNESDAY NIGHT INTO THURSDAY. THIS WILL BRING DRY
CONDITIONS DURING THIS BRIEF PERIOD. GOOD RADIATIONAL COOLING WILL
ALLOW FOR COLD TEMPS BY THURSDAY AM WITH LOWS IN THE LOW TO MID 30S
FOR MANY. AS IS TYPICAL, SOME OF THE SHELTERED LOCATIONS WILL LIKELY
BE COLDER.
THURSDAY NIGHT - SATURDAY NIGHT...
LOWER CONFIDENCE FOR THE LATE WEEK INTO THE WEEKEND TIME FRAME AS SE
CONUS RIDGING BUILDS, AND A DEVELOPING WARM FRONT NEAR OUR AREA
LIFTS NORTH. THIS WILL OCCUR IN RESPONSE TO SURFACE LOW PRESSURE
DEVELOPING OVER THE NORTHERN PLAINS AND STARTING TO PROGRESS TOWARD
THE UPPER MIDWEST. THE END RESULT FOR SENSIBLE WEATHER WILL FEATURE
WARMER TEMPS, ALONG WITH SHOWER AND PERHAPS SOME T-STORM CHANCES
WITH THE WARM FRONTAL ACTIVITY. WILL KEEP POPS IN FOR EACH PERIOD
DURING THIS TIME FRAME, BUT NOT EXPECTING A WASHOUT BY ANY MEANS.
LOOKING FOR HIGHS IN THE LOW AND MID 70S FRIDAY AND SATURDAY, WITH
MILDER OVERNIGHT LOWS IN THE 50S AS WELL.
SUNDAY - MONDAY...
MORE UNCERTAINTY CONTINUES INTO THE LATE WEEKEND AND EARLY NEXT
WEEK TIME FRAME. THERE IS SOME CONCERN FOR STRONGER THUNDERSTORM
DEVELOPMENT BY SUNDAY AS A MILD AND MOIST GULF AIRMASS SURGES
RECOVERS INTO OUR AREA AHEAD OF AN APPROACHING SURFACE LOW. THE
EXACT TIMING, PLACEMENT, STRENGTH OF THIS SYSTEM IS QUITE UNCERTAIN
FOR NOW, BUT THE OVERALL PATTERN DOES SUGGEST THAT SOME SEVERE
WEATHER COULD BE POSSIBLE IN THIS TIME FRAME, PERHAPS IN MULTIPLE
WAVES. SPC HAS PLACED OUR ENTIRE AREA IN A DAY 7 OUTLOOK, WHICH
LARGELY SEEMS TO BE AIDED BY SOME OF THE LATEST MACHINE LEARNING
RUNS. WILL SAY THAT NOT ALL OF THE DETERMINISTIC DATA IS ON BOARD,
SO NOT OVERLY CONFIDENT AT THE MOMENT. FOR EXAMPLE, THE 24/00Z ECMWF
WANSN'T AS IMPRESSED WITH THE SETUP, AND THEREFORE THERE ARE NO
NOTABLE SIGNALS IN THAT RUN OF THE EFI DATA FOR CAPE/SHEAR. STAY
TUNED TO THE LATEST FORECASTS AS THIS SYSTEM BECOMES MORE CLEAR
THROUGH THE WEEK.
AVIATION /00Z TAFS THROUGH 06Z WEDNESDAY/
ISSUED AT 733 PM EDT MON MAR 24 2025
VFR CONDITIONS ARE EXPECTED THROUGH THIS EVENING, WITH WINDS
CONTINUING TO EASE AFTER SUNSET TONIGHT. LIGHT WEST WINDS WILL
GRADUALLY BECOME VARIABLE OVERNIGHT, WITH LIGHT WINDS EXPECTED TO
CONTINUE THROUGH THE CURRENT FORECAST PERIOD. A MID-LEVEL CLIPPER
SYSTEM WILL INCREASE MOISTURE TONIGHT ACROSS THE REGION, WITH MID-
AND UPPER-LEVEL CLOUDS GRADUALLY BUILDING DOWN THROUGH THE NIGHT. A
BAND OF LIGHT RAIN SHOWERS IS EXPECTED TO DEVELOP LATE TONIGHT NEAR
HNB AND SPREAD EAST TOWARD SDF, LEX, AND RGA IN THE PRE-DAWN HOURS.
VISIBILITIES SHOULD GENERALLY BE VFR IN THE RAIN SHOWERS, THOUGH
OCCASIONAL DROPS TO MVFR VIS WITH RA/BR ARE POSSIBLE, ESPECIALLY AT
LEX. TOMORROW, MODEL GUIDANCE IS SHOWING AN EXTENDED PERIOD OF MVFR
CEILINGS AT SDF, LEX, AND RGA. WHILE GUIDANCE EVEN BRINGS LEX CLOSE
TO IFR CIGS, THINK THIS IS TOO PESSIMISTIC, SO HAVE TRENDED SOMEWHAT
HIGHER WITH CIGS TOMORROW. AS LOW PRESSURE MOVES BY TO THE SOUTH OF
THE REGION, WINDS WILL SWING AROUND FROM EASTERLY IN THE MORNING TO
NORTHWESTERLY IN THE AFTERNOON.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
UPDATE...CSG
SHORT TERM...BTN
LONG TERM...BJS
AVIATION...CSG
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