228
FXUS63 KLMK 021309
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
909 AM EDT SAT MAY 2 2026
KEY MESSAGES
* ISOLATED LIGHT RAIN SHOWERS MOVE IN FROM THE NW TODAY.
SPRINKLES TO VERY LITTLE RAINFALL AMOUNTS EXPECTED FOR AREAS
MAINLY ALONG THE I-165 CORRIDOR.
* WELL BELOW NORMAL TEMPERATURES TODAY, WITH HIGHS ONLY IN THE UPPER
50S TO LOW 60S. THESE TEMPERATURES WILL BE AROUND 15 DEGREES BELOW
NORMAL.
* AREAS OF FROST LIKELY SUNDAY MORNING ACROSS MOST OF SOUTHERN
INDIANA AND PORTIONS OF CENTRAL KENTUCKY. A FROST HEADLINE WILL
LIKELY BE NEEDED FOR SUNDAY MORNING.
* WEATHER PATTERN IS EXPECTED TO BECOME MORE ACTIVE NEXT WEEK.
SEVERAL SYSTEMS WILL BRING WIDESPREAD SHOWERS AND POSSIBLE
THUNDERSTORMS TO THE REGION TUESDAY THROUGH LATE WEDNESDAY.
UPDATE
ISSUED AT 909 AM EDT SAT MAY 2 2026
CURRENT RADAR IMAGERY SHOWS SOME LIGHT RETURNS UPSTREAM OF THE I-65
CORRIDOR. LIGHT RAIN WAS REPORTED IN THE LAST HOUR AT KHNB AND KSDF,
BUT WITH 10 MILE VISIBILITIES, LIKELY JUST SPRINKLES AND NOTHING
MEASURABLE. UPSTREAM SATELLITE IMAGERY SHOWS A FEW BUBBLES EMBEDDED
WITHIN THE MID DECK PERHAPS TRYING TO GET TALLER. LOOKING AT MODEL
SOUNDINGS FOR THIS AFTERNOON AND WITH AN UPPER TROUGH MOVING RIGHT
OVERHEAD, STILL LOOKS LIKE A FEW OF THOSE BUBBLES MAY GET TALL
ENOUGH TO PRODUCT SOME RUMBLES OF THUNDER AND WITH COLD AIR ALOFT
MAYBE EVEN GRAUPEL. BEST CHANCE FOR THAT THUNDER IS RIGHT ALONG THE
I-64 CORRIDOR AND POINTS SOUTH...WHICH IS OBVIOUSLY CLOSE TO SOME
BIGGER EVENTS TODAY IN LOUISVILLE. WILL KEEP WATCH ON RADAR AND HI-
RES MODEL TRENDS THROUGH THE MORNING AND AFTERNOON AND UPDATE AS
NEEDED.
OTHERWISE THE MORNING FROST ADVISORY WAS ALLOWED TO EXPIRE. WILL BE
LOOKING AT THE FORECAST FOR LATER TONIGHT ON THE NEED TO ISSUE
ANOTHER ADVISORY AT SOME POINT LATER TODAY.
SHORT TERM /THROUGH TONIGHT/
ISSUED AT 345 AM EDT SAT MAY 2 2026
IT IS AN UNUSUALLY CHILLY START TO THE DAY, WITH KY MESONET OBS
SHOWING TEMPS DOWN INTO THE UPPER 30S AND LOW 40S SO FAR THIS
MORNING. DESPITE SOME UPPER LEVEL CLOUD COVER, THE CAA AND NEARLY
CALM WINDS HAVE ALLOWED THESE SFC TEMPS TO BE NEARLY 10-15 DEGREES
BELOW NORMAL. FROST ADVISORY FOR THE BLUEGRASS RUNS UNTIL 13Z LATER
THIS MORNING.
FOR TODAY, A SHARP UPPER TROUGH AXIS WILL PIVOT ACROSS THE OHIO
VALLEY LATER THIS AFTERNOON, RESULTING IN AN INCREASE IN CLOUD COVER
FOR THE AFTERNOON AND EVENING HOURS. THIS UPPER LEVEL TROUGH IS
ALREADY DEVELOPING SOME LIGHT PRECIP ACROSS CENTRAL IL EARLY THIS
MORNING, EVIDENT BY REGIONAL RADAR MOSAIC. THESE LIGHT SHOWERS ARE
BEING SUPPORTED BY A MID-LEVEL VORT MAX THAT WILL BE STRETCHING
ACROSS THE AREA TODAY.
===== VERY LIGHT PRECIPITATION TODAY =====
THE CAMS HAVE A GOOD HANDLE ON SEEING LIGHT RADAR RETURNS MOVE
ACROSS THE WABASH VALLEY THIS MORNING, WITH THE BEST CHANCE FOR
LIGHT PRECIP OCCURRING GENERALLY ALONG AND WEST OF THE I-165 CORRIDOR
(AKA THE NATCHER PKWY) THROUGH THIS MORNING AND AFTERNOON. WE'LL
HAVE A GOOD AMOUNT OF LOW LEVEL DRY AIR IN PLACE ACROSS THE AREA
TODAY, WHICH WILL LEAD TO PRIMARILY VIRGA, THOUGH SOME VERY LIGHT
PRECIP MAY BE POSSIBLE. WILL KEEP LOUISVILLE IN A 10% CHANCE FOR
TODAY, AND STILL THINK THAT THE LOW LEVEL DRY AIR WILL WIN OUT OVER
ANY LIGHT RETURNS THAT COULD SNEAK A BIT MORE EAST THAN THE CAMS
SUGGEST.
OTHERWISE, HI-RES SOUNDINGS INDICATE THAT WE WILL HAVE QUITE STEEP
LOW LEVEL LAPSE RATES THIS AFTERNOON, AND PERHAPS SOME WEAK
INSTABILITY. GIVEN HOW LOW THE FREEZING LAYER WILL BE TODAY DUE TO
THE COOLER TEMPS, WE COULD SEE SOME GRAUPEL DEVELOPMENT IF WE GET A
STRONG ENOUGH CELL/UPDRAFT. HOWEVER, DEWPOINT DEPRESSIONS NEAR THE
SFC WILL BE NEARLY 20 DEGREES, WHICH COULD BE UNFAVORABLE FOR
GRAUPEL SURVIVAL TO THE SFC. ADDITIONALLY, THIS DRY LOW LEVEL LAYER
WILL SUBSTANTIALLY LIMIT OVERALL EXPECTED PRECIP, WITH THE HREF 90TH
PERCENTILE ONLY SUGGESTING 0.02" FOR WESTERN LOUISVILLE, THOUGH UP
TO 0.15" ALONG THE I-165 CORRIDOR. WITH ALL THIS SAID, GENERALLY
EXPECT ISOLATED LIGHT RAIN SHOWERS OR SPRINKLES TODAY, WITH ANY
ACTIVITY WINDING DOWN BY LATE AFTERNOON ACROSS SOUTH-CENTRAL KY.
===== BREEZY AFTERNOON WINDS AND COOLER TEMPERATURES=====
DUE TO THE STEEP LOW LEVEL LAPSE RATES, WE'LL LIKELY SEE OUR NNW SFC
WINDS PICK UP BY THE AFTERNOON. COULD SEE WIND GUSTS UP TO 20-25 MPH
FOR THE AFTERNOON. THIS WILL KEEP US IN A STRONGER CAA REGIME, WITH
TEMPS TODAY ONLY IN THE UPPER 50S AND LOW 60S. THIS TRANSLATES TO
MAX TEMPERATURES AROUND 15 DEGREES BELOW NORMAL FOR MAY 2. WINDS
EASE BY THE EVENING, WITH CLEARING CLOUD COVER AS THE UPPER TROUGH
AXIS SHIFTS EAST. THIS WILL LEAD TO A FAVORABLE NIGHT FOR FROST
DEVELOPMENT, WHICH IS DISCUSSED IN THE LONG TERM SECTION BELOW.
LONG TERM /SUNDAY THROUGH FRIDAY/
ISSUED AT 345 AM EDT SAT MAY 2 2026
===== SUNDAY - MONDAY =====
SFC HIGH PRESSURE WILL BE SETTLING INTO OUR AREA ON SUNDAY, WHICH
WILL SUPPORT A BRIEF DRY SPELL AND CONTINUATION OF BELOW NORMAL
TEMPS. SUNDAY MORNING WILL FEATURE COLD TEMPS DUE TO A LINGERING
COLD AIR MASS FROM SATURDAY, BUT WILL BE AMPLIFIED FROM GOOD
RADIATIONAL COOLING BY CALM WINDS AND CLEAR SKYCOVER. WE'LL LIKELY
SEE TEMPS DOWN INTO THE 30S AREA-WIDE, WITH HIGH CONFIDENCE IN
WIDESPREAD FROST DEVELOPMENT FOR AT LEAST EAST OF I-65. THERE IS A
BIT MORE UNCERTAINTY ON THE EXTENT OF FROST POTENTIAL ACROSS SOUTH-
CENTRAL KY, BUT STILL EXPECT AT LEAST SOME PATCHY FROST. THE NEED
FOR A FROST ADVISORY SUNDAY MORNING IS PRETTY MUCH A SLAM DUNK FOR
AREAS ALONG AND EAST OF I-65, BUT WILL ALLOW THE CURRENT FROST
ADVISORY TO EXPIRE LATER THIS MORNING BEFORE MAKING A DECISION ON IF
THE ENTIRE AREA WILL BE PLACED IN A HEADLINE FOR SUNDAY. WE ARE DRY
ON SUNDAY, WITH TEMPERATURES EVENTUALLY REACHING THE MID-60S BY THE
AFTERNOON. SHOULD HAVE A GOOD AMOUNT OF SUNSHINE, BUT COULD BEGIN TO
SEE SOME INCREASING CLOUDS FROM THE NORTH BY THE LATE AFTERNOON.
WE'LL BE UNDERNEATH NW FLOW ALOFT, AND BY SUNDAY NIGHT WE WILL HAVE
A QUICK-HITTING SHORTWAVE MOVE ACROSS THE OHIO VALLEY. WE'LL BE
LOCATED IN A WAA ZONE AHEAD OF AN ASSOCIATED FRONTAL BOUNDARY, WITH
INCREASE MOISTURE TRANSPORT INTO THE AREA DUE TO A WARM CONVEYOR
BELT OF LOW-LEVEL JETTING. THIS WILL SUPPORT OVERNIGHT SHOWERS AND
STORMS FOR OUR AREA. MODEL SOUNDINGS SHOW LITTLE TO NO INSTABILITY
PRESENT, WITH MEAGER LOW LEVEL LAPSE RATES, THOUGH WITH A LLJ
OVERHEAD, SHOULD HAVE HIGHER SHEAR PARAMETERS. CAN'T RULE OUT
SOME OVERNIGHT THUNDER, BUT SEVERE PROB IS LOW.
THE UPPER FLOW WILL GRADUALLY FLATTEN OUT ON MONDAY ACROSS OUR AREA,
BUT WILL SEE A DEEPENING UPPER LOW NORTH OF THE GREAT LAKES THAT
WILL BE RESPONSIBLE FOR SPINNING OFF SEVERAL VORTICITY WINGS INTO
THE OHIO VALLEY THROUGHOUT THE DAY. THIS WILL SUPPORT ADDITIONAL
PRECIP CHANCES MAINLY ACROSS OUR NORTH THROUGHOUT THE DAY, WITH A
MARGINAL SEVERE RISK NORTH OF OUR AREA ACROSS CENTRAL IN. WE'LL
CONTINUE TO HAVE A WAA PATTERN IN PLACE, SO OUR TEMPS WILL WARM BACK
INTO THE 70S BY THE AFTERNOON.
===== TUESDAY - LATE NEXT WEEK =====
THE UPPER FLOW WILL AMPLIFY BY TUESDAY AS A WESTERN US TROUGH PIVOTS
TOWARD THE CENTRAL US, WHICH WILL OPEN US BACK UP TO A PERSISTENT
SOUTHWEST FLOW REGIME. THIS PATTERN FAVORS A HIGHER MOISTURE FETCH
FROM THE GULF INTO THE REGION, WITH GUIDANCE CONTINUING TO SHOW A
NARROW MOISTURE TRANSPORT PLUME STRETCHING FROM EASTERN TEXAS TO THE
THE OHIO RIVER ON TUESDAY AHEAD OF AN ADVANCING COLD FRONT. SHOWERS
AND STORMS ARE EXPECTED TO INCREASE IN COVERAGE THROUGHOUT TUESDAY
AS A COLD FRONT APPROACHES THE OHIO VALLEY, WITH POPS PEAKING BY
TUESDAY NIGHT. MODEL SOUNDINGS INDICATE LITTLE TO NO INSTABILITY,
BUT PLENTY OF SHEAR GIVEN A LLJ OVERHEAD AND AMPLE MOISTURE. NSSL ML
GUIDANCE SHOWS A WEAK SIGNAL FOR SEVERE PROBS ON TUESDAY, BUT A
SLIGHTLY STRONGER SIGNAL FOR WEDNESDAY. THE COLD FRONT IS EXPECTED
TO PASS THROUGH ON WEDNESDAY, WHICH WILL PROVIDE MORE FORCING IN A
SATURATED AIRMASS. SOUNDINGS ALSO SUGGEST SOME INSTABILITY COULD BE
PRESENT, WITH HIGH SHEAR PARAMETERS, BUT TIMING OF THE FROPA WILL
DETERMINE LIKELIHOOD OF SEVERE RISK ON WEDNESDAY. FOR NOW, HIGH
PRECIP CHANCES WILL CONTINUE IN THE FORECAST FOR TUESDAY THROUGH
THURSDAY DUE TO THE COLD FRONT APPROACH AND EVENTUAL PASSAGE.
AFTER THE UPPER LEVEL TROUGH AXIS MOVES THROUGH ALONG WITH THE
SURFACE FRONT, A COOLER/DRIER AIRMASS WILL FILTER INTO THE REGION
FOR THE END OF THE WEEK. CURRENT GUIDANCE SUGGESTS DRIER CONDITIONS
FOR THURSDAY. HOWEVER, WEAK WAVES IN THE UPPER LEVEL FLOW COULD
RESULT IN ADDITIONAL SHOWERS BY FRIDAY.
AVIATION /12Z TAFS THROUGH 18Z SUNDAY/
ISSUED AT 654 AM EDT SAT MAY 2 2026
VFR CONDITIONS CONTINUE THROUGH THIS TAF PERIOD. REGIONAL RADAR
SHOWS SOME LIGHT RETURNS MOVING INTO THE HNB/SDF AREAS THIS MORNING,
THOUGH PLENTY OF DRY AIR IS PREVENTING ANY PRECIP FROM MAKING IT TO
THE GROUND FOR NOW. HOWEVER, EXPECT SOME ISOLATED LIGHT RAIN SHOWERS
THROUGHOUT THE DAY, WITH THE BEST CHANCE AT HNB THROUGH THE MORNING,
AND FOR BWG THROUGH THE AFTERNOON. CHANCES ARE NOT HIGH ENOUGH TO
MENTION AT SDF TODAY. OTHERWISE, NNW WINDS WITH SOME AFTERNOON GUSTS
UP TO 20 KTS POSSIBLE. CLOUDS INCREASE THROUGHOUT THE DAY TO A MID-
LEVEL CIG DECK, BUT EXPECT THOSE CLOUDS TO CLEAR OUT BY TONIGHT.
LMK WATCHES/WARNINGS/ADVISORIES
KY...NONE.
IN...NONE.
UPDATE...RJS
SHORT TERM...CJP
LONG TERM...CJP
AVIATION...CJP
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