620
FXUS63 KLMK 140137
AFDLMK
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LOUISVILLE KY
937 PM EDT THU MAR 13 2025
KEY MESSAGES
* INCREASING WIND GUSTS AND WARM WITH RECORD CHALLENGING AFTERNOON
HIGHS ON FRIDAY.
* A STRONG STORM SYSTEM WILL IMPACT THE REGION FRIDAY NIGHT THROUGH
SATURDAY NIGHT, BRINGING MULTIPLE ROUNDS OF SHOWERS AND
THUNDERSTORMS. THERE WILL BE TWO MAIN WAVES: THE FIRST ONE LATE
FRIDAY NIGHT/EARLY SATURDAY MORNING, AND THE SECOND SATURDAY
AFTERNOON AND EVENING. ALL SEVERE HAZARDS WILL BE POSSIBLE, WITH
STRONG GUSTY WINDS AS THE MAIN THREAT.
* NON-THUNDERSTORM WINDS WILL BE STRONG AND GUSTY FRIDAY AFTERNOON
THROUGH SATURDAY. THE MOST LIKELY TIME FOR THE STRONGEST GUSTS
WILL BE FRIDAY NIGHT WITH SPEED GUSTS OF 45 TO 50 MPH POSSIBLE. A
WIND ADVISORY HAS BEEN ISSUED WITH THIS FORECAST PACKAGE.
UPDATE
ISSUED AT 936 PM EDT THU MAR 13 2025
AFTER A FEW POP-THUNDERSTORMS AND SMALL HAIL EARLIER TODAY,
CONDITIONS HAVE BECOME MUCH MORE QUIET ACROSS THE REGION THIS
EVENING. TEMPS HAVE BEEN SLOWLY COOLING INTO THE 60S NOW, AFTER A
DAY WHERE MANY LOCATIONS REACHED THE UPPER 70S AND CLOSE TO 80. FOR
THE REST OF TONIGHT, THE FORECAST REMAINS IN GOOD SHAPE. MOSTLY
CLEAR SKYCOVER IS EXPECTED OVERNIGHT, WHICH IS GOOD NEWS FOR THOSE
STAYING UP LATE TONIGHT FOR THE TOTAL LUNAR ECLIPSE. TEMPS THROUGH
THE OVERNIGHT WILL REMAIN VERY MILD, WITH LOW TO MID 50S EXPECTED.
NO MAJOR CHANGES TO THE FORECAST ARE PLANNED FOR THE OVERNIGHT.
SHORT TERM /THROUGH FRIDAY/
ISSUED AT 357 PM EDT THU MAR 13 2025
WEAK UPPER LOW CONTINUES TO WORK EASTWARD OVER TN THIS AFTERNOON AS
A STALLED SFC BOUNDARY IS POSITIONED ALONG TO JUST NORTH OF THE OHIO
RIVER. HI-RES MODELS HAVE HINTED ALL DAY AT THE DEVELOPMENT OF
ISOLATED/SCATTERED CONVECTION ACROSS PARTS OF CENTRAL/SOUTHERN KY
BUT SO FAR ANY ACTIVITY THAT HAS TRIED TO DEVELOP HAS QUICKLY
DIMINISHED. AS CLOUDS START TO CLEAR AND TEMPERATURES WARM INTO THE
MID 70S WITH DEW POINTS IN THE LOW 50S, SBCAPE VALUES ARE EXPECTED
TO BE BETWEEN 1000-1500 J/KG LATER THIS AFTERNOON INTO THE EARLY
EVENING. GIVEN THE LACK OF ANY REAL SPARK, WILL CONTINUE JUST A LOW
END CHANCE (15-20%) OF AN ISOLATED STORM DEVELOPING THIS
AFTERNOON/EVENING.
AS WE GO OVERNIGHT, RIDGING WILL BUILD IN ALOFT FROM THE WEST AS
DRIER AIR ALOFT WORKS IN HELPING TO CLEAR SKIES OVER THE REGION.
NEGATIVELY-TILTED TROUGH WILL WORK ACROSS THE ROCKIES AS A SFC LOW
GOES THROUGH RAPID AND STRONG LEE CYCLOGENESIS OVER OVER THE CENTRAL
PLAIN TONIGHT INTO EARLY FRIDAY MORNING. AS THIS SFC LOW BOMBS OUT
OVER KS/NE THE SFC PRESSURE GRADIENT WILL START TO TIGHTEN OVER THE
OHIO VALLEY. INITIALLY, WINDS WILL REMAIN LIGHT THIS EVENING BUT
SLOWLY BEGIN TO INCREASE OUT OF THE SOUTH-SOUTHEAST. GIVEN THE
GENERAL LIGHT WINDS AND CLEAR SKIES, NOT ONLY WILL WEATHER BE NICE
TO VIEW THE TOTAL LUNAR ECLIPSE OVERNIGHT, TEMPERATURES WILL BE MILD
ONLY FALLING INTO THE LOW 50S. THE LONE EXCEPTION WILL BE PROTECTED
AREAS LIKE RIVER VALLEYS WHERE LOWS COULD BE IN THE MID/UPPER 40S.
THE BULK OF THE DAY TOMORROW IS DRY WITH MOSTLY SUNNY SKIES BUT
STRONG WAA WILL HELP BOOST TEMPERATURES INTO THE 80S AS PRESSURE
GRADIENT AT THE SFC STARTS TO TIGHTEN. LLJ WILL START TO INCREASE
INTO THE AFTERNOON AND WITH SOME MIXING, SOME STRONG GUSTS COULD MIX
TO THE SURFACE. AFTER SOME COLLABORATION WITH OUR NEIGHBORS, DECIDED
TO START OUR WIND ADVISORY AROUND 21Z AND CONTINUE IT INTO TOMORROW
NIGHT INTO SATURDAY. MORE WILL BE DISCUSSED IN THE LONG TERM
FORECAST BELOW. WHILE NOT WIDESPREAD, ISOLATED GUSTS OF 35-40 MPH
ARE POSSIBLE, MAINLY WEST OF I-65.
LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/
ISSUED AT 357 PM EDT THU MAR 13 2025
FRIDAY NIGHT...
A POWERFUL SHORTWAVE TROUGH OVER THE SOUTHERN HIGH PLAINS WILL
AMPLIFY AND MOVE INTO THE MS VALLEY FRIDAY NIGHT INTO SATURDAY.
ASSOCIATED SURFACE LEVEL CYCLONE WILL ALSO DEEPEN AS WELL AND MOVE
IN TANDEM WITH THE UPPER LEVEL TROUGH AXIS. AS THIS OCCURS, A 70-
80KT 500 HPA JET WILL CURL NORTHWARD FROM THE OZARKS INTO THE MID-MS
VALLEY. CONVECTION IS EXPECTED TO BE IN PROGRESS AT THE BEGINNING
OF THE PERIOD ACROSS IA/MO AND DOWN INTO THE OZARKS. THE
COMBINATION OF INSTABILITY AND SHEAR ACROSS THE MID-MS VALLEY WILL
SUPPORT THE DEVELOPMENT OF A SEVERE QLCS WITH ALL SEVERE WEATHER
HAZARDS BEING POSSIBLE. THIS QLCS LOOKS TO MOVE EAST-NORTHEAST INTO
NORTH IL/CENTRAL IN DURING THE LATE EVENING PERIOD. FURTHER SOUTH
FROM ROUGHLY THE ST. LOUIS AREA SOUTHWARD, THE CAMS SUGGEST THAT
SOMEWHAT MORE OF A BROKEN LINE OF STORMS WILL DEVELOP. HERE, WHERE
THE BETTER INSTABILITY AND SHEAR RESIDE, LOOKS TO SUPPORT SOME SORT
OF SEMI-DISCRETE CONVECTION INCLUDING MULTI-CELLS AND SUPERCELLS.
THIS ACTIVITY WILL HEAD EASTWARD DURING THE OVERNIGHT HOURS AND
EVENTUALLY WILL MOVE INTO WESTERN KY AND SOUTHWEST IN AFTER MIDNIGHT.
AS THE NIGHT WEARS ON, THE ATMOSPHERE WILL BECOME A BIT MORE HOSTILE
FOR CONVECTIVE DEVELOPMENT AND SUPPORT AS THE STORMS PUSH INTO THE
MIDDLE OHIO VALLEY. MODEL PROXIMITY SOUNDING ACROSS THE REGION
SUGGEST THAT SURFACE BASED INSTABILITY WILL DECREASE WITH TIME
OVERNIGHT. HOWEVER, THE MAJORITY OF THE SOUNDINGS DO STILL HAVE A
BIT OF ELEVATED INSTABILITY. WIND SHEAR REMAINS QUITE IMPRESSIVE
WITH BOTH DIRECTIONAL AND SPEED SHEAR PROFILES PRESENT WITH
SIGNIFICANT TURNING IN THE LOWEST LEVELS. WE DID NOTICE THAT SOME
CAMS HAVE SOME BACKED FLOW ALOFT WHICH RESULTS IN SOME
CONCAVE/CONVEX HODOGRAPHS. IN GENERAL, IT APPEARS THAT ENOUGH
FORCING AND INSTABILITY WILL BE PRESENT TO CONTINUE TO DRIVE
CONVECTION INTO OUR WESTERN AREAS, BUT THE INCREASING HOSTILE
ENVIRONMENT TOWARD THE I-65 CORRIDOR AND POINTS EAST, SUGGEST THAT
THIS LINE WILL LIKELY BECOME ELEVATED AND WEAKEN TOWARD SUNRISE. THE
MAIN SEVERE WEATHER THREATS WITH THIS LINE WOULD BE DAMAGING WIND
GUSTS IN EXCESS OF 60 MPH ALONG WITH POTENTIAL ISOLATED SPINUPS FROM
TIME TO TIME. I SUPPOSE THAT A LARGE HAIL THREAT COULD BE PRESENT,
BUT I THINK WE'D NEED A PRETTY TALL STORM AND UPDRAFT TO GET THAT.
OUTSIDE OF THE THUNDERSTORMS, THE GRADIENT WIND WILL BE STRONG AND
WE'LL SEE WIND GUSTS OF 35-40 MPH AT TIMES, WITH THE POTENTIAL TO
SEE HIGHER GUSTS HERE AND THERE. FOR THAT REASON, A WIND ADVISORY
HAS BEEN ISSUED FOR THE FRIDAY NIGHT PERIOD AND INTO THE DAY ON
SATURDAY.
SATURDAY AND SATURDAY NIGHT...
CONVECTION IS EXPECTED TO BE IN PROGRESS AROUND AT THE START OF THE
PERIOD, LIKELY EAST OF THE I-65 CORRIDOR. BEHIND THE LINE OF
STORMS, WE'LL SEE A BREAK IN THE PRECIPITATION FOR MUCH OF THE
MORNING HOURS. THE MAIN FORECAST CHALLENGE FOR THIS PERIOD IS HOW
MUCH DIURNAL DESTABILIZATION WILL BE SEEN IN ADVANCE OF THE NEXT
WAVE THAT WILL ARRIVE LATER IN THE DAY. CURRENT MODEL GUIDANCE HAS
A VARIETY OF SOLUTIONS HERE, WITH SOME SHOWING SKIES REMAINING
CLOUDY WITH VERY LITTLE IN THE WAY OF INSTABILITY, WHILE SOME ARE
MORE AGGRESSIVE WITH CLEARING AND DEVELOPING STEEP LOW-MID LEVEL
LAPSE RATES ACROSS THE REGION.
A COUPLED JET STRUCTURE ALOFT WILL FAVOR THE QUICK DEVELOPMENT OF
CONVECTION ACROSS THE REGION SATURDAY AFTERNOON. IT IS POSSIBLE,
GIVEN THE FLOW REGIME AND KINEMATIC/THERMODYNAMIC PROFILES THAT SOME
SCATTERED SEVERE CONVECTION COULD DEVELOP BEFORE A MORE WIDESPREAD
CONVECTIVE SHIELD DEVELOPS. GIVEN THE PROFILES, DAMAGING WINDS,
LARGE HAIL (PERHAPS VERY LARGE HAIL), AND ISOLATED TORNADOES COULD
OCCUR. ONE COMPLICATING FACTOR HERE IS THAT WIDESPREAD CONVECTIVE
DEVELOPMENT IS EXPECTED ACROSS THE DEEP SOUTH. SHOULD THIS
CONVECTION INDEED DEVELOP AND BECOME WIDESPREAD, THE NORTHWARD
TRANSPORT OF MOISTURE INTO THE TN/OH VALLEYS COULD BE QUITE
TEMPERED. OVERALL, I WOULD STRONGLY ARGUE THAT THE SEVERE THREAT ON
SATURDAY ACROSS OUR REGION IS CONDITIONAL.
WHILE THE SEVERE THREAT MAY BE CONDITIONAL, WE WILL HAVE TO DEAL
WITH MODERATE TO HEAVY RAINFALL THAT DEVELOPS IN ADVANCE AND JUST
EAST OF THE SURFACE LOW TRACK. MODERATE TO HEAVY RAINFALL MAY LEAD
TO SOME FLASH FLOODING IN AREAS. QPF AMOUNTS OF 2-3 INCHES LOOK
REASONABLE ACROSS THE ENTIRE CWA WITH ISOLATED HIGHER SWATHS BEING
POSSIBLE. SURROUNDING OFFICES DISCUSSED THE HEAVY QPF AND IT IS
POSSIBLE THAT A FLOOD WATCH MAY BE REQUIRED IN SUBSEQUENT FORECASTS.
AS THE SURFACE LOW HEADS NORTHEASTWARD, THE COLD FRONT TO THE WEST
WILL PUSH ON THROUGH RESULTING IN PRECIPITATION ENDING FROM WEST TO
EAST LATE SATURDAY NIGHT.
SUNDAY THROUGH THURSDAY...
UPPER TROUGH AXIS WILL PASS THROUGH THE REGION LATE SUNDAY AND EXIT
TO THE EAST ON MONDAY. A PERIOD OF QUIET WEATHER IS EXPECTED FOR
MONDAY AND TUESDAY AS HIGH PRESSURE BUILDS IN AT THE SURFACE AND
ALOFT. BY LATE WEDNESDAY THE NEXT UPPER LEVEL TROUGH AXIS WILL PUSH
TOWARD THE REGION DRAGGING A FRONTAL BOUNDARY THROUGH. THIS FEATURE
WILL LIKELY BRING ANOTHER ROUND OF SHOWER AND STORMS TO THE REGION.
HIGHS SUNDAY WILL BE IN THE 50S WITH OVERNIGHT LOWS IN THE LOW-MID
30S. TEMPERATURES WILL START TO MODERATE ON MONDAY WITH READINGS
CLIMBING INTO THE LOW-MID 60S WITH MANY AREAS SEEING 70S AGAIN BY
TUESDAY AND WEDNESDAY. LOOK FOR ANOTHER COOL DOWN BEHIND THE
AFOREMENTIONED FRONT WEDNESDAY NIGHT WITH THURSDAY'S HIGHS BACK IN
THE LOW-MID 50S.
AVIATION /00Z TAFS THROUGH 06Z SATURDAY/
ISSUED AT 747 PM EDT THU MAR 13 2025
VFR CONDITIONS ARE LIKELY THROUGHOUT THIS TAF PERIOD. EVENING
ISOLATED CONVECTION CONTINUES, BUT THIS ACTIVITY CONTINUES TO
DIMINISH IN INTENSITY. TSRA DOES NOT APPEAR LIKELY TO IMPACT ANY OF
THE TAF SITES GOING FORWARD. EXPECT CLEARING SKIES LATE THIS EVENING
WITH LIGHT SE WINDS.
FRIDAY, SOUTHERLY WINDS WILL INCREASE SUBSTANTIALLY BY THE AFTERNOON
AS AN AREA OF DEEP LOW PRESSURE DEVELOPS OVER THE CENTRAL PLAINS. A
BROKEN LINE OF STRONG TO SEVERE STORMS IS LIKELY TO SWEEP WEST TO
EAST ACROSS CENTRAL KY AND SOUTHERN IN 06-12Z SATURDAY, JUST BEYOND
THIS TAF PERIOD. PLAN FOR STRONG WINDS, +TSRA, AND ASSOCIATED TSRA
IMPACTS (IFR/LIFR VSBYS FOR SHORT PERIODS).
LMK WATCHES/WARNINGS/ADVISORIES
KY...WIND ADVISORY FROM 5 PM EDT /4 PM CDT/ FRIDAY TO 8 PM EDT /7
PM CDT/ SATURDAY FOR KYZ023>043-045>049-053>057-061>067-
070>078-081-082.
IN...WIND ADVISORY FROM 5 PM EDT /4 PM CDT/ FRIDAY TO 8 PM EDT /7
PM CDT/ SATURDAY FOR INZ076>079-083-084-089>092.
UPDATE...CJP
SHORT TERM...BTN
LONG TERM...MJ
AVIATION...EBW
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