Severe Thunderstorm Warning 191, NWS Louisville, KY

Area Forecast Discussion
National Weather Service Louisville KY
712 AM EDT Fri May 16 2025

.KEY MESSAGES...

*  SIGNIFICANT SEVERE WEATHER OUTBREAK POSSIBLE LATE THIS AFTERNOON
   INTO THIS EVENING.

*  All severe weather hazards are on the table, including damaging
   winds, large hail, tornadoes, and torrential rainfall. A few
   strong tornadoes and instances of very large hail are possible.

*  Strong to severe thunderstorms are also possible this morning
   west of Interstate 65, with large hail as the main hazard.

&&

.MESOSCALE...
Issued at 649 AM EDT Fri May 16 2025

Storms associated with an upper jet streak are moving very quickly
across Kentucky this morning, with storm motions near 70 mph. In the
last 30-60 min we have seen them sustain themselves better as they
push east of the I-65 corridor, and some stronger wind reports
suggest they're closer to becoming sfc based. Other storms in far
western Kentucky are on track to outrun the SE portion of WW 259
around 13Z, so we have coordinated with SPC to run a local extension
for the remainder of our Kentucky counties and one tier north of the
river into Indiana. This may be a bit generous over toward Lake
Cumberland, but seems a fair approximation given convective
behavior.

Issued at 336 AM EDT Fri May 16 2025

Boundary has lit up from the Shawnee National Forest in southern
Illinois ENE to near Henderson, and storms tapped into strong
elevated instability to produce vigorous cores aloft. Given the very
unstable and strongly sheared environment, as storms continue to
develop through early morning they will carry mainly a SVR hail
threat from the Pennyrile into the Hoosier National Forest and
sections of Kentucky west of Interstate 65. Damaging winds and even
a tornado or two can't be ruled out completely, but storms will have
a really difficult time becoming sfc based. Confidence is also
slightly diminished south of the WK Parkway but we could see
convection down toward BWG later in the morning.

&&

.SHORT TERM /THROUGH TONIGHT/...
Issued at 407 AM EDT Fri May 16 2025

A significant severe weather outbreak is possible later this
afternoon and this evening across the Ohio Valley. Storms developing
ahead of an incoming cold front will quickly become severe in a very
unstable and strongly sheared environment. All severe weather
hazards, including widespread damaging winds, very large hail, and
strong tornadoes are possible, as well as localized flash flooding.

Main bust potential hinges on the evolution of storms this morning,
which have developed over western Kentucky. These storms will have a
large hail threat of their own, especially west of Interstate 65.
While they will at least temporarily stabilize the atmosphere,
strong warm advection is likely to win out, allowing a fairly quick
recovery this afternoon.

With around 3000 J/kg of mixed-layer CAPE, 1000 J/kg of downdraft
CAPE, and 60 kt of effective shear, initially discrete storms will
organize into at least bowing segments. A few of the discrete cells
could produce very large hail and/or strong tornadoes, and line
segments could produce hurricane-force wind gusts. Spin-up tornadoes
will also be in play with any of the bowing structures as well.

The peak severe threat could be slightly delayed depending on how
quickly the atmosphere can reload after morning convection, but the
threat will mainly be focused on the evening hours. Initial discrete
cells could develop in the late afternoon.

It's also worth noting that in the late evening, the line will
become more east-west oriented, opening the door for excessive
rainfall especially over south-central Kentucky. Confidence in the
exact placement is low at this time, but it bears watching as the
event unfolds.

Bottom line, significant severe weather is possible late this
afternoon and this evening. Make sure you have multiple ways to
receive warnings and a plan in place should a warning be issued!

&&

.LONG TERM /SATURDAY THROUGH THURSDAY/...
Issued at 352 PM EDT Thu May 15 2025

By Saturday morning, the actual cold front will be pushing through
the area with most of the showers and storms exiting to our east.
The associated upper low will be over the Great Lakes with the
longwave trough axis extending south over the OH and TN Valleys
before flattening out against the subtropical ridge over the Gulf.
Weak CAA behind the front will result in climatological normal
temperatures for the weekend with highs in the mid to upper 70s to
lower 80s accompanied by breezy WSW winds on Saturday. Overall, most
will experience a fair weather weekend.

Southern KY will see a slight chance of showers on Sunday as the
southern edge of the new airmass begins to lift northward due to the
next low pressure system strengthening over the Central Plains. This
will begin another period of unsettled weather as we enter the
beginning of the new work week.

By Monday, a warm front will begin lifting across the region
resulting in warm and moist air advection, as PWATs surge into the
upper percentiles of SPC's sounding climatology. Models tend to
agree on convection from our west moving into our area by Monday
morning with another round Monday evening. The warm front appears to
stall over the region, prolonging our shower and storm chances into
Tuesday and Wednesday before the occluded low pushes through on
Wednesday. With model soundings advertising sufficient instability
and ML guidance also showing enhanced severe probabilities, severe
weather can not be ruled out. Details remain hazy this far out, but
will continue to monitor closely with subsequent forecast packages.
Stay tuned.

&&

.AVIATION /12Z TAFS THROUGH 18Z SATURDAY/...
Issued at 712 AM EDT Fri May 16 2025

Main challenge in this TAF set is timing and impacts of two
different waves of convection. Ongoing convection this morning will
mainly produce brief IFR vis in the heaviest rain, but cigs should
remain VFR with the exception of LEX and perhaps RGA. First wave of
storms will push east of the terminals by 15-17Z, giving way to
mainly mid-level cigs this afternoon with gusty SSW winds.

Next wave of more vigorous storms is expected early this evening.
Given the wind threat, opted to include a TEMPO with convective
winds starting around 23Z in HNB/BWG, closer to 00Z at SDF, and 01-
02Z in LEX and RGA.  This will also be the better shot at MVFR cigs
and IFR vis, and could warrant a prevailing mention in later TAF
issuances. Some uncertainty between waves at BWG and RGA as we could
have a lingering boundary draped across to focus convection sooner.

Should be a fairly sharp cutoff and clearing out of lower clouds
after the storms pass around midnight. Light SW winds and cirrus
ceilings heading into Sat morning.

&&

.LMK WATCHES/WARNINGS/ADVISORIES...
KY...None.
IN...None.

&&

MESOSCALE...RAS
SHORT TERM...RAS
LONG TERM...CG
AVIATION...RAS

Hazardous Weather Outlook
National Weather Service Louisville KY
413 AM EDT Fri May 16 2025

INZ076>079-083-090>092-KYZ028>043-045>049-053>057-063>067-073>078-
081-082-170815-
Orange-Washington IN-Scott IN-Jefferson IN-Dubois-Harrison IN-Floyd-
Clark IN-Hardin-Bullitt-Jefferson-Oldham-Trimble-Henry-Shelby-
Franklin-Scott KY-Harrison KY-Spencer-Anderson-Woodford-Fayette-
Bourbon-Nicholas-Nelson-Washington KY-Mercer-Jessamine-Clark KY-
Larue-Marion-Boyle-Garrard-Madison-Hart-Green-Taylor-Casey-Lincoln-
Allen-Barren-Monroe-Metcalfe-Adair-Russell-Cumberland-Clinton-
413 AM EDT Fri May 16 2025 /313 AM CDT Fri May 16 2025/

This Hazardous Weather Outlook is for portions of southern Indiana
and central Kentucky.

.DAY ONE...Today and tonight.

A significant severe weather outbreak is possible late this afternoon
into this evening. All severe hazards are possible, including
damaging winds, very large hail, and tornadoes, some of which could
be strong.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed.

GENERAL STORM MOTION OF THE DAY:

Storms today will move to the east-northeast at around 60 mph.

Any users of this storm motion must be aware that thunderstorm activity
can be erratic and constantly evolving.  Please use this with caution
and be prepared for changing conditions.

&&

More information, along with other weather, hydrological and
climate information can be found, at weather.gov/louisville.

INZ084-089-KYZ023>027-061-062-070>072-170815-
Crawford-Perry-Hancock-Breckinridge-Meade-Ohio-Grayson-Butler-
Edmonson-Logan-Warren-Simpson-
413 AM EDT Fri May 16 2025 /313 AM CDT Fri May 16 2025/

...SEVERE THUNDERSTORM WATCH 259 IN EFFECT UNTIL 10 AM EDT /9 AM
CDT/ THIS MORNING...

This Hazardous Weather Outlook is for portions of southern Indiana
and central Kentucky.

.DAY ONE...Today and tonight.

Please listen to NOAA Weather Radio or go to weather.gov/louisville on the
Internet for more information about the following hazards.

   Severe Thunderstorm Watch.

Thunderstorms this morning will be capable of producing large hail.

A significant severe weather outbreak is possible late this afternoon
into this evening. All severe hazards are possible, including
damaging winds, very large hail, and tornadoes, some of which could
be strong.

.DAYS TWO THROUGH SEVEN...Saturday through Thursday.

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation will likely be needed.

GENERAL STORM MOTION OF THE DAY:

Storms today will move to the east-northeast at around 60 mph.

Any users of this storm motion must be aware that thunderstorm activity
can be erratic and constantly evolving.  Please use this with caution
and be prepared for changing conditions.

&&

More information, along with other weather, hydrological and
climate information can be found, at weather.gov/louisville.

RAS

Special Weather Statement
National Weather Service Louisville KY
722 AM EDT Fri May 16 2025

INZ077-078-091-092-161145-
Washington IN-Floyd IN-Clark IN-Scott IN-
722 AM EDT Fri May 16 2025

...A STRONG THUNDERSTORM WILL IMPACT CLARK...NORTHERN FLOYD...
SOUTHERN SCOTT AND SOUTHEASTERN WASHINGTON COUNTIES THROUGH 745 AM
EDT...

At 722 AM EDT, Doppler radar was tracking a strong thunderstorm 11
miles northwest of New Albany, moving northeast at 55 mph.

HAZARD...Wind gusts up to 40 mph and penny size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor hail damage to vegetation is
         possible.

Locations impacted include...
Vienna, Charlestown, Sellersburg, Lexington, Galena, Blue River, New
Pekin, Borden, Greenville, and Saint Joseph.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

A Severe Thunderstorm Watch remains in effect until 1000 AM EDT for
south central Indiana...and central Kentucky.

&&

LAT...LON 3871 8564 3871 8561 3868 8561 3868 8558
      3866 8557 3861 8557 3861 8552 3852 8544
      3833 8595 3848 8607 3872 8565
TIME...MOT...LOC 1122Z 240DEG 49KT 3845 8592

MAX HAIL SIZE...0.75 IN
MAX WIND GUST...40 MPH

CG

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