Special Weather Statement, NWS Louisville, KY

Area Forecast Discussion
National Weather Service Louisville KY
154 PM EDT Mon Jun 21 2021

.Forecast Update...
Issued at 145 PM EDT Mon Jun 21 2021

Quick update to add Severe Thunderstorm Watch 301 basically along
and south of the Pkwys in central KY. Seeing a few cells/lines
trying to organize, and given warnings that have gone out so far,
decided to go ahead issue for the rest of the afternoon. Likely will
be able to trim the northern edge of the warnings as the hours
progress and that cold front continues to push southeast.

Issued at 1140 AM EDT Mon Jun 21 2021

Seeing radar light up this hour...with primary zone along an east-
west boundary from near Hartford to Winchester, KY. The western part
of this line is intersecting with the cold, which now has cleared
our counties in southwest IN. Seeing some post frontal showers as
well, which are being enhanced by the upper jet flow across the
Midwest. Expect coverage to continue increasing for the next several
hours. Latest HREF guidance gives several swatch of 0.5-1.5 inch
rainfall over the Commonwealth through this evening...with a few
more narrow swaths around 2 inches...in line with previous thinking
about flash flood potential. Still will have to watch for training
cells, especially given the moisture rich air in place ahead of this
cold front.

Made some subtle tweaks to the forecast and updated for the
afternoon wording.

Issued at 950 AM EDT Mon Jun 21 2021

Morning satellite imagery showing some deepening cumulus clouds over
Perry county in Indiana and also Harrison and Grayson counties in
Kentucky. Expect to see some radar blips here shortly from this
activity. Coverage still should increase as we get into the late
morning hours with widespread activity this afternoon as a cold
front moves into the region. Temperatures are near max values now
and with that cold front and those rains expect readings to fall
through the afternoon hours.

Two main concerns today are severe and flood potential. On the
latter, CREST soil moisture shows the most saturated areas as our
southeast IN counties and our Bluegrass counties. Fortunately,
though they may see the initial wave of convection, the heaviest
rainfall is expected this afternoon south of those locations. Flash
Flood Guidance is over 2"/hour over the rest of Central
Kentucky...so widespread flash flooding is not expected.  As for
severe potential, we did have a low-level jet across the region this
morning, but latest VAD wind profile shows those winds weakening.
Latest SPC mesoanalysis has some marginal shear values for organized
storms to develop. Will continue to monitor as the day goes along.

&&

.Short Term...(Today and tonight)
Issued at 320 AM EDT Mon Jun 21 2021

...Showers and Storms Expected Today...
...Isolated Damaging Winds and Flash Flooding Possible...

Early morning analysis reveals a 998mb sfc low over Wisconsin, with
a cold front trailing through northern Illinois and central
Missouri. Ahead of the frontal boundary, a 35-45kt southwesterly LLJ
extends across the Ohio Valley, evident by the KLVX VAD wind profile
which show 40kts at 2-3k ft. The LLJ has also helped keep sfc
conditions very warm and humid overnight. KY Mesonet temps currently
are in the mid-upper 70s. However at the time of writing this, the
SDF urban heat island is in full effect, with the low at KSDF so far
this morning being 81F.

Aloft, the upper trough and wind field will amplify as the low
deepens this morning. The upper level trough should become more
neutrally tilted by this evening, resulting in a SW to NE jet streak
over the Great Lakes and Ohio Valley regions, and the right entrance
region over KY. Sfc low pressure will continue NE as it deepens,
eventually into southern Canada by this afternoon. With sfc temps
staying in the upper 70s (and localized low 80s) this morning due to
the warm conveyor belt/LLJ, we will breach convective temperatures
very quickly ahead of the cold front and within the warm sector.

Hi-res CAMs suggest we'll see convection initiation ahead of the
cold front late morning or very early afternoon (thinking 15-16z),
and most likely across southern IN and central KY. Still think the
cold front will be located somewhere across southern IN between 12-
15z, so will continue to advertise the highest instability being
across central KY and just south of the Ohio River. Despite
extensive cloud cover, we should have MLCAPE of 2000+ J/kg. While
the instability will be sufficient, model sounding wind profiles
remain modest with unidirectional flow throughout the column. SPC
does include a 2% TOR risk for our eastern two-thirds of the CWA,
which seems to agree with the HRRR wind shear parameters and seems
rather marginal. Best chance for any spin up would be when
convection is more discrete early on, which is when a small region
of 0-1km SRH is at 100 m2/s2 and 0-1 km bulk shear is around 30 kts.
As the day goes on, wind profiles become even less supportive for
tornadoes. With the unidirectional wind fields expected through the
afternoon, upscale growth should lead to a primary threat of
damaging winds. Storms should be pushing east of the CWA by late
afternoon.

Other than the wind threat, PWATs of 1.9-2.0+ inches are among the
climate max, which will support torrential rain rates. Storms look
to be progressive enough to limit area-wide flooding concerns, but
localized flash flooding is possible.

Temperature look to peak around noon or so, but as the cold front
pushes through the region, temps will fall in the wake. Expect max
temps to range from 80F (southern IN) to the mid-upper 80s (Lake
Cumberland region).

Lingering pops will continue in the wake of the front as the upper
trough axis swings through the Midwest and the right entrance region
of the upper jet supports some lift. Pops will be exiting the region
by Tuesday morning. Storm total QPF ranges from half an inch or less
across our southern IN counties, to 1-1.5+ across central KY. Of
course, any heavy downpour with a storm will result in localized
higher rainfall amounts.

.Long Term...(Tuesday through Sunday)
Issued at 310 AM EDT Mon Jun 21 2021

Chamber of Commerce weather is expected during the middle of the
week with a modifying Canadian air mass. Temps will be well below
normal on Tuesday, and gradually recover from there, with highs back
near climo on Thursday with rising heights aloft and developing low-
level return flow.

Friday through the weekend will turn fairly unsettled as an upper
trof digs into the Upper Midwest and the Plains, setting up a deep
and moisture-rich SW flow into the Ohio Valley. Best chances for
showers and storms will be Fri night into Sat as a sfc front tries
to push into the Ohio Valley. Additional rounds of showers and
storms could follow Sunday as well, given a developing model
consensus that the front will hang up. Will have to keep a close eye
on QPF as we head through the week, as repeated heavy downpours
could easily lead to at least localized flooding.

&&

.Aviation...(18Z TAF Issuance)
Issued at 100 PM EDT Mon Jun 21 2021

Cold front near the KSDF terminal now will continue its
southeastward progress this afternoon. Seeing storm coverage
increase ahead of the front. Expect strong to severe wind gusts with
these storms as they pop up over the next few hours. Winds will
become more northwesterly behind the front. Conditions should
improve rapidly this evening, though some lower ceilings are
forecast just east of a BWG/LEX line. Did not go with poor
conditions at either site for the overnight, but will have to watch
to see if those conditions develop farther west than expected.

&&

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

Update...RJS
Short Term...CJP
Long Term...RAS
Aviation...RJS

Hazardous Weather Outlook
National Weather Service Louisville KY
1137 AM EDT Mon Jun 21 2021

INZ076>079-083-084-089>092-KYZ023>043-045>049-053>057-061>067-
070>078-081-082-221545-
Orange-Washington-Scott-Jefferson-Dubois-Crawford-Perry-Harrison-
Floyd-Clark-Hancock-Breckinridge-Meade-Ohio-Grayson-Hardin-Bullitt-
Oldham-Trimble-Henry-Shelby-Franklin-Spencer-Anderson-Woodford-
Fayette-Bourbon-Nicholas-Nelson-Mercer-Jessamine-Larue-Marion-Boyle-
Garrard-Madison-Butler-Edmonson-Hart-Green-Taylor-Casey-Lincoln-
Logan-Warren-Simpson-Allen-Barren-Monroe-Metcalfe-Adair-Russell-
Cumberland-Clinton-
Including the cities of Paoli, Salem, Scottsburg, Madison, Jasper,
English, Tell City, Corydon, New Albany, Jeffersonville, Lewisport,
Hawesville, Hardinsburg, Brandenburg, Hartford, Leitchfield,
Elizabethtown, Shepherdsville, Louisville, La Grange, Bedford,
Milton, New Castle, Shelbyville, Frankfort, Georgetown, Cynthiana,
Taylorsville, Lawrenceburg, Versailles, Lexington, Paris, Carlisle,
Bardstown, Springfield, Harrodsburg, Nicholasville, Winchester,
Hodgenville, Lebanon, Danville, Lancaster, Richmond, Morgantown,
Brownsville, Horse Cave, Greensburg, Campbellsville, Liberty,
Stanford, Russellville, Bowling Green, Franklin, Providence,
Scottsville, Glasgow, Tompkinsville, Edmonton, Columbia, Jamestown,
Burkesville, and Albany
1137 AM EDT Mon Jun 21 2021 /1037 AM CDT Mon Jun 21 2021/

This hazardous weather outlook is for portions of south central
Indiana and Central Kentucky.

.DAY ONE...This Afternoon and Tonight.

Thunderstorms are expected this afternoon. A few strong storms are
possible, and could produce locally damaging winds and torrential
rainfall. Depending on where the heavy rain occurs, localized
flooding will also be possible.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Multiple waves of thunderstorms will be possible Friday through
Sunday. Locations that receive repeated heavy rainfall could see
localized flooding.

.SPOTTER INFORMATION STATEMENT...

Spotters should report any stronger wind gusts as well as heavy rain
and flooding reports.

&&

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

CJP/RAS

Special Weather Statement
National Weather Service Louisville KY
127 PM EDT Mon Jun 21 2021

KYZ049-057-211800-
Clark-Madison-
127 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT EASTERN CLARK AND NORTHEASTERN
MADISON COUNTIES...

At 126 PM EDT, a strong thunderstorm was located near Westbend. The
storm is moving east at 35 mph.

Wind gusts up to 50 mph are possible with this storm.

Locations impacted include...
Winchester, Harris Ferry, Goffs Corner, Rightangle, Vianna, Sewell
Shop, Olivers, Mina, Agawam and Ruckerville.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding.

Frequent cloud to ground lightning is occurring with this storm.
Seek a safe shelter inside a building or vehicle.

LAT...LON 3792 8399 3790 8399 3786 8401 3787 8403
      3784 8400 3783 8404 3785 8406 3782 8407
      3785 8408 3784 8409 3784 8410 3781 8412
      3782 8410 3781 8408 3780 8408 3778 8411
      3778 8420 3806 8420 3806 8404 3794 8397
TIME...MOT...LOC 1726Z 180DEG 0KT 3792 8403

JDG

Special Weather Statement
National Weather Service Louisville KY
135 PM EDT Mon Jun 21 2021

KYZ027-028-053-211830-
Grayson-Hardin-Larue-
135 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT CENTRAL LARUE...NORTHEASTERN
GRAYSON AND SOUTHERN HARDIN COUNTIES...

At 135 PM EDT/1235 PM CDT/, a strong thunderstorm was located 8 miles
northeast of Leitchfield, moving east at 35 mph.

Winds in excess of 40 mph are possible with this storm.

Locations impacted include...
Elizabethtown, Hodgenville, Lyons, Saint Paul, Eastview, Roanoke,
Hansbrough, Addington Field Airport, Solway and Glendale.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding.

Frequent cloud to ground lightning is occurring with this storm.
Seek a safe shelter inside a building or vehicle.

LAT...LON 3760 8627 3763 8625 3775 8569 3774 8568
      3773 8569 3774 8567 3772 8565 3769 8563
      3769 8559 3766 8560 3762 8560 3761 8562
      3760 8560 3759 8561 3757 8561 3750 8626
      3759 8628
TIME...MOT...LOC 1735Z 261DEG 31KT 3755 8616

JDG

Special Weather Statement
National Weather Service Louisville KY
142 PM EDT Mon Jun 21 2021

KYZ045-046-054-211830-
Marion-Washington-Nelson-
142 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTH CENTRAL NELSON...
NORTHWESTERN MARION AND SOUTHERN WASHINGTON COUNTIES...

At 142 PM EDT, a strong thunderstorm was located 8 miles south of
Bardstown, moving east at 35 mph.

Winds in excess of 40 mph are possible with this storm.

Locations impacted include...
Springfield, New Haven, Loretto, Willisburg, Mackville, Burkes
Spring, Dant, Nerinx, Jenkinsville and Holy Cross.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

Frequent cloud to ground lightning is occurring with this storm.
Seek a safe shelter inside a building or vehicle.

LAT...LON 3770 8502 3759 8559 3762 8559 3763 8558
      3762 8557 3763 8557 3764 8558 3764 8559
      3768 8560 3769 8559 3770 8560 3774 8560
      3772 8543 3786 8501
TIME...MOT...LOC 1742Z 261DEG 31KT 3769 8549

JDG

Special Weather Statement
National Weather Service Louisville KY
209 PM EDT Mon Jun 21 2021

KYZ041-048-049-057-211845-
Fayette-Jessamine-Clark-Madison-
209 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT SOUTHWESTERN CLARK...
SOUTHEASTERN JESSAMINE...NORTHERN MADISON AND SOUTHEASTERN FAYETTE
COUNTIES...

At 209 PM EDT, a strong thunderstorm was located 8 miles southeast of
Nicholasville, moving east at 35 mph.

Winds in excess of 40 mph and half inch hail are possible with this
storm.

Locations impacted include...
Richmond, Nicholasville, Redhouse, Valley View, Jackson Ferry,
Logana, Little Hickman, Hunt, Flanagan and College Hill.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3772 8440 3773 8450 3775 8450 3776 8451
      3777 8451 3777 8454 3775 8454 3775 8456
      3773 8457 3773 8458 3791 8458 3794 8414
      3781 8412 3771 8410
TIME...MOT...LOC 1809Z 254DEG 30KT 3783 8443

DM

Special Weather Statement
National Weather Service Louisville KY
111 PM CDT Mon Jun 21 2021

KYZ026-061-211845-
Butler-Ohio-
111 PM CDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN BUTLER AND
SOUTHEASTERN OHIO COUNTIES...

At 111 PM CDT, a strong thunderstorm was located 11 miles east of
Central City, moving east at 35 mph.

Winds in excess of 40 mph and half inch hail are possible with this
storm.

Locations impacted include...
Morgantown, Casey, Beaver Dam, Mchenry, Rockport, Rochester, Monford,
Horse Branch, Mining City and Aberdeen.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3750 8668 3726 8654 3718 8690 3719 8691
      3722 8690 3723 8692 3724 8691 3724 8694
      3726 8696 3726 8697 3727 8698 3729 8698
      3730 8699 3732 8699 3735 8701
TIME...MOT...LOC 1811Z 254DEG 30KT 3728 8692

DM

Special Weather Statement
National Weather Service Louisville KY
213 PM EDT Mon Jun 21 2021

KYZ054-055-066-067-211845-
Boyle-Marion-Lincoln-Casey-
213 PM EDT Mon Jun 21 2021

...A STRONG THUNDERSTORM WILL AFFECT NORTHWESTERN LINCOLN...
SOUTHEASTERN MARION...BOYLE AND NORTH CENTRAL CASEY COUNTIES...

At 212 PM EDT, a strong thunderstorm was located 11 miles east of
Lebanon, moving east at 35 mph.

Winds in excess of 40 mph and half inch hail are possible with this
storm.

Locations impacted include...
Danville, Junction City, Hustonville, Brumfield, Boneyville, Alum
Springs, Caldwell Manor, Milledgeville, Parksville and Forkland.

Torrential rainfall is also occurring with this storm, and may cause
localized flooding. Do not drive your vehicle through flooded
roadways.

LAT...LON 3748 8467 3746 8511 3760 8516 3763 8506
      3763 8503 3764 8503 3770 8484 3770 8481
      3772 8479 3771 8474
TIME...MOT...LOC 1812Z 254DEG 30KT 3754 8504

DM