Special Weather Statement, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
248 PM CDT Wed Aug 11 2021

.SHORT TERM...(This evening through Thursday)
Issued at 246 PM CDT Wed Aug 11 2021

Storms continue across the area and deep wind shear and
instability are yielding supercells. Although low-level curvature
is not overly impressive, 100-150 m2/s2 0-1km SRH combined 25-30
kt 0-1km Bulk Shear and 0-3km MLCAPE near 200 J/Kg is providing an
environment that is producing tornadoes per SPC mesoa. Storm
motions continue to favor discrete storms off the cold front. This
threat will continue for the next hours, moving slowly southward.
The threat should end by 6 pm in southwest Wisconsin.

Heat index values will peak around 100F and at 5 pm the advisory
will be allowed to expire.

Clear conditions are expected overnight with a small chance of
thunderstorms across the far south Thursday afternoon.

.LONG TERM...(Thursday night through Wednesday)
Issued at 246 PM CDT Wed Aug 11 2021

From Thursday night through Friday night, a longwave trough will
be located across the Canadian provinces of Saskatchewan,
Manitoba, and Ontario, and from the Dakotas into the Great Lakes.
Rain chances will hinge on whether there will be any short waves
on the periphery of this trough. One of these waves will move
across the area on Thursday night. It looks like much of the
moisture transport will remain to our south and east. As a result,
the rain chances look to be scattered and on the light side. High
temperatures on Friday will be in the 70s with comfortable dew
points in the 50s.

For the upcoming weekend, there is some uncertainty on the location
of yet another shortwave trough. The GFS is the farthest north with
this wave and as a result the moisture transport is more focused in
areas west of the Mississippi River. This results in the development
of showers and storms. Meanwhile, the ECMWF keeps this shortwave
further southwest of the region as a result we remain dry. High
temperatures will range from the mid-70s to lower 80s. Dew points
will be in the 50s on Saturday and around 60 on Sunday.

For early next week, the models continue to differ on the location
of a cutoff low. The ECMWF has this low over the Great Lakes with
strong ridging over Quebec and New England and another one located
over the Central Plains. Meanwhile, the GFS has strong ridging over
the Upper Mississippi River Valley and Ontario and the closed low is
located over the Mid Mississippi River Valley. As a result, there is
low confidence on rain changes and temperatures.

&&

.AVIATION...(For the 18Z TAFS through 18Z Thursday afternoon)
Issued at 1151 AM CDT Wed Aug 11 2021

At KLSE, storms will be in the vicinity of the airfield for about
an hour or so before moving east. While unlikely, large hail
cannot be ruled out completely at the airfield...through about
2pm/19Z. It would depend on where storms form over the area.

At KRST, VFR is expected with any storms developing to the east.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Heat Advisory until 5 PM CDT this afternoon for WIZ061.

MN...None.
IA...Heat Advisory until 5 PM CDT this afternoon for IAZ030.

&&

SHORT TERM...Baumgardt
LONG TERM...Boyne
AVIATION...Baumgardt

Hazardous Weather Outlook
National Weather Service La Crosse WI
419 PM CDT Wed Aug 11 2021

IAZ011-WIZ043-044-053>055-130130-
Allamakee-Juneau-Adams-Vernon-Crawford-Richland-
419 PM CDT Wed Aug 11 2021

This Hazardous Weather Outlook is for parts of northeast Iowa and
western into central Wisconsin.

.DAY ONE...Today and Tonight

Tornado Watch until 8 pm. The severe storm threat is shifting east
and should be done by about 5 pm. At that time, the tornado watch
will be cancelled. Main impacts from any severe storms through 5
pm are damaging wind, large hail, and lightning. A brief tornado
cannot be ruled out.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

A few spotter groups, mainly in Wisconsin, may be needed briefly
this afternoon.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

IAZ030-WIZ061-130130-
Clayton-Grant-
419 PM CDT Wed Aug 11 2021

This Hazardous Weather Outlook is for parts of northeast Iowa
into southwest Wisconsin.

.DAY ONE...Today and Tonight

Tornado Watch until 8 pm. A few strong to severe thunderstorms
are possible this afternoon. Main impacts would be damaging wind,
large hail, and lightning. A brief tornado cannot be ruled out.

Storms should exit the area by 5-6pm.

In addition a heat advisory is in effect for heat index values
expected to exceed 100 degrees again this afternoon.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

A few spotter groups, mainly in Wisconsin, may be needed briefly
this afternoon if severe weather develops.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

IAZ008>010-018-019-029-MNZ079-086>088-094>096-WIZ017-029-032>034-
041-042-130130-
Mitchell-Howard-Winneshiek-Floyd-Chickasaw-Fayette-Wabasha-Dodge-
Olmsted-Winona-Mower-Fillmore-Houston-Taylor-Clark-Buffalo-
Trempealeau-Jackson-La Crosse-Monroe-
419 PM CDT Wed Aug 11 2021

This Hazardous Weather Outlook is for portions of northeast Iowa, southeast
Minnesota, and northcentral and western Wisconsin.

.DAY ONE...Tonight

No hazardous weather is expected at this time.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
227 PM CDT WED AUG 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0158 PM     HAIL             1 WNW CLIFTON           43.88N 90.37W
08/11/2021  M1.00 INCH       MONROE             WI   STORM CHASER

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
229 PM CDT WED AUG 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0155 PM     TSTM WND GST     CAMP DOUGLAS            43.92N 90.27W
08/11/2021  M41 MPH          JUNEAU             WI   AWOS

            AWOS STATION KVOK VOLK FIELD.

&&

JAR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
315 PM CDT WED AUG 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0315 PM     HAIL             VIROQUA                 43.56N 90.88W
08/11/2021  E0.25 INCH       VERNON             WI   LAW ENFORCEMENT

&&

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
322 PM CDT WED AUG 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0311 PM     HAIL             1 N VIROQUA             43.58N 90.89W
08/11/2021  U0.75 INCH       VERNON             WI   PUBLIC

            REPORT FROM MPING: DIME (0.75 IN.).

&&

JAR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
333 PM CDT WED AUG 11 2021

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0328 PM     HAIL             LA FARGE                43.58N 90.64W
08/11/2021  E0.25 INCH       VERNON             WI   PUBLIC

&&

Special Weather Statement
National Weather Service La Crosse WI
419 PM CDT Wed Aug 11 2021

WIZ054-061-112145-
Crawford WI-Grant WI-
419 PM CDT Wed Aug 11 2021

...A strong thunderstorm will impact portions of northeastern Grant
and southeastern Crawford Counties through 445 PM CDT...

At 419 PM CDT, Doppler radar was tracking a strong thunderstorm 9
miles south of Muscoda, or 18 miles northeast of Lancaster, moving
east at 30 mph.

HAZARD...Winds in excess of 40 mph and penny size hail.

SOURCE...Radar indicated.

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

Locations impacted include...
Boscobel, Fennimore, Preston, Montfort, Wauzeka, Centerville,
Woodman, Steuben, Highway 61 And County T, Werley, Harris Ridge,
Highways 60 And 61, County Roads K And T, Maple Ridge, Red Oak Ridge,
Boydtown, Kickapoo Indian Caverns and Easter Rock.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

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

A Tornado Watch remains in effect until 800 PM CDT for southwestern
Wisconsin.

&&

LAT...LON 4298 9078 4310 9097 4321 9079 4317 9066
      4313 9043 4291 9043
TIME...MOT...LOC 2119Z 257DEG 27KT 4306 9048

MAX HAIL SIZE...0.88 IN
MAX WIND GUST...40 MPH

DTJ