Special Weather Statement, NWS La Crosse, WI

Area Forecast Discussion
National Weather Service La Crosse WI
623 PM CDT Wed Jul 28 2021

.SHORT TERM...(Today into Thursday)
Issued at 150 PM Wed Jul 28 2021

Current GOES IR/VIS showing anvil debris from morning convection
eroding. This was allowing the atmosphere to recover with building
heat and humidity through the rest of this afternoon. Will leave
Heat Advisory run as is then (through 9 pm).

All attention then turns to higher-end severe threat going into this
evening/tonight as a cold front pushes southeast through the area.
This front will be pushing into a primed/high-CAPE environment with
plenty of bulk shear (0-3km in the 35-45kt range and 0-6km in the 50-
60kt range) per the RAP. Expecting discrete supercell activity to
initiate over northern MN and quickly congeal into a fairly solid line
with embedded bowing segments as the storms push into WI. Confidence
remains high on severity of storms which will include all related
threats including damaging winds (some 70-80 mph)/very large hail
(up to baseball size)/tornadoes and torrential downpours with
perhaps some localized flooding. Latest CAM consensus show primary
severe threat mainly along and north of I-94. At this time, looks
like the timing of this will be between the hours of 6 pm and
midnight.

Once the cold front/convection clears the area after midnight,
drier/cooler air starting to filter in on northerly winds thanks to
high pressure building in from Canada. Plan on lows falling into the
60s/lower 70s.

Thursday is looking like a pleasant day with clearing
skies/temperatures in the upper 70s to mid 80s/dew points in the
upper 50s to mid-60s as high pressure continues to build overhead.

.LONG TERM...(Thursday night thru Tuesday)
Issued at 150 PM CDT Wed Jul 28 2021

Overall, largely dry and cooler, less humid conditions expected for
the long term as broad upper troughing dominates the eastern half of
the CONUS.

The only potential fly in the ointment is with a stronger cold front
slated for Saturday accompanied by a chance of showers and storms.
Bulk shear 0-6km is progged at 30-45 kts, and with MLCAPE progged at
1000-1500+ j/kg there is the possibility for a few stronger storms
that we will need to monitor for severe weather potential should the
frontal timing hold of mainly Saturday afternoon and evening.

In the wake of this cold front, much cooler and very pleasant
conditions look to be on tap to finish out the weekend and continue
into early next week.

&&

.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 623 PM CDT Wed Jul 28 2021

Severe thunderstorms are still expected to move southeastward
through Wisconsin. There is low confidence with how far west the
storms develop and track. With KLSE still falling under the western
edge extent of these storms, have decided to keep VCTS in the TAF at
this time. Will watch closely as storms approach this evening.

Otherwise, VFR conditions are expected through the period with winds
becoming northerly by tomorrow morning.

&&

.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Heat Advisory until 9 PM CDT this evening for WIZ054-061.

MN...Heat Advisory until 9 PM CDT this evening for MNZ079-086>088-
     094>096.

IA...Heat Advisory until 9 PM CDT this evening for IAZ008>011-018-019-
     029-030.

&&

SHORT TERM...DAS
LONG TERM...McClure
AVIATION...Peters

Hazardous Weather Outlook
National Weather Service La Crosse WI
657 PM CDT Wed Jul 28 2021

IAZ008>011-018-019-029-030-MNZ079-086>088-094>096-WIZ017-029-
032>034-041>044-053>055-061-291100-
Mitchell-Howard-Winneshiek-Allamakee-Floyd-Chickasaw-Fayette-
Clayton-Wabasha-Dodge-Olmsted-Winona-Mower-Fillmore-Houston-
Taylor-Clark-Buffalo-Trempealeau-Jackson-La Crosse-Monroe-Juneau-
Adams-Vernon-Crawford-Richland-Grant-
657 PM CDT Wed Jul 28 2021

This Hazardous Weather Outlook is for portions of southeast
Minnesota...northeast Iowa and southwest into central Wisconsin.

.DAY ONE...Tonight

Severe storms are expected tonight, especially across western and
central Wisconsin. The strongest storms will have the potential to
produce damaging wind gusts near 70 mph, large hail and a tornado
or two. Localized urban flooding will also be possible.

.DAYS TWO THROUGH SEVEN...Thursday through Tuesday

No hazardous weather is expected at this time.

.SPOTTER INFORMATION STATEMENT...

Some spotter groups will likely be needed this evening, mainly
across Wisconsin.

.EMERGENCY MANAGEMENT COORDINATION...

No webinar is scheduled.

04

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
1142 PM CDT WED JUL 28 2021

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

1135 PM     TSTM WND GST     4 SSE NEW LISBON        43.83N 90.13W
07/28/2021  M45 MPH          JUNEAU             WI   AWOS

            AWOS STATION K82C MAUSTON AIRPORT.

&&

JAR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
1143 PM CDT WED JUL 28 2021

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

1115 PM     TSTM WND GST     4 ENE SPARTA            43.97N 90.73W
07/28/2021  M45 MPH          MONROE             WI   AWOS

            AWOS STATION KCMY SPARTA/FORT MCCOY AIRPORT.

&&

JAR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
1144 PM CDT WED JUL 28 2021

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

1124 PM     TSTM WND GST     CAMP DOUGLAS            43.92N 90.27W
07/28/2021  M45 MPH          JUNEAU             WI   AWOS

            AWOS STATION KVOK VOLK FIELD.

&&

JAR

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
1212 AM CDT THU JUL 29 2021

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

1000 PM     TSTM WND DMG     NEILLSVILLE             44.56N 90.59W
07/28/2021                   CLARK              WI   CO-OP OBSERVER

            POWER LINES AND POLES DOWN IN AREA. ROUGHLY 390 RESIDENTS
            WITHOUT POWER. TIME ESTIMATED.

&&

SHEA

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE LA CROSSE WI
1226 AM CDT THU JUL 29 2021

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

1202 AM     TSTM WND GST     1 NNW ONALASKA          43.90N 91.23W
07/29/2021  M45 MPH          LA CROSSE          WI   PUBLIC

            MEASURED 45 MPH WIND GUST.

&&

JAR

Special Weather Statement
National Weather Service La Crosse WI
1226 AM CDT Thu Jul 29 2021

IAZ011-030-MNZ096-WIZ053>055-061-290700-
Clayton-Allamakee-Houston-Richland-Vernon-Crawford-Grant-
1226 AM CDT Thu Jul 29 2021

...A LINE OF STRONG THUNDERSTORMS WILL AFFECT PORTIONS OF SOUTHEAST
MINNESOTA...NORTHEAST IOWA AND SOUTHWEST WISCONSIN OVERNIGHT...

At 1224 AM CDT, radar indicated strong thunderstorms were located
along a line extending from Sauk City to near Muscoda to near Viroqua
to near Caledonia. Movement was south at 45 mph.

Winds in excess of 40 mph are possible with these storms.

Locations impacted include...
Platteville, Prairie Du Chien, Viroqua, Waukon, Lancaster, Caledonia,
Guttenberg, Elkader, Lansing, Boscobel, Fennimore, Cuba City, Monona,
Spring Grove, Muscoda, Hazel Green, Dickeyville, Cassville, McGregor
and Stoddard.

Torrential rainfall is also occurring with these storms, and is
causing localized flooding. Do not drive your vehicle through
flooded roadways.

LAT...LON 4254 9064 4264 9071 4268 9090 4265 9090
      4264 9147 4373 9165 4362 9098 4329 9044
      4329 9019 4317 9020 4321 9029 4320 9043
      4251 9043 4251 9064
TIME...MOT...LOC 0524Z 349DEG 39KT 4326 8974 4324 9043 4357 9097 4367
9155

Rieck