Severe Thunderstorm Watch 399

Issued

Jul 28, 2021, 7:17 PM CDT (00:17 UTC)

Expired

Jul 29, 2021, 2:00 AM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Particularly dangerous situation

Yes

Largest hail expected

2 in

Strongest gust expected

80 kt

The La Crosse radar (KARX), 161 km from the middle of the area, began a volume at 00:17 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Two or more tornadoes

20%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

95%

One or more gusts of 65 knots or more

90%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

40%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 1378 Severe potential...tornado watch likelyJul 28, 5:09 PM CDT
• Mesoscale Discussion 1379 Severe thunderstorm watch 399Jul 28, 8:59 PM CDT
• Mesoscale Discussion 1380 Severe thunderstorm watch 399Jul 28, 9:51 PM CDT
• Mesoscale Discussion 1381 Severe thunderstorm watch 399Jul 28, 10:17 PM CDT
• Mesoscale Discussion 1382 Severe thunderstorm watch 399Jul 28, 11:24 PM CDT
• Mesoscale Discussion 1384 Severe thunderstorm watch 399...400Jul 29, 1:34 AM CDT

836 
WWUS20 KWNS 290015
SEL9  
SPC WW 290015
MNZ000-WIZ000-LMZ000-290700-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 399
NWS Storm Prediction Center Norman OK
715 PM CDT Wed Jul 28 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  parts of east-central Minnesota
  much of Wisconsin
  Lake Michigan

* Effective this Wednesday night and Thursday morning from 715 PM
  until 200 AM CDT.

* Primary threats include...
  Widespread damaging winds expected with isolated significant
    gusts to 90 mph likely
  Scattered large hail likely with isolated very large hail events
    to 2 inches in diameter possible
  A tornado or two possible

SUMMARY...Strong/severe thunderstorms are forecast to increase in
coverage over the next 1 to 2 hours, evolving into a large,
well-organized cluster/possible derecho while moving rapidly
southeastward.  Along with potential for a few tornadoes, widespread
damaging winds are expected -- including a few significant gusts
possibly reaching 90 MPH locally.

The severe thunderstorm watch area is approximately along and 70
statute miles either side of a line from 65 miles southwest of
Duluth MN to 40 miles northeast of Milwaukee WI. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU9).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Severe Thunderstorm Watch means conditions are
favorable for severe thunderstorms in and close to the watch area.
Persons in these areas should be on the lookout for threatening
weather conditions and listen for later statements and possible
warnings. Severe thunderstorms can and occasionally do produce
tornadoes.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 398...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 80 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
30050.

...Goss

Severe Thunderstorm Watches in Wisconsin, 2021Severe Thunderstorm Watches in Minnesota, 2021Every severe thunderstorm watch in 2021

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.