Severe Thunderstorm Watch 421

Issued

Jul 19, 2017, 3:29 PM CDT (20:29 UTC)

Expired

Jul 19, 2017, 9:00 PM CDT

In force

6 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

65 kt

The La Crosse radar (KARX), 69 km from the middle of the area, began a volume at 20:32 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

2%

Ten or more severe wind reports

80%

One or more gusts of 65 knots or more

50%

Ten or more severe hail reports

60%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

90%

• Mesoscale Discussion 1347Jul 19, 12:11 PM CDT
• Mesoscale Discussion 1351Jul 19, 2:38 PM CDT
• Mesoscale Discussion 1354Jul 19, 5:11 PM CDT
• Mesoscale Discussion 1355Jul 19, 6:32 PM CDT
• Mesoscale Discussion 1357Jul 19, 8:19 PM CDT

807 
WWUS20 KWNS 192026
SEL1  
SPC WW 192026
IAZ000-MNZ000-WIZ000-200200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 421
NWS Storm Prediction Center Norman OK
330 PM CDT Wed Jul 19 2017

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Northeast Iowa
  Southeast Minnesota
  Southwest Wisconsin

* Effective this Wednesday afternoon and evening from 330 PM
  until 900 PM CDT.

* Primary threats include...
  Widespread damaging winds likely with isolated significant gusts
    to 75 mph possible
  Scattered large hail likely with isolated very large hail events
    to 2 inches in diameter possible
  A tornado or two possible

SUMMARY...A fast-moving bow echo over southern MN will track across
the watch area late this afternoon, posing a threat of damaging wind
gusts and perhaps hail.

The severe thunderstorm watch area is approximately along and 35
statute miles north and south of a line from 40 miles southwest of
Rochester MN to 125 miles east southeast of Rochester MN. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU1).

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 420...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 65 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
29040.

...Hart

Severe Thunderstorm Watches in Wisconsin, 2017Severe Thunderstorm Watches in Iowa, 2017Severe Thunderstorm Watches in Minnesota, 2017Every severe thunderstorm watch in 2017

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.