Severe Thunderstorm Watch 470

Issued

Aug 28, 2021, 3:57 PM CDT (20:57 UTC)

Expired

Aug 28, 2021, 11:00 PM CDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2 in

Strongest gust expected

70 kt

The Omaha radar (KOAX), 157 km from the middle of the area, began a volume at 21:00 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

5%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

40%

Ten or more severe hail reports

30%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

70%

• Mesoscale Discussion 1630 Severe potential...watch possibleAug 28, 2:43 PM CDT
• Mesoscale Discussion 1634 Severe thunderstorm watch 470Aug 28, 7:28 PM CDT

581 
WWUS20 KWNS 282056
SEL0  
SPC WW 282056
IAZ000-NEZ000-SDZ000-290200-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 470
NWS Storm Prediction Center Norman OK
400 PM CDT Sat Aug 28 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Northwest Iowa
  Central to northeast Nebraska
  Southeast South Dakota

* Effective this Saturday afternoon and evening from 400 PM until
  900 PM CDT.

* Primary threats include...
  Scattered damaging winds and isolated significant gusts to 80
    mph possible
  Isolated very large hail events to 2 inches in diameter possible
  A tornado or two possible

SUMMARY...Multiple clusters should develop from southeast South
Dakota into central Nebraska with a risk of mainly wind and hail.

The severe thunderstorm watch area is approximately along and 55
statute miles east and west of a line from 10 miles east northeast
of Sioux Falls SD to 50 miles west southwest of Kearney NE. For a
complete depiction of the watch see the associated watch outline
update (WOUS64 KWNS WOU0).

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 469...

AVIATION...A few severe thunderstorms with hail surface and aloft to
2 inches. Extreme turbulence and surface wind gusts to 70 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
27025.

...Grams

Severe Thunderstorm Watches in Nebraska, 2021Severe Thunderstorm Watches in South Dakota, 2021Severe Thunderstorm Watches in Iowa, 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.