Severe Thunderstorm Watch 440

Issued

Aug 14, 2021, 3:28 PM MDT (21:28 UTC)

Expired

Aug 14, 2021, 10:55 PM MDT

In force

7 hr

Issued by

the Storm Prediction Center

Largest hail expected

2.5 in

Strongest gust expected

60 kt

The North Platte radar (KLNX), 126 km from the middle of the area, began a volume at 21:30 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

5%

One or more EF2 to EF5 tornadoes

2%

Ten or more severe wind reports

40%

One or more gusts of 65 knots or more

20%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

40%

Six or more combined severe hail and wind reports

80%

• Mesoscale Discussion 1525 Severe potential...watch possibleAug 14, 12:50 PM MDT
• Mesoscale Discussion 1527 Severe thunderstorm watch 440Aug 14, 6:37 PM MDT

832 
WWUS20 KWNS 142126
SEL0  
SPC WW 142126
COZ000-KSZ000-NEZ000-SDZ000-150500-

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 440
NWS Storm Prediction Center Norman OK
325 PM MDT Sat Aug 14 2021

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  northeastern Colorado
  northwestern Kansas
  western Nebraska including the Panhandle
  southwestern South Dakota

* Effective this Saturday afternoon and evening from 325 PM until
  1100 PM MDT.

* Primary threats include...
  Scattered large hail and isolated very large hail events to 2.5
    inches in diameter possible
  Scattered damaging wind gusts to 70 mph possible

SUMMARY...Thunderstorms are currently increasing in coverage near
the Black Hills of southwestern South Dakota, and should continue to
expand/spread south-southeastward with time over the next several
hours.  Very large hail will likely remain the primary severe risk
initially, with damaging winds an increasing likelihood with time,
as storms grow upscale linearly into the evening.

The severe thunderstorm watch area is approximately along and 65
statute miles east and west of a line from 35 miles northeast of
Rapid City SD to 60 miles south of Imperial 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.

&&

AVIATION...A few severe thunderstorms with hail surface and aloft to
2.5 inches. Extreme turbulence and surface wind gusts to 60 knots. A
few cumulonimbi with maximum tops to 500. Mean storm motion vector
33025.

...Goss

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