Tornado Watch 320

Issued

Jun 12, 2017, 5:35 PM MDT (23:35 UTC)

Expired

Jun 13, 2017, 2:00 AM MDT

In force

8 hr

Issued by

the Storm Prediction Center

Largest hail expected

4 in

Strongest gust expected

70 kt

The Rapid City radar (KUDX), 63 km from the middle of the area, began a volume at 23:38 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

50%

One or more EF2 to EF5 tornadoes

20%

Ten or more severe wind reports

50%

One or more gusts of 65 knots or more

30%

Ten or more severe hail reports

40%

One or more hailstones of 2 inches or more

30%

Six or more combined severe hail and wind reports

95%

• Mesoscale Discussion 1001Jun 12, 5:05 PM MDT
• Mesoscale Discussion 1004Jun 12, 8:02 PM MDT
• Mesoscale Discussion 1006Jun 12, 10:14 PM MDT

263 
WWUS20 KWNS 122333
SEL0  
SPC WW 122333
NEZ000-SDZ000-WYZ000-130800-

URGENT - IMMEDIATE BROADCAST REQUESTED
Tornado Watch Number 320
NWS Storm Prediction Center Norman OK
535 PM MDT Mon Jun 12 2017

The NWS Storm Prediction Center has issued a

* Tornado Watch for portions of 
  Northwestern Nebraska
  Western and southern South Dakota
  Northeastern Wyoming

* Effective this Monday afternoon and Tuesday morning from 535 PM
  until 200 AM MDT.

* Primary threats include...
  A few tornadoes possible
  Scattered damaging winds and isolated significant gusts to 80
    mph possible
  Scattered large hail and isolated very large hail events to 4
    inches in diameter possible

SUMMARY...Supercells should move into the watch area from the
southwest, offering a threat for tornadoes and large to giant hail. 
Activity should evolve into one or two complexes of storms with an
increasing risk of severe wind later this evening into tonight,
across the Badlands/Black Hills region and points northeast from
there.

The tornado watch area is approximately along and 100 statute miles
east and west of a line from 90 miles northwest of Rapid City SD to
55 miles southwest of Valentine NE. For a complete depiction of the
watch see the associated watch outline update (WOUS64 KWNS WOU0).

PRECAUTIONARY/PREPAREDNESS ACTIONS...

REMEMBER...A Tornado Watch means conditions are favorable for
tornadoes and 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.

&&

OTHER WATCH INFORMATION...CONTINUE...WW 316...WW 317...WW
318...WW 319...

AVIATION...Tornadoes and a few severe thunderstorms with hail
surface and aloft to 4 inches. Extreme turbulence and surface wind
gusts to 70 knots. A few cumulonimbi with maximum tops to 550. Mean
storm motion vector 22035.

...Edwards

Tornado Watches in South Dakota, 2017Tornado Watches in Nebraska, 2017Tornado Watches in Wyoming, 2017Every tornado 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.