

842 

WWUS20 KWNS 212208

SEL1

SPC WW 212208

MTZ000-NDZ000-SDZ000-WYZ000-220500-



URGENT - IMMEDIATE BROADCAST REQUESTED

Severe Thunderstorm Watch Number 301

NWS Storm Prediction Center Norman OK

410 PM MDT Sat Jul 21 2018



The NWS Storm Prediction Center has issued a



* Severe Thunderstorm Watch for portions of

  Far Eastern Montana

  Western North Dakota

  Western South Dakota

  Northeast Wyoming



* Effective this Saturday afternoon and evening from 410 PM until

  1100 PM MDT.



* Primary threats include...

  Scattered large hail likely with isolated very large hail events

    to 2.5 inches in diameter possible

  Isolated damaging wind gusts to 70 mph possible

  A tornado or two possible



SUMMARY...Storms will continue to develop and intensify in several

different areas across the region, including a well-organized

cluster of storms already ongoing across northeast Montana into

northwest North Dakota. Large hail and damaging winds will be the

primary concerns as storms, including a few supercells, spread

east/southeastward across a relatively narrow axis of moderately

unstable air through this evening.



The severe thunderstorm watch area is approximately along and 55

statute miles east and west of a line from 25 miles north northeast

of Sidney MT to 55 miles southwest of Rapid City SD. 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 300...



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 550. Mean storm motion vector

29025.



...Guyer

