SPC Severe Thunderstorm Watch 418

WW 418 SEVERE TSTM MT WY 152015Z – 160500Z

URGENT - IMMEDIATE BROADCAST REQUESTED
Severe Thunderstorm Watch Number 418
NWS Storm Prediction Center Norman OK
215 PM MDT Sun Jun 15 2025

The NWS Storm Prediction Center has issued a

* Severe Thunderstorm Watch for portions of 
  Central and eastern Montana
  North central Wyoming

* Effective this Sunday afternoon and evening from 215 PM until
  1100 PM MDT.

* Primary threats include...
  Scattered damaging winds and isolated significant gusts to 80
    mph likely
  Scattered large hail and isolated very large hail events to 3
    inches in diameter likely
  A tornado or two possible

SUMMARY...Thunderstorms are expected to increase in coverage and
intensity through the afternoon while spreading eastward from the
higher terrain.  The storm environment initially favors supercells
with very large hail (2-3 inch diameter), while upscale growth into
clusters is expected this evening with an increasing threat for
60-80 mph outflow winds.  Favorable storm interactions could also
support an isolated tornado or two this evening.

The severe thunderstorm watch area is approximately along and 100
statute miles north and south of a line from 30 miles west of
Harlowton MT to 10 miles east northeast of Baker MT. For a complete
depiction of the watch see the associated watch outline update
(WOUS64 KWNS WOU8).

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
3 inches. Extreme turbulence and surface wind gusts to 70 knots. A
few cumulonimbi with maximum tops to 550. Mean storm motion vector
27020.

...Thompson

Read more