A severe line of storms is crossing through Gallatin County this afternoon and evening with large hail a possibility. Details HERE:

Effective this Sunday afternoon and evening from 455 PM until
1100 PM MDT.

Hail to 2 inches in diameter... thunderstorm wind gusts to 70
mph... and dangerous lightning are possible in these areas.

The Severe Thunderstorm Watch area is approximately along and 100
statute miles east and west of a line from 55 miles south of
Bozeman Montana to 40 miles northwest of Havre Montana. For a
complete depiction of the watch see the associated watch outline
update (wous64 kwns wou1).

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.

Discussion... svr threat increasing over ww area through remainder
afternoon... as activity moves newd out of persistent E-central
ID/swrn Mt convective genesis region... and additional tstms develop
along and E of ewd-moving boundary over W-central Mt. With at least
mrglly favorable moisture/buoyancy and plenty of deep-layer shear
for supercells... small bows and svr multicells all are possible with
large hail and damaging gusts.