The NWS Storm Prediction Center has issued a
* Severe Thunderstorm Watch for portions of
central and north central Montana
* effective this Wednesday afternoon and evening from 305 PM
until 1000 PM MDT.
* Primary threats include...
several large hail events with a few very large hail events to 2
inches in diameter possible
several damaging wind gusts to 70 mph possible
a few tornadoes possible
The Severe Thunderstorm Watch area is approximately along and 90
statute miles east and west of a line from 40 miles northeast of
Cut Bank Montana to 60 miles west southwest of Lewistown Montana.
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.
Other watch information... continue... ww 327...
Discussion... convection will increase in coverage/intensity through
the afternoon as surface heating continues along and E of a stalled
front... and in advance of a midlevel trough rotating nnewd from ID.
Steep lapse rates/moderate instability and moderately strong
vertical wind shear will support supercells the next few hours... and
eventual growth into clusters/line segments later this evening.
Large hail and damaging winds will be the main threats... though a
tornado or two cannot be ruled out if a supercell is able to remain
discrete and move along the stalled front.
Aviation... a few severe thunderstorms with hail surface and aloft
to 2 inches. Extreme turbulence and surface wind gusts to 60
knots. A few cumulonimbi with maximum tops to 500. Mean storm
motion vector 19030.
... Thompson
