Special Weather Statement, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
200 PM MDT Thu Aug 6 2020

.DISCUSSION...An upper level trough is driving a surface cold
front across the northern Rockies. Between this afternoon and
tonight, much of the area will see scattered thunderstorms as a
result. Southwest Montana, including Butte are the most likely to
be affected by thunderstorms this evening, though there will be
some storms in northwest Montana too.

Friday will start out breezy as the region will be on the cool
side of the front. Temperatures will also be 10 to 15 degrees
cooler than today.

The rest of the weekend will be very nice as well, with no rain
expected and temperatures will warm into the upper 70s to mid 80s
across most of the region.

Next week the region will remain on the fringes of a ridge of high
pressure from the southwest US and more active weather is expected to
the north. Several troughs will move through and keep the ridge
pushed down while it remains strong enough to drive the troughs
and the jet stream to north. The result will be pleasant weather
with some breezes and near average temperatures.

Models show that it all starts to break down towards the end of
the week. Thursday and Friday could see a deep trough and strong
cold front move into the region. At that lead time uncertainty
remains high, especially for timing. However, about 70 percent of
ensemble members across 3 prominent model systems show a
significant cold trough affecting the northern Rockies in mid-
August.

&&

.AVIATION...Scattered showers and thunderstorms are possible
across southwest Montana impacting mainly BTM from 06/2000z to
07/0000Z. Confidence is low, but SMN, GPI and MSO may encounter an
isolated thunderstorm through 07/0300Z. Erratic winds to 40 knots
are possible besides the usual lightning and small hail threats.
Also gusty westerly winds will impact most terminals through
07/0300Z. GPI will experience mainly a southerly breeze overnight
as a large upper level trough swings through. Expect breezy and
VFR conditions on Friday.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...ID...&&

Special Weather Statement
National Weather Service Missoula MT
439 PM MDT Thu Aug 6 2020

MTZ007-062330-
Butte/Blackfoot Region MT-
439 PM MDT Thu Aug 6 2020

...SIGNIFICANT WEATHER ADVISORY FOR NORTHEASTERN DEER LODGE...EAST
CENTRAL GRANITE AND SOUTHEASTERN POWELL COUNTIES UNTIL 530 PM MDT...

At 438 PM MDT, Doppler radar was tracking strong thunderstorms along
a line extending from 11 miles south of Drummond to 8 miles southeast
of Deer Lodge. Movement was northeast at 40 mph.

Half inch hail and winds in excess of 40 mph will be possible with
these storms.

Locations impacted include...
Deer Lodge, Garrison, Finn, Maxville, Jens, Brock Creek, Goldcreek,
Blossburg, Avon and Elliston.

LAT...LON 4642 11231 4639 11235 4639 11240 4633 11246
      4634 11247 4633 11253 4630 11257 4627 11256
      4624 11259 4648 11330 4690 11280 4683 11279
      4683 11254 4670 11253 4670 11241 4666 11240
      4666 11232 4663 11230 4657 11232 4654 11230
TIME...MOT...LOC 2238Z 226DEG 35KT 4650 11314 4632 11260