Special Weather Statement, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
232 PM MDT Fri Jul 27 2018

.DISCUSSION...We are looking at another active afternoon and
evening across western Montana, with the development of scattered
thunderstorms. Hires forecast models indicate that the
thunderstorm coverage will become more widespread across west-
central and southwest Montana later this afternoon and early
evening. The main threat from these thunderstorms will be
frequent lightning and gusty winds. It's not out off the question
for a couple of these thunderstorm to become quite strong. The
strong storms could produce small hail and wind gusts up to 40 to
45 mph. Activity will diminish after sunset, though a few rain showers
and isolated thunderstorms could continue through the overnight
hours across the region.

We could be looking at a repeat day for Saturday with regard to
storms and temperatures. While afternoon high temperatures across
western Montana will run slightly below normal for this time of
year, north- central Idaho valleys will remain at or slightly
above normal. What thunderstorms do develop, are not expected to
be as strong as what me might see today.

A warm ridge is still expected to build over the Northern Rockies
Sunday through Tuesday and then begin to break down with a front
on Wednesday. There remains a concern that the heat over central
Idaho and portions of northwest Montana on Tuesday could be an
issue for those sensitive or planning to be outside during that
time-frame. Have a plan to be well hydrated and have an air-
conditioned location in mind to cool off.

We have introduced a chance for thunderstorms over the southern
Clearwater Mountains and Camas Prairie on Tuesday and Tuesday
night. Confidence is low at this time for the exact placement of
the shower activity as other areas could be affected. With the
ridge breaking down on Wednesday, have introduced a chance for
showers and thunderstorms across portions of central Idaho and
southwest Montana. Weather models are not showing much in the way
of precipitation amounts, but there is indication by the ensemble
guidance and GFS that there is potential in these areas. Also
there is a question of how hot portions of western Montana will
get on Wednesday. If some areas do not experience clouds or
showers or the ridge is a little slower to shift east, high
temperatures could be warmer than forecast.

By the end of the week, the flow becomes more zonal (westerly)
which will bring slightly cooler temperatures, breezy and drier
conditions.

&&

.AVIATION... Showers and thunderstorms will be the rule across
western Montana and portions of the Clearwater Mountains through
at least 28/0300Z. Expect lightning, gusty winds over 35 knots,
hail to penny size, and brief heavy rain with low visibility.
There is a chance that one of the storms could approach severe
strength and would form along I-90 east of Bearmouth to the
Continental Divide. These storms could be capable of one inch hail
and gusty winds to 50 kt. Another round of showers and
thunderstorms will be possible across western Montana on Saturday.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...Red Flag Warning until 9 PM MDT this evening East Lolo...West
     Lolo.

ID...None.
&&

Special Weather Statement
National Weather Service Missoula MT
303 PM MDT FRI JUL 27 2018

MTZ004>006-272200-
Bitterroot/Sapphire Mountains MT-Missoula/Bitterroot Valleys MT-
Lower Clark Fork Region MT-
303 PM MDT FRI JUL 27 2018

...SIGNIFICANT WEATHER ADVISORY FOR SOUTH CENTRAL MISSOULA AND
NORTHERN RAVALLI COUNTIES UNTIL 400 PM MDT...

At 303 PM MDT, Doppler radar was tracking a strong thunderstorm over
Lolo, or 9 miles southwest of Missoula, moving southeast at 15 mph.

Pea size hail and winds in excess of 30 mph will be possible with
this storm.

Locations impacted include...
South Missoula and Lolo.

This storm may intensify, so be certain to monitor local radio
stations and available television stations for additional information
and possible warnings from the National Weather Service.

LAT...LON 4663 11398 4675 11424 4686 11414 4677 11385
TIME...MOT...LOC 2103Z 302DEG 12KT 4678 11413