Special Weather Statement, NWS Missoula, MT

Area Forecast Discussion
National Weather Service Missoula MT
310 PM MDT Tue Aug 8 2017

.DISCUSSION...A north and east flow has pushed through much of
western Montana this afternoon producing gusty winds. This flow
has pulled more smoke south out of Canada, further degrading air
quality, especially for northwest Montana. Smoke will likely
linger over the Northern Rockies for periods through the week.

Another shortwave of energy will be sliding south into western
Montana, and will help kick off scattered showers and
thunderstorms after 4PM this evening. The locations that have the
best chance to see this convection, will be areas in western
Montana, east of highway 93, and north of the I-90 corridor. Areas
along the ID/MT border will have a chance, but will be much more
isolated. Lemhi County in Idaho will also see showers and
thunderstorms. Gusty outflow winds up to 40 mph and lightning will
be the biggest impacts.

Showers and thunderstorms will diminish after midnight, but will
have a chance to return for much of the same areas mentioned above
tomorrow (Wednesday) afternoon. However, the coverage will be
less, compared to today.

Later this week, Thursday and Friday, the ridge that has been
focused over the West Coast will slide east and become centered
over the Northern Rockies. These large-scale stable conditions
will likely cause valley smoke issues to continue, if not get
worse by the end of the week. Some moisture from a remnant low
pressure system moves into the area under the ridge, allowing
chances for scattered afternoon thunderstorms both of these days.

Saturday afternoon has potential to be a warm and dry day, ahead
of a bigger pattern change. Models have continued to struggle with
how to handle a trough that develops off the West Coast, with some
models showing a cool, wet system slowly moving toward the
Northern Rockies early next week, while other models show a
weaker, drier system that stays mostly in Canada. Confidence is
low in either exact scenario at this time, but at least a brief
pattern change seems more likely by early next week.

&&

.AVIATION...Isolated thunderstorms with brief gusts to 35 kts are
possible at valley airports this afternoon, but these will not be
widespread. Apart from the local wind gusts, isolated lightning
and heavy rain are also possible. Smoke will continue to limit
visibilities for all areas today. Overnight into Wednesday
morning, breezy north and east winds are likely as another system
moves along the Divide.

&&

.MSO WATCHES/WARNINGS/ADVISORIES...
MT...None.
ID...None.
&&

Special Weather Statement
National Weather Service Missoula MT
421 PM PDT TUE AUG 8 2017

IDZ005-082345-
Northern Clearwater Mountains ID-
421 PM PDT TUE AUG 8 2017

...SIGNIFICANT WEATHER ADVISORY FOR NORTH CENTRAL CLEARWATER COUNTY
UNTIL 445 PM PDT...

At 420 PM PDT, Doppler radar was tracking a strong thunderstorm 14
miles northeast of Elk River moving southeast at 15 mph.

Winds to 40 mph will be possible with this storm.

This storm will remain over mainly rural areas of north central
Clearwater County but could impact boaters on Dworshak Reservoir.

LAT...LON 4687 11606 4694 11584 4679 11559 4670 11594
TIME...MOT...LOC 2320Z 320DEG 13KT 4687 11590