Area Forecast Discussion
Issued by NWS Missoula, MT

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FXUS65 KMSO 262030

Area Forecast Discussion
National Weather Service Missoula MT
230 PM MDT Wed Jul 26 2017

.DISCUSSION...Almost another repeat of yesterday`s hot and dry
conditions except for the increased chance for thunderstorm
activity over southern Idaho County, southern Ravalli County,
Lemhi County to Silver Bow Counties this afternoon and evening. A
line of continuous showers with a few embedded waves extends from
northeastern Oregon east and south towards Lemhi County. This line
is expected to generally shift northward with time. The
thunderstorms will be wetter from Lemhi County north and east,
meaning that very heavy rainfall rates of up to 0.50 per hour
will be possible under the direct storm cores. Will have to
monitor storms as they could possibly affect a few of the flood
prone areas including Highway 93 south of Salmon to Ellis and 4th
of July Creek to Tower Creek. Stay tuned to any further products
that we may issue later on if confidence grows for any potential
flash flooding potential. Also another threat will be gusty winds.
At this point wind gusts to 40 mph are generally possible, but
couldn`t rule out an isolated downburst to 50 mph. Smoke has
increased across west-central Montana over the last three days and
this trend is expected to continue.

Remnants of shower activity could continue to move northward
towards west-central Montana tonight. With this possibility have
introduced dry thunderstorms into the forecast for locations
including over Mineral County, Missoula and Mission Valleys
through Thursday morning. Weather models aren`t necessarily
producing much storm activity, but pattern recognition and
moderately strong upper level forcing would suggest isolated
activity. Main threats would be lightning and possibly a few wind
gusts to 25 mph.


.AVIATION...Smoke has accumulated to the point that it is starting
to reduce visibility at the KMSO airport. Expect this to continue
overnight. Could see visibility forecast lower by a few miles
between 27/1200z and 27/1700z. Showers and thunderstorms are
expected for KSMN and KBTM today between 26/1900z and 27/0400z.
Main threats will be gusty winds to 35 knots, heavy rainfall
potentially with up to 0.50 per hour rates under the cores,
lightning and small hail. Night-time showers with a few weak
thunderstorms are possible over north-central Idaho north and east
into west-central Montana between 27/0500z and 27/1200z but
confidence is low. More thunderstorm activity is expected on
Thursday from central Idaho into southwestern Montana including



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