722
FXUS65 KMSO 180829
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
229 AM MDT Thu Jul 18 2024

.DISCUSSION...Showers and thunderstorms have been moving through
central Idaho and west-central to northwest Montana overnight,
associated with a low-pressure system in eastern Washington. Radar
projections generally agree that storms will end by sunrise,
except in northwest Montana, where they may linger until around 9
AM.

For the rest of today, forecast models indicate additional high-
based smoke moving into the Northern Rockies from the west and
southwest. Increased westerly winds are expected this afternoon,
and isolated thunderstorms are forecast along the Divide.

The high-pressure ridge is expected to reamplify from Friday
through Sunday, likely keeping smoke in the forecast and impacting
weekend temperatures.

Two scenarios for this weekend`s heat are nearly equally
probable:

Scenario 1: Smoke will thin enough to allow for maximum heating
potential across central Idaho and western Montana. If this
occurs, some of the hottest daytime temperatures of the season
could be seen in many valley locations, with potential all-time
record highs in jeopardy.

Scenario 2: Smoke continues to thicken or remains thick enough to
inhibit full heating potential across the region. This would
result in temperatures being about 10 to 20 degrees cooler than
the maximum potential forecasted.

By mid-next week, the high-pressure ridge is expected to break
down, leading to more unsettled weather, including thunderstorms
and possible showers, along with lightning and gusty winds. Cooler
temperatures are also likely to follow.


&&

.AVIATION...Thunderstorms associated with a low-pressure system
passing through the region will linger in northwest Montana until
around 18/1400z, according to radar projections. These projections
also indicate isolated thunderstorms along the Divide this
afternoon, accompanied by 15-25 knot gusts due to a tightening
pressure gradient. Smoke from regional and local wildfires will
create hazy skies and localized visibility reductions.



&&

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

$$