040
FXUS65 KMSO 010749
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
149 AM MDT Fri Aug 1 2025

.DISCUSSION...


KEY MESSAGES:

-  The KMSX Radar (Missoula, MT local weather radar) will remain
offline due to scheduled maintenance through the first week of
August.

- Widespread shower and thunderstorm activity continues Friday
  into Saturday

- Short break from unsettled weather on Sunday, more rain on
  Monday


A persistent closed low pressure circulation continues to spin
off the coast of British Columbia while high pressure builds east
of the Continental Divide today. This high/low configuration will
keep the Northern Rockies under southwest flow aloft which will
keep the Pacific moisture coming, so the theme of anomalously
high precipitable water that we`ve seen over the last several days
will again hold true this afternoon. Furthermore, an embedded
shortwave disturbance will fuel widespread showers and
thunderstorms throughout the Northern Rockies (with the exception
of Lemhi County) this afternoon. Model soundings indicate deep
instability. With the upper level jet nowhere to be seen, steering
winds will be weak and thunderstorms that do develop will be slow
movers and heavy rainers. Frequent lightning, small hail, and
gusty winds of 30 to 40 mph will accompany the rain.

The trough will continue to bring chances for rain on Saturday,
when the focus for precipitation and convection moves to northwest
Montana. Lincoln, Flathead, and Lake counties will be favored. All
told, 48 hour precipitation totals ending Saturday night will be
about 0.20 inches on the low end to a little over an inch for
mountain locations in those counties.

A transient ridge will build over the Northern Rockies, bringing a
short break from unsettled weather, although some isolated
thunderstorm chances will remain along the Continental Divide and
for Idaho and Lemhi counties. While high pressure builds over the
Northern Rockies, a trough of low pressure will move onshore along
the Pacific Northwest. Ensemble solutions are in good agreement
for this trough to reach the Northern Rockies and bring more rain
for Monday afternoon. Although not all solutions are on board yet,
most are pointing towards a period of mostly dry westerly flow
aloft with some shortwaves moving along the northern border for
the latter half of the week.


&&

.AVIATION... A short wave trough will move through the Northern
Rockies airspace this afternoon, bringing widespread showers and
thunderstorms to the region this afternoon. Expect thunderstorm
activity to start around 01/2100Z. Storms will be capable of heavy
rain causing decreased visibility to about 4SM, frequent
lightning, and gusty winds to about 30-40 kts. Shower activity
will move north of about Interstate 90 after sunset and continue
into Saturday.


&&

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

$$