731
FXUS65 KMSO 181002
AFDMSO

Area Forecast Discussion
National Weather Service Missoula MT
402 AM MDT Fri Sep 18 2026

.DISCUSSION...

KEY MESSAGES:

- Thunderstorms today causing gusty outflows and heavy rain.

- Steady precipitation tonight into Saturday south of I-90.

- Warming and drying trend Sunday into the first part of next
  week.

Satellite and radar is showing the next round of showers and
thunderstorms moving into Lemhi county and southwest Montana this
morning. The activity is expected to increase in coverage and
intensity this afternoon. Storms this afternoon will be capable of
gusty and erratic winds along with moderate to heavy rainfall.
This evening the storms will convert to stratiform steady rain
with the main focus of the precipitation being south of the I-90
corridor.

A ridge of high pressure will be building over the region Sunday
into the first part of next week. This ridge will cause a warming
and drying trend over the Northern Rockies.


&&

.AVIATION... Showers and thunderstorms will be impacting KSMN this
morning. The activity will steadily move to the north and increase
in coverage during the afternoon. The best activity will be south
of the I-90 corridor today, so KMSO, KHRF, KSMN and KBTM have the
best potential of being impacted by these storms. Then during the
overnight hours the convection will transition to stratiform
steady precipitation.

&&

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

$$