969 FXUS65 KMSO 060905 AFDMSOArea Forecast Discussion National Weather Service Missoula MT 305 AM MDT Mon Oct 6 2025
.DISCUSSION...
KEY MESSAGES:
- Widespread frost/freeze this morning and again on Tuesday morning
- Dry with seasonable temperatures through midweek
Flow aloft will become northwesterly this afternoon on the heels of a departing trough. A ridge of high pressure will build over the Northern Rockies early this week. Before the ridge becomes established, cold air leftover from the departing trough and clear skies will result in cold overnight low temperatures this morning and again on Tuesday morning. Expect low temperatures to be about 5 to 10 degrees below normal. The valleys of western Montana and the higher valleys of north-central Idaho will see lows into the 20s. Typically colder locales such as Seeley Lake, Polebridge, Philipsburg, and the upper Clark Fork and Blackfoot River valleys could easily see teens for lows. The lower valleys of Idaho and Clearwater counties will not be quite as cold, but do still expect frost in the mornings. Daytime high temperatures will rebound nicely, gradually increasing throughout the week to about 10 degrees above normal by the end of the week.
Speaking of the end of the week, most ensemble model members are indicating unsettled weather arriving later in the week through the weekend, though timing and intensity are still rather uncertain.
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.AVIATION... Dew point depressions of only a few degrees early this morning, along with calm winds, are pointing to fog formation this morning at all Northern Rockies terminals. Decreased visibility lasting until about 06/1500Z will be possible. Otherwise, expect light winds and mostly clear skies this afternoon and tonight as high pressure builds through midweek.
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.MSO WATCHES/WARNINGS/ADVISORIES... MT...Freeze Warning until 10 AM MDT this morning for Flathead/Mission Valleys...Missoula/Bitterroot Valleys.
ID...Frost Advisory until 9 AM PDT this morning for Orofino/Grangeville Region.
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NWS MSO Office Area Forecast Discussion