textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Strong westerly winds this afternoon and evening with the passage of a dry cold front.

- Rain and snow showers return this weekend, especially in the mountains. Thunderstorms are possible on Saturday afternoon.

Wind advisories remain in effect across western Montana through this evening. Widespread gusts of 30 to 40 mph have already been observed. Peak wind gusts are expected between noon and 6 PM this evening, with gusts between 40 and 50 mph becoming common. The Mission and Bitterroot Valleys, along with the I-90 corridor from Deer Lodge to Butte and Montana 1 from Georgetown Lake to Anaconda, are at the highest risk for these stronger gusts. Isolated gusts over 50 mph are possible.

Winds will decrease tonight and remain calmer through the rest of the work week. Temperatures will continue to run a few degrees above normal for this time of year.

The next storm system (trough) will move inland over the West Coast by Saturday and Sunday. There is still significant uncertainty in the forecast regarding how this system will develop. On Saturday, southwesterly winds will create a favorable environment for showers and thunderstorms. There is a 15 to 25 percent probability of enough atmospheric energy for thunderstorm development between noon and 6 PM Saturday. Any storms that develop could produce lightning, gusty winds, and small hail.

Regarding mountain snow, the path of the low pressure system will determine if high-elevation areas see a light dusting or several inches of snow by Sunday or Monday. Some forecast models suggest the storm will interact with cold air pushing south from Canada, which could result in a foot or more of snow for the mountains.

AVIATION

Expect strong winds this afternoon with the most intense gusts occurring between noon and 6 PM MDT. Widespread gusts between 35 to 45 mph (30-40 knots) are expected. Winds will begin to diminish after 9 PM tonight (08/0300Z). VFR (mostly clear) flying conditions are expected on Wednesday, with westerly winds generally staying under 25 mph (20 knots).

MSO WATCHES/WARNINGS/ADVISORIES

MT...Wind Advisory until 9 PM MDT this evening for Bitterroot/Sapphire Mountains...Butte/Blackfoot Region... Flathead/Mission Valleys...Kootenai/Cabinet Region...Lower Clark Fork Region...Missoula/Bitterroot Valleys... Potomac/Seeley Lake Region...West Glacier Region.

ID...None.