textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Lingering mountain snow and slick roads along the Divide will persist this morning before tapering off by the afternoon.

- A strong ridge of high pressure builds in this weekend, bringing sunny skies and warm temperatures by Sunday.

- The next chance for showers and cooler temperatures arrives by the middle of next week.

Lingering wrap-around moisture will continue to wring out snow showers over the higher terrain, and along the Continental Divide, through mid-morning. If you are traveling over mountain passes along the Divide for the morning commute, expect periods of slick conditions to persist.

By this afternoon, precipitation will rapidly taper off as drier air moves into western Montana and north-central Idaho. High pressure begins to build overhead on Saturday, kicking off a beautiful weekend with clearing skies, light winds, and a noticeable warming trend.

The ridge of high pressure will be firmly entrenched over the interior Northwest on Sunday and Monday. Afternoon high temperatures will soar 10 to 15 degrees above seasonal averages, with many valley locations comfortably reaching into the 60s.

As we head into Tuesday, the ridge axis will begin to shift east ahead of our next Pacific weather maker. A broad trough in the jet stream is forecast to move onshore and approach our area by Wednesday. This will usher in a return to breezy winds, cooler temperatures, and scattered rain showers that will likely persist through Thursday. There is considerable uncertainty concerning the evolution of the next upper-level trough. While national guidance and medium-range models agree on a return to a cooler and more unsettled pattern, there are notable differences regarding the depth of the trough. If the trough digs deeper into the Great Basin, we could see a more prolonged period of widespread valley rain and accumulating mountain snow mid-week. If the system remains flatter and faster, the region will experience a quicker burst of wind and showers with lower precipitation totals.

AVIATION

Widespread MVFR/IFR conditions will linger through 03/1500Z this morning, primarily along the Continental Divide and over the, as exiting wrap-around moisture produces mountain obscurations, low ceilings, and snow showers. Conditions will improve from west to east after 03/1800Z as the low-pressure system departs and drier air filters into the region. Expect a return to widespread VFR conditions at all terminals by this afternoon, with clearing skies and light winds carrying into Saturday.

MSO WATCHES/WARNINGS/ADVISORIES

MT...Winter Weather Advisory until 6 AM MDT early this morning for Bitterroot/Sapphire Mountains...Butte/Blackfoot Region.

Winter Weather Advisory until noon MDT today for Potomac/Seeley Lake Region...West Glacier Region.

ID...Winter Weather Advisory until 5 AM PDT early this morning for Southern Clearwater Mountains.