textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Showers and possible thunderstorms tonight into Thursday for northwest Montana

- Warming for the remainder of the work week

- A weak disturbance on Saturday causing slightly cooler temperatures and potential of light showers near Glacier NP

High pressure to our west will maintain a generally settled weather pattern for most of today. However, a weather disturbance moving in from Canada will bring increased cloud cover and a higher chance of precipitation this evening and overnight. Showers and thunderstorms are expected to develop around 5pm near the Idaho Panhandle border, potentially reaching as far south as Missoula. By 9:00 PM, this activity will shift primarily toward northwest Montana, with the greatest chances focused near the Canadian border. A few of these evening storms could become strong, carrying the potential for gusty winds, lightning, and small hail.

As the high pressure system moves closer to the Northern Rockies on Thursday, showers will linger along the Continental Divide, including the Glacier National Park area, while the rest of the region will experience clearing skies. Another weak weather system will arrive late Friday night into Saturday morning. While forecast confidence is high for widespread cloud cover with this passing system, a very dry air mass in place will significantly limit the chance for measurable rainfall. Regardless of whether precipitation reaches the ground, Saturday will feature cooler, near-normal daytime high temperatures.

By Sunday, confidence is exceptionally high that strong high pressure will build directly over the region. This will usher in a period of completely dry conditions and a noticeable warming trend across Western Montana and North Central Idaho. Expect this warm and quiet weather pattern to persist through early next week.

AVIATION

VFR conditions will generally prevail across the airspace through the afternoon under the influence of high pressure to the west. However, aviation impacts are expected to increase after 06/2300Z as a Canadian disturbance initiates scattered showers and thunderstorms along the Idaho border, potentially impacting the KMSO terminal area. By 07/0300Z, the convective focus will shift northward into northwest Montana, bringing the highest probabilities for TSRA to the KGPI vicinity near the Canadian border. The primary aviation hazards associated with the stronger thunderstorm cores this evening will include erratic gusty outflow winds to 30 kts, lightning, small hail, and temporary MVFR conditions due to reduced visibility and lowering ceilings in heavier precipitation.

MSO WATCHES/WARNINGS/ADVISORIES

MT...None. ID...None.