textproduct: Missoula

DISCUSSION

Key Messages:

* Critical Fire Weather Conditions across Northern Rockies, Saturday afternoon through Saturday night.

* Choppy wave activity on area lakes for Saturday afternoon and evening.

* Relatively cool airmass in place Sunday through early next week, but summer warmth returns thereafter.

The warm ridge of high pressure currently over the Northern Rockies will provide a few more days of hot afternoon temperatures. Anticipate most low elevations warming into the 90s and 100s (F). Despite these temperatures being in line with recent trends, remember to take take frequent breaks, drink plenty of water, seek shade, and never leaving any person or pet in a parked vehicle. There is a 70 percent probability of showers and thunderstorms developing across Lemhi County Idaho and portions of southwest Montana this evening.

The ridge of high pressure is anticipated to break down Saturday through Sunday, resulting in gusty winds and low relative humidity across the Northern Rockies. Red Flag conditions will develop at many locations. Those recreating on area lakes, particularly Flathead Lake, will experience choppy wave activity Saturday afternoon through late evening. A cold front is expected to sweep across the Northern Rockies Saturday evening.

A relatively cool airmass is projected to rush over the Northern Rockies Saturday night through Sunday. Gusty winds will return during daytime Sunday and once again increase wave activity on area lakes. However, the cooler daytime temperatures should keep afternoon humidity a bit higher compared to Saturday.

Prepare for very efficient radiational cooling across the Northern Rockies overnight Sunday. High mountain valleys will cool to the 30s in many locations by Monday morning.

Long range ensembles generally agree that a warm high pressure ridge will return to the Northern Rockies around the middle of next week. Models also tend to agree that the next iteration of our summertime ridge will be several degrees cooler than the current ridge.

AVIATION

High density altitude will continue due to heat through Saturday. Smoke from area wildfires and increasing west winds aloft will be the main aviation weather impacts over the Northern Rockies for the next 24 hours. Also, there is a 70 percent probability that showers and thunderstorms will develop 31/2100Z through 01/0400Z roughly between KSMN and KBTM. Anticipate erratic wind gusts to 40 knots near any thunderstorm that develops. Terrain will be occasionally obscured during this time as well. A surface cold front will increase wind gusts to 30 knots beginning around 01/2000Z.

MSO WATCHES/WARNINGS/ADVISORIES

MT...Red Flag Warning from 2 PM Saturday to 9 PM MDT Sunday for Deerlodge/West Beaverhead...East Beaverhead.

Red Flag Warning from 2 PM Saturday to midnight MDT Saturday night for Bitterroot...East Lolo...Flathead Reservation... Flathead/Glacier Park...Kootenai...West Lolo.

ID...Red Flag Warning from 11 AM to 8 PM PDT Saturday for Palouse/Hells Canyon.

Fire Weather Watch from Saturday morning through Saturday evening for Palouse/Hells Canyon.