textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- Thunderstorms return to Lemhi County Idaho and southwest Montana this weekend.

- A warming trend continues through mid-week with generally mild weather ahead.

A surge of southwest monsoon moisture currently visible on water vapor satellite imagery in northern California and southern Oregon will work its way into our region this evening. Tomorrow that moisture will interact with a shortwave dropping out of the northwest, and cause some thunderstorms in Lemhi county, ID and southwest Montana. Some of the very sparsely populated wilderness areas in southern Idaho count may be impacted also. The amount of moisture isn't exceptional, but it will be enough to fuel some thunderstorms and cause cloud to ground lightning.

Otherwise, pleasant weather continues to be the norm with a ridge axis over the US West Coast. The weak trough that will trigger some thunderstorms in southwest Montana tomorrow will just cool temperatures a few degrees across the region through Monday. Then the ridge will strengthen again and expand eastward. That will cause a warming and drying trend across most of central Idaho and western Montana, along with lighter winds. High temperatures are expected to peak near 90 degrees in western Montana on Wednesday, which will be one of the hottest days of the year so far.

AVIATION

The ridge along the US West Coast will continue to keep mild conditions across the region through the next week. The only potential interruption we can see so far is some scattered thunderstorm potential affecting terminals KSMN and KBTM tomorrow (Saturday).