textproduct: Missoula

DISCUSSION

KEY MESSAGES:

- A cold front arriving this morning will bring cooler temperatures and gusty northeast winds of 20 to 30 mph across western Montana.

- High pressure builds by midweek, bringing a dry warming trend with valley temperatures returning to the 70s and 80s.

The Northern Rockies are sitting under northerly flow aloft as high pressure amplifies to the west and a broad trough of low pressure sites to the east. The low to the east will send a backdoor cold front over the Continental Divide early this morning. The front will bring cooler temperatures and strong northeast winds. Expect windy conditions across western Montana throughout Monday, with northeast wind gusts reaching 20 to 30 mph at times. Wind direction becomes more northerly on Tuesday as the upper level jet becomes oriented almost straight out of the north and a tight pressure gradient sets up over the Northern Rockies between the high to the west and the low to the east. Strong winds will eventually spill into the valleys of north-central Idaho on Tuesday afternoon.

That gradient will relax on Wednesday as the ridge of high pressure expands eastward and encompasses the Northern Rockies. Daytime high temperatures will bounce back up to about 10 degrees above normal. Along with the increase in temperatures, a weak shortwave will bring chances for precipitation on Wednesday into Thursday morning. By Thursday and Friday, most valley locations will see afternoon high temperatures climbing back into the 70s, with the lower valleys of north-central Idaho reaching the low 80s.

AVIATION

A backdoor cold front will bring increasing northeast winds to KGPI early this morning. Expect gusts of 20-30 knots lasting until about 04/1200Z this morning, then picking up again later this afternoon, around 04/2200Z. All other terminals will also see increasing easterly winds (northerly at KHRF) this afternoon and evening to about 20 knots. Aviators flying over the Continental Divide in northwest Montana today will experience chances for precipitation resulting in obscured terrain along with gusty north or northeasterly winds. Gusty winds continue through Tuesday, though wind direction become more northerly.

MSO WATCHES/WARNINGS/ADVISORIES

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