textproduct: Great Falls

KEY MESSAGES

- Scattered showers and a few thunderstorms develop later this evening, persisting into Saturday.

- Warm and largely dry beginning Sunday, lasting through much of next week.

- Occasionally breezy next week as upper level ridging is briefly broken down at times.

UPDATE

/Issued 836 PM MDT Fri May 8 2026/

The main adjustment to the update this evening was adding in showers a little bit sooner across North-Central MT. Showers have started to develop this evening. These showers will continue overnight and into Saturday. With weak instability in the area, I can't rule out a few isolated lightning strikes. -Wilson

DISCUSSION

/Issued 836 PM MDT Fri May 8 2026/

- Meteorological Overview:

A quick moving wave cutting through the upper level ridge across the Pacific NW and Northern Rockies will result in increased coverage of showers and thunderstorms the remainder of the afternoon and evening, mainly across Central and North-central Montana. Showers continue through the night and into Saturday before slowly subsiding later in the day.

A drier and warmer stretch then develops Sunday as upper level ridging builds in once again. This largely continues through much of next week, though there will be several attempts to break down the ridge. The first looks to be on Monday as a wave progresses eastward near the Canadian border beginning late Sunday night. Breezy winds will be favored near the Canadian border as this wave passes by Monday. A few showers near the Canadian border cannot be completely ruled out Monday as this wave moves through.

Confidence in when the next attempt to break down the ridge will occur toward the middle of next week is much lower at this time. A more southwesterly flow aloft does look to be in place when the next wave moves through, which would favor a more active thunderstorm day. -AM

- Forecast Confidence & Scenarios:

Winds associated with ridge breakdown late Sunday night and Monday:

The initial wave of stronger winds aloft passes over the Rocky Mountain Front late Sunday night. The lack of any ridgetop stability gives confidence that stronger winds will not be realized at the surface in any widespread fashion in this area. As daytime mixing ensues Monday the stronger winds aloft are already beginning to exit eastward. That said, there does look to be at least a brief stretch in Blaine county and vicinity toward the afternoon where gustier winds will develop. The probability for a 50 mph gust in and around Blaine county Monday is roughly 30%. -AM

AVIATION

09/06Z TAF Period

Coverage in showers from a line from Cut Bank to Lewistown will increase from scattered to widespread overnight. Showers transition to stratiform rain early in the morning. Low VFR to MVFR conditions are possible with precipitation through the morning. Coverage in rain decreases in the morning, but isolated showers can linger throughout the day today. Across the southwest, clouds will clear throughout the early morning. -Wilson

PRELIMINARY POINT TEMPS/POPS

GTF 48 66 43 82 / 80 40 10 0 CTB 46 65 41 78 / 60 40 10 0 HLN 44 69 41 81 / 30 10 0 0 BZN 40 66 36 79 / 30 10 0 0 WYS 33 61 30 72 / 10 10 0 0 DLN 39 66 37 80 / 10 0 0 0 HVR 45 69 40 82 / 30 30 10 0 LWT 43 59 39 77 / 90 80 20 0

TFX WATCHES/WARNINGS/ADVISORIES

None.