Area Forecast Discussion

DISCUSSION

KEY MESSAGES:

- Hot, dry, and smoky conditions continue through this week.

- Isolated thunderstorms remain a threat for southwest Montana including Butte.

- No end in sight for the smoke.

- Even hotter, drier, and windy conditions to end the week.

- Cool down to near average temperatures next weekend, though it remains dry.

Not much change from the forecast yesterday. A ridge driven by the Southwest Monsoon remains in place over the region through this week. Central Idaho and western Montana will remain 5-10 degrees above average for this time of year through Saturday. Waves of monsoon moisture will move through the ridge causing some thunderstorms, but that will mainly be in southwest Montana. Butte will be on the northwestern edge of this area of thunderstorms with the best chance for thunderstorms Wednesday evening.

The smoke in the region depends on how much is produced in Oregon each day. While the dry weather isn't helping wildland fire fighters at all, at least there isn't any lightning forecast to start new fires in that region. As fire suppression efforts continue in Oregon, the fires should slowly produce less smoke, but that's impossible for us to predict. Smoke conditions will vary from day to day, but over the next week we see no reason for a general improvement in conditions.

The ridge strengthens again late this week, causing temperatures of 10-15 degrees above average for Friday and Saturday. As this is happening, a trough from the Gulf of Alaska will move into western Canada and start to push against the ridge. This is a classic break-down-of-the ridge pattern and usually involves a dry cold front. Current forecasts have trended slower with the cold front, so the main impacts will be increased southwest winds on Friday and Saturday.

After Saturday, the majority of ensembles are showing a robust cool down with temperatures Sunday and Monday within a few degrees of average for this time of year. Unfortunately, this front isn't bringing any moisture with it, so it will be only a minor slow down of the bad fire weather conditions we're seeing this week.

AVIATION

A ridge over the region is dominating the region with both good and bad impacts. The good impacts are no thunderstorm impacts at area terminals expected for a few days. The bad impact is that it keeps pushing smoke from the many wildland fires in Oregon into our region. So far, terminals KMSO, KGPI, and KHRF have been the most impacted, and we expect that to continue for the next few days. Visibility at area terminals will only temporarily and very rarely drop below 5 miles with smoke.

MSO WATCHES / WARNINGS / ADVISORIES

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