WEATHER DISCUSSION: Hazy skies and areas of smoke picked up for the region Sunday as high temperatures slightly warmed, seen in the low to upper-80s. Skies were mostly sunny and partly cloudy, widespread haze being the biggest concern for the forecast that will continue through the overnight hours and through the start of the upcoming work week as well.
Southwesterly flow ahead of an approaching trough off the Pacific Northwest coast is weakening ridge that has been in place across the west. Initial impacts have been widespread smoke pushing East and Northeast across Central and North Central Montana. The bulk of the most dense smoke near the surface looks to move east of the region by Monday morning, though pockets of smoke will remain tonight and tomorrow.
Another impact of the switch to a southwesterly flow is the increasing coverage of showers and thunderstorms through the week. The main concern to will be for the showers and thunderstorms that develop across Southwest Montana. Further north, coverage of thunderstorms looks to be less, partly due to the smoke.
A slight cool down of temperatures is on the way Monday with highs expected in the mid to upper-70s and low to mid-80s. Skies will be mostly sunny to partly cloudy with winds around 5 to 10 mph and gusts around 20-30 mph. Winds look to lighten towards the evening and overnight hours.
Brief shortwave ridging Monday afternoon will limit coverage of showers and thunderstorms, even with the trough still approaching the Pacific Northwest coastline. This troughing moves even closer Tuesday and stalls out across the interior Pacific Northwest through Thursday. This period will allow showers and thunderstorms to develop each afternoon Tuesday through Thursday. Current guidance favors Wednesday and Thursday as the days with the best opportunity for a more organized thunderstorm threat.
Heading toward Friday and the weekend the upper troughing shifts toward the Northern Rockies, meaning a possibility for more precipitation as temperatures cool.
