WEATHER DISCUSSION: Rest of today through Monday night...primary forecast concern throughout the period will be rainfall amounts over Southwest and into portions of North Central Montana. Highs today sat in the 80’s and 90’s with breezy conditions and cloud cover across the region.
A tilted longwave trough along with a closed low centered over Northern California will slowly lift northeast beginning midnight tonight. At the surface, low pressure currently developing over Southern Alberta will continue to strengthen, pulling a cold front south and across North Central early Monday morning. As of this afternoon, showers and thunderstorms are developing through the overnight hours tonight across the Northern Rockies. While most thunderstorms through this evening and the early morning hours on Monday will be generally producing gusty and erratic winds at best, some concerns of isolated strong to severe storms can’t be ruled out. Any storm that does become severe would be capable of large hail and damaging winds. The main threat from any shower or thunderstorm through the overnight hours tonight will be brief periods of heavy rainfall. The passage of the cold front, widespread cloud cover, and precipitation will help to keep high temperatures well below normal during the day on Monday, with locations only warming into the mid- 50s to upper 60s. Precipitation coverage and intensity will gradually decrease through the evening hours on Monday with only isolated mountain precipitation lingering into the morning hours on Tuesday.
Past Tuesday, daily chances for showers and thunderstorms are occuring, as well as a return to near normal seasonal temperatures back to the upper 70s and low 80s for most locations.
SUNDAY NIGHT: Showers and thunderstorms likely with some storms producing rain on the heavier side. Cloudy with lows in 50’s. 19 to 24 mph decreasing to 6 to 11 mph in the evening. Winds could gust as high as 33 mph
MONDAY (LABOR DAY): Showers and thunderstorms likely. Cloudy then mostly cloudy, with highs in 60’s and lows around 50’s. 5 to 20 mph winds.
TUESDAY: Mostly sunny then partly cloudy with highs in 70’s and lows in 50’s. 5 to 10 mph winds.
WEDNESDAY: Chance of showers. Sunny then mostly cloudy, highs in 70’s to 80’s and lows in 50’s. 6 to 15 mph winds with gusts up to 20 mph.
THURSDAY: Sunny then mostly clear with highs in 70’s and lows in 40’s.
FRIDAY: Sunny then mostly clear with highs near 80 and lows around 50’s.