A cool start to the week will give way to a warmer and somewhat more unsettled pattern across Billings, south central and southeast Montana, and northern Wyoming. Temperatures rebound into the 80s and lower 90s by midweek, while periodic chances for showers and thunderstorms return beginning Tuesday.TUESDAYA weak disturbance lifting north from Wyoming will bring scattered showers and a few thunderstorms, first near the Montana-Wyoming border and then expanding north through the day. Severe weather is not expected, but a brief shower or rumble of thunder will be possible across much of the region. Highs will remain in the upper 70s and lower 80s.WEDNESDAYA noticeable warm-up begins as temperatures climb into the upper 80s and lower 90s. A passing front may generate breezy conditions and a few isolated showers or thunderstorms, but many locations should remain dry. Billings, Hardin, Sheridan, and Miles City could all approach 90 degrees.THURSDAYWarm late-summer weather continues with highs generally in the upper 80s to lower 90s. While an isolated afternoon thunderstorm cannot be ruled out, much of the day looks dry with a mix of sunshine and passing clouds.FRIDAYTemperatures remain above normal with many lower-elevation communities reaching around 90 degrees. A few showers or thunderstorms may develop during the afternoon and evening, but widespread precipitation is not anticipated.SATURDAYThe warm pattern holds through the weekend. Most of south central and southeast Montana, along with northern Wyoming, will see highs in the mid 80s to lower 90s. Isolated thunderstorms remain possible during the afternoon and evening hours.SUNDAYSlightly cooler temperatures arrive, but highs will still reach the 80s for most areas. A few showers and thunderstorms remain in the forecast as uncertainty increases regarding the evolution of weather systems over the western United States. ...read more read less