A surface low developed off the Canadian Rockies and will travel eastward today with a weak cold front. This will create some showers and thunderstorms along the boundary in the afternoon from Dillon to Lewistown. An isolated thunderstorm could reach as far north as Helena. Highs will still be in the 70s and 80s, even with a cold front coming through.
Aside from stray showers on the east side of the Big Horn Mountains, Friday will be a mainly dry day again. Temperatures will reach the upper 70s to low 80s.
Saturday will be the warmest day of the year for many. An amplified upper-level ridge ahead of a slow-moving cold front ushers in much warmer air from the southwest. Highs reach the 80s and 90s for most east of the Continental Divide. However, with the added instability created by the approaching trough, afternoon thunderstorms will pop in western Montana.
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