Unique Cloud, Not the Dog, Keeps Temps from Reaching Records

Posted at 5:50 PM, Apr 29, 2021
and last updated 2021-04-29 20:26:09-04

A RED FLAG WARNING has been issued for parts of northern and northeast Montana for Friday and Saturday afternoons.

Montana is home to some unique weather. A chinook arch cloud formation is one of them, forming when invisible upper level moisture is lifted over the Continental Divide. This moisture cools and condenses, forming a cloud with a well defined back edge that does not move. In this picture, you can see the back edge of the cloud. Significant amounts of upper level moisture will continue to interact with the Divide on Friday resulting in a continuation of this mountain wave cloud. The cloud will in turn block the sun and keep temperatures slightly cooler. While it will be a warm day, temperatures for those blocked by this cloud will stay well shy of record highs. There will be more sunshine farther east in the state and temperatures will be warmer there. Friday likely will still be the warmest day of the year so far with highs in the 70s and low 80s. A few areas in eastern Montana will top out in the mid 80s. Low humidity and moderate wind will increase the fire danger. Saturday a cold front will approach with the chance of isolated showers and thunderstorms mainly over the southern half of the state. Temperatures will slowly start to cool off. Sunday will have widespread clouds and showers, with high temperatures dipping back below normal. Mountain snow will return on Sunday as well, although accumulation will not be significant. Wet snowflakes could mix with the rain showers down to 5000' by Sunday evening. Scattered showers and cool conditions will continue for Monday and Tuesday next week before another warm up late in the week.

Have a great day.
Curtis Grevenitz
Chief Meteorologist