Weekend dries out ahead of next monsoonal moisture push Monday

Thursday, August 1, 2019

A cool and cloudy Thursday in Steamboat Springs is the result of monsoonal moisture from the south moving overhead. We’ll see a good chance of showers today before conditions dry heading into and lasting most of the weekend. By later Sunday, another push of monsoonal moisture will increase precipitation chances for Monday, and though moisture will decrease for the rest of work week, enough will hang around for the usual chance of afternoon and early evening storms.

Most of the U.S. is currently dominated by an expansive ridge of high pressure centered over the Rocky Mountains. A subtropical disturbance that is currently traveling through the ridge has brought plenty of moisture but cool temperatures to our area, with the 64 F noontime temperature running over 10 F below typical for this time of day.

There is no strong lifting from the subtropical disturbance, so the cool temperatures from the thick cloud cover has inhibited surface heating enough to reduce, but not eliminate, the chance of showers for today and tonight. In fact, thinning cloud cover to our southwest has allowed a line of storms to form in the southwestern corner of the state, and these may be headed toward our area later this afternoon or evening.

As the subtropical disturbance moves east of our area on Friday, temperatures will warm to near our average of 82 F, with further warming and drying expected for Saturday as the ridge of high pressure amplifies over the west.

Concurrently, a series of disturbances drops toward the Gulf of Alaska from the north and split, with some of the energy staying offshore around the Pacific Northwest coast and some racing across the Canadian Plains later in the weekend. Meanwhile, another subtropical disturbance is advertised to move north along the western periphery of the ridge of high pressure over the west even as this ridge is flattened by the disturbance moving across Canada, so look for increasing clouds later Sunday, with precipitation chances increasing again for Sunday night and Monday as this disturbance moves near our area.

The ridge over the west stays put during the work week as it is anchored between the disturbances off the Pacific Northwest coast and the developing Canadian Plains disturbance that is forecast to turn into a strong storm just north of the Great Lakes by the end of the work week. Even though our area will warm and dry for the rest of the work week, enough moisture will remain under the ridge for the typical chance of afternoon and evening storms.

By the following weekend, weather forecast models have the the Pacific Northwest disturbance moving eastward along the southern Canadian border, which significantly flattens the ridge of high pressure over the west. Dry air is advertised to our north, but monsoonal moisture remains to our south, leading to an uncertain forecast for that weekend.