Another monsoonal surge next week after drier weekend
Thursday, July 13, 2017
A building western ridge of high pressure has brought drier air to the Steamboat Springs area as of late yesterday afternoon. As discussed in the previous forecast, northern Colorado was close to the boundary separating drier air to our north and west from monsoonal moisture to our south, and Tuesday the boundary moved north allowing for another day of wetting rains. By Wednesday afternoon, drier and cooler air moved over our area as the boundary moved southward precluding significant precipitation.
The western ridge looks to dominate our weather through the weekend and into Monday. Hot temperatures and the possibility of daily afternoon storms are on tap as remaining low-level moisture is cooked by the strong summer sun as it recirculates under the ridge of high pressure.
Meanwhile, a storm off the coast of British Columbia mixes with some cool western Canadian air as advertised by the European ECMWF last week. As the storm moves to our north late in the weekend, a trailing cool front may be the focus of stronger storms later Monday and Monday night.
The storm will flatten and elongate the ridge of high pressure eastward, which opens the door to another monsoonal moisture surge in the southerly flow on the west side of the ridge. This one looks to hang around longer than the last one, with good moisture over our area through most of the work week. Some cloud cover will keep the hot temperatures at bay, and storm cells that move over our area will be capable of producing locally heavy showers.
Extended-range models are in disagreement with regards to the evolution of another weak wave moving to our north near the end of the work week. The European ECMWF is more aggressive in bringing the storm eastward, interrupting the monsoonal moisture tap a day earlier than the American GFS, as we head into a weekend advertised to be drier than the preceding work week.
