Thursday, July 6, 2017
A ridge of high pressure centered over the Great Basin will be nudged eastward this weekend by incoming Pacific energy. The weak southerly to southwesterly flow on the west side of the ridge will allow the monsoonal moisture pooling around the Sonora Desert to move northward, increasing mid and upper level moisture over the Steamboat Springs area for Friday and Saturday. The additional moisture will create high-based afternoon and early evening storms that will produce more gusty and erratic wind than rain, and possibly some dry lightening, as the lower levels of the atmosphere remain quite dry.
By Sunday, the Pacific energy traveling over the top of the ridge will interrupt the fledgling monsoonal flow from the southwest, with drier air moving over the area in weak westerly flow. There will still be the possibility of afternoon storms though, as the meager low-level moisture is lifted by the strong surface heating of mid-summer and interacts with some of the grazing Pacific energy to our north.
On Monday, more Pacific energy again pushes the western ridge eastward into the Great Plains, and a better monsoonal tap of moisture appears around Tuesday. While mid and upper level moisture is carried northward by southerly flow on the west side of the ridge, low level moisture may also receive a boost from a tropical storm moving westward south of Baja. Northern Colorado will have a much better chance of wetting rains starting around Tuesday and extending through the work week and into next weekend, as moisture falling from any storm will not encounter the very dry lower-level air present for this weekend.
Longer-range models, as of today, want to keep the monsoonal flow around after next weekend as well, hopefully leading to a far wetter July as compared to June as tropical waves of energy move northward over the Sonora Desert and eventually across the Great Basin.