Friday, May 5, 2017
The beautiful weather in the Steamboat Springs today will hang around for most of tomorrow before the current ridge of high pressure is nudged to our east by an approaching Pacific wave. This wave will split as it approaches the West Coast, with much of the energy diving south along the California Coast and forming a closed low pressure system cut off from the main jet stream.
Moisture and limited energy will eject over our area starting later tomorrow, bringing breezy southwest winds and afternoon clouds. The dry lower levels of the atmosphere will allow rain that falls to evaporate before reaching the ground (virga), bringing gusty afternoon winds in places.
By Sunday, the now well developed cutoff low will assume a relatively long-lived position along the California - Arizona - New Mexico border. As the lower atmosphere moistens, and more moisture and energy eject from the spinning low to our southwest, thunderstorm chances and coverage will increase for Sunday.
These cutoff lows are notoriously difficult to predict since there is no strong upstream forcing to move the storm along. The end result is that timing and position of precipitation is nearly impossible to get right this far out, and a slight southern shift in the storm southward would greatly diminish our precipitation chances while a shift further north would increase the chances.
That being said, current forecasts have the chance of afternoon storms for both Monday and Tuesday before the cutoff low lumbers eastward through most of the work week. Models have the storm more or less over Colorado around midweek, bringing cooler and much wetter weather to Colorado for Wednesday and some or most of Thursday.
A very complicated pattern then ensues, with interactions between additional Pacific energy approaching the coast, the cutoff low and even energy swinging back westward from an East Coast storm that developed from our storm this past Monday and Tuesday. While earlier in the week it looked like summer-like weather would return after the cutoff low moved east of us, more unsettled weather now looks more likely heading into next weekend.