The computer models are diverging significantly on the “tail of the scorpion” on this incoming front and the two troughs that pass over us in the next few days. First, a Pacific front blows through on Monday with its upper air accompaniment racing to the northeast. But then this monumentally strong wave disturbance barges in from Canada over the Rockies and actually deploys toward the SSW while intensifying and curling into an upper center, this center trailed by a gigantic mass of cold air that oozes over most of the US. High pressure levels in the cold air, 1060-1065 millibars initially, may set some records here and there in the northern Rockies.
The “best/worst” full display of this predicted sequence is here from our friends at Environment Canada, and the output from last night, of which one panel is shown below.
This panel at left, from that Canadian model run, is the most exciting panel of future weather I have seen this winter!
Now, if you’re a bit jingoistic about models and want to know about our US model results for this situation, I have to tell you, sadly, that they do not have this “good” a configuration over the SW as far as precip goes.
There is no upper vortex, Virginia, over western AZ in the US models, as in shown in the upper left panel here.
And that makes all the difference in whether AZ will get much precip out of this second of a two part event. In the US models, such an upper low does not form over AZ but rather just a bitterly cold slug of air, mainly dry, intrudes on us and that second strong upper trough just trucks on by.
So, its a dicey situation, but, because my dad was Canadian (from Winnipeg) and I really want to see some precipitation here after a rainless January, I am going to say that this Canadian model is the correct one, jingoism aside.
Furthermore, in order to have precipitation, which I believe will be rain changing to SNOW here at about 3200 feet on Wednesday, there will first have to be clouds (silly, haha), the latter my specialty at the University of Washington.
I love clouds and the way they present themselves in this gorgeous Sonoran Desert environment that we are so lucky to live in. So, there oughta be some interesting clouds beginning today as the cirrus zipping on by begin to announce this monumental change from our mundane, but glorious weather of late. And, of course with that fast moving river of air called the jet stream settles over us, there’ll be some windy periods, too.
The worst part of this scenario is the bitter cold that will likely get here after this mammoth upper low center goes by, and if the US models are correct, it will only get here that bit sooner.
Below, this morning’s cirrus, full of portent, over Mt. Sara Lemmon.
