Here’s what we got now for a jet stream regime. The jet stream, that raging river of wind between the deep cold air of the northern latitudes and the deep warm air of the tropics and sub-tropics, is crashing into Washington and British Columbia from the Pacific. We have remain in the quiescent warm air of a “ridge”, a slight poleward bulge of warm air in this case extending toward Montana at map time (5 PM LST yesterday). This has been going on for the past two weeks. Boring, but really nice, too.
When the jet stream extrudes itself southward, as over the central and eastern US, it drags cold air southward, too. Here is an example of the US temperature change over the past 24 h associated with the current pattern from The Weather Channel:
But look below at what has happened, the models say, by mid-month, as shown in the following four panels! The jet stream has buckled over the West Coast and has extruded down into AZ, a wet and cold pattern in the interior of the West has developed with lots of precip around here predicted.
Since these storms weren’t on yesterday’s model runs, so’s you can’t count on them. BUT, having said that, we can hope anyway. I will interject that I have a feeling that this is going to be correct, no quantitative stuff here. This due to the type of winter we have already been experiencing, a feeling it will return to that mode.
Here are some examples from IPS Meteorstar‘s rendering of the WRF-GFS model run from last night. The greenish-looking maps are the ones showing where the high and low pressure centers are predicted to be and the green those regions where the model thinks it has rained in the prior 12 h. Look at all the green in AZ. The reddish orange maps show the jet stream, that river of storms and how they will be guided. If correct, the storms will be steered from the interior of Canada down into the Southwest,which means that these storms will be not only cold, but damn cold, to cuss that bit for emphasis.
The first pair of maps are valid for Sunday afternoon, the 16th, at 5 PM LST, and the second pair for Tuesday morning, the 17th at 5 AM LST.
Enjoy dreaming about more rain…and probably low snow levels in a couple of weeks.