Potentially warm and very wet or very cold and unsettled weather, or both?

Quick update tonight. The numerical models are starting to come into agreement that a major change in the prevailing weather pattern will occur by day 7. The GFS has a simultaneous incursion of the subtropical jet and an extremely deep retrogressive cold low over the PacNW by day 7, bringing extremely cold and unsettled conditions to NorCal and very warm, wet, and stormy conditions to SoCal during the same time frame. This is a highly unstable setup, and so one or the other regime will eventually win out. Which one, and when, remains to be seen. It is possible that we will see an Arctic outbreak on Saturday and Sunday–with very low snow levels–followed by a Pineapple Express-type subtropical storm next week. Again, I cannot emphasize enough that the forecast will certainly change dramatically (and has been with each run). But…day 7 now appears to be the date of reckoning, since a pattern change (or one sort or another) is very likely by then. More as the week progresses.

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