Monday January 6, 2025
Weather West —
Heading into the new year, from mid-December, it appeared likely that the already extreme precipitation disparity between very wet northern California and bone dry southern California would continue. And…it certainly did, with rather frequent soakings continuing north of the Interstate 80 corridor (which has remained an almost bizarrely sharp dividing line!), occasional rains as far south as the northern Central Coast, and near zero precipitation south of that point. These have been relatively warm storms, too, maintaining overall warmer than average temperatures across nearly all of California in recent weeks (except the far northern mountains and, interestingly, a narrow swath of highly-populated coastal SoCal, which has actually been relatively cool and foggy with poor air quality under a stagnant and subsident airmass).
The remarkable “precipitation dipole” across California has, at this point in early January, now reached essentially historic proportions. Portions of San Diego County have seen their driest start to the season (and 9-month period overall) in over 150 years; the contrast between (anomalously wet) NorCal and (record dry) SoCal is even more anomalous than either the northern wet or southern dry anomalies on their own. It is truly a matter of the precipitation “haves” and “have nots” at the moment–and there is no real prospect for this to change in the short term; even in the long term, it remains possible this overall dipole persists for the rest of the season (though hopefully with less extreme intensity).