The Ridiculously Resilient Ridge Returns…Again

Mar 24, 2021 at 8:00am

Daniel Swain

The first half of March was actually a reasonably active weather period for much of California, with several cold cut-off lows bringing bouts of showery and unstable conditions. Widespread (if brief) bursts of small hail brought unusual wintry coatings to many areas, and quite a few folks witnessed some thunderstorm activity. Precipitation, while widespread, did not ultimately result in heavy accumulations in most places. Thus, despite these widespread March showers, precipitation totals for the month of March are on track to end up below average across most of the state. Were March the only dry month this year, that wouldn’t be much of a problem–but in a year when many folks were hoping for a drought-busting March Miracle, this was a rather disappointing showing.

The 2020-2021 “rainy season” to date has, in fact, turned out to be exceptionally dry across portions of California. I think this probably slipped in under the radar, given everything else that has transpired in the world over the past few months, but some parts of northern California (including the SF North Bay, Mendocino County, and much of the central/northern Sacramento Valley) are currently experiencing their driest season since the 1976-1977 drought (and a few places are running behind even that infamous season). This is doubly concerning as these same regions experienced a top-5 driest winter on record just last year–so this is now year two of exceptionally low precipitation in these areas. All of this is amplified by the prolonged periods of record high temperatures and drying offshore winds last year–both of which reduced water availability beyond what would be expected from precipitation deficits alone.

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