The first moderate to strong atmospheric river (AR) of this Fall/Winter is on the horizon for California between Sunday-Monday.
You’ll also notice two weaker atmospheric river waves prior to Sunday-Monday. Forecast liquid precipitation totals are impressive through Tuesday.
This moisture is what California needs after a bone-dry Summer, but the downside is that it almost always comes too fast and results in flash flooding.
How Much Snow
How much snow? Snow levels will be a problem as usual with AR’s. The surge on Sunday-Monday might be the best chance for heavy high elevation Sierra snow from Mammoth to Tahoe to Shasta. It could be measured in feet.
What kind of pattern supports this “Pineapple Express”? Upper-level winds reach back towards Hawaii (and elsewhere) and transport rich plumes of moisture into California. That moisture gets slammed into the Sierra Mountain Range and squeezed out.
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