Warming and a very dry pattern ahead

Filed in Uncategorized by on January 17, 2007 5 Comments

That “weak” upper low that dropped down the coast last light managed to produce some very interesting weather over the past 24 hours. Here’s a chronology: a rain and snow mix fell last evening in parts of the Sacramento Valley, w/ little or no accums. Black ice formed on the roadways in these same areas once skies cleared, and numerous accidents resulted. Brief light to moderate showers fell as snow in the hills near Eureka south to the northern Bay Area from mid afternoon until midnight Tuesday, generally above 1000 feet. 1-3 inches was reported NE of Angwin in Sonoma County, and lower down in the valley, near Santa Rosa, thick ice, which formed from water from the evening’s rain showers, closed roads and caused accidents. Mt. Hamilton and Mt. Diablo both received 1-2 inches of snow which remains on the ground tonight. In the Santa Cruz Mountains and on the more mountainous peaks on the southern San Francisco Peninsula, significant accumulating snowfall did occur, 1-3 inches of it, in fact, and this also remains on the ground tonight. Even more impressive is the storm’s aftermath in SoCal. Convective activity picked up as the low approached the SoCal bight, and with cold air already in place at the surface, freezing rain occurred early in the morning, even in coastal valleys. After this icy glaze was already in place, a few heavier showers and isolated thunderstorms dropped a quick 1-4 inches of snow in places such as the Malibu Hills (remember the wildfire last week?) and the I-5 corridor. Accumulating hail fell in western parts of the city of Los Angeles proper, and cars had a very tough time negotiating the nearly 2 inches of pea-sized hailstones that covered the road in some spots. The freezing rain was the most interesting aspect of this little system, as the conditions even in the coldest of patterns here in CA are more conducive to snow than freezing rain (which requires a  cold surface and a relatively warm layer >32 degres 1000-3000 ft. above the surface). All in all, a exciting but brief interlude in a protracted boring weather pattern. Did any readers see any frozen precip. from this system? Let us know…

Long term: blah. The blocking high will be centered right over us for days and possibly weeks to come, bringing very dry and fairly warm weather (fire weather concerns in SoCal and possibly even further north). Not much else to say…