Our cold system is moving out of CA this afternoon. Snowfall was very significant on the high Sierra peaks–as much as 4-6 feet of accumulation on the peaks. Snow accumulated to very low elevations in NorCal…in Orleans, up by Eureka and with an elevation of only 450 feet, nearly 6 inches of snow fell. Many other valley locations saw 1-3 inches of the white stuff, as did certain neighborhoods in Redding. Snow fell in the mountains of the Bay Area, dumping nearly half a foot on Mt. Hamilton, 4-5 inches on Mt. Diablo, 2-3 inches on Mt. Tamalpais, a dusting on some of the East Bay Hills, and a very impressive 8-10 inches on Mt. St. Helena. Several highways were closed over the past few days, including the Grapevine, which saw local accums. in excess of 5 inches. We managed some rumbles of thunder here in San Rafael and elsewhere across the northern part of the state, but nothing too severe. SoCal really missed out on this one, though heavy rain didn’t really fall anywhere from this system. The snowpack has been boosted substantially, however. Temps will warm and skies will clear going into the weekend. A weak MJO event currently entering the Pacific could lead to some jet amplification next week, but this is anything but certain. Even if it occurs, SoCal will probably stay dry, and even NorCal will see relatively little precip. The GFS wants to try to dig a mean trough off the coast and bring some more cold and showery weather to the state beyond day 7. The MJO may prevent this from happening, or the cold air could override any tropical forcing present. We shall see, but I’m not particularly impressed by the current MJO signal. In the longer term, it appears that La Nina conditions are developing quite rapidly in the equatorial Pacific Ocean. This La Nina episode could be rather strong, given its early and rapid development. Typically, moderate to strong La Nina events correlate to significantly drier and cooler winters in California. However, given the aclimatological response to this year’s weak to moderate El Nino event, especially in SoCal, would not be entirely suprised if it ended up bringing more precip to the state than this year. Because this year will probably end up being moderately dry in the north and extremely dry in the south, next year’s rainfall will determine whether we enter a period of geniune drought. We’re OK for this summer–check out this link (long movie, but worth watching) to see how the snowpack has been bolstered in recent weeks–but we are going yo be left in a vulnerable situation going into the next rain year.

Side note: this blog has recently been the target of quite a few spam attacks, so updates have been more sporadic than usual as a great deal of moderation has been required. Sorry for the technical problems…