Shift to More Unsettled Weather Pattern Across Northern California……..

October 15th, 2014

“Shift to more unsettled weather pattern across Northern California, but no major rain events on the horizon,” says Daniel Swain of

The following excerpts on the drought situation in California come from a recent article by Daniel Swain from posted October 13, 2014.

“Warm, dry, and occasionally windy conditions have been the rule across most of California over the past two weeks. While California is certainly no stranger to early fall heat waves–in fact, coastal parts of the state are famous for them–the early part of October was remarkably warm even by local standards. A slew of cities from the San Diego area all the way up toward the Mendocino Coast set daily high temperature records during the first half of October, and San Francisco had its warmest start to any October on record.”

“Away from the far North Coast, where 2+ inches of rain fell during September, any moisture that had been deposited earlier by September precipitation has long since evaporated.”

Unsettled weather on the way for NorCal, but no big storms on the horizon.

Precipitation from this first system should actually be considerably less than that received during the September system in most places, with only around a tenth of an inch for Sacramento and San Francisco. The mountains and foothills may see up to a few tenths of an inch, and the far North Coast could up to 1-2 inches. A second system later this week may bring more precipitation to the state, and some of the models suggest that rain may be a little more significant and make it a bit further south that with the first system. Thus, prospects for widespread significant precipitation from either of the two systems this week are low (with the exception of far NorCal, where some favored mountain regions could pick up 2-3 inches over the next 7-8 days).”

Prospects for the rest of fall (and beyond?)

“Seasonal forecasts are always tricky in California, though now that we’ve reached mid-October it may be possible to offer some modest insights about what’s likely to occur during the next two months.”

“The official CPC forecast and recent CFS model ensemble projections both suggest that November will be drier than usual across most of California, and the CFS suggests that December may also be fairly dry.”

“A weak El Nino continues to chug along in the Pacific, but the dynamical models forecast little strengthening though the winter, so it appears that strong ENSO teleconnections won’t play a role this winter.”

“While the upcoming pattern is not conducive to the kind of heavy precipitation-bearing systems that could bring drought relief to California, it is nonetheless nice to see the return of some zonal flow over this part of the Pacific (as opposed to the persistently “blocked” storm track associated with the Ridiculously Resilient Ridge over the past couple of winters).”

“However, it’s still too early to say whether persistent ridging will return later in the season. NCEP’s CFS model has been consistently suggesting the possibility of very wet conditions in California during the January-February-March 2015 period.”

“7 of 8 models depict dry conditions in California during December-January-February, with the CFS being the lone model projecting (very) wet conditions.”

“As I’ve pointed out before, model skill for winter precipitation in California at 3+ month lead times is still pretty low, so I wouldn’t put too much stock into any of these forecasts.”

“But it certainly bears repeating that there is presently no sign of meaningful drought relief on the horizon–either in the short run or long run. ”  © 2014 WEATHER WEST

California’s drought condition and its impact on the California Almond crop is an important topic for our readers. Blue Diamond would like to thank Mr. Swain for allowing us to post excerpts of his articles on our website.