Northern California has been in the grip of a "La Nina" weather pattern, explained Dave Reynolds of the National Weather service. A La Nina forms when surface temperatures in the ocean are colder than normal, keeping storm systems from forming out at sea to sweep in along the coasts carrying moisture.
Both Reynolds and Accuweather senior meteorologist Paul Pastelok say the La Nina period is ending and the area will be transitioning to a more neutral pattern with temperatures hovering right around normal if not slightly above.
"The jet stream is starting to work its way south," said Pastelok. "We'll be seeing some big systems coming into the northwest."
Pastelok said October is going to see an end to the very warm temperatures that have been in the area during the past few months. Expect a cool trend with rain in November, he added.
While the National Weather Service is not predicting major storms in November, Reynolds did say a meteorological phenomenon called a Madden/Julian Oscillation could dump a lot of precipitation on the area during the winter months.
"In years that we have this neutral weather pattern we can get a mini-El Nino. It comes in over the course of 45-60 days and can cause a week or two of heavy rain," he noted
The Old Farmer's Almanac is predicting a mostly dry winter with a spike in rainfall amounts in December. The Almanac also calls for significantly lower temperatures from November to April, with average temps down as much as 2 degrees.
Pastelok's forecast disagrees, saying temperatures will be 1 to 2 degrees above normal during the December-February period.
As for snowfall, all three forecasts seem to indicate there will be good snowfall in November, leading to a decent base, but after that the precipitation at higher elevations will be less.
The Almanac is predicting that the majority of the snow will go to the north of the Tahoe region. Pastelok said that while Donner Summit normally gets 400 inches of snow between December and February, skiers could see only half that much this winter.
Add to that the expectation of warmer weather, and skiers may be looking at wet conditions with a lighter than average base.
However Reynolds said the National Weather Service has data that indicates a weak El Nino could develop late in the winter bringing rain and snow with it. Reynolds said he did not believe that any late developing weather system will be enough to offset the dry seasons preceding it.
Data on the Almanac Web site paints a less than exciting picture of the coming months. Between November and May, it is expecting 7.9 inches of rain in Northern California. That is down from the average of 13.5 inches.