[env-trinity] Sacbee: Dry winter ahead, state’s experimental forecast warns

Tom Stokely tstokely at att.net
Mon Dec 2 09:15:09 PST 2013


http://www.sacbee.com/2013/11/29/5956742/dry-winter-ahead-states-experimental.html 

Dry winter ahead, state’s experimental forecast warns
 
By Matt Weiser
mweiser at sacbee.com
Published: Friday, Nov.
29, 2013 - 1:20 pm
Last Modified: Saturday,
Nov. 30, 2013 - 12:31 pm
Despite a hint of rain and snow in the forecast
next week, the Sacramento region and California as a whole can expect a third
dry winter ahead.
That’s according to an “experimental” long-range
forecast released this week by the California
Department of Water Resources. The forecast covers the 2014 water
year, which runs from Oct. 1, 2013, through Sept. 30, 2014. It calls for
“mostly dry conditions for most of California,” with dry conditions being
especially likely in the south state.
The forecast was done for the state by Klaus
Wolter, a Ph.D. meteorologist and research associate at the Cooperative
Institute for Research in Environmental Sciences, at the University of
Colorado, Boulder.
Wolter made a similar dry prediction for the
state last year, which at first appeared “destined for failure,” he said. That
was because December 2012 was extremely wet, partly due to the arrival of a
series of atmospheric river storms. Such storms tap into tropical moisture in
the far western Pacific Ocean and channel it into a narrow stream often aimed like a fire hose directly at
California.
“However, the remainder of the season was record
dry, producing an overall result of dry for the water year,” Wolter said in a
statement.
In a hint that suggests a similar outcome this
year, the near-term forecast calls for a major change in the weather for
Sacramento and Northern
California on Monday. A storm is expected to drop out of the Pacific Northwest, bringing a chance of rain to the Valley through Wednesday and snow in the Sierra Nevada through
Thursday.
But don’t get too excited yet.
“It’s a fairly dry system, so it doesn’t look
like a whole lot,” said Craig Shoemaker, a meteorologist at the National
Weather Service in Sacramento. “It doesn’t have a really deep
moisture plume.”
Temperatures are also predicted to drop sharply
with the storm. Overnight lows in Sacramento could get as cold as 34 degrees on
Wednesday night.
Shoemaker said the storm could generate as much
as 8 inches of new snow in the Sierra
Nevada, where most ski resorts still have limited terrain open, if they are open at all. The snow level could
drop as low as 2,000 feet on Tuesday night.
State officials intend the experimental forecast
to help residents, business
owners and policymakers prepare for winter.
The National
Weather Service typically does not make a detailed long-range winter
weather forecast. Its Climate Prediction Center, however, does offer a less
specific three-month forecast. The most recent, issued Nov. 21, indicated neither
wet nor dry conditions for California.
A third dry winter could have severe
implications, since most of the state’s water storage reservoirs are severely
depleted after two drought years. California is heavily dependent on winter
storms for the water supply it needs to survive summer. The state typically depends on just three months –
December through February – for half its annual precipitation, although freak
storms in other months can make a big difference,
As for the winter ahead, state officials caution
the final outcome is difficult to predict, partly because neither El Niño nor
La Niña conditions dominate in the Pacific Ocean this year.
The former condition indicates the ocean is warmer than average, while the
latter is cooler. A strong signal in either direction can make predictions
easier.
This winter, forecasters say the ocean will be in
a “neutral” condition, though Wolter said it could shift into an El Niño
pattern by springtime.
 
Call The Bee’s Matt Weiser at (916)321-1264.
Follow him on Twitter @matt_weiser.
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