A strengthening El Nino suggests Washington will have another warm winter, possibly deepening the state’s drought, State Climatologist Nick Bond said Monday.
“The odds are for a warmer and drier winter overall,” he said. “And a lower than normal snowpack at the end of it.”
Climatologists for several months this year saw a weak El Nino, a warming of the Pacific Ocean that often presages a mild Northwest winter. After dipping in some places in April, sea temperatures increased in May, according to a report Monday by the National Oceanic and Atmospheric Administration.
The agency now says there’s a 80 to 90 percent chance that El Nino conditions will persist until at least the end of the year, up from a 50 to 60 percent chance in early March.
“There no question it’s out there, and it’s honking,” said Bond, a University of Washington research meteorologist. “There’s almost no doubt it will be there the remainder of the year.”
This could be good news for California, which typically receives soaking winter rains during El Nino years.
But Washington can expect only near normal precipitation to go with higher temperatures, a repeat of the 2014-15 winter.
A second straight mild winter could build on hardships, particularly for irrigation-dependent farmers in the Yakima Basin and the Olympic Peninsula rain shadow who rely on melting snow to keep river levels up.
El Nino’s greatest effect on temperatures and precipitation typically occurs between January and March, according to NOAA. The El Nino may have weakened by then, Bond said. “That’s the silver lining to this.”
Bond called “last winter mostly a fluke” as warm weather kept snowpacks small, even though rainfall was near normal or above average in most of Washington.
By mid-spring, rain-filled Yakima River reservoirs were full and held about 1 million acre-feet of water. But without melting snow to replenish the reservoirs, the U.S. Bureau of Reclamation has estimated that by Oct. 1 the reservoirs will hold only 110,00 acre-feet, instead of the usual 320,000, creating a deficit heading into the winter.
Melting snow from the Olympic Mountains normally keeps the Dungeness River high enough for farmers to draw from, even as salmon migrate upstream to spawn. This summer, the river is expected to fall to record lows, possibly forcing mandatory cutbacks on irrigators.
In May, temperatures were above normal across Washington, according to the state climatologist.
NOAA predicts above average temperatures between June and August for Washington, Oregon, Idaho and California.
The agency forecasts below average rainfall in Western Washington and northwest Oregon. The rest of Washington and Oregon, as well as California and most of Idaho, have equal chances of above or below normal precipitation, according to the agency.
Source: www.capitalpress.com