Don’t put off those seasonal tasks like cleaning your gutters and waxing your snowboards just yet, but long-range forecasts show an increasing chance of a warmer, drier winter across the Northwest.
In addition, the USDA’s National Integrated Drought Information System said the Northwest is experiencing abnormally dry conditions and moderate drought north of Seattle.
“That’s the way it is looking,” said meteorologist Kirby Cook at the National Weather Service in Seattle.
Although the next week or so will see cooler temperatures and rain around Whatcom County, the summer-long dry spell could continue for the next several months.
Only last year’s wet rainy season and heavy snow in the North Cascades kept the region from thirsting for water over a dry spell that dates to last spring.
Combined May through August rainfall was 1.49 inches as measured at Bellingham International Airport, far below the normal rainfall of 6.75 inches for that period.
Cook said an El Niño pattern is taking shape in the tropical Pacific, which usually means a warmer — and sometimes drier — winter for Western Washington and the Northwest.
“(But) that doesn’t mean we’re not going to get rain,” Cook said. “We should always be ready. We could still get significant storms, even in a dry year.”
NOAA’s ENSO Alert System shows that there’s a 60 percent chance of El Niño conditions in the Northern Hemisphere, increasing to 70 percent by winter.
ENSO, the acronym for El Niño southern oscillation, is a climate phenomenon that has three phases, according to NOAA’s climate.gov.
In general , El Niño is a warming of sea surface temperatures along the equator west of South America. Its opposite is La Niña, a cooling of sea surface temperatures.
Both can affect weather worldwide.
In the Northwest, an El Niño generally means warm, dry winters and La Niña generally brings cold and wet winters.
Western Washington is coming off a pair of La Niña winters that resulted in heavier than normal rain in the lowlands and more snow in the mountains.
Last fall and winter rainfall was about 6 inches above normal, with 35.06 inches of rain from September 2017 through April 2018, compared to a normal rainfall of 29.07 inches for that period.
Some 844 inches of snow fell last season at the Mount Baker Ski Area, making it one of the top 10 winters with the most snowfall. Average snowfall at the ski area is 633 inches, according to its website.
At the Climate Prediction Center, the Northwest’s outlook for October through December sees above-normal temperatures and below-normal rainfall.
Those chances increase for the period of December through February, which shows a stronger probability of above-normal temperatures but with normal precipitation.
Extended forecasts looking at March through May show a continued stronger chance of above-normal temperatures coupled with normal rainfall.
“What that does to the drought is tough to say,” Cook said. “The thing to remember is that there’s a lot of uncertainty. If you were going to hedge your bets, you’d probably hedge for a drier fall.”