Seattle has never experienced this many days without rain
Western Washington is countering its record-setting rainy season with a record-setting dry stretch.
Tuesday officially marks the 52nd day without measurable rain at Sea-Tac Airport, making the current dry spell the longest on record. And there’s no rain in forecast for the next five days. The previous record of 51 days without rain was set in 1951 between July and August.
“So it’s been a long time,” said Dana Felton, a meteorologist with the National Weather Service in Seattle.
A new federal climate report says extreme heat waves have become more common and extreme cold waves less common since the 1980s. However, Cliff Mass, University of Washington Climatologist, said the latest heatwave can’t be attributed to global warming.
The current 2017 dry stretch shares a lot in common with the previous record-setting 1951 event. Just like this past winter, Seattle experienced above normal rainfall prior to the dry spell in 1951.
“Taking the October through April time frame — which is the time frame we set the record for this year — the 1950-51 (winter) was the sixth wettest,” Felton said. “This year we got just short of 45 inches between October and April, and in that year was a little over 42 inches. That’s a lot of rain. Our normal for the entire year is 37.5 (inches).”
Looking ahead, the National Weather Service’s Climate Prediction Center currently has the region slated for above-normal temperatures from September to November, with about normal rainfall. While climate outlooks can change, the service was pretty accurate when predicting the current warm and dry summer weather.
No rain and Washington’s water supply
The extended period without rain comes as the region experiences a heat wave. According to University of Washington Climatologist Cliff Mass, the much drier and warmer western Washington weather is due to a high pressure system along the West Coast.
Despite the dry stretch, Washington’s water supply is quite good for the season. Most of the state’s rivers and streams are currently registering normal and above normal stream flow. This comes after considerable rain filled the region’s reservoirs over the fall and winter months. Snowpack in the mountains was also above average last winter.
“If you take the yearly rainfall since January 1, we are over 8.5 inches above normal, still, even with this dry spell,” Felton said. “…in the summer, our normal rainfall for July is 7/10 of an inch and for August it’s .88. So in this two-month window we normally only get an inch and a half of rain.”
Felton said that even though the region is experiencing an extended lack of rainfall, there is no concern of a water shortage.
Meanwhile air pollution levels around the Puget Sound region are expected to remain somewhat moderate until mid-week.
Erik Saganic, Air Resources Specialist with the Puget Sound Clean Air Agency, says we could see more wildfire smoke build by Wednesday.
Forecasters say we have until the end of this week before the weather changes and the wildfire smoke clears.
Check the latest air quality index here.