It happened. It finally rained. After 14 consecutive dry days, western Washington finally received some measurable rain overnight on Tuesday. The 14-day stretch of dry mid-winter days fell just shy of the record at Seattle-Tacoma International Airport (SEA) of 15 days set in 1963.
Going back through all Seattle weather records dating back to the 1890s, the all-time mid-winter dry streak record set at the Seattle Federal Building in 1901 was 18 days. Another long mid-winter dry streak came in 1915 with 14 days, and this month’s dry streak tied that mark.
Below average rain this month
After a wet start to the month, the 14-day period of dry weather has resulted in below-average rainfall across western Washington. As of midnight Tuesday, SEA has received 3.38 inches of rain this month, more than an inch and two-thirds below average. Olympia is more than three and two-thirds of an inch of rain below average.
Big change to wetter weather
The big ridge of high pressure aloft that steered Pacific weather systems well to the north for two weeks has weakened and moved inland, opening the door for weather systems to move ashore. Several weather systems will spread rain into western Washington at times through the weekend, though Saturday looks like a break in the rain. Expected rain amounts, though, will quite likely not be enough to make up this month’s rain deficit.
Temperatures are expected to rise above average as well. High temperatures will warm into the 50s, with lows only dropping into the 40s. The average high temperature in late January is in the upper 40s.
Mountain snow status
The period of mid-winter dry weather has not been good for an already hampered mountain snowpack. At mid-month, the NW Avalanche Center reported the Olympics and Cascades were only ranging from 40 to 55% of average snow depth. And no snow had fallen until Wednesday, and that snow has been quite light.
The Natural Resources Conservation Service monitors the amount of water in the snowpack and reports that the water content ranges from 35-45% of average, with the exception of around 80% in the North Cascades…