From The Tacoma News Tribune:

La Niña’s arrival became official Thursday, according to scientists at the Climate Prediction Center in Maryland, an arm of the National Oceanic and Atmospheric Administration.

“It’s about time,” said atmospheric scientist Ed Sarachik, a University of Washington professor and co-director of the Center of Science in the Earth System.

Equatorial sea temperatures began dropping below normal in November, but NOAA doesn’t define the condition as La Niña until it has persisted for three consecutive months.

“This pattern will favor continued drought in parts of the South and Southwest from Arizona to Arkansas and Louisiana, and above-normal precipitation in the Northwest and the Tennessee Valley,” said Vice Adm. Conrad Lautenbacher, NOAA administrator.

[snip]

Since the start of the water year that began last October, 27.3 inches have fallen at Sea-Tac Airport. The average is 20, according to the National Weather Service.

Olympia, which is typically wetter, has outdone itself with 38.4 inches since Oct. 1. The average total for this time of year is almost 10 inches less.