WALLA WALLA -- Weekend storms dumped nearly a month's worth of water on the city Saturday and Sunday.
A thunderstorm that blew in Saturday evening deposited 1.37 inches of rain as measured at Walla Walla Regional Airport. Showers that followed it Sunday brought another .35 inches, putting this month on track to be one of the wetter Mays on record.
Normal rainfall for May, based on a 30-year average, is 1.95 inches.
As of this morning, preliminary data shows 3.05 inches of precipitation have fallen so far this month, said Doug Weber, a meteorologist with the National Weather Service office in Pendleton.
Saturday's precipitation tied as the third-heaviest one-day rainfall for May recorded in recent years, Weber said. An identical amount fell May 30, 2000, and only two other days in May, one in 1991 and one in 1971 had heavier downpours.
The thunderstorm also delivered wind gusts that topped out at 56 mph as measured at the airport.
If the rains continue, this month could break into the top-five wettest Mays on record, Weber said. The fifth-highest precipitation total is 3.35 inches recorded in May 1990. The wettest May in recent record was 6.63 inches in May 1991.
The weekend storms were the product of a weather system that moved through the Pacific Northwest starting Saturday. The storms broke rainfall records in the Puget Sound region, dropping 1.78 inches in less than 24 hours at Seattle-Tacoma Airport.
According to a blog written by Cliff Mass, professor of atmospheric sciences at the University of Washington, the rainfall was not the product of a "pineapple express," which is caused by moisture streaming out of the southwest from the tropics and subtropics. The weekend storms were from the southeast and associated with a deep upper trough.
The weather pattern brought clouds and precipitation to southern California as well, including snow in the Sierras and the California coastal mountains, Mass wrote.
Andy Porter can be reached at email@example.com or 526-8318.
May rainfall records
Saturday's rain was measured at 1.37 inches at Walla Walla Regional Airport. The total tied as the third-heaviest rainfall recorded in Walla Walla in May. Previous records are:
1.7 inches on May 26, 1971
1.49 inches on May 17, 1991
(tie) 1.37 inches on May 30, 2000
(tie) 1.37 inches on May 14, 2011
As of this morning, preliminary data shows 3.05 inches of rain have fallen this month, putting this May on track to break into the top five wettest Mays in recent times. The top five rainfall totals for May in Walla Walla are:
6.63 inches in May 1991
4.13 inches in May 1962
3.80 inches in May 2000
3.40 inches in May 1993
3.35 inches in May 1990