A flash flood watch is in effect across the Inland Northwest today for a potential repeat of powerful thunderstorms that hit the region over the past week.
National Weather Service forecasters said a combination of forces is coming together for what they termed a “classic thunder pattern.”
The chance of thunderstorms is 80 percent today in Spokane and Coeur d’Alene, dropping to 50 percent tonight.
A stalled low-pressure area off the Oregon and California coast was expected to move northeast today and gather moisture as it draws air northward ahead of it.
Part of the expected moisture is coming from the remains of Hurricane Fabio that gathered across the intermountain West on Thursday.
At the same time, a new low-pressure area from the Gulf of Alaska is dropping southward and is expected to provide a “kicker” to move the Oregon low-pressure area inland, causing thunderstorms to form.
On Tuesday, meteorologists reported 1,700 lightning strikes in a six-hour period. Today’s weather pattern appears even more favorable for thunderstorms, they said.
Last weekend, heavy downpours clogged drains on Interstate 90 in Spokane, slowing traffic. The rain also caused localized flooding in east and southeast Spokane.
On Thursday, Spokane reached 91 degrees by 5 p.m., making it the eighth day this month with a high of 90 or warmer. The hottest day so far this year was July 8 at 98 degrees.
The region should undergo significant cooling starting today, as highs go to the lower 80s and lows drop into the upper 50s through the weekend. Drier air should bring sunshine over the weekend. By Monday, highs will fall to the middle 70s with mostly sunny skies.
The record high for today is 106 degrees, set in 1931. The average high is 84.
Spokane International Airport has measured 0.59 inches of rain this month, which is normal for the season. Some areas, however, have seen much higher totals.