Severe Thunderstorms with Strong Winds, Massive Lightning, Heavy Rain, and Hail Hit Eastern Washington

As predicted, a line of strong thunderstorms moved through eastern Washington yesterday, with dramatic impacts.   The radar image at 8:45 PM last night is shown below.  Red is associated with very heavy rain or hail.

The line of thunderstorms was associated with strong gusts from storm outflow.  The maximum gusts yesterday are shown below.  Some reached over 70 mph!

The result was lots of downed trees and branches, with thousands losing power.   As an example, here is a picture sent to me by Bob Powers of Mabton, Washington (near Yakima).

This event brought massive lightning, with thousands of individual strokes (see below), a measure of the great instability and vertical development of these storms.

This event also produced very heavy rainfall and impressive totals.  Many locations exceeded 1 inch (see below).

And some exceeded 2-3 inches!

This heavy rain not only moistened the soil, but will keep the reservoirs high.

A stunning aspect of this event is how well high-resolution weather models predicted it.  We have come a very, very long way during the past decades.

This weekend should bring mid-60s in the west and around 80F in the Columbia Basin, with dry conditions.  Enjoy.

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Announcement

I will hold a special online Zoom session at 10 AM on Saturday for Patreon supporters. 

Severe Thunderstorm Threat On Thursday

There is a significant chance of several thunderstorms tomorrow (Thursday) over eastern Washington, eastern Oregon, and northern Idaho, with the potential for heavy rain, lots of lightning, and strong winds.

The Spokane National Weather Service office has a severe thunderstorm warning out:

And the NOAA Storm Prediction Center has a moderate level of warning (yellow), which is very unusual for our region.

The predicted strong thunderstorms will move in during the afternoon.  The National Weather Service high-resolution HRRR model shows an intense line of thunderstorms (convection) moving through around 10 PM Thursday.

Three hours later, the line crosses the Canadian border with some showers reaching western Washington.

The line of thunderstorms will be associated with very strong winds in eastern Washington, with some gusts exceeding 60 mph (see wind gust forecast at PM tomorrow, below).  I suspect the wind farms will be "feathered" to reduce damage.

Heavy precipitation will also fall, with the HRRR model going for huge totals over the Oregon Cascades.  Substantial rainfall (over a half inch) over the Yakima River drainage.

The UW forecast model is also producing heavy rain over eastern Washington, which should be a great relief to those concerned about drought.

Localized flooding in river valleys is possible.

Why the potential for such an intense event?    

The "set-up" is illustrated in the upper-level map below (for 500 hPa pressure, about 18,000 ft).

An upper-level trough of low pressure is approaching (yellow arrow), producing uplift that can release atmospheric instability.  A second trough to the south (red arrow) is moving moist, unstable air in from the southwest northward into our region.   Upslope on the eastern slopes of the Cascades will contribute additional meteorological fuel.

In short, later tomorrow will be an exciting time from the Cascades and to the east.

Announcement

I will hold a special online Zoom session at 10 AM on Saturday for Patreon supporters.