Friday, May 5, 2017

Extraordinary Lightning Strikes over the Northwest

This morning, I took a look at the 24-h lightning strike map for the region and my jaw dropped (see the map below).   Many hundreds (if not thousands) of lightning strikes hit our region, with southwest WA and the eastern side of Puget Sound country getting more lightning than I have ever seen before in a day. Simply amazing.


Why so much lighting for this event?   Certainly, the record breaking amounts of atmospheric moisture streaming into the area the previous two days are prime candidates.  Large amounts of moisture act like "fuel" for thunderstorms, since as the air rises in the cumulonimbus clouds, the moisture condenses, releasing latent heat, which makes the air more buoyant.

Another measure of the intensity of the thunderstorms yesterday were their heights.   Typical thunderstorms around here usually rise to 15,000-20,000 feet at most.  Wimpy stuff.  But yesterday, several of the storms climbed to over 40,000 ft, as shown by the echo-top radar product shown below.


One of my graduate students went to the University of Oklahoma and even he was impressed.  Torrential rain fell out of some of the more intense cells.   In Auburn, 1.3 inches of rain fell in less than two hours.  That is a deluge.

Well, the thunderstorms are over now, and light rain is moving in associated with a (typical) Pacific front.  Oh well...


Finally, for the skiers in the crowd, the NW Avalanche Center is having their annual fundraiser, this time for improving mountain weather stations.  More information here.  And if you want to join local weather lovers at the Puget Sound American Meteorological Society meeting, check below.
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On Saturday May 6th, Larry Schick, lead meteorologist for the US Army Corps of Engineers in Seattle, will talk about Flood Risk Management and Atmospheric Rivers in Western Washington at 3pm at the Seattle Public Library Montlake branch2401 24th Ave. E., Seattle, WA 98112, http://www.spl.org/locations/montlake-branch/mon-getting-to-the-branch All are invited.  Refreshments as well.

15 comments:

John K. said...

"One of my graduate students went to the University of Oklahoma and even he was impressed"

I grew up right in the middle of Tornado Alley. As a child, I remember being awestruck watching the sky explode every few days. That happens all summer long back there - it is a beautiful sight to behold. While out here we have the mountains, back there they have the sky. Our maritime weather out here is boring in comparison.. except perhaps for the occasional cyclone coming ashore from the Pacific.

Bernadette said...

North Tacoma had an incredible amount of rain, around 5:30 pm, in just a half-hour or so. Within a few short minutes our lawn was under water and we had water pouring in under the doors. We face due west, over the Narrows. It was extraordinary. Does anybody know how much rain fell during that deluge?
Bernadette

Colleen said...

We missed out in north Whatcom County. Was so looking forward to a genuine thunder & lightning storm, but it fizzled out before reaching us. Wind picked up slightly around 5pm, a few ominous booms now & then and that was that.

Alistair said...

Cliff, just wondering how the lightning strike map is recorded? Presumably it's done via satellite, but could you say a little more about how that works? What is actually being detected or measured?

Thanks.

Alistair Spence,
Wedgwood, Seattle.

ginnaville said...

Bernadette; A civilian observer (CW1002) near N. Vassault St. and N. 50th St. recorded rain starting at approximately 4:45 pm. At 5:24 the gauge was up to .42 inch, but by 5:39 it was .90 inch! Texas type numbers for awhile for you folks in Tacoma.

Stinky_Wizzleteats said...

Curious how there are strikes out over the Pacific, but hardly any over the Sound. You can almost trace the shoreline.

Matt said...

On the lighting map there are + and - , what do those denote?

Ansel said...

I slept outside under my porch so I could watch. It was like old times back in Connecticut. As cliff says, there hasn't been anything like this in years.

Nancy Devine said...

For a point if comparison it would be interesting to see a "normal" Seattle lightning strike map.

John Marshall said...

Anyone notice the very unusual convergence zone at 5:50pm Friday... it starts in Discovery Bay and crosses Admiralty Inlet to end up near Bellingham. Never seen a strong CZ this far north. Outside of Puget Sound in the Strait.

Susan said...

Imaging artifact. The blue layer is on top, obscuring the red. Look closely at the coastline, Columbia river, even the Canadian border and it becomes clear...

Kurt Klimisch said...

Yes, please do a post on the lightning map. Compare to a "usual" thunderstorm in the Puget Sound.

Organic Farmer said...

Yes!
It poured! Well over an inch in my rain gauge near the Admiralty inlet. Largest single rain event we have had since March I would guess.

Admiralty inlet gets in caught in the "normal" east/west CZ at times, but this one was weird, so North/south in orientation.

John K. said...

Cliff, the definition of a lightning strike is when lightning reaches something on the ground. Are these charts actually showing strikes, or are they showing any lightning activity, including that between clouds (which is most of it)?

Ellen Baker said...

As for the big event, Glacier WA witnessed two full hours of lightning between clouds with loud, near continuous rolling thunder that echoed through the mountains (about 6:20 pm through 8:20 pm). The event was so (pardon the pun) striking that I made some short audio recordings, but they're dominated by the sharp patter of rain. I may do some audio editing to isolate the thunder which was awesome (I'm originally from Pennsylvania).