May 30, 2020

The Main Act is About to Begin, But Lack of Radar Coverage is a Problem

As predicted, the second.....and probably more potent...line of thunderstorms is now moving northward near the Oregon/WA border.

The latest visible satellite image (4:26 PM) shows several major, strong convective systems entering Washington State.  The one on the right has good radar coverage from the Pendleton, Oregon NWS radar, but the western one is in the well-known radar hole over the eastern slopes of the Cascades.

The radar image at the same time (below), shows intense radar returns with the eastern storms (red colors), but the western systems have poor coverage so we don't know how strong they are.  Since they are heading for the Cascades and western WA, this is not good.

Over the past half hour, lightning sensors have shown massive lightning in these storms (see below, each strike is shown by an "X")

There are some strikingly strong winds with this line of thunderstorms, with some gusts reaching 60-70 mph! (see the max gusts over the past hour below)

Notable weather enthusiast, Dr. Peter Benda of Bellevue, went storm chasing in the Tri-Cities today, and the picture of the mammatus clouds beneath the anvil of the approaching storm is scary (see below)

And is another shot from Dr. Benda as the storm got close. Beautiful.  And you can see heavy rain falling out of the cumulonimbus.

And if you want to experience some of the strong outflow winds from the storm, check out the video he sent:

And there was hail with some of the more intense storms.  Here is a video provided by Pam Hayes showing the squash bass sized hail that hit around Tumalo, Oregon (just northwest of Bend) around 2 PM:

These storms will sweep northward during the next few hours.  Expect severe weather in the Columbia Basin and we will see how much of the action will get over the Cascades.  At the very least, the west side will have plenty of rain and some lightning.  The latest NWS HRRR forecast for 7 PM shows strong storms moving towards Ellensburg and Wenatchee, with others heading in the direction of Spokane, with light to moderate rain over the westside.  Without good radar coverage east of the Cascade crest, we won't be about to document the details there.


  1. Cliff Mass, I always love how you make the weather so much more nuanced, approachable and fascinating. Thank you for taking the time to share your knowledge and expertise with us.

  2. I haven't seen you mention them but I wonder what your opinion is

  3. Many thanks...sharing above and beyond what is typical...that's exceptionalism.

  4. I was thinking the same thing, Mark. Right now they are showing Ritzville getting hammered. There is very little action close to the crest, or west of it (unlike this morning). We'll see if that continues.

  5. Storm just approaching Kelowna BC now

  6. I can be of some help with the lack of coverage on the east slopes of the Cascades. We are camping along Peshastin Creek, north of Blewett Pass. Only a few claps of thunder between 5 and 7pm, a fair amount of rain, and about a 25 degree drop in temperature being the most impressive feature. Nothing special to speak of here, given the tone of the forecasts.

  7. Thanks Cliff.
    From 100 miles east of Seattle:
    We are about 5 miles NE of the Ellensburg airport (KELN).
    The storm came just before 5 pm and got serious an hour later:
    30 May 6:53 pm 53 48 83 N 44G60 1.75
    The high temp for the day was 87; did not last long.
    The line above shows sustained wind of 44 and a gust of 60.
    No hail near, as far as I know. Heard thunder, but off aways.
    At 8:45 the wind has gone to mid-20s. Sun for a short time before dusk. Our power went off and came right back, but clocks and such had to be reset.

  8. I've measured 0.57" of precip at my location in NW Bellingham since just before 10AM. This is the greatest daily precipitation measurement since 2/5. This May has now been the wettest May at BLI since at least 2014 (precip records at BLI before 2014 are unavailable on WU).

  9. Hey Cliff,

    Here in Bend, Oregon we got a very strong storm cell (about 130PM) and just before it hit town the skies and horizon turned into fantastic shades of dark green and aquamarine. What creates that remarkable effect?

  10. Some healthy rain showers here in Everett during the day, but not much wind...guess we missed the brunt of those storms...there was some thunder too, but not much of a light show.

  11. Moderate thunderstorm on the Bothell-Mill Creek line Saturday morning, around 7-8 AM I think. But nothing compared to an Eastern or Rocky Mountain style thunderstorm, with nearly simultaneous thunder an lightning like to blast you out of your chair.


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