Thunderstorms arrive, and leave, on schedule Monday evening, bringing spots of heavy rain

Much cooler this evening after a record run of 90 degree weather
Published: May. 15, 2023 at 9:47 PM PDT
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That was fun this evening! Thunderstorms developed over and east of the Cascades as expected, but just as they started dropping down into the foothills they fell apart. That was the case south of the Columbia River in Oregon. But as that activity fell apart, a strong thunderstorm popped up over the south Washington Cascades. That one became quite intense as it passed over Yacolt, reached max intensity north of Battle Ground, then weakened as it headed southwest toward Vancouver. Radar at 5:20pm looked like this


That’s 68dBZ, comparable to a powerful Eastern Oregon thunderstorm and rare west of the mountains. I see a few reports of 1″ plus rainfall around Amboy and Yacolt.


Pat Timm (Clark County longtime weather forecaster/enthusiast) has a reliable report of 2.50″ rain just about right under that white area on the radar. And about 1.00″ of that in 10 minutes! A warm airmass can produce big rain totals. But most of us in the area remained dry or nearly dry. Take a look at stations that reported measurable rain


It was mainly or all dry south of about Hwy 26 & I-84. Nothing fell south of Portland. Another way to look at it is lightning strikes. At the peak of the activity (around 5:30pm), 57 strikes were recorded in 1/2 hour.


I counted about 140 strikes detected in Clark County, but only 1 or 2 south of the Columbia River in Multnomah County. I didn’t see any in Washington County or southward in the valley.

Okay, a quick update on our historic May heatwave. We overachieved again today with a high of 92. That makes 4 consecutive days at/above 90 degrees, a historic event in Portland. We’ve never seen more than 3 consecutive

Record long May heatwave
Record long May heatwave(kptv)

We’ve broken SIX daily records so far...3 record warm overnight lows and 3 record warm daytime highs


The 63 degree low this morning will be the warmest May low temperature on record IF it stays above 63 through midnight. That appears likely at this point. The previous record warm low was 62.

That’s it for this evening...I’ll be on TV at 10 and 11. That includes a great video of the Yacolt thunderstorm from Oca Hoeflein’s drone! Looks nice eh?

Wx Blog
Wx Blog(kptv)