'Sasquatch showers': A record 145 Seattle rainy days, but Wednesday wasn't one of them?!?

Clouds loom over Downtown Seattle Wednesday afternoon, as its buildings reflect blue skies nearby to the south toward Sea-Tac Airport. (Photo: Zack Heistand)

SEATTLE -- It didn't just rain, it poured.

Rain pattering our windows was loud enough here at KOMO HQ near Seattle Center, it drowned out the incessant chatter of the news scanners. Hail plinked off windows and cars. Storm drains struggled to keep up. Instant puddles flooded the landscape.

"I was out laying mulch in my yard under blazing sunshine," said KOMO photographer Stephen Ramaley.

Then the skies opened up.

"I was soaked down to my you-know-whats."

We've had 145 days with measurable rain since October 1st -- far and away a record amount for that time period since records have been kept in the late 1800s.

But someday when future meteorologists gaze back upon Seattle climate books and look up April 26, 2017, it'll appear as one of the few days it didn't rain.

Wednesday's weather was somewhat unique in a few ways -- not just one, but two Puget Sound Convergence Zones formed and took turns soaking much of the Puget Sound region.

The first Zone formed in the mid-afternoon and swept through North and Downtown Seattle with torrential rains and even some hail:

The University of Washington recorded 0.16" of rain in 21 minutes.

That zone fizzled as it passed just south of downtown. But don't worry, a second Puget Sound Convergence Zone formed a short time later in Snohomish County.

By the end of the night, Everett's Paine Field reported 0.69" of rain for the day -- quite wet! Volunteers with the CoCoRahs weather spotter group reported rain totals ranging from 0.75-1.15 inches across northern King and southern Snohomish County. The University of Washington ended up with 0.24".

But guess how much fell at Sea-Tac Airport?

Zero. (Well, officially a Trace, but that means not enough to measure.) It has to register at least 0.01" at Sea-Tac to count as a rainy day in our record books.

Neither Convergence Zone made it far enough south to the airport -- a side effect to how the Convergence Zones form. In a nutshell, the rain forms as winds split around the Olympic Mountain and collide over that North King/Southern Snohomish County area, causing convection and rain. But the colliding winds have an opposite drying effect on either side of the zone and the colliding air sinks back down on either side of the zone. Typically it can be quite sunny just on either side of where it's raining, as evidenced by this visible satellite image:

Sea-Tac was in that dry slot all day long. So 145 days of rain this rainy season, but Wednesday wasn't number 146.

It made me think of perhaps a new term to describe rainfall around here. Sure we have frequent showers, isolated showers, spot showers, scattered showers, etc...

Wednesday, we had "Sasquatch Showers". For some people who lived in the region, stories and legends abound about the showers' existence -- even some grainy photo evidence -- but from where you sit, you have no definitive proof, and official sources will tell you it never happened.

"But wait, it DID rain on April 26th -- Sea-Tac even says so! Is this a conspiracy?"

Now, some of you who really could not believe Wednesday didn't have any official rain might have gone and checked Sea-Tac's stats yourself, and went, "Ah-HA! Scott messed up! I see 0.01" of rain reported at 12:53 a.m.! "

True, Sea-Tac did get measurable rain on the calendar day that was April 26. But we can blame Germany for why it doesn't actually count for statistical purposes. Germany was the one who came up with that whole Daylight Savings concept, and this month, 12:53 a.m. is Pacific Daylight Time.

However, all official weather records are kept on Pacific Standard Time year 'round so as to not have inconsistencies in the data. Thus, official daily climate statistics are measured from midnight-to-midnight Pacific Standard Time -- or 1 a.m. to 1 a.m. Pacific Daylight Time. That 0.01" that fell at 12:53 a.m.? Counted in April 25th's total...

So for those who have stumbled upon this blog in the future while doing research on this record-breaking winter - maybe put an asterisk next to that rainy day stat. For most Seattleites, the count feels like it should read 146!

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