Forget plain ol' snow showers: Seattle goes straight to thundersnow

SEATTLE -- If you had a weather bingo card, you'd most likely have a bingo now with the wide -- and wild variety of weather that moved through the Puget Sound region Monday.

The morning brought about 1-3" of snow in spots, mainly on the Eastside. Then an active Puget Sound Convergence Zone hit in the afternoon, complete with rain, hail, graupel, heavy snow -- and even some lightning!

Staff at the Space Needle managed to capture a lightning strike hitting the landmark's top:

I counted four other lightning strikes as I filmed the transition from rain to hail to snow outside:

And Mark D. Lim also managed to capture the lightning strike:

The wild weather was courtesy of an active Puget Sound Convergence Zone, which is formed by colliding winds that wrap around the Olympic Mountains. This zone was intense enough to drop the temperature 6 degrees in minutes to the mid 30s and brought a rare thundersnow.

The Zone was expected to fizzle by late evening and temperatures were to climb back into the upper 30s, melting the new snow.

A Winter Weather Advisory remains in effect until 9 p.m. for the Seattle Metro and Eastside areas but the bulk of the snow was expected in the convergence zone.

Round 1 wasn't too shabby either

The thundersnow came on the heels of a round of snow earlier Monday morning that ranged around 1-2" in the Seattle Metro area and Eastside areas above a few hundred feet. Spotters in Monroe and Mill Creek reported 1.5", while Sand Point in Seattle had 1.2 inches and Kenmore and Canyon Park have reported 1" each.

But the shower appeared to have the greatest intensity around the Kirkland and Redmond areas, where spotters reported between 2-3 inches of snow. A spotter on Redmond Hill at 554 feet reported 4 inches of snow. It was enough to cause a few school delays and changes to bus routes.

The main arterial roads and freeways were in good shape, but some hilly side roads were slick, and there were reports of some spin-outs in the areas where more than an inch fell, including North Seattle/Ravenna areas, Kirkland and Redmond.

In Kirkland, a school bus slid off NE 120th just east of Slater and partially into a culvert. No one students were on board and no one was hurt, said a Lake Washington school district spokesperson.

And in Redmond, a semi truck got stuck trying to go up NE 156th and 40th:

WSDOT says they had 25 plows out treating roads - -mainly between North Seattle and Everett.

Heavy shower + cold time of morning = snow

The snows Monday weren't any part of any arctic outbreak or big winter storm. Basically, an area of showers managed to find its way into the heart of the city during the coldest time of the morning during a weather pattern that was marginal for snow.

Snow began just after 5 a.m. and increased in intensity as the morning commute got under way. Temperatures were in the mid 30s in the hours after midnight, but the showers were heavy enough that it cooled the atmosphere a couple of degrees toward freezing and drove the snow levels down to near sea level. Ironically, this cooling engine has failed a number of times earlier this winter and has led to marginal forecasts that failed -- including Sunday. But it finally all came together Monday morning.

We'll remain on this edge of rain/snow Monday night into Tuesday morning so we may see a repeat of scattered wet rain/snow showers Tuesday morning with minor accumulations, especially above a few hundred feet. But again temperatures will warm into the 40s again Tuesday changing any showers to rain.

By Wednesday we'll finally warm up enough to where it's all rain, so snow fans, soak up this morning's slush while you can!

Snow totals:

  • Redmond Ridge: 4.0"
  • Lopez Island: 3.8"
  • Kirkland: 3.0"
  • Bothell: 2.5"
  • Woodinville: 2.5"
  • Redmond: 1.8"
  • Mill Creek: 1.5"
  • Seattle/Sand Point: 1.2"
  • Kenmore: 1.0"
  • Canyon Park: 1.0"
close video ad
Unmutetoggle ad audio on off