Hunker down this hump day: Severe thunderstorms are expected to move into the Seattle area on Wednesday evening, with the forecast showing the slimmest of chances that a tornado could touch down.
Thunderstorms are relatively rare in the Emerald City. The forecast calls for highs in the 70s and a 30% to 50% chance of thunder and lightning Wednesday evening in Western Washington, as a low-pressure system moves in from the Pacific Coast, according to the National Weather Service.
“We don’t see this setup very often at all, actually, for Western Washington,” said NWS meteorologist Maddie Kristell.
No need to panic. The threat of tornadoes is less than 5%, according to the weather service. But there will definitely be high winds. For a thunderstorm to be “severe,” in meteorological terms, that means wind gusts could reach 58 mph or we could get hail of at least an inch in diameter.
The last significant tornado in Western Washington touched down in Port Orchard in December 2018. The EF-2 twister damaged dozens of homes, traveling 1.4 miles with peak winds around 130 mph, the strongest tornado in the state since 1986.
“The threat of tornadoes is unlikely, but rotation or a brief spin up cannot be fully ruled out,” according to a weather service briefing Tuesday afternoon.
Go inside, grab a blanket, light a candle and stay away from windows.
“Basically, we’ve got a low-pressure system offshore, and it’s positioned in a way that’s really favorable for the development of more robust thunderstorms than we typically see in our area, with an increased likelihood that they may be of the severe variety,” Kristell said.
Thunderclouds may start rolling across the Olympic Peninsula as early as 10 a.m. Wednesday. The Storm Prediction Center ranked the impending storms as having a “slight” risk of becoming severe after 5 p.m. west of the Cascades, as far north as Whidbey Island and as far south as the Columbia River. The storms will likely be short-lived. High winds and hail may impact the Interstate 5 corridor. The brunt of the storm will impact the evening commute.
Kristell said there’s about a 15% to 30% chance of hail in the region.
If you have pets or livestock, move them inside and secure any items that could be blown away by the heavy winds.
The possible thunderstorms will follow a delightfully balmy Tuesday, when the high temperature recorded at Seattle-Tacoma International Airport hit 73 degrees, shattering the previous daily record of 64 degrees set on March 25, at 1969.
The weather will simmer down Thursday with rain showers and lows in the upper 50s. Friday will bring a similar forecast.
