The Pacific Northwest is bracing for a surge of unseasonably severe weather this week, with record-breaking warmth on Tuesday followed by a strong storm system expected to bring widespread thunderstorms, lightning, hail, and gusty winds on Wednesday.

Forecasters say Tuesday’s temperatures could set new records across the region, with the Puget Sound region potentially hitting 70 degrees. Warmer conditions are also expected to contribute to mountain snowmelt, prompting a hydrologic outlook for some areas.

The National Weather Service (NWS) has extended a severe thunderstorm risk area across western Washington, Vancouver Island, and much of Oregon and eastern Washington.

“The strongest storms that develop could become severe and capable of producing hail up to 2 inches or more in diameter, outflow wind gusts as high as 60 mph or more, and/or an isolated brief tornado,” NWS said in its forecast discussion.

Prognosticators are saying that Wednesday’s system could bring one of the most significant storms we’ve seen in the Puget Sound region in quite some time. NWS has even placed the area under a Marginal Risk for severe thunderstorms on Wednesday, meaning there’s a chance of:

  • Damaging wind gusts
  • Large hail (1” or more)
  • Heavy rainfall
  • Cloud-to-ground lightning
  • And while unlikely, a brief tornado spin-up cannot be ruled out.

Thunderstorms may begin as early as mid-morning over the Olympic Peninsula, with more widespread storm activity expected in the afternoon and evening hours.

Experts say that now’s the time to prepare:

Pacific Northwest Weather Watch Video Forecast

“This is one of the most unstable weather setups we’ve seen in the Pacific Northwest, with conditions more reminiscent of Tornado Alley,” local meteorologist Michael Snyder of Pacific Northwest Weather Watch said in his video forecast.

“Lightning, heavy rain, and gusty winds are probably the biggest threats right now, but you cannot even rule out tornadoes with this kind of setup,” Snyder added.

Thunderstorms are expected to develop early Wednesday morning along the coast before moving inland. A second wave of storms is likely to form by Wednesday afternoon, with supercell-like structures possibly bringing hail and damaging winds.

By late week, a cooler, wetter pattern will return, bringing an end to the region’s unusual unstable system. However, forecasters warn that storm activity on Wednesday will be highly dependent on daytime heating—meaning that more sunshine could result in stronger, more volatile storms.

Residents are urged to stay updated on weather alerts and prepare for potential severe storms throughout the day Wednesday.