PORTLAND, Ore. (KOIN) — Feast your eyes on the system that is moving through the Pacific Northwest this afternoon. Clouds covering both Washington and Oregon like a canopy. Plenty of rain with your occasional thunderstorm trying to develop. This thunderstorm threat is going to carry over to Wednesday. In fact, it may even be a bit more aggressive tomorrow with the support of colder air.
The threat of thunderstorms in the Willamette Valley is limited. Most locations west of I-5 will be at a higher threat than those east. You can check out the graphic below to get a good idea of the locations that may be more prone to some lightning or a heavier shower. There are some systems that may bring in some strong storms for the Cascade foothills and locations to the east. This is not going to be that type of system. I would be most concerned for areas of the Oregon coast and then some inland on Tuesday afternoon and evening. At this time we aren’t expecting anything severe, but the wind may be gusty and there could be a few lightning strikes.
Speaking of wind, it sure was a breezy start to the day. Unsettled weather dominating the forecast because of that area of low pressure we discussed in the morning blog and the front that was moving in. It looks like we barely topped off in the 30 mph range this morning, with Eugene and the I-205 bridge taking the cake at 33 mph. That is under the wind alert criteria from the NWS but it’s strong enough to make for quite the battle if you’re riding your bike in for a commute. Today wouldn’t have been the best day for that, but I know that some folks are committed (and good for you, seriously!).
The Oregon coast was expecting stronger wind and they received it. Astoria topping off at 55 mph and Garibaldi, coming in with a wind gust of 70 mph! That’s pretty impressive, even battling Cape Foulweather for the strongest wind gust. A lot of communities coming in at 50 mph and that is why they had a High Wind Warning this morning, which is now expired. Watching out for some coastal flooding because of the tidal overflow today. Some of the prone spots, like highway 101 near Tillamook, may have some issues.
I want to finish this blog off with one last weather model graphic about the potential for a storm or two on Wednesday. We are working with more of a traditional cold pool of air on Wednesday, which is likely going to help support some thunderstorms on Wednesday. This will likely extend east of I-5 and cover more locations than on Tuesday. The graphic below depicts a parameter called CAPE (convective available potential energy), not to be confused with the geographic definition of a cape. You can think of that as fuel for thunderstorms. Notice the big swath of purple and pink, that is going to be the locations that will be at a higher risk for thunderstorms on Wednesday. This may mean some small hail or graupel, it may also mean some heavier showers and a lightning strike. Just be ready for a little more aggression to the cells tomorrow.