PORTLAND, Ore. (KOIN) — It’s that time of year again when afternoon storms build over the Cascades. Thursday and Friday is no exception to this springtime rule.
Warmer afternoon highs will help destabilize the atmosphere over Oregon and Washington’s mountainous areas by the end of the week. Portland’s afternoon and evening temperatures will climb nearly 10-15 degrees above normal.
That puts highs in the mid 80s, helping increase the thunderstorm potential east of Interstate 5.

The thunderstorm potential remains over Oregon and Washington’s Cascades Thursday afternoon. Lightning will be the biggest threat to those spending time in the backcountry. Flooding rain, hail, and gust winds also remain a threat to those caught unprepared.

Oregon and Washington’s thunderstorm threat becomes more widespread Friday afternoon and evening. The area highlighted on the map above is a guide to where the storms might develop and move over. However, storms may potentially roll out of this highlighted area and into more populated locations Friday.
The chance for thunderstorms Friday is slim in Portland, but it is possible.
Overall, thunderstorms will be visible from the Portland metro area Thursday and Friday. The building clouds will likely be seen primarily over the mountains.

Hikers and other outdoor enthusiasts need to remain weather aware. Lightning is the biggest threat to those caught outdoors Thursday and Friday. Early morning activities that conclude by the early afternoon hours will leave those seeking some outdoor time the safest.