PORTLAND, Ore. (KOIN) — Thursday is the last mild day in Portland as the summer sizzle brings temperatures to record-breaking conditions.

Sunny skies continue Thursday across western Oregon and Washington. That sunshine will push temperatures into the mid to upper 70s by the early evening hours. This comes as Portland prepares for record-breaking temperatures by the weekend.

A ridge of high pressure brings the heat later this week

A ridge of high pressure is expected to build over the western half of the country. That will help warm temperatures by nearly 20 degrees from Monday to Friday.

Rapid warming trend expected in Portland later this week

Portland’s held firm with its low to mid-90-degree records in mid-May for nearly 50 years. Those records will likely fall Saturday through Monday.

Afternoon highs will climb nearly 20 degrees from Monday’s high of 68 degrees. Nearly a 30-degree jump is expected with a return of the mid-90s by Saturday.

This prolonged heat wave poses the biggest threat to those that can’t seek shelter indoors or for those without air conditioning.

Now is the time to prepare for the excessive heat. Staying hydrated, wearing loose-fitting clothing, taking breaks indoors or in the shade frequently, and checking on neighbors will be practices essential to surviving this latest round of summer heat.