A thermally-induced surface trough, pushing the airflow offshore is the scenario responsible for the increase in temperatures that will take us well above seasonal norms through the weekend. Forecasters with the National Weather Service have issued heat watches and warnings for various locations throughout Oregon and Southwestern Washington through Sunday.

Heat watches

Friday starts the short heat wave off with totally clear skies and a high of 90. Unlike previous evenings this week, the low overnight will only dip to 60 degrees making it harder to cool off living spaces. Please remember to check on the elderly and on folks living without cooling systems.

There's still some debate from the forecast models on what high temps will be on Saturday. At this point it looks likely we'll climb over the mid 90s and get very close to 100 degrees.

The coast looks toasty as well with the beaches seeing temperatures into the high 80s or low 90s. So, no relief there. Here's a list of Multnomah County cooling centers and Washington County cooling centers open this weekend.

Forecasters are also watching for a possible southwest marine surge moving along the central coast Saturday night and Sunday. This could cool things off a bit for Sunday especially in areas south of Salem where it's possible temps will stay in the low 90s. However, temperatures should remain very high (near 100) for the north and central Willamette Valley, Clark County and the western section of the Gorge on Sunday.

This extreme heat isn't expected to hold on for long. By Monday we should see a shift to a more onshore flow and temperature moving back down about 15 degrees with highs in the mid 80s.