The National Weather Service Has Issued an Excessive Heat Watch for Portland This Week

A ridge of high pressure—not unlike the heat dome that set record temperatures in June—is about to move in over the coast and the Willamette Valley.

Another heat wave is about to hit Portland.

The National Weather Service issued an excessive heat watch for Northwest Oregon this Wednesday through Saturday. It warns that temperatures in Portland could climb past 105 degrees. The warmer weather starts tomorrow, when temperatures will likely reach the 90s.

A ridge of high pressure—not unlike the heat dome that set record temperatures in June—is about to move in over the coast and the Willamette Valley. It’s expected to be at its most intense Thursday and Friday. But it doesn’t look hot enough to actually be considered a heat dome, let alone a record-breaking one.

“This is more just a standard heat wave,” says Rebecca Muessle, a meteorologist at NWS. “This is not uncommon to see this time of year.”

Unlike with June’s heat wave, temperatures will cool overnight and won’t ramp up until later in the day. Though at around 70 degrees, the expected overnight lows might not feel like a major cool-off.

“Those highs, while very hot, are only going to last for a few hours,” says Muessle. “We’ll see some cooling overnight, but maybe not as much as we’d like.”

Fortunately, the heat wave won’t last long. Temperatures will slowly start to cool on Saturday, and will continue to drop early next week.

Still, NWS is urging caution this week.

Northwest Oregon residents are encouraged to avoid strenuous activity during the hottest parts of the day, and practice caution when swimming in lakes and rivers, many of which will still be comparatively cold.

“Heatstroke can hit anyone,” says Muessle. “We really want to make sure that people know the signs of heatstroke, know where the cooling shelters are and take care of themselves.”

A current map of cooling spaces in Multnomah County can be found here.

For more advice on what to do when it’s hot outside, the Portland Bureau of Emergency Management has compiled a list of resources and advice on everything from recognizing signs of heat stress to caring for animals and plants.