PORTLAND, Ore. (KOIN) — Multnomah County Chair Jessica Vega Pederson has announced a state of emergency beginning Friday due to forecasts calling for dangerously hot temperatures as it prepares to open cooling centers that day.

This comes after the National Weather Service announced an excessive heat warning for the Portland area effective noon on Thursday, July 4 through 11 p.m. on Sunday, July 7, with forecasts pointing to hitting triple digits over the weekend. Oregon Gov. Tina Kotek also announced the state is mobilizing emergency resources to combat the potential record-breaking heat.

The county's emergency declaration is effective at noon on Friday, July 5 until noon on Monday, July 8. County officials noted that the forecast will likely exceed 100 degrees on Saturday and Sunday and that "temperatures may not drop enough at night to offer needed relief."

"Obviously we've been watching this and it hasn't trended in a very favorable way for us," said Multnomah County Director of Emergency Management Chris Voss.

While officials said the county and its partners are preparing to open the cooling centers and offer other cool spaces amid the dangerously hot forecast, the exact locations and hours won't be announced until the day before. KOIN 6 News asked the county why the wait is necessary.

"There's a lot of resources, and dollars, and people that actually do this. And so for us to make sure that we're going to be there for the highest risk days, it means that sometimes we're careful when we put together a process so that we're not there when the community doesn't need these resources," Voss said.

Though officials said on Tuesday that the final decision about whether the cooling centers would open wouldn't be made official until Thursday, they've seemingly changed their tune Wednesday. Voss said that county officials are "lining up locations for cooling center, recruiting staff and developing plans."

"Everyone should be thinking about how they can keep themselves cool, and making plans to support friends and family who might need help,” he said.

County health officials said people who spend prolonged time outdoors — including those experiencing homelessness — those who are very young or old, and those with health conditions are particularly vulnerable to heat-related illness.

“Whether you’re staying home this weekend or out and about, we need everyone to look out for one another," said Multnomah County Health Department Health Officer Dr. Richard Bruno in a statement. "If you have air conditioning, now’s the time to invite older family members and friends over. Call and check on friends and seniors who may be at increased risk of heat-related illness. ‘’

Those going to music festivals and sporting events are also at risk of heat-related illness as attendees typically spend lots of time outside, with little access to shade and water, Bruno said.

More information about available cooling locations can be found on this interactive map on Multnomah County's website.

Cooling centers in neighboring counties

In Clackamas County, the emergency operations center was activated Wednesday morning to prepare their response. A cooling day center will be available Thursday at Father's Heart in Oregon City (when libraries are closed).

Starting Friday, the Beaverton City Library Main and Murray Scholls Branch will operate as cooling centers in Washington County, with the main branch extending lobby hours until 9 p.m. through Sunday. More information about Washington County cooling centers can be found on an interactive map on their website.

Clark County in Washington also plans to open two day centers on Friday, in addition to coordinated medical outreach for the homeless.