A significant heat wave is building across western Washington and the wider Pacific Northwest. Forecasters say temperatures over the next few days are expected to flirt with a record 90 degrees, marking one of the hottest stretches of the season so far for a region more used to mild summer weather.
Records were already being set. A 65-year-old record high was broken at Hoquiam, while the mercury climbed to 81 degrees in Seattle, 82 degrees at Sea-Tac and 86 degrees in Olympia, signaling how widely the heat has spread across the area.
The hot weather is being driven by a strong ridge of high pressure combined with an offshore flow of air. That pattern is expected to keep pushing temperatures upward over the coming days, rather than allowing the usual cooling influence of marine air to take hold.
Officials have responded with formal alerts. A heat advisory is in effect from 11 a.m. Sunday until 5 a.m. Tuesday, while farther south an extreme heat warning has been posted for the Portland area, where conditions are expected to be even more intense.
Part of what makes this stretch dangerous is the lack of overnight relief. Lows are only expected to drop into the low and mid 60s, leaving little chance for homes, buildings and the human body to cool down before the heat ramps up again the following day.
Forecasters are tracking cooler, marine air arriving by Tuesday to finally ease the temperatures. The peak is expected around Monday, which also coincides with the first World Cup match at Seattle Stadium, where readings close to 90 degrees would break a record for that date.