Heat Warning Extended, New Records Possible: Puget Sound Forecast

SEATTLE — Puget Sound’s marathon of warmth will stretch on a little longer, with an “excessive heat warning” now in place through Saturday, but next week is shaping up to be much milder — and there could even be a little rain on the horizon.

The National Weather Service said Thursday that dangerously hot afternoons would carry into the first part of the weekend, extending its heat warning until 9 p.m. Saturday. If Seattle breaks the threshold a fifth time Saturday, as is the current forecast, the Emerald City will tie its record for most consecutive 90-degree days.

Sunday will still be very warm but should land a few degrees cooler before the big shift Monday.

“This persistent upper ridge looks to stick around mainly throughout Saturday, which will give us again another hot day across the interior, with temps again in the low to mid 90s,” NWS Seattle wrote Thursday. “There is increasing confidence that Sunday will [still be] a hot day for the interior. The uncertainty is focused on how far the marine relief will push inland.”

Air quality problems continue for some; Phase 1 burn ban in King County

Air quality concerns will also continue along the Cascade foothills and in parts of southeast Pierce County, where the Puget Sound Clean Air Agency has issued an ozone alert, with air quality ranging from “unhealthy for sensitive groups” to “unhealthy” for communities including Issaquah, North Bend and Enumclaw.

(Puget Sound Clean Air Agency)

“Ozone levels are well into UNHEALTHY FOR SENSITIVE GROUPS at Enumclaw as of Thursday (and at Issaquah as well on Wednesday),” the agency wrote Thursday. “We may even reach levels of UNHEALTHY Friday and Saturday given the slight build up over time.”

Officials expect the air will clear as temperatures cool, improving Sunday through Monday.

The extended run of dry weather has also increased fire dangers across the region, prompting the King County Fire Marshal on Thursday to issue a phase one burn ban, starting Friday. The burn ban applies strictly to yard debris and does not apply to recreational fires or grills.

Cooler days and some moisture next week

The latest forecasts show temperatures tumbling back into the mid-70s by Monday, bringing with it the first slight chance of some rain in quite some time. A marine layer should help keep things on the milder side for most of next week, with a few chances for rain and some potential for thunderstorms.

“With this trough coming onshore, there is rotating moisture that will deepen the marine layer,” wrote Kayla Mazurkiewicz, a meteorologist at NWS Seattle. “For Monday through Thursday, there may be enough moisture for showers. There is also a possibility for a few thunderstorms early on in the week (which will need to be monitored in the next coming days for increased fire weather, as fuels have become more drier due to the heat). Overall, expect more seasonal temperatures next week and a much needed break from the heat.”

Source: Bellevue Patch