Excessive Heat Warning Issued Across Puget Sound

SEATTLE — An incoming heat wave has the National Weather Service issuing an excessive heat warning for Puget Sound and almost all of Western Washington.

The warning, upgraded from a heat watch Wednesday morning, covers the western half of the state from up in Bellingham, through the Seattle-Tacoma metro, and down into Yakima and Hoquiam. The only places it doesn't touch are the coast, which should be clear and cool, and the northeastern Olympic Peninsula around Forks, which remains under a less-severe heat advisory.

The warning went into effect at noon Wednesday, and will remain through 7 p.m. on Saturday. During that time, the National Weather Service is predicting "dangerously hot conditions", especially as the heat continues to pour in Thursday and Friday. While Wednesday will be warmer than average with highs in the mid 80s and lower 90s, Thursday and Friday will see temperatures grow to the upper 90s, near 100 degrees.

That's not as hot as the June heat wave, which killed over 100 Washingtonians and was the state's deadliest weather event ever, but it is hot enough to "significantly increase the potential for heat related illnesses," the weather service said.

Experts are warning residents to take extra precaution if they work outside, avoiding strenuous activities in the midday if possible. They also advise wearing lightweight and loose fitting clothes, and to take frequent rest breaks indoors or in cool environments. Staying hydrated will also help stave off heat sickness.

Older adults, young children, and people with mental illnesses or chronic diseases are at particularly high risk during heat waves, and are encouraged to take advantage of local cooling centers, especially if they don't have convenient access to AC or other means of cooling off. A number of cooling centers will be open over the coming few days in King and Pierce counties.

Finally, the National Weather Service warns that pets and children should not be left outdoors or in hot vehicles.

There will be some reprieve from the heat overnight. According to the latest forecast, late night temperatures should bottom out in the mid to upper 60s, well out of the danger zone.

The high heat also means there will be an increased threat of wildfires through the end of the week. The National Weather Service says it will be particularly dry and unstable along the western slopes of the Northern and Central Cascades, priming them for wildfires. Washington has already seen an above-average fire season, and most counties have issued comprehensive burn bans, as has as the Department of Natural Resources.

The DNR is also warning drivers not to park their cars in dry, grassy areas, as the residual heat from the car can be enough to ignite dry grass.

Unfortunately, even if new wildfires don't spark up, Western Washington is still forecasted to see some smoke and haze, though hopefully it will remain high in the sky. The high-pressure forecast that is pulling all the heat into Puget Sound is also expected to bring in smoke from wildfires burning in Northern California. The latest forecast from the Puget Sound Clean Air Agency predict the air quality will dip down into the "moderate" range Thursday through Saturday, and may potentially turn unhealthy for sensitive groups in the upper elevations.

After Saturday, that high level haze be blown away by westerly winds. Those winds are also expected to push out the high pressure zone, cooling the region and lowering high temperatures into the mid 70s by Sunday.