Western Heat Wave May Near All-Time Record Highs in Oregon and Washington; Rare 100-Degree Heat Possible in Seattle

Jonathan Belles
Published: August 2,2017
A blistering heat wave will sear the West Coast into this weekend, threatening some all-time record highs in parts of Oregon and Washington, pushing Seattle toward a rare triple-digit high.
The National Weather Service (NWS) has issued excessive heat warnings and heat advisories from parts of Washington and western Idaho to portions of central California and western Nevada.

Current Heat Alerts

The NWS office in Portland, Oregon, warned this heat wave could be the city's strongest in eight years.
The peak of the heat wave will persist into Thursday, with highs in the 100s commonplace from California's Central Valley and western Nevada into Oregon and much of Washington's lower elevations away from the immediate Pacific coast. Some of the hottest interior locations may even flirt with 110-degree highs.
(MORE: Hottest Temperatures Recorded in All 50 States)

Forecast Highs

Dozens of daily record highs were set Wednesday, including: Portland, Oregon (103 degrees), Medford, Oregon (112 degrees), Salem, Oregon (107 degrees), Eugene, Oregon (102 degrees), Seattle (91 degrees), Quillayute, Washington (98 degrees), Reno, Nevada (104 degrees), Montague, California (107 degrees), Modesto, California (106 degrees), Mt. Shasta City, California (101 degrees), Stockton, California (105 degrees), Pendleton, Oregon (100 degrees), Redmond, Oregon (100 degrees), Roseburg, Oregon (108 degrees), Klamath Falls, Oregon (99 degrees), Eureka, Nevada (99 degrees), and Winnemucca, Nevada (104 degrees).
The 107-degree high in Salem, Oregon, Wednesday was only 1 degree shy of the all-time record high of 108 degrees, set most recently on Aug. 9, 1981. In addition, Quillayute, Washington, reached its second-hottest temperature on record Wednesday with a high of 98 degrees.
Heat relief will slowly begin arriving west of the Cascades this weekend as a batch of slightly cooler temperatures reaches the Pacific coast. Temperatures will remain above average, however.
Temperatures are not expected to cool much during the overnight hours, especially on Thursday and Friday mornings.
(MAPS: 10 Day U.S. Forecast Highs/Lows)

Potential All-Time Records in Jeopardy

Roughly a handful of cities will flirt with their all-time record highs.

	Current All-Time Record High	When it May Occur This Week
Eugene, Oregon	108 degrees (Aug. 9, 1981)	Thursday
Medford, Oregon	115 degrees (July 20, 1946)	Thursday
Portland, Oregon	107 degrees (most recently Aug. 10, 1981)	Thursday
Salem, Oregon	108 degrees (most recently Aug. 9, 1981)	Thursday
Olympia, Washington	104 degrees (most recently July 29, 2009)	Thursday

In records dating to 1894, Seattle has only had three days of 100-plus-degree heat, all in July:

• July 29, 2009: 103 degrees
• July 20, 1994: 100 degrees
• July 16, 1941: 100 degrees

Seattle could flirt with that rare century mark on Thursday.
(MORE: How Often Your City Reaches 100 Degrees)
The dry ground will contribute to the heat wave in the Emerald City. Sea-Tac Airport is currently in one of its longest streaks without measurable precipitation on record, last seeing rain on June 17.
In Portland, Oregon, this may be only the eighth heat wave in 77 years featuring at least three consecutive days of triple-digit highs. There's a chance that Portland could see four days in a row with triple-digit heat this week, and that would be a first since August 1981.
While not necessarily threatening all-time record highs, this heat wave may also push Reno, Nevada, to their record number of 100-plus-degree high days for any year.
(MORE: Pacific Northwest Been the Country's Most Extreme Weather Region in 2017)

Why the Heat Wave?

Temperatures will be climbing due to a building ridge of high pressure aloft in the West, pushing the jet stream well into northern British Columbia.
Near this expansive, bulging high, sinking air will minimize cloud cover and allow temperatures to soar to the record values detailed above.
(MORE: August Temperature Outlook)

A ridge of high pressure will bring summer heat for the early part of August in the West.

A Few Tips to Beat the Heat

• Remember to stay hydrated even if you don't feel thirsty.
• Wear light-colored clothing to stay cool.
• Take breaks if you must be outside, and find shade when you feel hot.
• Always "look before you lock" your car to make sure you haven't left your kids or furry friends in the backseat.
• Check up on your friends and neighbors that may be more susceptible to summer heat.

(MORE: 4 Things Extreme Heat Does to Your Body)

Recap: Record Highs This Week

Several daily record highs were set Tuesday, Aug. 1, including: Medford, Oregon (110 degrees), Montague, California (107 degrees), Reno, Nevada (103 degrees - tied), Salem, Oregon (101 degrees),  and Mt. Shasta City, California (100 degrees).
MORE ON WEATHER.COM: Heat Waves Plagues the Southwest, June 2017

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