Preliminary weather data shows Washington might have broken its all-time heat record — in addition to shattering several local records — on Tuesday, though the temperatures have yet to be confirmed by a state climate committee, meteorologists said.
Two stations in Chelan County — one in Peshastin and one in Ardenvoir — recorded 119-degree highs Tuesday afternoon, surpassing the state’s previous all-time high of 118 degrees, which was recorded on August 5, 1961, at the Ice Harbor Dam, just east of the Tri-Cities.
The potential new, statewide record is among a handful of other all-time highs east of the Cascades, according to the National Weather Service’s Spokane office. During a heat wave that’s hospitalized dozens of people and killed at least two over the past few days, Omak, Ephrata, Wenatchee, Yakima and Spokane all surpassed their previous highest recorded temperatures on Tuesday, hitting 117, 116, 114, 113 and 109 degrees, respectively.
“A lot of these previous records were set in August 4 and 5 in 1961,” NWS meteorologist Laurie Nisbet said Tuesday afternoon. “There was a big heat wave during that time.”
While meteorologists feel comfortable declaring new records for individual cities, Mark Turner, observing program leader at the National Weather Service’s Spokane office, said they want to wait a bit longer before officially announcing a new record for the state.
“Our sites, called automated surface observing system (units), are the ones at Sea-Tac (International Airport) or Spokane International (Airport) in an area on an airfield that doesn’t have any obstructions, like trees or buildings,” he said.
Because many sites in the state are on people’s roofs or behind buildings and could be near a running air-conditioning unit or sitting in some shade, the sensors could capture inaccurate temperatures, Turner said.
The type of sensor each station has also matters. NWS usually uses aspirated environmental shelter sensors, which draw air across them without getting caught.
“Those are the ones where we have super high confidence in whatever they’re reading,” Turner said. “(The temperature) is not getting affected by any other factors.”
In the next couple of weeks, the State Climate Extremes Committee, which evaluates the climatological records of individual states, will visit the two Chelan County sites and likely others that reported preliminary 118-degree temperatures to confirm whether they recorded accurate temperatures, Turner said.
While Eastern Washington will slowly cool down as the week progresses, temperatures will still remain significantly above averages for this time of year with essentially no cloud coverage, Nisbet said. Wednesday is expected to be at least one to three degrees cooler than Tuesday, continuing to ramp down on Thursday — though the region will still likely hit triple digits.
“Through the 4th of July weekend, we’re still going to be really hot and dry,” with temperatures in the low-100s, she said. By Sunday, Eastern Washington will likely land in the upper 90s to low 100s and by Tuesday, the region is expected to see widespread temperatures in the 90s.
The average temperature for early July, however, is about 81 degrees, so cities east of the Cascades are still about 10 to 15 degrees hotter than usual, Nisbet said.
Because the air has been so dry, Nisbet also warned residents particularly in Eastern Washington to be cautious of creating sparks this week. On Sunday, a blaze burned through more than 2,000 acres near Lind in Adams County, though it’s since been contained.
“This extreme heat is coming on the heels of extreme drought, and we’re looking down the barrel of a holiday that may not like that combination,” Turner said, urging people to be safe when handling sparklers or fireworks this weekend.