Heat wave is peaking in Tri-Cities. But expect hotter than normal temps for 2 more weeks

The temperature was climbing Tuesday in the Tri-Cities in what was expected to be the hottest day of the historic heat wave baking the Pacific Northwest.

Just before noon the temperature had already reached 100.

The National Weather Service was forecasting a high of 117 at Pasco and 118 at Hanford, which would tie the state’s all time record high of 118 recorded most recently until the current heat wave at Ice Harbor Dam east of Pasco in August 1961.

The record was tied Monday when the temperature reached 118 in Dallesport, Wash., in Klickitat County.

The weather service forecast highs are a center of a range, and if temperatures are at the top of the range, it is possible for the Tri-Cities or Hanford to set a new state record.

Temperatures should cool a bit later in the week.

Even though highs will remain well above normal in the Tri-Cities, a drop in overnight lows should provide some relief, according to the weather service.

A high of 111 is forecast for Wednesday, dropping to 104 Thursday through Saturday, 102 on July 4 and 101 on Monday, according to the weather service.

Lows could fall from 78 forecast for Tuesday night to as low as 72 on Thursday night and Saturday night.

Normal temps

Normal average highs at the end of June are in the mid 80s and normal average lows are in the mid 50s in the Tri-Cities, according to the weather service. Normal highs average about 90 degrees in the Tri-Cities in July.

The Weather Channel, which issues a two-week forecast, expects high temperatures to remain above 100 at the Tri-Cities Airport until July 12, when it forecasts a high of 99.

The excessive heat warning issued for all of Washington and most of Oregon has been extended in the Tri-Cities through 8 p.m. Sunday, July 4.

More record highs were set Monday in the Tri-Cities area, according to preliminary data collected by the weather service.

The temperature at the Tri-Cities Airport in Pasco reached 114 on Monday, 1 degree cooler than Sunday when a new June record was set.

The high still set a daily record, beating the previous record of 111 set in 2015.

At the Hanford Meteorology Station an all-time high temperature was recorded, with daily temperature records kept there since World War II.

The high of 115 beat the former record high of 114 set on June 27, 2021. The record for the date was 111 set in 2015.

Heat across Northwest

Other heat records fell across the Northwest United States and in Canada on Monday.

Lytton, British Columbia, about 80 miles north of the Washington state line reached 118, beating the all-time record of 116 it set for Canada a day earlier.

In Portland, the high reached 116 on Tuesday, setting a new all-time high for the city for the third day in a row.

The city’s streetcar system canceled service for the day after tweeting a photo of a heat-damaged power cable. Some streets buckled in the heat.

AccuWeather reported that public outdoor pools in Portland closed because lifeguards got sick in the heat.

In Seattle, a record high of 108 was recorded Monday. The Seattle Times reported that as of 2019, just 44% of homes there were air conditioned.

Avista utility customers in the Spokane area lost electric service for part of Monday as Avista was required to reduce electric load on its system and turn off power temporarily.

Tri-Cities area utilities were warning Monday that rolling power blackouts were a possibility on Tuesday as extreme heat put stress on the Bonneville Power Administration transmission system.

This story was originally published June 29, 2021 at 12:25 PM.