The heat wave impacting the Pacific Northwest is forecast to continue into the weekend as a ridge of high pressure sits over the Western United States and Canada. The National Weather Service offices in both Pendleton and Spokane have extended their excessive heat warnings for their portions of the Columbia Basin to last until 23:00 Sunday. In the Tri-Cities, this will include all of Water Follies weekend, as well as the Watershed Music Festival at the Gorge Amphitheater near George.
Friday and Saturday are likely to be the hottest days in both locations with temperatures reaching to or just above 110° during the afternoons in the Tri-Cities and just below that value around George. While the river may moderate temperatures by a few degrees in adjacent parks like Columbia Park in Kennewick, five degrees below 110 is still very hot. The Gorge Amphitheater is too far from the Columbia to benefit from river-driven cooling.
Don’t expect much cooling overnight. Lows are not expected to get below 70° this weekend except in high elevations and well sheltered locations. The water temperature measured at McNary Dam near Umatilla was recorded at 70° on Wednesday which is not exceptionally unsafe, but is worth noting if you plan on getting into the river.
Otherwise, if you plan to be outside this weekend drink plenty of fluids, spend as much time in shade as possible, avoid being outside during the hottest time of the day, and watch those around you. If you are drinking alcohol, remember to also drink water because alcohol has a dehydrating effect on the body. Know the signs of heat exhaustion and heat stroke and seek medical attention when needed.
These events come during the hottest time of the year, with the average high in the Tri-Cities at 94°. Still, this is unusually hot and may set daily records:
| Day | Forecast High | Record (Year) |
| Friday | 110° | 107° (2014) |
| Saturday | 110° | 111° (2020) |
| Sunday | 108° | 109° (2020) |
Cooling is expected to begin Monday when highs are forecast to not make it above 100°. By midweek, the Tri-Cities may even struggle to get above 90°. By this point, the Tri-Cities are likely to have experienced eight consecutive days above 100° and six above 105° (a new record if the forecast proves accurate). More details on the cooling trend in the coming days.
