At a Glance
- A historic heat wave is searing the Northwest and western Canada.
- All-time record highs have been smashed.
- Some relief has arrived near the Pacific Ocean, but it won't for several more days well inland.
A historic heat wave has already smashed all-time records in the Northwest and western Canada, and while some relief has arrived for areas closer to the coast, interior locations will continue to bake in record heat into the July Fourth holiday weekend.
Almost 60 locations in the Pacific Northwest and western Canada have already tied or set new all-time heat records for any day.
We have a complete breakdown of all the notable all-time heat records and other oddities from this event in the link below.
(MORE: A Running List of All-time Heat Records Shattered)
Excessive heat alerts are in effect across a large part of the Northwest, from Northern California and northwest Nevada to parts of Washington, Oregon, Idaho and Montana.
These alerts include Medford, Oregon; Boise, Idaho; Billings, Montana; and Spokane, Washington.
(MORE: Heat More Deadly Than Tornadoes, Flooding, Lightning)
Now, let's see when relief is in store.
Relief West of the Cascades
Let's begin with some good news.
For those west of the Cascades, cooler - or more accurately less hot conditions - have arrived.
This is because of a push of air cooled by the Pacific Ocean that began surging northward along the coast and squeezing through the gaps in the coastal range mountains Monday is having some influence. Also, the massive upper level heat dome of high pressure is now gradually sloshing east, away from the Northwest.
This should keep highs generally in the 80s in Seattle and 80s or low 90s in Portland over the next several days That's still warmer than the average 70s for this time of year, but at least it's a significant step down from the torrid record-smashing heat.
Interior Northwest, Northern Rockies
A very slow downward trend in temperatures is forecast the rest of this week into the Fourth of July holiday weekend for eastern Oregon and eastern Washington.
Excessive heat warnings continue in parts of eastern Oregon and eastern Washington through July 4.
While not necessarily all-time record-smashing, this heat will bulge eastward into Idaho, Montana, the Dakotas and Minnesota, also lasting into the holiday weekend.
At least a scattering of daily record highs is likely for interior parts of the Northwest over the next several days.
Impacts, Safety Tips
The hot conditions will be particularly dangerous for vulnerable groups, such as the sick and the elderly. The National Weather Service (NWS) has useful heat safety tips that can be incorporated into a daily routine when extreme heat sets in:
-Job sites: Stay hydrated and take breaks inside as often as possible.
-Indoors: Check up on the elderly, sick and those without air conditioning.
-In vehicles: Never leave children or pets unattended – look before you lock.
-Outdoors: Limit strenuous activities and find shade. Drink plenty of water and avoid alcohol.
The Heat Dome
The reason behind this record-smashing heat wave was a hot dome of high pressure that built into the region as the jet stream took a far-north arcing path into western Canada.
(MORE: The Relationship Between This Extreme Heat Wave and Climate Change)
Sinking air underneath this high-pressure system has sent high temperatures soaring more than 30 or even 40 degrees above average for this time of year.
The ongoing drought has only worsened the heat wave, allowing the parched ground to heat up more efficiently.
The Weather Company’s primary journalistic mission is to report on breaking weather news, the environment and the importance of science to our lives. This story does not necessarily represent the position of our parent company, IBM.
