A very large and intense ridge of high pressure has developed over the southwestern US, and this ridge containing heights of over 594 decimeters will be responsible for bringing above average temperatures to much of the West this week and weekend. Now while most areas won’t experience record heat, temperatures will certainly be higher than normal.
Temperatures briefly cooled over the past weekend due to the remnants of Hurricane Bud bringing clouds and rain to the Four Corners states. Moisture is now nowhere to be found, which will allow for the dry air to heat up rather quickly once the sun rises. This Wednesday, widespread high temperatures of 5 to 15 degrees above average will take over the West Coast. The higher elevations of California will warm up even further to levels of up to 20 degrees above average. The hot spot relative to average will be in the Pacific Northwest with temperatures up to 30 degrees above normal. That will translate to actual high temperatures in the 80s and 90s across Washington and Oregon, where a few cities may break record highs, up to 90s and 100s in the Southwest. Some locations in the desert region will even rise into the 110s.
The heat will relax somewhat in the Northwest on Thursday thanks to an upper-level distance passing through, which will bring in a few showers to the region. Despite this, temperatures will still be up to 10 degrees above average across much of the western US, although the immediate coastline will be a touch cooler than normal due to the chilly sea surface temperatures. The Southwest will continue to bake with highs of up to 20 degrees above average. In terms of actual high temperatures, it will range from the 70s and 80s across the Northwest up to the 90s and 100s in much of the Southwest. Death Valley may top off at 120 degrees as the heat dome peaks in intensity.
Beginning Friday, the dome will begin to become stretched out as its axis shifts offshore. It will still be hot going into the weekend, however. On Friday, temperatures will be near-average in the Northwest with high temperatures only in the 60s and 70s for the most part due to scattered showers and thunderstorms; A few locations will still rise into the 80s. The most intense heat will become confined to the Southwest where highs will remain well above average, translating to actual high temperatures into the 90s and 100s. Highs in the 110s will be commonplace in the desert areas.
These kinds of temperatures will persist into Saturday and Sunday, although it will briefly warm back up into the 80s to perhaps 90s in the Pacific Northwest on Sunday ahead of another upper-level trough arriving early-next week. This trough will usher in a new round of thunderstorms, posing the risk for severe storms across the interior.