Cheryl Peterson asked this question and this is the number one question I’ve received recently: What does it take to break up the heat pressure dome? Or does it eventually just go away?
First, let’s start with what’s happening. First of all, you go to the Pacific Northwest and the Gulf of Alaska, and what you’re seeing are warmer than average temperatures. And when they’re this high above average, what happens is a ridge of high pressure is created. The Jetstream is moved to the north. And the cool air is kept mostly in Canada. This ridge of high pressure has been so strong that we haven’t seen any meandering of the jet stream. This has allowed a dome of high pressure to form and basically remain in place for two months straight. Usually there’s a meandering of the jet stream where a summer high pressure ridge is able to move around. Most summers you get showers and thunderstorms from sea breeze storms with average temperatures in the mid 90s. It’s always hot. But this summer has been exceptionally hot!
What needs to happen is a cool air intrusion by a buckle in the jet stream to move in the cooler air. The issue with this is that the waters in the northern Pacific aren’t cool yet. We have to wait for this to happen before the Jetstream can move. We may have to wait until we get a little closer to fall for this to happen. In fact, the next two weeks look like there’s not any kind of major change from this area of high pressure besides moving a little the west or to the east.
The problem with this high pressure dome is the North Pacific isn’t cooling yet. So the jet stream is not moving and the dome now feeds off itself. When the high pressure dome developed in July it got dry. That led to more heat, more heat led to evaporation. More evaporation led to more dry weather, more dry weather led to more heat, more evaporation and it’s become a vicious cycle to where we now we have fire dangers. We have red flag warnings we have burn bans. We have a lot of issues now with this pattern and we honestly just have to wait until closer to fall to see any kind of change to this weather pattern.
On top of all this we’ve had record warm mornings. We’ve had 16 record high minimum temperatures, in fact, for 11 straight days, August 5th throuh 15th the lowest temperature we had was 81 degrees. The range was 81 to 83 degrees. The reason the incredibly warm the Gulf of Mexico. Some Gulf waters have temperatures in the upper 80s and even 90+ degrees. Our winds at the surface and sometimes the upper levels come out of the south, the Southwest for the southeast. That’s pumping in the warmth and the result has been mornings in the 80s with more expected through Tuesday of next week. I also have no change in the triple digit afternoon heat all the way through the start of September and only one small chance of rain on Tuesday.