As a weather weenie, I actually click on the ‘forecast discussion’ link on National Weather Service pages so I can geek out on all the meteorological details behind a forecast. But in all the years I’ve been doing this (and there have been many), I’ve rarely seen language like this:
OF COURSE...OUR SCREAMING MESSAGE CONTINUES TO REVOLVE AROUND THE HEAT WAVE. NEAR RECORD TO RECORD TEMPERATURES HIGH EXPECTED WITH SOME ALL TIME RECORDS POTENTIALLY BEING BROKE.
As I’m writing this, it is 8:15 p.m. in California, and near Furnace Creek in Death Valley National Park the temperature stands at 118 degrees F. That’s just four or five degrees down from today’s high temperature. But it’s nothing compared to what may be coming.
Looking forward, it’s possible that the record for highest temperature ever reliably recorded on planet Earth could be tied or broken before this epic heat wave is all over. This has been reported widely, and one of the first to do so was my colleague Andrew Freedman over at Climate Central.
But what exactly is going on? Perhaps you’ve heard that the extreme high temperatures in the region are due to a dome or ridge of high pressure over the West. But what does that actually look like? The illustration at the top of this post gets at that question.
Keep in mind that the picture shows a hypothetical dome, not the real one causing all the trouble right now. And its position is shifted eastward.
Check out the excellent explanation of this phenomenon by the National Weather Service. Here’s a snippet:
Summertime weather patterns are generally slower to change than in winter. As a result, this mid-level high pressure also moves slowly. Under high pressure, the air subsides (sinks) toward the surface. This sinking air acts as a dome capping the atmosphere.
This cap helps to trap heat instead of allowing it to lift. Without the lift there is little or no convection and therefore little or no convective clouds (cumulus clouds) with minimal chances for rain. The end result is a continual build-up of heat at the surface that we experience as a heat wave.
The dome over the West is locked in place because of a giant kink in the jet stream:
That kink is stuck in place for now, and it looks like it is going to remain that way for awhile. I’ll be watching to see whether this results in a new record for highest temperature ever recorded on Earth.