I really don’t have much to say at this point that hasn’t already been said about the heat. But this is my blog so let me say a few things anyways.
This is an alarming level of heat across the globe this summer.
The oceans are at their warmest level on record.
A good reason why can be found on this map of departure from normal for the temperature of the oceans. The North Atlantic in particular is pretty alarmingly warm for this time of year.
Concurrently, land temperatures have been setting records regularly on a global basis this year. We’ve spiked to record levels of heat across the world this summer.
And perhaps to show how weather is variable and not EVERYONE is super hot you can see this map. In particular, the Eastern U.S. has been enjoying a pretty mild summer overall. But when taken in aggregate, this is the world at its hottest levels ever.
Northern Hemisphere sea ice isn’t at its lowest level ever, but the trend of less and less sea ice during the summer does continue this year, as it is in the bottom portion of the graph overall.
So what does this have to do with severe weather?
There are a lot of reasons I think for the spike in high temperatures this year, some situational and some as part of longer-term warming of the planet we’ve been seeing for a few decades. Still, this has led to what has been a pretty steady drumbeat of severe weather across the U.S. and Canada since February.
Yet, tornado numbers are closer to average than not because we’ve not seen a widespread tornado outbreak day in months.
The season will continue up north, though probably slightly slower than it has been. But, as we move towards the fall, I think the much warmer than average Gulf of Mexico mixed with what has been a fairly active subtropical jet thanks to El Niño (warmer than usual waters in the Equatorial Pacific), the fall season may end up being pretty busy this year on the Plains.
The Ridge Is Dominant
For now, the ridge of high pressure that has been creating a near-constant heat wave from the Southern Plains to the Southwest will amplify and expand this week, pushing the jet stream flow northwards along with any major severe weather threats.
We’ve been able to keep a steady stream of severe weather threats over the Plains due to northwest flow riding over the ridge and down onto the Plains when it was more compact. When the ridge looks like this, you tend to keep the threats over the Northern Plains/Canada/the Midwest.
And when the ridge looks like this, hot temperatures will be present coast to coast in the southern 1/2 of the United States.
Looking towards the Southwest, the models look to have been right about July being a very quiet month for the monsoon, as moisture will remain on the low-end side for much of the region. The moisture fetch from the Gulf of Mexico is basically nonexistent through this week, with only the Gulf of California bringing moisture north into Southern Arizona.
But a more pronounced surge of moisture is likely to come further inland during the 6-10 day range, with the monsoon pattern likely becoming more widespread as we move into August.
The Bottom Line
The record heat we’re seeing globally will continue to have meaningful impacts on our weather. With the combined very warm North Atlantic and Equatorial Pacific, mixed with a continued warm Gulf of Mexico, we’ll likely continue to see a very active storm pattern across the U.S. this summer. Whenever the ridge flattens and weakens through the next 30-45 days, expect a more active monsoon pattern to emerge in the Southwest.
When the ridge finally shifts east and south again into the late stages of summer and early stages of fall, I suspect the severe weather pattern will move south again, with several really intriguing transition season monsoon events in the SW and traditional setups on the Plains.