It's been odd reading in the news about heat waves gripping the US as here in California it's been a cool summer. It's more than just a "This week it's cool out" phenomenon, though. It's been cooler than normal the past few months here in coastal California. I already knew that from my own gut sense (I notice the weather every day though I don't record it rigorously) but it was interesting to see it confirmed, and explained, in articles I read today when I looked up why it's such a thing that California is cooler than the rest of the US.
First, here's a picture of what I'm talking about:

This is a chart from a week ago. It shows that over a near-term forecast range (6-10 days) coastal California will have lower than average temperatures while much of the rest of the US is above normal.
As a specific example of what "Below" normal means, high temps the past few days around my home have averaged 76° F. That's 5° below the local average for this time of year. That's where my gut sense of it being cool comes from. A difference of a degree or two, I wouldn't notice. But a 5 degree difference, especially persistently, I do notice. And occasionally grouse about here in my blog because I look forward to enjoying summer-y summer weather!
As far as why there's this temperature discrepancy across the US, worsening summer heat waves are part of what's happening with global climate change. What's happening in California is an older, not-man-made pattern. A strong ocean current brings cold water from the Gulf of Alaska down to the Pacific coast of northern California. High pressure zones have been causing us to get winds from across the ocean. The wind cools over the cold water and acts like a natural air conditioner for coastal California. At some point the high pressure nexus will shift and winds will blow offshore.... Then we'll get heated air from the east blowing over us instead of cool ocean air. But for now the high pressure pattern is sticking in "A/C is ON" position.
The existence of this cooling pattern in California does not contradict the existence or impact of human-caused Global Warming. As a recent blog on Weather West argues, 100 years ago this cool summer weather wouldn't have been unusual in California. The significant global warming of the last 50 years ago puts it at contrast with the new normal. And yes, there always will be "cold snaps" even in a world of global warming. There will always be winter blizzards, too, in Minneapolis and Buffalo. Global Warming is about the averages shifting in significant ways. Summers, in general, are getting more intense, and days of sub-zero winter weather in the snow belt are getting fewer.
First, here's a picture of what I'm talking about:

This is a chart from a week ago. It shows that over a near-term forecast range (6-10 days) coastal California will have lower than average temperatures while much of the rest of the US is above normal.
As a specific example of what "Below" normal means, high temps the past few days around my home have averaged 76° F. That's 5° below the local average for this time of year. That's where my gut sense of it being cool comes from. A difference of a degree or two, I wouldn't notice. But a 5 degree difference, especially persistently, I do notice. And occasionally grouse about here in my blog because I look forward to enjoying summer-y summer weather!
As far as why there's this temperature discrepancy across the US, worsening summer heat waves are part of what's happening with global climate change. What's happening in California is an older, not-man-made pattern. A strong ocean current brings cold water from the Gulf of Alaska down to the Pacific coast of northern California. High pressure zones have been causing us to get winds from across the ocean. The wind cools over the cold water and acts like a natural air conditioner for coastal California. At some point the high pressure nexus will shift and winds will blow offshore.... Then we'll get heated air from the east blowing over us instead of cool ocean air. But for now the high pressure pattern is sticking in "A/C is ON" position.
A Cool Summer in Parts of California Doesn't "Disprove" Climate Change
It's sad I have to point this out, but I do. Beause there are climate idiots (not just skeptics but fools) out there who sneer when there's a cold week, "So much for ‘‘Global Warming’’!"The existence of this cooling pattern in California does not contradict the existence or impact of human-caused Global Warming. As a recent blog on Weather West argues, 100 years ago this cool summer weather wouldn't have been unusual in California. The significant global warming of the last 50 years ago puts it at contrast with the new normal. And yes, there always will be "cold snaps" even in a world of global warming. There will always be winter blizzards, too, in Minneapolis and Buffalo. Global Warming is about the averages shifting in significant ways. Summers, in general, are getting more intense, and days of sub-zero winter weather in the snow belt are getting fewer.