If you think November was unseasonably warm…
It was the second warmest November in Philadelphia's recorded history. Temperatures averaged 5.6 degrees above "normal."
Well, the first 10 days of December have been even more extreme, averaging about 7 degrees above normal. And by the time we go another week into the month, I estimate that December will be about 12 degrees above normal. That's more than half of the month.
In order for us to end up with an average December, the rest of the month would have to be the coldest ever recorded here!
It's not just here…
Below is a map of temperatures compared to normal (or "anomalies") over the entire country Friday. EVERY part of the country east of the Rockies is WAAAY warmer than normal:
And yes, all of southern Canada is relatively warm, too. So how could we get anything but unseasonably mild air moving in here? We can't. Even a northwest wind coming from Canada would bring in mild air.
It's an awfully frustrating pattern for cold and snow lovers. But if it makes them feel any better, they're saving a lot on heating bills.
Our record weekend…
Here's a map of temperature anomalies for Sunday, Dec. 13, at the time the Eagles will be playing the Buffalo Bills at The Linc:
Every place in the pink or purplish colors will be near or at record levels. Here are some of our local records, many of which are likely to be broken:
And what about the rest of December?
We're still looking for any changes in the overall weather pattern, whether it's in the U.S. or elsewhere around the globe. There are no borders in the atmosphere, so what happens in China or the North Pole or Russia could have an impact on our weather sometime in the future.
As mentioned in previous blogs, we especially look for "blocking patterns" that can influence weather thousands of miles from where they form.
But a global view shows something else unusual – there are NO significant blocks anywhere in the Northern Hemisphere even by Dec. 20 (in this map from the European Model, the world's best this far out):
This means it's going to be hard for a major pattern shift before Christmas. Temperatures could be closer to normal by then, but as for the chances of a total reversal of the mild pattern? I'd have to say there's no evidence of that at this point.
I had predicted November to be 4 to 6 degrees above normal. It was +5.6. In my winter forecast issued Nov. 13, I predicted December would be about 4 degrees above normal. If anything, that number is going to be too low. And I predicted January would be about 6 degrees above normal, with only 7 total inches of winter snow by Jan. 31.
There's no reason to change those forecasts at this time. But that doesn't mean the whole winter will be like that. There is still a good chance of a big reversal for the second half of the winter season.
So what's causing this extreme warmth?
No one can talk responsibly about this widespread record warmth without mentioning El Niño. This is close to the strongest one ever recorded in 1997-98. Here is the latest map of ocean temperatures compared to normal ("anomalies"):
That giant area of red in the Tropical Pacific shows the El Niño clearly. There's an unbelievable amount of heat that transfers from the ocean to the atmosphere, and it has impacts all over the world. You can see some of the impact on global temperatures for October, for example:
So much of the globe is warmer than normal, especially the U.S., Canada, and Australia, while Eastern Europe is one of the few areas colder than normal. Overall, this fall has set global temperature records, and 2015 will go down as the warmest ever recorded – by far.
But it's not all El Niño. If it's as strong as the 1997-98 version, why are global temperatures so much higher?
Climate scientists agree that at least some of the increase is due to the overall warming of the earth. That suggests, for example, that a similarly strong El Niño 20 years from now will lead to a significantly warmer world than what we see now.
Glenn "Hurricane" Schwartz
Chief Meteorologist, NBC10 Philadelphia