With each passing day the odds of 2015 going into the record books as the warmest year on record globally are rising. Those odds currently stand at 93 percent, according to NASA. That's up from 87 percent at the end of August.
September was the second warmest on record globally according to NASA.
NOAA has the odds of 2015 surpassing 2014 as the warmest year globally even higher. The odds of 2015 coming in as the new warmest year on record stand at 97 percent, according to NOAA. Temperature graphs for the warmest years on record show 2015 has a significant, probably insurmountable lead through September over the previous warmest years on record globally.
2015 extremely unlikely to lose its lead
Following this three-step approach, we estimate a 97% probability that 2015 will become the warmest year on record. - NOAA
Climate Central has some interesting perspective NASA and NOAA's analysis, and on the warmth in 2015 as earth continues a remarkable string of 'top 15 warmest years on record' globally.
Both groups arrived at their odds by using statistical methods that only took into account how unusually warm the year has been so far and how such year-to-date temperatures have compared to the overall annual average in the existing 134-year record.
Given that El Niño is expected to persist over the next few months, peaking in late fall or early winter, it is unlikely that the remaining three months of the year will be relatively cool enough to erase the lead 2015 has built so far.
All that warmth is having major repercussions around the globe, from bleaching vulnerable coral reefs to exacerbating the historic drought in California, which is also expected to record its warmest year.
The background warming from excess heat trapped in the atmosphere makes it more likely that such hot records will be set and less likely that cold ones will. Of the 15 warmest years on record, 13 have occurred since 2000, according to a Climate Central analysis, while the last year that was record cold was 1911.
U.S.: Record warmth in the West
This has been the warmest year on record for several western states. Minnesota has been on the eastern edge of that warmth, recording the 19th warmest year on record through September in 2015. Several eastern states have recorded cooler than average temperature this year so far.
September was warm across most of the United States. Minnesota basked in a band of warmth last month with temperatures running six degrees warmer than average.
It was the warmest September on record for Minnesota, Wisconsin and Michigan among other states.
Super El Niño rivals 1997-98 event
All signs in the tropical Pacific now indicate our current El Niño event rivals the 'El Niño climate event of the century' in 1997-98. NASA has some images that show just how similarly the two events are unfolding.
More on the unfolding monster El Niño from Climate Central.
Ocean temperatures are the most common metric to define the intensity of El Niño, but ocean heights also provide a valuable measure. Red indicates where sea levels are higher than normal while blue shows areas where sea levels are lower than normal. Both El Niños show sea level anomalies of up to 8 inches across the eastern tropical Pacific (and corresponding drops in other parts of the ocean basin).
The changes in sea level can have a dramatic impact locally on coral communities, but it’s how those warmer, higher waters affect the atmosphere that really matters globally.
“Over North America, this winter will definitely not be normal,” Bill Patzert, a climatologist at the Jet Propulsion Laboratory, told NASA Earth Observatory.
El Niño generally favors rainy weather over the Southern tier of the U.S. and warm weather from Alaska through the Northern Rockies. The super El Niño in 1997-98 also helped unleash mudslides in California — a major concern this year with the state in the depth of a record-setting drought.
Of course it’s worth stressing that no two El Niños are alike. And El Niño doesn't guarantee specific impacts, but rather tips the odds in their favor.
Minnesota's winter forecast?
I still think odds favor a (much) warmer than average winter across Minnesota. That's the historical bias in El Niño winters across the northern United States.
So how did winter turn out in the strongest El Niño events in the past? During the 1997-98 El Niño event, meteorological winter (Dec-Feb) in the Twin Cities was 11 degrees warmer than average. In the also super sized 1982-83 event, meteorological winter was 8 degrees warmer than average.
Not all El Niño events are created equal, but the overall odds of a milder than average winter in the Upper Midwest and Great Lakes run somewhere between between 65 and 85 percent.
El Niño winters in Minnesota also favor less than average snowfall overall historically.
It's not a slam dunk, but the odds heavily favor a milder than average winter across Minnesota. Chances are you may be shoveling less than average snowfall as well. We'll still get our share of cold fronts and some sub-zero nights, but this massive El Niño event should take the edge off our upcoming Minnesota winter.
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