Warmest November on Record, NASA Data Shows

By Tom Yulsman 

(Cross-posted from CE Journal)

NASA's Land-Ocean Temperature Index, or LOTI, for each month over the past 10 years, through this past November. Published by NASA's Goddard Institute for Space Studies, it is a measure of how much global temperatures have departed from the 1951 to 1980 base period. Credit: NASA GISS/Tom Yulsman

The table above shows the Land-Ocean Temperature Index, or LOTI, for each month over the past ten years, through this past November. Published by NASA’s Goddard Institute for Space Studies (GISS), it is a measure of how much global temperature has departed from the 1951 to 1980 base period.

I’ve copied the data just for the past ten years, but the entire chart shows that this past November was not only the warmest over the past decade, but also the warmest since record keeping began in 1880. This is despite current strong La Niña conditions, which tend to hold temperatures down.

The column at the extreme right of the chart shows that the last 12 months (Dec. 2009 through Nov. 2010) comprised the warmest such period on record.

UPDATE 12/10/10 12:15 p.m.: NASA has just released it’s November temperature anomaly maps. Here’s how temperatures varied from the 1951-1980 base period around the globe that month:

Temperature departures from average during November 2010, relative to the 1951-1980 base period. Credit: NASA GISS.

The current strong La Niña is evident in this map as the bluish — meaning cool — surface water in the equatorial Pacific. Meanwhile, major parts of the Arctic and Russia, as well as the Antarctic Peninsula, were unusually warm.

The picture was different for the United States during November.

According to the National Climatic Data Center, November temperatures averaged across the country were near-average.

That said, autumn in the United States, meaning the Sept-Oct.-Nov. period, was warmer than average — thanks mostly to high temperatures in September and October. (My home state, Colorado, was much warmer than normal). Since 1895, only 13 autumns have been warmer.

November temperatures in the United States were strongly influenced by two large-scale climatic patterns: La Niña and a strongly negative Arctic Oscillation. (Click on the links for more information about these phenomena.)

“The opposing temperature influences of these two atmospheric patterns contributed to a national temperature rank near the middle of the historical distribution,” according to the NCDC’s most recent report.

The current La Niña episode is the third strongest on record, using a scale called the Multivariate ENSO Index, or MEI. During a La Niña year, winter conditions in the United States tend to be warmer and drier than average in the Southeast, and cooler and wetter than average in the Northwest.