Very warm November assures 2012 will be warmest year in U.S. history - added comments 12/14/12

A person on Facebook shrugged this off, saying records are set every 2-3 years. That might be true for a record for a particular day. After all, there are 365 days in the year. This beats the previous record for the year by 1.0°F above the previous record. As I pointed out, if this happened every three years for 100 years, it would add up to 33°F ! An ever increasing series of record highs is not just inconsequential business as usual

I have an M.A. in math, and think of this in terms of a series. You could theoretically have an forever increasing series that has a limited value. The amount of the increases would have to get increasingly smaller fast enough.
Eg., if your starting temperature is zero, and you increase it successively by
1/2, 1/3, 1/4, 1/5, ... the result would have no bound. No matter how large a number you chose, if you added enough terms, you would get a larger number.
But if the increases where 1/2, 1/4, 1/8, 1/16, ..., you would never get quite to 2.

However, in real life, there is a limit to how accurate a temperature could be measured. And it will be uaually be rounded off to tenths, or at most hundredths, when being reported. If you continued to have measurable increases, you would have an unbounded series. Eg., if you broke the record by 0.1°F every 3 years, in 100 years, that would be an increase of 3.3°F in the record. In 200 years, an increase of 6.7°F, etc.

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2306

Posted by: Dr. Jeff Masters, 4:39 PM GMT on December 07, 2012 +36
The heat is on again in the U.S. After recording its first cooler-than-average month in sixteen months during October, the U.S. heated up considerably in November, notching its 20th warmest November since 1895, said NOAA's National Climatic Data Center (NCDC) in their latest State of the Climate report. The warm November virtually assures that 2012 will be the warmest year on record in the U.S. The year-to-date period of January - November has been by far the warmest such period on record for the contiguous U.S.-- a remarkable 1.0°F above the previous record. During the 11-month period, 18 states were record warm and an additional 24 states were top ten warm. The December 2011 - November 2012 period was the warmest such 12-month period on record for the contiguous U.S., and the eight warmest 12-month periods since record keeping began in 1895 have all ended during 2012. December 2012 would have to be 1°F colder than our coldest December on record (set in 1983) to prevent the year 2012 from being the warmest in U.S. history. This is meteorologically impossible, given the recent December heat in the U.S. As wunderground's weather historian Christopher C. Burt reported, an early-December heat wave this week set records for warmest December temperature on record in seven states. December 2012 is on pace to be a top-20% warmest December on record in the U.S.

-----

Posted by: Dr. Jeff Masters, 4:39 PM GMT on December 07, 2012 +36
The heat is on again in the U.S. After recording its first cooler-than-average month in sixteen months during October, the U.S. heated up considerably in November, notching its 20th warmest November since 1895, said NOAA's National Climatic Data Center (NCDC) in their latest State of the Climate report. The warm November virtually assures that 2012 will be the warmest year on record in the U.S. The year-to-date period of January - November has been by far the warmest such period on record for the contiguous U.S.--a remarkable 1.0°F above the previous record. During the 11-month period, 18 states were record warm and an additional 24 states were top ten warm. The December 2011 - November 2012 period was the warmest such 12-month period on record for the contiguous U.S., and the eight warmest 12-month periods since record keeping began in 1895 have all ended during 2012. December 2012 would have to be 1°F colder than our coldest December on record (set in 1983) to prevent the year 2012 from being the warmest in U.S. history. This is meteorologically impossible, given the recent December heat in the U.S. As wunderground's weather historian Christopher C. Burt reported, an early-December heat wave this week set records for warmest December temperature on record in seven states. December 2012 is on pace to be a top-20% warmest December on record in the U.S.

November 2012 was the 8th driest November on record for the U.S., and twenty-two states had top-ten driest Novembers. The area of the contiguous U.S. experiencing moderate-to-exceptional drought grew from 59% on November 6 to 62% on December 6. This is the largest area of the U.S. in drought since 1954.