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12-month stretch ending in April is warmest on record, NOAA says

The lower 48 states experienced their third-warmest April on record and the January through April period ended being the warmest on record in the U.S. NBC's Brian Williams reports.

The previous 12 months were the warmest in the U.S. since record keeping began in 1895, government scientists reported Tuesday, with the period averaging 55.7 degrees Fahrenheit — nearly three degrees warmer than the average May-April.

"We were expecting the 12-month period to be warm, but I was somewhat surprised to see it record warm," lead researcher Jake Crouch of the National Oceanic and Atmospheric Administration told msnbc.com.

What's more, that 12-month record could be broken soon if this month posts above average warmth. That's because May 2011 was abnormally cool, so it actually weighed down the earlier 12-month average, Crouch said.

"Depending on how May 2012 turns out, the June 2011-May 2012 period will likely surpass the 12-month record that we just broke," added Crouch, who authored the monthly State of the Climate Report for NOAA.

"The big story moving forward," he said, could be "lack of precipitation and the development of drought going into summer and the agricultural growing season. Some of the regions we are keeping an eye on: the Southeast, the Southern Rockies and Southern Plains, and the Northeast."

Wayne Parry / AP

Folks take to the beach in Belmar, N.J., on April 17. Area merchants said the warmth had boosted their sales by up to 30 percent more than what they normally would be at this time of year.

Highlights from the report:

  • 12-month temps: Between May 2011 and April 2012 temperatures were 2.8 degrees above average, topping the earlier record of 2.7 degrees warmer set in November 1999 to October 2000. All 10 warmest consecutive 12 months have been since 1999. 
  • Cities with record warmth in January-April include: Atlanta, Boston, Chicago, Detroit, New York City, Philadelphia, Tampa and Washington.
  • April temps: Last month was the third warmest April on record at 55 degrees — 3.6 degrees above average.

The monthly report follows one issued for March that found 15,000 records were broken in what became the warmest March on record.

NOAA does not attribute the warmer temperatures solely to manmade global warming since other, natural factors influence weather as well. Instead, it notes that that the warmth is indicative of what one would expect with climate change.

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