Environmental

NOAA: Winter Season Fourth Warmest on Record for U.S.


Washington, DC–(ENEWSPF)–March 7, 2012.  Warmer-than-average temperatures dominated the northern and eastern regions of the country in December, January and February, leading to the fourth warmest winter on record for the contiguous United States. The winter season was also drier-than-average for the Lower 48, with dry conditions experienced across the West and the Southeast but wetter-than-average conditions in the Central and Southern Plains and parts of the Ohio Valley.

The average contiguous U.S. temperature during the December-February period was 36.8 degrees F, 3.9 degrees F above the 1901-2000 long-term average — the warmest since 2000. The precipitation averaged across the nation was 5.70 inches, 0.78 inch below the long-term average. 

U.S. climate highlights — winter season

    • Warmer-than-average temperatures were widespread with twenty-seven states in the Northern Plains, Midwest, Southeast and Northeast having winter temperatures ranked among their ten warmest. Only New Mexico had winter temperatures below the 20th century average.
  • Statewide precipitation totals were mixed during the winter season. The western states were particularly dry with California having its second driest winter on record at 7.82 inches below average. Montana was eighth driest, and Oregon and Idaho were both tenth driest for the season. Drier-than-average conditions were also present across the Northern Plains, Southeast, and Northeast. Above-average precipitation occurred in the central United States, from the Ohio Valley into the Southern Plains.
  • The warm and dry conditions during the 2011-2012 winter season limited snowfall for many locations. According to data from the Rutgers Global Snow Lab, snow cover extent during winter was approximately 237,000 square miles below the 1981-2010 average — the third smallest winter snow cover footprint in the 46-year satellite record. Snowpack was particularly limited across parts of the West, where parts of California, Nevada, and Arizona had snowpack less than half of average.
  • For the winter period, NOAA’s U.S. Climate Extremes Index — an index that tracks the highest 10 percent and lowest 10 percent of extremes in temperature, precipitation, drought and tropical cyclones — was the ninth highest value in the 102-year period of record, with nearly one-third of the nation experiencing climate extremes as defined by this index. The elevated value was largely driven by extremes in warm daily maximum and minimum temperatures across the Northeast, Upper Midwest, and Ohio Valley.
  • Despite a record cold January, Alaska had a near-seasonal averaged temperature at 1.4 degrees F below average, ranking as the 35th coldest winter in the 94-year record for the state. A warmer-than-average December and February balanced the very cold January temperatures, resulting in a winter temperature nearer the long-term average.

U.S. climate highlights — February

    • During February, the contiguous United States experienced above-average temperatures with a national average temperature of 38.3 degrees F. This was 3.6 degrees F above average, making it the 17th warmest on record.
  • Much-above-average temperatures were present across the Great Lakes, Mid-Atlantic, and Northeast during February. The Massachusetts statewide average temperature tied with 1998 as the warmest February on record at 7.9 degrees F above average. In total, 12 states had February temperatures ranking among their ten warmest.
  • Precipitation totals were mixed during February, resulting in a nationally-averaged precipitation total 0.25 inch below the long term average of 2.02 inches.
  • Dry conditions were present across the West, Southeast, and Midwest. The Northeast was particularly dry, where New York, Vermont, New Hampshire, Massachusetts, Connecticut, Rhode Island, and New Jersey each had a top ten dry February. In contrast, South Dakota, Nebraska, Kansas, and Louisiana had February precipitation totals among their ten wettest.
  • According to U.S. Drought Monitor, as of February 28th, about 39 percent of the contiguous United States was experiencing drought conditions, a slight increase compared to the beginning of the month. However, the percent area experiencing the worst category of drought, called D4 or exceptional drought, shrank from 3.2 percent to 2.5 percent. Drought conditions generally improved across the Southern Plains where there has been above-average precipitation for several months. Drought conditions deteriorated across parts of the Southeast and the West, which had been drier than average.
  • According to the Rutgers Global Snow Lab, the monthly snow cover extent across the contiguous United States was approximately 1.0 million square miles, which was 139,200 square miles below the 1981-2010 average. The small monthly snow cover extent was in spite of several large winter storms which impacted the Rockies and Northern Plains during the month.
  • According to preliminary data from NOAA’s Storm Prediction Center, there were 57 tornado reports during February, nearly twice the average number of tornadoes for the month. Most of the tornadoes occurred the 28th and 29th, when a strong storm system spawned several strong tornadoes from Nebraska to Tennessee, causing an estimated 13 fatalities.
  • A list of selected February temperature and precipitation can be found here

Source: noaa.gov


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