U.S. climate highlights – first quarter of 2011, rolling six- and 12-month periods

  • It was the tenth driest first quarter for both the South and Southwest climate regions.   New Mexico, Oklahoma, and Texas experienced their second, fifth and ninth driest January-March period, respectively.
  • Both the rolling six-month and 12-month periods generally show that the northern United States has been generally wet, while the South has been dry.
  • On the six-month timescale, October 2010 through March 2011, above-average precipitation occurred across much of the West, the Northern Plains and the Northeast. Nevada and Vermont each had its third-wettest such period, followed by Pennsylvania (fifth wettest), New York (eighth), and Utah (ninth). The southern plains, Midwest and Southeast were generally dry during the period, with more unusual dryness focused in the South Central United States. It was the fourth driest October 2010 – March 2011 for Texas, sixth driest for Oklahoma, seventh for Arkansas and Louisiana, and the eighth driest for New Mexico.
  • Over the past 12 months, April 2010 – March 2011, a belt of abnormal wetness stretched from the western Great Lakes to the Pacific Northwest. Wisconsin had its wettest such period. Its precipitation average of 41.52 inches was more than 10 inches above its 20th century average. Additionally, Iowa, Minnesota, and North Dakota experienced their second wettest such period. Precipitation was below normal in the South during this period. It was the fourth driest in Louisiana, fifth driest in Arkansas, ninth driest in Florida, and 10th driest in Mississippi.

NCDC’s State of the Climate reports, which assess the current state of the climate, are released soon after the end of each month. These analyses are based on preliminary data, which are subject to revision. Additional quality control is applied to the data when latereports are received several weeks after the end of the month and as increased scientific methods improve NCDC’s processing algorithms.

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