by Jeff Masters, excerpted from the WunderBlog
February is gone, and the non-winter of 2011–2012 is the history books as the fourth warmest in U.S. history, said NOAA’s National Climatic Data Center yesterday. The winter average temperature of 36.8°F was just 0.4°F cooler than the warmest winter on record, the winter of 1999–2000. If you lived in the Northern Plains, Midwest, Southeast and Northeast, it seemed like winter never really arrived this year — 27 states in this region had top-ten warmest winters. Across the U.S., only New Mexico (41st coolest) and Alaska (35th coolest) had winter temperatures colder than average. According to NOAA’s Climate Extremes Index, the percent area of the U.S. experiencing extremes in warm maximum temperatures (top 10% on record) was 49 percent — the 4th highest value since the index began being computed in 1911. Jackson, Kentucky, Mount Pocono, Pennsylvania, and Trenton, New Jersey all had their warmest winter on record.
Third least snowy winter on record for the contiguous U.S.Warm and dry conditions during the winter of 2011–2012 led to snow cover extent that was the 3rd lowest in the 46-year satellite record, according to data from the Rutgers Global Snow Lab. Snowfall was particularly low across parts of the West, where much of California, Nevada, and Arizona had a snowpack less than half of average. Fortunately, the West had a near-record snowpack the previous winter, so this year’s lack on snow will not cause serious water availability problems during the summer. In the Upper Midwest, the lack of a winter snowpack will substantially reduce the chances of spring flooding along the Mississippi and Missouri rivers. NOAA issues their annual spring flood outlook on March 15, and it is likely to show a much lower risk of flooding compared to last year, when 1-in-100 to 1-in-500 year floods hit much of the Missouri and Lower Mississippi rivers. However, the remarkably low snow cover this winter over the Upper Midwest will allow soils to dry out much more quickly than usual, leading to increased chances of summer drought. The latest Drought Monitor map shows moderate to severe drought covering nearly all of Minnesota and Northwest Iowa; these regions are at high risk of suffering damaging drought conditions during the summer growing season.
— Jeff Masters is Co-founder of the Weather Underground. This piece was originally published at the WunderBlog.
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