Significant weather events for May 2012 in the U.S.
Warmth across much of the continental U.S. last month secured an impressive list of weather records. So far, the lower 48 have seen their warmest spring on record, as well as the warmest year-to-date, and the warmest 12-month since record keeping began in 1895. '
These records derive from the unusual warmth the eastern two-thirds of the lower 48 states have been experiencing. In May, only the northwestern states did not experience warmer-than-average temperatures, according to the U.S. the National Atmospheric and Oceanographic Adminstration.
For the season overall, 31 states had record warmth for the season, and 11 others had spring temperatures that ranked among their 10 warmest. Only Oregon and Washington had spring temperatures near their averages.
Earlier this year, NOAA named winter — December, January and February cumulatively — as the fourth-warmest for the lower 48. Meteorologists and climate experts attributed this unusually mild winter to the configuration of the jet stream, a band of westerly high-altitude winds. [Was It Climate Change?]
May saw cooler-than-average conditions in Alaska and drought in Hawaii. Precipitation patterns across the country were mixed; rainfall improved drought conditions in the Northeast, for example, but ongoing drought, combined with windy conditions, created ideal wildfire conditions across the Southwest, NOAA's monthly report stated.