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A Look Back at 2011/ A Look Ahead at 2012 John Lewis, Senior Forecaster National Weather Service Little Rock, Arkansas
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The Year So Far 2011 started with widespread drought conditions following a winter with below normal precipitation. Most of Arkansas was hammered with heavy rain in April and May, with a hot and dry summer to follow. Most recently, there was one deluge after another in November and early December.
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The Year So Far It has been a year of extremes (feast or famine)!
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Breaking It Down 2011 (Thru Oct)
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Breaking It Down June – Oct, 2011
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Drought Status October 25, 2011 An extreme to exceptional drought was noted in much of southwest Arkansas.
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Fronts (boundaries) moved into Arkansas from the northwest and stalled. Heavy rain focused along and north of the fronts. Wet Pattern November/Early December, 2011
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A Lot of of Rain Nov 12 – Dec 11, 2011 Rainfall
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A Lot of of Rain Nov 12 – Dec 11, 2011 Departure (+/-)
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Drought Status An extreme to exceptional drought remained in the far southwest. December 6, 2011
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Drought Status December 6, 2011 An extreme to exceptional drought remained in the far southwest. +11.76” -18.53”
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Arctic Oscillation (AO)
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La Niña Conditions Below normal sea surface temperatures (SST) were noted in the equatorial Pacific.
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La Niña Setup WestEast Stronger Westward Trade Winds
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La Niña Setup WestEast Warm Surface Water Cool Water/Upwelling
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La Niña Pattern
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Winter Forecast Temperature Below Normal Above Normal
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Winter Forecast Precipitation Below Normal Above Normal
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Drought Status December 6, 2011
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Drought Outlook Through February, 2011 Arkansas should mostly stay out of the drought business, with improvement possible in the southwest.
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January – March Precipitation Typical La Niña There is usually a wet signal from Arkansas to the Ohio Valley by late winter/early spring.
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The Forecast Significant precipitation this winter will be most likely in northern/eastern Arkansas, with lesser amounts expected in the southwest (where departures from normal are already extreme). Be prepared for an active late winter/early spring, with severe storms and at or above normal precipitation. Flooding could become a problem, especially in the White River basin.
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Drought Frequency Little Rock Norm Precip = 50” <45” <40” 1920s 6 3 1930s 3 1 1940s 3 2 1950s 4 1 1960s 3 2 1970s 2 0 1980s 1 1 1990s 5 1 2000s 4 2 Since the 1870s… Three Consecutive Years < 45” 5 times (last 1998-2000) Three Consecutive Years < 40” Never
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On the Web Visit the National Weather Service Little Rock website at this address… http://www.srh.noaa.gov/lzk or Google… National Weather Service Little Rock
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The End Thanks for coming!
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