A Look Back at 2011/ A Look Ahead at 2012 John Lewis, Senior Forecaster National Weather Service Little Rock, Arkansas
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.
The Year So Far It has been a year of extremes (feast or famine)!
Breaking It Down 2011 (Thru Oct)
Breaking It Down June – Oct, 2011
Drought Status October 25, 2011 An extreme to exceptional drought was noted in much of southwest Arkansas.
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
A Lot of of Rain Nov 12 – Dec 11, 2011 Rainfall
A Lot of of Rain Nov 12 – Dec 11, 2011 Departure (+/-)
Drought Status An extreme to exceptional drought remained in the far southwest. December 6, 2011
Drought Status December 6, 2011 An extreme to exceptional drought remained in the far southwest ” ”
Arctic Oscillation (AO)
La Niña Conditions Below normal sea surface temperatures (SST) were noted in the equatorial Pacific.
La Niña Setup WestEast Stronger Westward Trade Winds
La Niña Setup WestEast Warm Surface Water Cool Water/Upwelling
La Niña Pattern
Winter Forecast Temperature Below Normal Above Normal
Winter Forecast Precipitation Below Normal Above Normal
Drought Status December 6, 2011
Drought Outlook Through February, 2011 Arkansas should mostly stay out of the drought business, with improvement possible in the southwest.
January – March Precipitation Typical La Niña There is usually a wet signal from Arkansas to the Ohio Valley by late winter/early spring.
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.
Drought Frequency Little Rock Norm Precip = 50” <45” <40” 1920s s s s s s s s s 4 2 Since the 1870s… Three Consecutive Years < 45” 5 times (last ) Three Consecutive Years < 40” Never
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The End Thanks for coming!