La Nina is a pattern in the Pacific Ocean that creates water temperatures cooler than normal. That temperature change along the equator in the Pacific causes global weather patterns to shift. In Texoma that shift means that the jet stream (which guides storm systems that create rain, thunderstorms, severe weather and winter weather) to the north. And, if the jet stream is north then all the effects of the jet, as mentioned above, will shift north. Therefore, Texoma has been left dry.
The La Nina event in the Pacific began July of 2010. And, as is often with most weather events there is a lag between a cause and an effect. The effect of the La Nina was delayed between two and four months across North America. The effect in Texoma was delayed three months. We didn't truly begin to feel the effects until October and it became very evident by Halloween of 2010.
From that time until now we have experienced a period of extreme dry and warm/hot weather with very few brief breaks. And that is how we are now more than 16 inches below normal.
Here is how it breaks down month by month.
Oct 2010: Normal Rain: 3.11" Actual Rain: 1.51" Difference: -1.60"
Nov 2010-Normal Rain: 1.68" Actual Rain: 0.23" Difference: -1.45"
Dec 2010-Normal Rain: 1.68" Actual Rain: 0.13" Difference: -1.55"
Jan 2011-Normal Rain: 1.12" Actual Rain: 0.25" Difference: -0.87"
Feb 2011-Normal Rain: 1.58" Actual Rain: 0.39" Difference: -1.19"
Mar 2011-Normal Rain: 2.27" Actual Rain: 0.06" Difference: -2.21"
Apr 2011-Normal Rain: 2.62" Actual Rain: 0.35" Difference: -2.27"
May 2011-Normal Rain: 3.92" Actual Rain: 2.29" Difference: -1.63"
Jun 2011-Normal Rain: 3.61" Actual Rain: 0.02" Difference: -3.59"
Jul 2011-Normal Rain: 0.37" Actual Rain: 0.00" Difference: -0.37"
Data is as of Wednesday, July 6, 2011.
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