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America’s Drought

December 11, 2012
tags:

By Paul Homewood

 

Preliminary Year-to-Date Divisional Precipitation Ranks

http://www.ncdc.noaa.gov/temp-and-precip/maps.php?ts=ytd&year=2012&month=11&imgs[]=Divisionalprank&submitted=Submit

 

We have heard much this year about the US drought, but how does it compare with other droughts in past years?

 

Precipitation totals for Dec 2011-Nov 2012 rank as the 12th driest since 1895. In other words, it’s something you get about every 10 years on average. Furthermore, the trend is clearly towards higher rainfall.

 

NOAA, National Environmental Satellite, Data, and Information ServiceNational Climatic Data Center, U.S. Department of Commerce

 

Climate At A Glance

Most Recent 12-Month Period (Dec – Nov) Precipitation
Contiguous United States


Most Recent 12-Month Period (Dec – Nov) 1901 – 2000 Average = 29.14 Inches
Most Recent 12-Month Period (Dec – Nov) 1895 – 2012 Trend = 0.15 Inches / Decade

Output Graph

http://www.ncdc.noaa.gov/oa/climate/research/cag3/na.html

 

Meanwhile the Palmer Drought Severity Index shows a similar picture. This year clearly does not compare with the run of years in the 1930’s and 50’s. Moreover, as the bottom graph illustrates, the longer term drought measures, using a 36 month average, show nothing out of the ordinary at all.

 

multigraph

http://www.ncdc.noaa.gov/temp-and-precip/time-series/index.php?parameter=pdsi&month=11&year=2012&filter=12&state=110&div=0

 

multigraph

http://www.ncdc.noaa.gov/temp-and-precip/time-series/index.php?parameter=pdsi&month=11&year=2012&filter=36&state=110&div=0

 

So where does all this leave us? America has always had droughts in the past, and will continue to in future. Although the intensity of droughts has declined over the last century, particular regions will still experience severe droughts from time to time.

Last year it was Texas. This year it is Nebraska/Wyoming. Yet even here, the rainfall trends show a definite long term increase.

 

NOAA, National Environmental Satellite, Data, and Information ServiceNational Climatic Data Center, U.S. Department of Commerce

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Climate At A Glance

Most Recent 12-Month Period (Dec – Nov) Precipitation
Northern Rockies and Plains Region


Most Recent 12-Month Period (Dec – Nov) 1901 – 2000 Average = 16.93 Inches
Most Recent 12-Month Period (Dec – Nov) 1895 – 2012 Trend = 0.04 Inches / Decade

Output Graph

 

This is the world we live in. We cannot control it. We just need to get used to it.

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