Palmer Drought Index 1895-2011 shows moderately above normal moisture most years since late 1960's, dry periods in mid '30s and mid 50's

"Climate Change Indicators in the United States," epa.gov

Chart from 1895-2011, moderately above normal moisture most years since late 60's, extremes in mid '30s and mid 50's. 2012 is known to have been dry but snow and rainfall in winter 2013 have significantly mitigated drought conditions.

NOAA Drought chart US 48 contiguous states, 1895-2011:

"This chart shows annual values of the Palmer Drought Severity Index,
averaged over the entire area of the contiguous 48 states. Positive values represent wetter-than-average conditions, while negative values represent drier-than-average conditions. A value between -2 and -3 indicates moderate drought, -3 to -4 is severe drought, and -4 or below indicates extreme drought. The thicker line is a nine-year weighted average. Data source: NOAA, 2012 ^4"

"Average drought conditions across the nation have varied since records began in 1895. The 1930s and 1950s saw the most widespread droughts, while the last 50 years have generally been wetter than average (see Figure 1)."

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3/4/13, "Drought areas shrinking as snow and rain fall," Reuters

"Meteorologists said the significant winter rainfall and snow have so far eliminated the drought, the worst in 50 years in the United States, in an area roughly from Illinois eastward."...

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About Palmer Drought Severity Index:

3/5/13, "</sup>Palmer Drought Severity Index," drought.gov (scroll down)

<sup>"The PDSI is updated weekly by the Climate Prediction Center. It is based on rainfall, temperature and historic data, and is computed based on a complex formula devised by W.C. Palmer in 1965. Although the Palmer is the main drought index used by the U.S. government, it is slow to detect fast-emerging droughts, and does not reflect snowpack, an important component of water supply in the western United States."

Here is another historical Palmer Chart including 2012</sup>
and going through Jan. 2013:

"Contiguous U.S. Palmer Drought Severity Index (PDSI), February-January 1896-2013," National Oceanic and Atmospheric Administration, National Climatic Data Center


 



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