Readers might find some location specific data regarding drought and long-term trends interesting in light of all the above. Data is for 3 Arizona cities. Flagstaff in the north. Prescott 90 miles south of Flagstaff, and Phoenix 100 miles south of Prescott.
FLAGSTAFF, AZ
Located in northern AZ about 90 miles north of Prescott at 7400 ft in thick pine forests.
Historical average annual precip 21.77 inches
Total precip inches
2006 22.47
2007 16.92
2008 21.95
2009 12.94
2010 32.04
2011 14.06
2012 10.68
2013 ~1.50 to date
Average precip 2006-2012 18.72 inches. Or 86% of historical average.
PRESCOTT, AZ
Prescott is a mountain town at 5400 ft elevation and sits in a pine forest in the middle of the state.
Historical precip annual average (incl 1898 to 2005) is 19.04 inches
Total precipitation inches
2006 11.38
2007 15.39
2008 17.08
2009 11.28
2010 15.17
2011 13.34
2012 9.22
2013 2.12 thru today
2006-2012 average annual precip 13.27 inches
2006-2012 average is only 70% of historical average.
1998 was the last year in Prescott when annual precip was ABOVE the historical average. By far the longest stretch of time in the 114 year record. One could probably make the claim that the old records are not relevant any longer and new normals have set in. I note, in light of the IPO/PDO discussion that 1998 is when the current negative phase of the PDO started and was, of course, the date of our last strong El Nino.
PHOENIZ, AZ
Is located in the 'Valley" of AZ at 1117 ft in the Sonoran Desert.
Historical average annual precipitation 8.07 inches
Total precipitation in inches
2006 5.88
2007 5.74
2008 6.57
2009 2.68
2010 12.26
2011 4.38
2012 4.46
2013 2.02 to date
2006-2012 average 6.00 inches. Or 74% of the historical average.
For all cities one can see the effect of the last 3 years of drought pretty clearly, but also that since 2006 (7 1/2 years of data) that a significant decline from the norm has happened across the breadth of AZ as would be expected given the drought predictions. It is obviously too early to state that the long-term precipitation decline is already underway, but the data is leaning that way.