State Climate Update for Arizona

Conditions through February 2006

 

 

 

 

Based upon analysis by the Monitoring Group of the Governor’s Drought Task Force, precipitation data are stratified into the following drought categories for the 7 climate divisions for Arizona.

           

Numerical Category

Description

Precipitation Percentile

0

no drought

40.01 – 100

1

abnormally dry

25.01 – 40.00

2

moderate drought

15.01 – 25.00

3

severe drought

5.01 – 15.00

4

extreme drought

0.00 – 5.00

 

 

 

 

SHORT TERM CONDITIONS: 1-6 MONTHS

Recent warm and very dry conditions continued during February across Arizona. Air temperatures for the past 1-, 3-, and 6-month periods were above average for all regions of the state. Precipitation totals for recent months are extremely low, with the entire state characterized by amounts indicative of “severe” to “extreme” short-term drought. The only exception is during February across northwestern Arizona (CD 1), where the month can be characterized as “abnormally dry”. The Palmer Drought Severity Index (PDSI) has fallen dramatically since the wet winter of 2004-05. The PDSI indicates moist conditions only along the western edge of the state (CDs 1 and 5), but the recent dryness in these two areas is very likely to significantly drop the PDSI values in the coming months. Elsewhere, the PDSI signals very dry conditions.

 

 

Temperature

Precipitation

PDSI

CD1

85.7

29.5 (1)

70.5

CD2

65.2

3.6 (4)

8.0

CD3

90.2

9.8 (3)

9.8

CD4

73.2

2.7 (4)

5.4

CD5

82.1

24.1 (2)

87.5

CD6

92.0

3.6 (4)

4.5

CD7

83.0

7.1 (3)

8.9

 

FEBRUARY 2006: percentiles of temperature,

precipitation (with drought category),

and Palmer Drought Severity Index

for the 7 Arizona climate divisions

 


 

 

Temperature

Precipitation

CD1

92.0

2.7 (4)

CD2

74.1

0.9 (4)

CD3

92.0

0.9 (4)

CD4

84.8

0.9 (4)

CD5

92.0

0.9 (4)

CD6

97.3

0.9 (4)

CD7

91.5

0.9 (4)

 

DECEMBER 2005 - FEBRUARY 2006: percentiles of temperature,

and precipitation (with drought category) for the 7 Arizona

climate divisions


 

 

Temperature

Precipitation

CD1

91.0

4.5 (4)

CD2

84.7

0.9 (4)

CD3

91.9

0.9 (4)

CD4

88.3

0.9 (4)

CD5

96.4

14.9 (3)

CD6

99.1

0.9 (4)

CD7

92.8

0.9 (4)

 

SEPTEMBER 2005 – FEBRUARY 2006: percentiles of temperature,

and precipitation (with drought category) for the 7 Arizona

climate divisions


 

 

INTERMEDIATE TERM CONDITIONS: 12-24 MONTHS

The intermediate time periods of 1 and 2 years define the break point in the more recent drought conditions. The past 12 months have been marked by dryness characteristic of “extreme drought” across 5 of the 7 Arizona climate divisions. The period represents the conditions generally since the end of the wet period of winter 2004-05. The two areas of exception are again along the western edge of the state, where northwestern Arizona (CD 1) is characterized by 12-month precipitation indicative of “moderate drought” and precipitation in southwestern Arizona (CD 5) was of an amount indicative of “abnormally dry” conditions.

 

There is very little evidence of drought within the state when examining precipitation totals for the past 2 years. Only one region registered precipitation totals suggestive of drought; precipitation for southeastern Arizona (CD 7) ranked only in the 22nd percentile, which is indicative of “moderate drought”.

 

Temperatures across the state were well above normal for the past 2 years, and most significantly so across southern Arizona.

 

 

Temperature

Precipitation

CD1

82.9

20.7 (2)

CD2

81.1

4.5 (4)

CD3

86.9

5.0 (4)

CD4

79.3

1.8 (4)

CD5

91.9

31.1 (1)

CD6

98.2

3.6 (4)

CD7

91.9

0.9 (4)

 

MARCH 2005 – FEBRUARY 2006: percentiles of temperature,

and precipitation (with drought category) for the 7 Arizona

climate divisions


 

 

 

Temperature

Precipitation

CD1

85.5

90.0 (0)

CD2

90.0

67.3 (0)

CD3

89.1

77.3 (0)

CD4

95.5

49.1 (0)

CD5

91.8

95.0 (0)

CD6

95.5

72.7 (0)

CD7

87.7

22.7 (2)

 

MARCH 2004 – FEBURARY 2006: percentiles of temperature,

and precipitation (with drought category) for the 7 Arizona

climate divisions


 

LONG TERM CONDITIONS: 36-48 MONTHS

The pattern of precipitation rankings for the longer-term 3-year period across the state closely matches that for the past 2-year period. The 36-month precipitation totals were above average for 5 of the 7 climate divisions in Arizona. Only across the southeastern (CD 7) and east-central (CD 4) portions of the state did the precipitation fall far below average. Across southeastern Arizona the 3-year precipitation total is suggestive of “severe drought”, while that across east-central Arizona is indicative of “moderate drought” conditions.

 

Dryness is more evident for the longer 4-year period. Only two regions of the state (northwestern (CD 1) and southwestern (CD 5)) are characterized by 4-year precipitation totals that are above average, while three regions of the state (northeastern (CD 2), west-central (CD 3), south-central (CD 6)) can be characterized as “abnormally dry” over the past 4 years. The long-term problematic areas within the state are the east-central (CD 4) and southeastern (CD 7) regions, where 4-year precipitation totals are suggestive of “severe drought” conditions.

 

Temperatures for the period were well above the historical median; however, to some extent the longer time periods likely reflect the general climatic changes of the past several decades in addition to the recent warmth that typically accompanies dryness in Arizona.

 

 

Temperature

Precipitation

CD1

84.4

77.1 (0)

CD2

90.8

50.0 (0)

CD3

93.6

57.8 (0)

CD4

97.3

20.2 (2)

CD5

90.8

88.1 (0)

CD6

95.4

52.3 (0)

CD7

92.7

10.1 (3)

 

MARCH 2003 – FEBRUARY 2006: percentiles of temperature,

and precipitation (with drought category) for the 7 Arizona

climate divisions


 

 

 

Temperature

Precipitation

CD1

87.0

51.9 (0)

CD2

91.7

33.3 (1)

CD3

97.2

33.3 (1)

CD4

98.2

9.3 (3)

CD5

96.8

75.0 (0)

CD6

98.2

26.9 (1)

CD7

99.1

8.3 (3)

 

MARCH 2002 – FEBRUARY 2006: percentiles of temperature,

and precipitation (with drought category) for the 7 Arizona

climate divisions


 

 

SUMMARY

● The recent warm and extremely dry conditions continued across the entire state of

Arizona during February 2006.

 

● Precipitation totals for recent months are extremely low, with the entire state characterized by amounts indicative of “severe” to “extreme” short-term drought over the past 1 to 6 months.

 

● The Palmer Drought Severity Index (PDSI) has fallen dramatically since the wet winter of 2004-05. The PDSI indicates moist conditions only along the western edge of the state (CDs 1 and 5); elsewhere, the PDSI signals very dry conditions.

 

● The past 12 months have been marked by dryness characteristic of “extreme drought” across 5 of the 7 Arizona climate divisions, and dryness or drought elsewhere.

 

● There is very little evidence of drought within the state when examining precipitation totals for the past 2 years; drought is evident only across southeastern Arizona (“moderate drought”) during the period.

 

● The 36-month precipitation totals were above average for 5 of the 7 climate divisions in Arizona; however, across southeastern Arizona the 3-year precipitation total is suggestive of “severe drought”, while that across east-central Arizona is indicative of “moderate drought” conditions.

 

● The long-term problematic areas within the state are the east-central and southeastern regions, where 4-year precipitation totals are suggestive of “severe drought” conditions.