State Climate Update for Arizona – Conditions through December 2005

 

 

December 2005                                                                                                                                                                                                                  

The month of December was mild and extremely dry across the state. The mean monthly temperature ranked between the 71st percentile and the 81st percentile, except in northwestern Arizona (CD 1) where the mean monthly temperature ranked rather highly in the 91st percentile. Precipitation totals were impressively low, with amounts indicative of “severe” to “extreme” one-month drought conditions across the entire state. Four regions of the state (CDs 2, 3, 5, and 6) recorded no precipitation for the month. The two areas suffering from the driest conditions recently were actually the least dry across the state in December – east-central (CD 4) and southeastern (CD 7) Arizona. Still, the December precipitation totals in these two areas were only of the 11th and 13th percentiles respectively. Residuals of the wet 2004-05 winter are the still relatively high (wet) Palmer Drought Severity Index values across much of the state. The values continue to indicate rather moist to very moist conditions across much of the state, except for in east-central (CD 4) and southeastern (CD 7) Arizona, where the PDSI has trended significantly toward lower values, or dry conditions, in recent months.

 

 

Temperature

Precipitation

PDSI

CD1

91.0%

3.6% (4)

86.5%

CD2

71.2%

0.9% (4)

66.7%

CD3

81.1%

0.9% (4)

71.2%

CD4

71.2%

11.7% (3)

18.9%

CD5

78.4%

0.9% (4)

97.3%

CD6

81.1%

0.9% (4)

72.1%

CD7

76.6%

13.5% (3)

19.8%

 

1-month percentiles of temperature, precipitation (with drought category), and Palmer Drought Severity Index for the 7 Arizona climate divisions


 

 

October 2005 – December 2005                                                                                                                                                                                    

Except for across southwestern Arizona (CD 5), Fall and early Winter was very dry across the state. Most problematic were precipitation totals across northeastern (CD 2), east-central (CD 4), south-central (CD 6), and southeastern (CD 7) Arizona, where precipitation totals suggestive of “severe drought” for the three-month period were recorded. Slightly better seasonal conditions existed in west-central Arizona (CD 3; “moderate drought”) and northwestern Arizona (CD 1; “abnormally dry”). Temperatures for the three-month period were high, with the greatest warmth in southwestern and south-central Arizona (CDs 5 and 6; 94th percentile).

 

 

 

Temperature

Precipitation

CD1

87.4%

39.6% (1)

CD2

75.7%

7.2% (3)

CD3

88.3%

17.1% (2)

CD4

85.6%

6.3% (3)

CD5

94.6%

49.6% (0)

CD6

94.6%

9.0% (3)

CD7

87.4%

6.3% (3)

 

3-month percentiles of temperature, and precipitation (with drought category) for the 7 Arizona climate divisions


 

July 2005 – December 2005                                                                                                                                                                                           

Six-month precipitation values representing conditions from mid-summer through early winter again indicate dryness for all of Arizona except for the western portion of the state (CDs 1 and 5).  The driest six months occurred across eastern Arizona (CDs 2, 3, 4, and 7), where six-month precipitation totals were suggestive of “extreme drought”.  Dry conditions also characterized the south-central (CD 6; ”moderate drought”) portion of the state. Statewide, temperatures from mid-summer through early winter were considerably above the long-term median, and approaching unprecedented levels across the southern tier of the state (CDs 5, 6, and 7).

 

 

 

Temperature

Precipitation

CD1

85.6%

42.3% (0)

CD2

82.0%

8.1% (3)

CD3

86.5%

14.4% (3)

CD4

88.3%

9.0% (3)

CD5

96.4%

58.6% (0)

CD6

96.4%

24.3% (2)

CD7

91.0%

5.4% (3)

 

6-month percentiles of temperature, and precipitation (with drought category) for the 7 Arizona climate divisions


 

January 2005 – December 2005                                                                                                                                                                                    

There is no evidence of drought within the state when examining precipitation totals for the past twelve-month period. In fact, most regions were characterized by well above normal precipitation, including totals in the 90th percentile across western Arizona (CDs 1 and 5). Continuing a trend in recent years, the driest area of the state over the past twelve months is the southeast (CD 7; “abnormally dry”). Temperatures across the state were well above normal for the past 12-month period, and most significantly so across the southern (CDs 5, 6, and 7) and northeastern (CD 2) parts of the state.

 

 

Temperature

Precipitation

CD1

82.0%

91.9% (0)

CD2

92.8%

65.8% (0)

CD3

88.3%

79.3% (0)

CD4

82.9%

65.8% (0)

CD5

91.0%

90.1% (0)

CD6

95.5%

79.3% (0)

CD7

90.1%

26.1% (1)

 

12-month percentiles of temperature, and precipitation (with drought category) for the 7 Arizona climate divisions


 

January 2004 – December 2005                                                                                                                                                                                    

Twenty-four month precipitation values continue to indicate rather wet conditions across the state, as all regions but the southeast (CD 7) were comfortably above the long-term median value, and well above across the western portion of the state. The two-year precipitation total was characteristic of “abnormally dry” conditions across southeastern Arizona (CD 7), which is in great contrast to the southwestern part of the state (CD 5). Mean temperatures for the two-year period were rather high across the state, but less so in the northwestern (CD 1) and southeastern (CD 7) portions of the state.

 

 

Temperature

Precipitation

CD1

80.0%

93.6% (0)

CD2

90.0%

74.5% (0)

CD3

87.3%

82.7% (0)

CD4

95.5%

57.3% (0)

CD5

86.4%

96.4% (0)

CD6

91.8%

79.1% (0)

CD7

80.0%

29.1% (1)

 

24-month percentiles of temperature, and precipitation (with drought category) for the 7 Arizona climate divisions


 

January 2003 – December 2005                                                                                                                                                                                    

Precipitation totals for the longer-term three-year period indicate conditions that are not as wet when considering the past two years; however, the 36-month precipitation totals were above average for five of the seven climatic regions in Arizona, with another region (east-central, CD 4) very near average (42nd percentile). Only across the southeastern portion of the state (CD 7; 13th percentile) did the precipitation fall far below average. Here, the total precipitation for the period is suggestive of “severe drought” conditions. Temperatures for the period were well above the historical median; however, to some extent the longer three-year time period likely reflects the more general climatic changes of the past several decades.

 

 

Temperature

Precipitation

CD1

86.2%

89.0% (0)

CD2

92.7%

65.1% (0)

CD3

94.5%

69.7% (0)

CD4

97.3%

42.2% (0)

CD5

93.6%

92.7% (0)

CD6

96.3%

70.6% (0)

CD7

91.7%

13.8% (3)

 

36-month percentiles of temperature, and precipitation (with drought category) for the 7 Arizona climate divisions


 

January 2002 – December 2005                                                                                                                                                                                    

Forty eight-month precipitation values indicate clear evidence of longer-term drought conditions across two areas of the state, with abnormally dry conditions across another three areas. All regions within the state, except for the northwest (CD 1) and southwest (CD 5), have been characterized by less than average precipitation over the four-year period. Precipitation totals for the period indicate “abnormally dry” conditions across the northeastern (CD 2), west-central (CD 3), and south-central (CD 6) portions of the state. Long-term conditions suggestive of “severe drought” exist across southeastern (CD 7) and east-central (CD 4) Arizona, as both are characterized by 48-month precipitation that is in the 10th-11th percentile range. Temperatures for the 4-year period are near unprecedented highs but, again, this is likely to be at least somewhat of a reflection of longer-term trends rather than shorter-term anomalies.

 

 

Temperature

Precipitation

CD1

85.2%

51.9% (0)

CD2

90.7%

38.0% (1)

CD3

97.2%

36.1% (1)

CD4

98.2%

11.1% (3)

CD5

91.7%

76.9% (0)

CD6

93.5%

34.3% (1)

CD7

93.5%

10.2% (3)

 

48-month percentiles of temperature, and precipitation (with drought category) for the 7 Arizona climate divisions


 

 

  

Summary                                                                                                                                                                                                                            

December 2005 was characterized by warmth and extreme dryness across the entire state, including the driest December on record for northeastern, west-central, southwestern, and south-central Arizona. However, except for across east-central and southeastern Arizona, the wet fall and winter conditions of 2004-05 were still reflected in high (wet) Palmer Drought Index Values across the state. This may be a bit misleading, as of concern is the re-emergence of dry conditions across much of the state, especially in southeastern and east-central Arizona, over the past 3-6 months.

 

On the longer term, there exists little or no evidence of drought across Arizona over the past 12-to-24 months, with generally much greater than normal precipitation during the period. However, long-term drought is clearly evident on the 36-month time frame across southeastern Arizona, and dryness and drought across east-central and southeastern Arizona is obvious on the 48-month time frame.

 

Overall, the southeastern and east-central regions of Arizona continue to struggle with long-term precipitation totals suggestive of drought, and recent precipitation totals indicate re-emerging dry conditions across much of the state.