State Climate Update for Arizona – Conditions through October 2005

 

 

October 2005                                                                                                                                                                                                                      

The month of October was characterized by above normal precipitation across much of the state. The exception was the southeastern portion of the state (CD 7), where October precipitation was of an amount that can be described as “abnormally dry”. The western portion of the state (CDs 1, 3, 5) was much wetter than normal. Palmer Drought Severity Index values continue to indicate very moist conditions across much of the state. However, rather large changes in the PDSI toward lower values, or drier conditions, occurred across east-central (CD 4) and southeastern (CD 7) Arizona. Temperatures across the state were rather high, but the dryness in southeastern Arizona was coupled with cool conditions relative to the rest of the state

 

 

Temperature

Precipitation

PDSI

CD1

74.8%

88.3% (0)

96.4%

CD2

70.3%

56.8% (0)

85.6%

CD3

73.0%

75.7% (0)

83.8%

CD4

75.7%

43.2% (0)

31.5%

CD5

78.4%

89.2% (0)

100%

CD6

88.3%

57.7% (0)

85.6%

CD7

69.4%

36.0% (1)

32.4%

 

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


 

 

August 2005 – October 2005                                                                                                                                                                                          

Precipitation for the three-month period that represents the end of summer and the beginning of fall mirrors the pattern of October. Precipitation was near normal across the northeastern (CD 2), west-central (CD 3), and south-central (CD 6) portions of the state, wetter than normal across the west (CDs 1, 5), and “abnormally dry” across the east-central (CD 4) and southeastern (CD 7) Arizona. Temperatures for the three-month period were rather high, with the greatest warmth in south-central Arizona (CD 6; 91st percentile).

 

 

 

Temperature

Precipitation

CD1

73.9%

68.5% (0)

CD2

62.2%

45.1% (0)

CD3

68.5%

42.3% (0)

CD4

56.8%

36.0% (1)

CD5

80.2%

82.0% (0)

CD6

91.0%

59.5% (0)

CD7

63.1%

39.6% (1)

 

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


 

May 2005 – October 2005                                                                                                                                                                                                

Six-month precipitation values indicate evidence of drought conditions in southeastern (CD 7:  “severe drought”) and east-central (CD 4; “moderate drought”) Arizona. Dry conditions characterize the northeastern (CD 2) and west-central (CD 3) parts of the state, while precipitation for the 6 months was near normal in the northwestern and south-central portions (CDs 1, 6) of Arizona. The southwestern part of the state (CD 5) continues to show rather wet conditions with the 6-month precipitation total for the area. Statewide, temperatures from late spring through early fall were considerably above the long-term median, but not approaching unprecedented levels, except in south-central Arizona (CD 6; 95th percentile).

 

 

 

Temperature

Precipitation

CD1

75.7%

63.1% (0)

CD2

72.1%

30.6% (1)

CD3

79.3%

37.8% (1)

CD4

74.8%

20.7% (2)

CD5

84.7%

77.5% (0)

CD6

95.5%

55.9% (0)

CD7

85.6%

11.7% (3)

 

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


 

November 2004 – October 2005                                                                                                                                                                                    

There is no evidence of drought within the state when examining precipitation totals for the past 12-month period. Most regions were characterized by well above normal precipitation, including totals in the 90th percentile for 5 of the 7 regions and the second wettest October-September period on record across southwestern Arizona (CD 5). The relatively drier area continues to be across the southeast (CD 7; 59th percentile). Still, the 12-month precipitation total in that region was above the long-term median. Temperatures across the state were above normal for the past 12-month period, but again, the values were not near unprecedented levels.

 

 

Temperature

Precipitation

CD1

75.5%

97.3% (0)

CD2

88.2%

95.5% (0)

CD3

80.9%

96.4% (0)

CD4

76.4%

87.3% (0)

CD5

77.3%

99.1% (0)

CD6

87.3%

92.7% (0)

CD7

77.3%

59.1% (0)

 

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


 

November 2003 – October 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 2-year precipitation total was characteristic of “abnormally dry” conditions across southeastern Arizona (CD 7), the driest region over the past two years, and in great contrast to the southwestern part of the state (CD 5). Here, the past 24-month November-October period was the wettest on record. Mean temperatures for the 2-year period reflect the trend toward warming over the last several decades, as temperatures were of the 78th – 94th percentile across the state.

 

 

Temperature

Precipitation

CD1

79.8%

95.4% (0)

CD2

89.9%

84.4% (0)

CD3

88.1%

89.0% (0)

CD4

94.5%

67.9% (0)

CD5

86.2%

100% (0)

CD6

89.9%

84.4% (0)

CD7

78.9%

38.5% (1)

 

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


 

November 2002 – October 2005                                                                                                                                                                                    

Precipitation totals for the longer 3-year period indicate conditions that are not as wet when considering the past two years, as a portion of the very dry year of 2002 enters the timeframe. Rather dry conditions are evident across the southeastern portion of the state (CD 7; 21st percentile), where the total precipitation for the period is suggestive of “moderate drought” conditions. Elsewhere, precipitation was above the long-term median for the 3-year period. Temperatures for the period were well above the historical median; however, the longer 3-year time period likely illustrates the more general climatic changes of the past several decades to some extent.

 

 

Temperature

Precipitation

CD1

85.2%

88.0% (0)

CD2

91.7%

71.3% (0)

CD3

93.5%

75.0% (0)

CD4

97.2%

51.9% (0)

CD5

92.6%

95.4% (0)

CD6

94.4%

75.9% (0)

CD7

88.9%

21.3% (2)

 

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


November 2001 – October 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 two areas. All regions within the state, except for the southwest (CD 5), have been characterized by less than average precipitation over the 4-year period. Precipitation totals for the period indicate “abnormally dry” conditions across the 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 9th-10th 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

86.0%

57.9% (0)

CD2

92.5%

41.1% (0)

CD3

97.2%

37.4% (1)

CD4

98.1%

9.4% (3)

CD5

93.5%

81.3% (0)

CD6

97.2%

35.5% (1)

CD7

94.4%

10.3% (3)

 

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


 

 

  

 

 

Summary                                                                                                                                                                                                                             

October 2005 was characterized by above normal rainfall across the state, except for across southeastern and east-central Arizona, where conditions were rather dry. Except for across these two areas, the wet fall and winter conditions of 2004-05 were still reflected in high (wet) Palmer Drought Index Values for much of the state. Problematic has been the re-emergence of dry conditions across southeastern and east-central Arizona over the past 3-6 months. 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 evident on the 36-month time frame across southeastern Arizona, and dryness and drought is evident across much of the state on the 48-month time frame. The most critical areas of dryness over the past 4 years are located across southeastern and east-central Arizona. In these areas, precipitation was of an amount suggestive of “severe drought”. Included within the 4-year period is the very dry year of 2002.

 

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 on the short term.