State Climate Update for Arizona – Conditions through January 2006

 

January 2006                                                                                                                                                                                                                      

Recent warm and very dry conditions continued during January across Arizona. The ranking of mean monthly temperature ranged from the 67th percentile (northeast) to the 94th percentile (southwest). Precipitation totals were extremely low, with amounts indicative of “severe” to “extreme” one-month drought conditions across the entire state. Two regions of the state (CDs 5 and 6) recorded no precipitation for the month. Momentum from the wet 2004-05 winter in the Palmer Drought Severity Index has been erased across nearly all of the state. PDSI values continue to indicate rather moist to very moist conditions across the western edge of the state (CDs 1 and 5); however, the recent dryness in these two areas is very likely to significantly drop the PDSI values in the coming months.

 

 

Temperature

Precipitation

PDSI

CD1

86.6%

12.5% (3)

77.7%

CD2

67.0%

8.9% (3)

10.7%

CD3

79.5%

4.5% (4)

16.1%

CD4

83.9%

5.4% (3)

10.7%

CD5

83.3%

3.6% (4)

96.4%

CD6

94.6%

1.3% (4)

8.0%

CD7

83.9%

10.7% (3)

14.3%

 

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


 

 

November 2005 – January 2006                                                                                                                                                                                    

The period of late fall through early winter was extremely dry across Arizona. No portion of the state was immune from the dry conditions as precipitation totals for the 3-month period November through January were virtually unprecedented within the 112-year record. In all regions of the state, the 3-month precipitation total was suggestive of short-term “extreme drought”. Temperatures for the three-month period were high, with the greatest warmth across the southern (CDs 5, 6, 7) and northwestern (CDs 1, 3) portions of the state.

 

 

Temperature

Precipitation

CD1

91.9%

1.8% (4)

CD2

77.5%

1.8% (4)

CD3

90.1%

0.9% (4)

CD4

87.4%

1.8% (4)

CD5

93.7%

1.8% (4)

CD6

96.4%

0.9% (4)

CD7

91.0%

1.8% (4)

 

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


 

August 2005 – January 2006                                                                                                                                                                                          

Six-month precipitation values representing conditions from late summer through early winter again indicate dryness for all of Arizona except for the southwestern portion of the state (CD 5).  The driest 6 months occurred across east-central Arizona (CD 4; “extreme drought”) and across northeastern, west-central, south-central, and southeastern Arizona (CDs 2, 3, 6, 7; “severe drought”). Statewide, temperatures from late summer through early winter were considerably above the long-term median, and approaching unprecedented levels across south-central and southeastern Arizona (CDs 6, 7).

 

 

 

Temperature

Precipitation

CD1

84.7%

26.1% (1)

CD2

77.5%

6.3% (3)

CD3

85.6%

8.1% (3)

CD4

86.5%

2.7% (4)

CD5

92.8%

46.0% (0)

CD6

97.3%

11.7% (3)

CD7

85.6%

7.2% (3)

 

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


 

February 2005 – January 2006                                                                                                                                                                                      

There is much less evidence of drought within the state when examining precipitation totals for the past 12-month period. Only one region registered precipitation totals suggestive of drought – precipitation for southeastern Arizona (CD 7) ranked only in the 11th percentile, which is indicative of “severe drought”. Northeastern (CD 2) and east-central (CD 4) Arizona received amounts of precipitation suggestive of “abnormally dry” conditions. Conversely, characterized by well above normal precipitation was western Arizona (CDs 1 and 5), with totals ranking near the 75th percentile. 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) Arizona.

 

 

Temperature

Precipitation

CD1

81.1%

76.6% (0)

CD2

82.9%

29.7% (1)

CD3

84.7%

43.2% (0)

CD4

81.1%

25.2% (1)

CD5

90.1%

75.7% (0)

CD6

96.4%

46.9% (0)

CD7

90.1%

11.7% (3)

 

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


 

February 2004 – January 2006                                                                                                                                                                                      

Twenty-four month precipitation values indicate generally wet conditions across the state, as all regions but the southeast (CD 7) were above the long-term median value, and well above across the western portion of the state. The 2-year precipitation total was characteristic of “moderate drought” across southeastern Arizona, which is in great contrast to the southwestern part of the state (CD 5). Mean temperatures for the 2-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

89.1%

78.2% (0)

CD3

87.3%

81.8% (0)

CD4

94.5%

53.6% (0)

CD5

88.2%

94.6% (0)

CD6

91.8%

75.5% (0)

CD7

79.1%

24.6% (2)

 

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


 

February 2003 – January 2006                                                                                                                                                                                      

The rankings of precipitation totals for the longer-term 3-year period across the state closely match those of the past 2 years. The 36-month precipitation totals were above average for 5 of the 7 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; 16th 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 3-year time period likely reflects the more general climatic changes of the past several decades.

 

 

Temperature

Precipitation

CD1

84.4%

87.2% (0)

CD2

90.8%

67.0% (0)

CD3

93.6%

70.6% (0)

CD4

97.3%

42.2% (0)

CD5

90.8%

93.6% (0)

CD6

93.6%

67.9% (0)

CD7

89.9%

16.5% (2)

 

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


 

February 2002 – January 2006                                                                                                                                                                                      

Forty eight-month precipitation values indicate clear evidence of longer-term drought conditions across 2 areas of the state, with dry conditions across another 3 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 4-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 a 48-month precipitation total that is in the 8th percentile. Temperatures for the 4-year period are near unprecedented highs but, again, this is likely to be at least somewhat a reflection of longer-term trends rather than shorter-term anomalies.

 

 

Temperature

Precipitation

CD1

86.1%

50.0% (0)

CD2

91.7%

34.3% (1)

CD3

97.2%

30.6% (1)

CD4

98.2%

8.3% (3)

CD5

92.6%

74.1% (0)

CD6

97.2%

27.8% (1)

CD7

96.3%

8.3% (3)

 

48-month 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 January 2006. Two areas of the state (southwest, south-central) witnessed a second straight month with no precipitation. Two other regions of the state that recorded no precipitation in December received only a marginal amount in January. The momentum of the wet fall and winter conditions of 2004-05 has ended across almost the entire state in the metric of the Palmer Drought Severity Index. The re-emergence of extremely dry conditions across all regions of the state is clearly evident; the low precipitation totals from November 2005 through January 2006 are virtually unprecedented within the 112-year record.

 

On the longer term, there is much less evidence of drought across Arizona over the past 12-to-36 months, with generally greater than normal precipitation during the period. The exception is across southeastern Arizona, where drought conditions are evident in the precipitation totals for the past 12-month (“severe drought”) and 24-/36-month (“moderate drought”) periods. Conversely, the western edge of the state has been rather wet during the same period. Southeastern Arizona is joined by east-central Arizona as regions with 4-year precipitation totals suggestive of “severe drought” conditions. During that period, much of the remainder of the state has been “abnormally dry”.

 

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