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Climate of 2006 - May
Texas
Drought
National Climatic Data Center, 15 June 2006
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Statewide Overview /
Southern Texas Overview /
Southern Texas Paleo Perspective
 Statewide Overview
Southern Texas Overview
Paleoclimatic Perspective
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May 2006, Pre-Instrumental Perspective, Southern Texas
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The graph below (annual values in light blue, 5-year weighted average in dark blue) shows the winter-spring (November-May) precipitation, 1896-2006, for Texas Division 9. The value for 2006 (4.98") is the 2nd lowest since 1896, after 1971 (3.16"). The most striking multi-year anomaly in this record is the 1950s drought (indicated with orange bar), which had seven consecutive years (1950-1956) with below-average winter-spring precipitation.
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The graph to the left also shows a 341-year tree-ring record (1652-1992; annual values in light red; 5-year smoothed values in dark red) that corresponds well to the variability in November-May precipitation. This record is the average of three tree-ring chronologies (Douglas-fir, post oak, and Montezuma bald cypress) from Texas and northern Mexico. The correlation between the annual values of the tree-ring record and November-May precipitation is 0.686, indicating a high degree of shared variance. The tree-ring record captures the multi-year variability of the observed precipitation record particularly well.
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The tree-ring record, as a proxy for precipitation, can put the winter precipitation variability of the last century in southern Texas into a much longer perspective. The record shows a number of individual years in the approximately 250 years prior to 1895 that may have had very low winter-spring precipitation similar to the lowest values in the past century. Among multi-year droughts, the 1950s appears unusually persistent and severe even in the context of the entire tree-ring record. Prior to 1950, the ring-width index was below average for seven years in a row only once (1711-1717; red bar), and the total cumulative ring-width anomaly for that period was not as great as for 1950-1956, suggesting it was not quite as severe as the 1950s drought.
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Resources:
References:
- Big Bend (Texas):
- Cook, E. R., Meko, D. M., Stahle, D. W., and Cleaveland, M. K., 1999. "Drought reconstructions for the continental United States." Journal of Climate 12: 1145-1162.
- South Texas Composite (Texas):
- Therrell, M. D., 2000. "The historic and paleoclimatic significance of log buildings in South-central Texas." Historical Archaeology 34: 25-37.
- Rio Sabinas (Mexico):
- Therrell, M. D., Stahle, D. W., Cleaveland, M. K., and Villanueva-Diaz, J., 2002. "Warm Season Tree Growth and Precipitation over Mexico." Journal of Geophysical Research 107 (D14), 10.1029/2001JD000851.
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U.S. Regional Drought /
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