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Calendar year 2007 ended up being one of the top ten wettest years on record for most spots across the Colorado River basin. For example, it was the 7th wettest at Austin-Bergstrom, the 12th wettest at Austin-Camp Mabry, the 4th wettest at San Antonio and the second wettest at Victoria. But 2007 was actually a tale of two distinctly different weather patterns. The first 8 months of the year were among the wettest January through August periods on record. It was the wettest January through August period on record at Austin-Bergstrom and at San Antonio and the 4th wettest January through August on record at Camp Mabry. But the weather pattern turned distinctly drier beginning in September, with most of Central and South Texas recording below normal rainfall since late August/early September. In fact, data shows the period of September through December being among the top ten driest September through December periods on record, with rainfall generally between 25 and 50 percent of normal at most locations. Parts of the Hill Country have only recorded around 2 to 2.5 inches of rain since October 1. The National Drought Monitor has noted the recent dry weather, and has placed all of South Texas and the Hill Country under the designation of "abnormally dry", or the first stage of drought. The greatest impacts from the recent dry spell is a high fire danger and poor range conditions due to the lack of soil moisture near the surface. Note that if the dry conditions persist for another week, the drought monitor is expected to declare drought conditions deteriorating to "moderate" category, or the second stage of drought over much of the Hill Country and Interstate 35 corridor. The developing drought conditions are due in large part to a moderate La Nina atmosphere/ocean pattern in the Pacific Ocean. Recent data indicates this is the 8th strongest La Nina on record. La Nina's typically cause drier than normal weather across Texas and much of the southern US during the fall and winter seasons. Their effect on spring and summer weather is not as strong. The most recent long-range outlooks call for continued drier than normal weather across Central and South Texas through at least April. The outlook for this summer is still somewhat unclear, but drier than normal weather is likely to continue. Temperatures look to be well above normal the remainder of winter, continuing through this summer. |
Bob Rose,
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