The 60-day rainfall for July through August continued slightly below normal at Abilene (3.81 inches, which was 0.12 inches below normal) and well above normal at San Angelo (6.53 inches, which was 3.73 inches above normal). At many other locations across West Central Texas, the 60-day rainfall was approximately 200 to 300 percent of normal while Coleman and the southern part of Shackelford Counties averaged near 100 percent of normal rainfall. Crockett County had 50 percent of normal rainfall.
The U.S. Drought Monitor as of August 28th, issued through the National Drought Mitigation Center, indicated that severe drought conditions persist across Shackelford County while a moderate drought was reported across Coleman, Jones, Haskell, and Throckmorton Counties of the Big Country. The remainder of the Big Country reported abnormally dry conditions. A corridor from Robert Lee to Ballinger and south across San Angelo to Junction were also abnormally dry.
For the 60 day period from July through late August, the temperature reached or exceeded 100 degrees in Abilene about 16 days, and in San Angelo the century mark was reached or exceeded about 22 days. This intense heat produced high evaporation rates on the order of .33 to .50 inches per day. The above normal rainfall was quite beneficial to overcome daily evaporation.
Current Status with the Climate System
The NOAA Climate Prediction Center says, “El Nino conditions have developed and will persist into winter of 2009.” (For more information, please go to www.cpc.noaa.gov and click on the link to El Nino/La Nina.) When El Nino conditions occur, it means above normal temperatures or warmer ocean waters across the equatorial pacific waters. Normally, El Nino conditions usually have the most impact on the winter season across West Central Texas from December through February. Please stay tuned for the winter weather outlook.
Climate Outlook for Fall 2009
Current conditions and model forecasts favor the continued development of a weak-to-moderate strength El Niño into the Northern Hemisphere Fall 2009, with the likelihood of at least a moderate strength El Niño during the Northern Hemisphere Winter 2009-10.
The 90-day temperature and precipitation outlook for this upcoming fall season (September through November), from the Climate Prediction Center, indicates a 33 percent chance for both temperatures and precipitation to be above, below or near normal across West Central Texas. Or in another words, we just don’t know.
What we do know, is that next to May and June, September and October are two of the wettest months of the year for West Central Texas. Abilene averages around 2.90 inches for each of the months, while San Angelo averages around 2.95 for September and 2.57 inches for October.
Long range models show a breakdown of the ridge and a more progressive trough pattern that could result in better rain chances for the second week of September. Remember that some of the most significant floods to impact West Central Texas have occurred during the months of September and October.