Volume 20 Number 8 AUGUST 2007

Summer returned to parts of the state this month while other areas continued a trend this summer of cooler temperatures and wet conditions. Also, Tropical Storm Erin formed in the Gulf of Mexico and made landfall along the middle Texas coast on August 16^th.

High pressure built in across the Southern Plains early in the month resulting in more typical summer like temperatures for parts of the state. This was particularly the case in areas of north and central Texas. Dallas/Forth Worth recorded an average monthly temperature of 87.8° F, which was 3.4° above normal. Shreveport’s average temperature of 86.3° F was over 3° above normal. Temperatures in central and west Texas were generally at or slightly below normal. The exception was in El Paso, which recorded an average temperature of 83.4°F, which was more than 2° above normal. Southeast Texas observed temperatures around 2°F above average.

Precipitation patterns were varied across the state. On August 16^th, Tropical Storm Erin made landfall near Lamar, Texas brining heavy rain to parts of southeast Texas and the Hill Country. Houston recorded 2.59” of rain on the 16^th, causing flash flooding as a result of bayous over spilling their banks. For the month, Houston recorded 8.05” which was over 4 inches above normal. San Antonio, Corpus Christi, and Victoria also recorded above average precipitation totals. Portions of north and east Texas, where the ridge of high pressure was strongest, saw the least amount of rain. Dallas/Fort Worth and Shreveport only saw 0.35” and .61”, respectively. Rainfall rates across west Texas and the Panhandle were especially varied. El Paso and Del Rio were below average. San Angelo and Abilene, however, were well above average, recording 6.55” and 7.07”, respectively.

Hurricane Dean formed in the western Atlantic late in the month and became a category 5 hurricane as it traversed the Caribbean. The strong ridge of high pressure anchored over the southeastern United States steered Dean well to the south of Texas as it made landfall in Mexico.

AUGUST 2007

* Complete temperature data were unavailable. Temperatures are rounded to the nearest whole degree.

*HDD - Heating degree-day: Refer to the Monthly Average chart for a definition T = Trace (<0.005")

*CDD - Cooling degree-day: Refer to the Monthly Average chart for a definition M: Information not available.

CLIMATIC AVERAGES FOR SEPTEMBER

Records are at the current site, other records may have occurred at previous sites.

*CDD - Cooling degree-day: The difference between the mean individual daily temperature and 65°F, with one

CDD resulting for each degree above the standard 65°F during one day.

*HDD - Heating degree-day: The difference between the mean individual daily temperature and 65°F, with one

HDD resulting for each degree below the standard 65°F during one day.

All times given for sunrise, sunset, and moon phase times are calculated for the intersection of

Meridian 99°10' W and parallel 31°23' N, which is the approximate geographic center of the state.

Climate-related Agricultural Information

http://agnews.tamu.edu/dailynews/stories/CROP/

Past Weather Events in September

September 16, 1875: Hurricane. Struck Indianola, Calhoun County. Three-fourths of town swept away; 176 lives lost. Flooding from the bay caused nearly all destruction.

September 8-9, 1900: Hurricane. Galveston. The Great Galveston Storm was the worst natural disaster in U.S. history in terms of human life. Loss of life at Galveston has been estimated at 6,000 to 8,000, but the exact number has never been exactly determined. The island was completely inundated; not a single structure escaped damage. Most of the loss of life was due to drowning by storm tides that reached 15 feet or more. The anemometer blew away when the wind reached 100 miles per hour at 6:15 p.m. on the 8^th. Wind reached an estimated maximum velocity of 120 mph between 7:30 and 8:30 p.m. Property damage has been estimated at $30 to $40 million.

September 8-10, 1921: Rainstorm. Probably the greatest rainstorm in Texas history, it entered Mexico as a hurricane from the Gulf. Torrential rains fell as the storm moved northeasterly across Texas. Record floods occurred in Bexar, Travis, Williamson, Bell and Milam counties, killing 215 persons, with property losses over $19 million. Five to nine feet of water stood in downtown San Antonio. A total of 23.98 inches was measured at the U.S. Weather Bureau station at Taylor during a period of 35 hours, with a 24-hour maximum of 23.11 on September 9-10. The greatest rainfall recorded in United States history during 18 consecutive hours fell at Thrall, Williamson County, 36.40 inches fell on Sept. 9.

September 8-14, 1961: Hurricane Carla. Port O'Connor; maximum wind gust at Port Lavaca estimated at 175 mph. Highest tide was 18.5 feet at Port Lavaca. Most damage was to coastal counties between Corpus Christi and Port Arthur and inland Jackson, Harris and Wharton counties. In Texas, 34 persons died; seven in a tornado that swept across Galveston Island; 465 persons were injured. Property and crop damage conservatively estimated at $300 million. The evacuation of an estimated 250,000 persons kept loss of life low. Hurricane Carla was the largest hurricane of record.

September 9-13, 1971: Hurricane Fern. Coastal Bend. Ten to 26 inches of rain resulted in some of the worst flooding since Hurricane Beulah in 1967. Two persons killed; losses were $30,231,000.

September 5, 2000: Excessive heat resulted in at least eight all-time high temperature records around the state, one of which was Possum Kingdom Lake which reached 114°F. This day is being regarded as the hottest day ever in Texas.

Dr. John Nielsen-Gammon (State Climatologist)

Adam Wiley (Undergraduate Assistant)