by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of August 2002 saw near normal temperatures and near normal precipitation. The Summer upper air high was weaker in 2002 than in some of the past few summers, which saw torrid temperatures. Furthermore, green vegetation acted to hold down temperatures. Compared with August 2001, the month was 0.5 deg. warmer and 1.36 inches drier.
Year-to-date rainfall through August 31 was 12.33 inches drier than in 2001. Twelve-month precipitation was 102.9 percent of normal. The 30-day outlook for August 2002 had called for near normal temperatures and near normal precipitation.
The week July 28-August 3 was one degree warmer than normal, and there was no rainfall. During the week, upper air high pressure dominated the area's weather. The air mass was quite moist during the first half of the week, which held up nighttime low readings. Drier air worked its way into the region from the northeast on the 31st, which lower nighttime readings slightly, but allowed for daytime readings to rise.
A disturbance, rotating around the southern edge of the upper air high, generated showers and thunderstorms on the afternoon the 3rd. A 66-mph wind gust was clocked at Tyler--Pounds Field Airport at 3:02 p.m., and there were power outages on the evening of the 3rd. The week's average temperature was 85.5 deg., 0.8 warmer than the same week in 2001. There was no rain during the same week in 2001, either.
The week August 4-10 saw temperatures one degree cooler than normal, and rainfall about 150 percent of normal. Two disturbances in the Easterlies crossed during the week, and produced rainfall. The first was on the 3rd/4th, and the second on the 9th. Relatively dry air was present in the area for much of the week. This allowed nighttime temperatures to lower. The upper air high pressure ridge was not particularly strong, which held daytime temperatures down. Furthermore, the continuing effects of wet weather during June and July kept vegetation green. Tropical Storm Bertha was in the Northern Gulf of Mexico between the 4th and 8th. Its effect on East Texas weather was to keep winds out of the northeast during much of the week. Haze reduced visibility on the afternoons of the 7th, 8th, and 9th. The upper air high trapped pollutants near the surface.
The week's average temperature was 83.0 deg., which was 2.5 deg. cooler than the previous week. The week was 2.3 deg. cooler than the same week in 2001, and there was no rain during that week. The week August 11-17 was two degrees cooler than normal, and rainfall was about 15 percent of normal. The upper air high pressure weakened at mid-week, with an upper air trough in place between the 13th and 16th. A cold front went stationary just north of the area on the 14th. The result was general thunderstorm activity to the south of Tyler, with only widely scattered showers here. Temperatures also lowered at mid-week, with record low maxima set at Lufkin and Shreveport, and approached at Tyler on the 15th. At late-week, the upper air trough weakened, and high pressure began re-asserting itself. The week's average temperature was 81.5 deg., and rainfall was 0.08 inch. The temperature was 1.5 deg. lower than the previous week. The week was 0.3 deg. cooler than the same week in 2001, and 0.18 inch drier.
The week August 18-24 saw temperatures about two degrees warmer than normal, and there was no rainfall. Upper air high pressure controlled the week's weather. There was a disturbance in the Easterlies which crossed on the 21st and 22nd. This brought showers as far north as Cherokee County on the afternoon of the 22nd, and into Gregg County on the same afternoon. Shortening daylight allowed for slightly lower nighttime readings. The week's average temperature was 84.6 deg., which was 3.1 deg. warmer than the previous week. The week was 1.5 deg. warmer than the same week in 2001, and 1.43 inches drier.
The week August 25-31 saw temperatures two degrees cooler than normal, and rainfall about twice normal. An upper air disturbance combined with a decaying cold front to bring widespread and locally heavy rainfall on the 25th and 27th Severe thunderstorms occurred in Tyler late on the afternoon of the 25th, and on the morning of the 27th,resulting in tree-limb and minor property damage.
Surface high pressure built in from the northeast on the 28th. This brought a slightly cooler and drier air mass. It also resulted in the accumulation of atmospheric pollutants, which caused haze between the 28th and 31st. Temperatures began warming late in the week as moist and warmer air returned. The week's average temperature was 79.6 deg., which was 5.0 deg. cooler than the previous week. Compared with the same week in 2001, the week was 2.6 deg. warmer and 0.80 inch drier.
The reporting period for temperatures and phenomenon on each day is for the twenty-four hours ending at midnight hours GMT--6 p.m. CST and 7 p.m. CDT. The reporting period for precipitation is for the twenty-four hours ending at noon GMT--6 a.m. CST and 7 a.m. CDT. All times are given using the twenty-four hour clock, and are expressed in Greenwich Mean Time.
Observations are from NWS Station 41/9207/4 in Tyler, Texas. The term "normal" refers to averages from the standard climatic period 1971-2000.
MX MN OBS PCPN REMARKS
AUGUST 2002, RECORDS AND SUMMARY: