The month of July 2002 saw near normal temperatures and above normal precipitation. The wet late-Spring and early-Summer kept vegetation green and soils moist. This kept temperatures from rising for much of the month to the extent which occurred in 1998 and 2000. The month was 0.2 deg. warmer than July 2001, and 3.16 inches wetter. Year-to-date rainfall through July 31st was 10.97 inches less this year than last. Twelve-month precipitation is 105.9 percent of normal. The 30-day outlook for July 2002 had called for above normal temperatures and near normal precipitation.
The week June 30-July 6 saw temperatures one degree cooler than normal and rainfall about twice normal. A cut-off upper air low meandered around Northeast Texas through the 3rd. This brought measurable rainfall daily through the 3rd, and brought to ten the number of consecutive days upon which rainfall was recorded. A strong thunderstorm on the afternoon of the 1st caused wind and lightning damage. The week was one degree cooler than the same period in 2001, and 270 percent wetter.
The week July 7-13 saw temperatures two degrees warmer than normal, and rainfall 120 percent of normal. For most of the week, upper air high pressure suppressed rain, and warmed temperatures. On the 12th, a new upper air storm dropped southward, generating thunderstorms on the afternoons of the 12th and 13th. Some thunderstorms on the 12th reached severe limits. The week was one degree warmer than the same period one year ago, and there was no rain during that week in 2001. The week's average temperature in 2002 was 85.0 deg., which was 4.3 warmer than the previous week.
The week July 14-20, 2002 was two degrees cooler than normal, and saw 300 percent of normal precipitation. A closed upper air low, which moved into the region on the 12th, continued within range through the 16th. This brought rain daily, with continuous rain for 13 hours on the 16th. The presence of clouds and rain, and later of moist soils and lush vegetation held down temperatures. Late in the week, upper air high pressure built northward from the Gulf of Mexico. This allowed for a warming trend. In comparison with the same week in 2001, the week was 1.6 deg. cooler. There was no rain during the same week in 2001. Temperatures during the week averaged 2.7 deg. cooler than the previous week in 2002.
The week July 21-27, 2002 was three degrees warmer than normal, and there was no rain. Surface and upper air high pressure controlled the weather during the week. Green vegetation from rains of the previous four weeks held up nighttime temperatures, and held down daytime readings slightly. The upper air high pressure ridge was weaker this Summer than it had been during previous summers. There were widely scattered afternoon showers and thunderstorms between the 23rd and 26th. These were due to a shear axis which was over the region. This was all left of an upper air storm and cold front, which dissipated on the 24th. Nacogdoches was deluged with 4.02 inches of rain on the afternoon of the 25th. The week's average temperature was 86.5 deg. This was 4.2 deg. warmer than the previous week, and 0.7 deg. warmer than the same week in 2001.
There was no rain during the same week in 2001, as well. The month ended warm and dry, with high humidities. Upper air high pressure continued in place, and was responsible for this.
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
July 2002, RECORDS AND SUMMARY: