The month of September 2000 was warmer and much drier than normal. It was a month of sharp temperature contrast. The first few days of the month saw record high temperatures, with an all-time monthly high maximum record established. Rainfall was spotty and scant. This continued a dry spell which began in late-June. In fact, September 2000 was the fourth driest September on record. Driest was September 1899 when no rain fell. In 1931, 0.09 inch fell, and 0.13 inch in 1907. The last week of the month saw very cool temperatures, with readings running much below normal. The two weeks in between saw a gradual lowering of temperatures. A large upper air high pressure ridge was the culprit for both the high temperatures and low rainfall. As days continued shortening, the excessive heat eased. September 2000 was 0.8 deg. warmer than September 1999, and 2.49 inches drier.
Cumulative rainfall since the first of the year is 2.31 inches less in 2000 than it was through month's end in 1999. Precipitation over the past twelve months is 87.1 percent of normal. About 75 percent of the rain over the past year fell during March, April, May, and early June. Precipitation between July 1 and September 30, 2000 was but 10.1 percent of normal The thirty-day outlook had called for near normal temperatures and near normal rainfall.
The week August 27-September 2 saw temperatures nine degrees warmer than normal and no rainfall. A potent upper air high pressure ridge controlled the weather for the week. The 107-degree maximum on the 1st established a daily and monthly record, and was also the warmest so late in the season. The 104-degree high on the 2nd equalled the daily record for that date. There were widely scattered afternoon showers and thunderstorms on the 1st and 2nd. The city did receive a trace on the afternoon of the 2nd.
Temperatures during the week September 3-9 were five degrees warmer than normal, and there was no rainfall. Daily high temperature records were set on the 3rd and 4th. On the 5th, a cool high pressure ridge built in from the northeast. This lowered temperatures through the 7th. On the 8th, a tropical low in the Western Gulf of Mexico, which was briefly a tropical depression, spread cloudiness in from the southeast. This held down temperatures on the 8th and 9th. Parts of the area received rain on the 7th and 8th, with this generally confined to the southern and eastern counties.
Temperatures cooled somewhat during the week September 10-16, with readings averaging only four degrees above normal. Rainfall was about one-eighth of normal. A pair of cold fronts moved through--one on the 12th and the second on the 15th. The rain occurred with the first front, in the form of widely scattered light showers. Heavy rain did occur with the first front over the extreme north and extreme west of the region, with Terrell measuring 1.95 inches in a mid-afternoon downpour on the 12th. Surface high pressure, building in behind the front of the 15th, brought much cooler and much drier air to the region.
The week September 17-23 saw no rainfall, and temperatures three degrees warmer than normal. The first half of the week, with a sharp warm-up at mid-week as a Tropical Maritime air mass moved back over the region. The week September 24-30 cooled, with temperatures seven degrees below normal and rainfall about ten percent of normal. A strong front crossed the region on the 24th. This lowered temperatures, and brought the week's rainfall, which fell as scattered to numerous showers on the 24th and 25th. Surface high pressure controlled the weather through the end of the week. Though daytime readings rose after the 27th, nighttime minima remained below normal.
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
September 2000, RECORDS AND SUMMARY: