The month of May 2008 saw near normal temperatures and above normal precipitation. Compared with May 2007, the average temperature was identical, and rainfall was 2.35 inches less. Year-to-date rainfall through month's end was 3.88 inches less in 2008 than in 2007. An abrupt transition to a summertime pattern occurred around the 18th. The first half of the month was cooler than normal, with the last half running warmer than normal. The thirty-day outlook for May 2008 had called for near normal temperatures and near normal precipitation.
The week April 27-May 3 saw temperatures about 5 degrees below normal, and rainfall near normal. A line of severe thunderstorms crossed the region on the morning of the 2nd, ahead of a cold front. This system spawned a tornado which touched down three or four times between Van Zandt and Panola Counties. Though the warning sirens were sounded in Tyler, the storm did not touch down in the city, but small hail did fall. The cold ended very warm temperatures, and introduced a period of a few days of cooler than normal readings. The week's average temperature was 64.5, which was 7.7 deg. Cooler than the previous week. Rainfall was 0.80 inch. Compared with the same week in 2007, the week was 7.0 degrees cooler, and 3.00 inches drier.
The week May 4-10 saw near normal temperatures and near normal rainfall. The week began cool, but warmed on the 6th when Tropical Maritime air returned. A series of upper air disturbances brought severe weather to parts of the region on the evenings of the 7th and 10th, though not to Tyler. The first 90-degree temperature came on the afternoon of the 9th, marking the beginning of the warm season. The week's average temperature was 70.5 deg., and rainfall was 1.02 inches. Temperatures were 6.1 deg. Higher than the previous week. Compared with the same week in 2007, the week was 6.0 degrees cooler, and 0.43 inch drier.
The week May 11-17 saw temperatures about 6 degrees below normal, and rainfall about 300 percent of normal. The week began cool, with a strong and slow-moving storm system crossing between the 13th and 15th. This brought rains of between three and ten inches to the area, along with severe weather on the night of the 13th and morning of the 15th. The weak cold front which trailed the storm brought only slight cooling, with upper air high pressure building into the area at late-week, and warming temperatures. The week's average temperature was 66.7 deg., which was 3.8 deg. Cooler than the previous week. Rainfall was 3.15 inches. Compared with the same week in 2007, the week was 4.8 deg. Cooler, and 3.09 inches wetter.
The week May 18-24 warmed dramatically, with temperatures running about 5 degrees above and rainfall under 5 percent of normal. After starting with a dry air mass, upper air high pressure built overhead. Gulf moisture began its return on the 21st. The result was well above normal temperatures through the week, with high relative humidities after mid-week. The week's only rain came with a weak crossing upper air disturbance overnight the 17th/18th. The week's average temperature was 78.8 deg., and rainfall was 0.03 inch. This was 12.2 deg. Warmer than the previous week. Compared with the same week in 2007, the week was 6.3 deg. Warmer, and 2.21 inches drier.
The week May 25-31 saw temperatures about 3 degrees above normal, and near normal rainfall. Upper air high pressure controlled the region's weather for much of the week. The exception was on the 26th and 27th when upper air disturbances crossed from low pressure aloft over the Southwestern United States. Light showers fell on the afternoon of the 26th, and heavy rains affected the northern and central counties on the 27th. There were also reports of severe weather on the latter day. The week's average temperature was 79.3 deg., and rainfall was 1.27 inches. This was 0.5 deg. Warmer than the previous week. Compared with the same week in 2007, the week was 4.2 deg. Warmer, and 0.42 inch wetter.
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
May 2008, RECORDS AND SUMMARY: