by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
January 2007 goes into the record books as the third wettest in Tyler since record-keeping began in 1896. The month was also slightly colder than normal. Compared with January 2006 one of the warmest Januaries on record, the month was 11.1 deg. Colder, and 4.12 inches wetter.
Twelve-month precipitation is approaching normal. Through January 31, more than 93 percent of normal rainfall had occurred during the preceding twelve months. This compares with 57.9 percent of twelve-month normal rainfall through January 31, 2006 at the nadir of the drought. Though drought conditions have improved markedly in East Texas to "waning" in Tyler and moderate at some other locations, drought, severe to extreme conditions persist over parts of South Central and Southwest Texas.
The thirty-day outlook for January 2007 had called for near normal temperatures and above normal precipitation.
The week December 31, 2006-January 6, 2007 saw near normal temperatures and rainfall about 150 percent of normal. Polar Maritime air was over the area during the week, with chilly temperatures until moist air began overriding the surface air mass on the 3rd. An upper air low, crossing on the 4th, brought general rains of one to three inches in the region. Cold fronts on the 4th and 6th lowered temperatures back closer to seasonal normals, after above-normal readings on the 4th and 5th. The week's average temperature was 47.5 deg., which was 2.5 deg. Cooler than the previous week. Precipitation was 1.34 inches. Compared with the same week in the previous year, the week was 11.2 deg. Cooler, and there was no rainfall in 2006.
The week January 7-13 saw temperatures nearly 6 degrees above normal, and rainfall about 300 percent of normal. The week began cool, but ended very warm. A cold front on the 7th was followed by reinforcing fronts on the 8th and 9th. This held down temperatures, and brought rain to the entire area on the 7th. Tropical Maritime air returned rapidly on the 11th ahead of a massive storm which crossed between the 13th and 15th. An Arctic outbreak accompanied the storm system, dramatically lowering temperatures as it eased through the area. On the afternoon of the 13th, there was a 42-degree temperature difference between stations along Red River and those near the East Texas Lakes. This storm brought torrential rains on the 13th and 14th, which averaged between 3 and 7 inches. There were numerous reports of flooding and road closures on the 13th. The week's average temperature was 52.7 deg., and rainfall was 2.56 inches. This was 5.2 deg. Warmer than the previous week. Compared with the same week in 2006, the week was 3.2 deg. Cooler, and 2.04 inches wetter.
The week January 14-20 saw temperatures about 13 degrees below normal, and precipitation about 650 percent of normal. It was a week of long periods of bad weather. Temperatures were below freezing for 74 consecutive hours between 5 a.m. on the 15th and 7 a.m. on the 18th. The 236-hour overcast string included the entire week, having begun at 3 p.m. on the 11th and ending at 11 a.m. on the 21st. Arctic air covered the region during the entire week, with three storm systems affecting the region. The slow-moving storm of the 13th-15th brought more than six inches of rain to the city, and filled Lake Palestine, which had been nearly five feet down in mid-December. Two periods of wintry precipitation occurred: light freezing rain on the 15th, and a freezing rain/sleet mix on the 17th which closed schools, and left a one-tenth inch ice glaze. Reinforcing cold fronts on the 14th, 16th, and 18th held down temperatures. There was slight warming towards the end of the week when the final storm crossed on the 19th and 20th bringing additional rainfall. The week's average temperature was 34.2 deg., which was 18.5 deg. Colder than the previous week. Precipitation was 4.46 inches, of which 0.14 inch was frozen. Compared with the same week in 2006, the week was 20.9 deg. Colder, and 4.42 inches wetter.
The week January 21-27 saw temperatures about 2 degrees cooler than normal, and rainfall less than one-half normal. Cold fronts on the 21st, 24th, and 27th held down temperatures, though the week was not as bitterly cold as was the previous week. Gusty winds followed each front for about eighteen hours, lowering wind chill equivalent values. The fronts of the 21st and 27th caused rain over much of the region. Rain with the front of the 24th was confined mainly to the southern counties. A split upper air flow regime meant that upper air storm systems moved eastward out of the Southwestern United States to cause periods of cloudiness and rainfall. The week's average temperature was 45.9 deg., which was 11.7 deg. Warmer than the previous week. Rainfall was 0.40 inch. Compared with the same week in 2006, the week was 5.7 deg. Cooler, and 3.75 inches drier. Cold air held in the region during the final four days of the month, with a reinforcing cold front and crossing storm on the 30th. Some rain fell over the southeast. A stronger storm began crossing on the 31st, bringing a rain/sleet mix in the Tyler with no ice accumulation.
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
January 2007, RECORDS AND SUMMARY: