The month of November 2000 was the wettest November in National Weather Service records for Tyler. During the month, the city received 13.32 inches of precipitation. This is more than 300 percent of normal, and replaces November 1946 when 12.09 inches fell in the record books. Otherwise, the month was colder than normal. The reason for the heavy rains was the present for much of the month of a storm over the Southwestern United States, which sent disturbances across the area. These interacted with Gulf of Mexico moisture in place over the area. These storms frequently pulled down cold air masses in their wake. That, along with the precipitation, accounts for the colder than normal temperatures.
November 2000 was 9.1 degrees colder than November 1999, and 12.56 inches wetter. Year-to-date rainfall through November 30 was 50.06 inches in 2000, compared with 38.11 for 1999. The wet latter half of October and November have erased the rainfall deficit which began in mid-July. Area reservoirs rose steadily through the month, though they were still below full pools at month's end, since so much of the precipitation was absorbed into the ground. Rainfall over the twelve months ending November 30 was 118.6 percent of normal.
Four new daily records were set during the month, for precipitation or cold.
The thirty-day outlook for November 2000 called for near normal temperatures and above normal precipitation.
The week October 29-November 4 saw temperatures ten degrees warmer than normal and rainfall about 800 percent of normal. An upper air trough formed over the Western United States. This feature would be responsible for continuing substantial rainfall well into November.
As disturbances plunged down the west side of this feature, rounded its base, and then ejected northeastward across the Plains, they resulted in general rains. The rain event of the 29th-30th brought isolated occurrences of severe weather to West and Central Texas, along with widespread rains to East Texas.
The disturbances which began crossing on the 1st also caused severe weather--this time over West, Central and South Texas. There was none in East Texas.
There were, however, torrential rains over the western and northern portions of the region on the early-morning of the 2nd, and to all of the region on the day of the 3rd and overnight of the 3rd/4th. A let-up on the 4th brought only light rain to most of the area.
During most of this week, the area was in the warm sector of the storm. A weak cold front did move through on the 2nd, but its boundary served mainly as a focusing mechanism for the rain, and allowed a surface wave to form on the 3rd which enhanced rainfall at that time.
Numerous flash flood warnings were required from early-morning of the 2nd through overnight of the 3rd/4th.
Precipitation during the week totaled 8.05 inches in Tyler, with similar or higher amounts to the south, west, and north. Amounts to the east were less--averaging around four inches. Single-day rainfall records for Tyler were set on the 2nd and 4th.
The week November 5-11 saw temperatures eight degrees colder than normal and rainfall about 233 percent of normal. The mean upper air trough over the west continued. A cold front crossed on the 7th, introducing Arctic air into East Texas, which persisted through the 11th.
This put the area into the cold sector of the storm. A disturbance crossed on the 5th, bringing rainfall which averaged about an inch.
Another crossed on the 8th, with rain averaging between one and two inches.
Neither severe weather nor flash flooding accompanied these. Some locations, which did not experience a freeze in early October, had one on the 9th, though freezing or below temperatures were generally confined to the north and east. Points in the west and south had still not observed a freeze by the 11th. The two-week rainfall total in Tyler for the period ending on the 11th stood at 10.50 inches.
The week November 12-18 saw temperatures 12 degrees below normal, and rainfall 150 percent of normal. Three migratory storms crossed during the week--on the 12th, 16th, and 18th. The first brought significant rainfall, the second light amounts, and the third significant rainfall over the southern counties but light amounts over the remainder of the area. Sleet was mixed with rain on the 18th as the drops cooled through evaporation when falling through dry air just above the surface. There were no ice accumulations reported. Tyler experienced its first freeze of the season on the morning of the 14th. By the 15th, readings had reached or fallen below freezing at all area stations. The main weather feature of the week continued to be an upper air low over Western North America, with disturbances rounding its base and crossing the Plains. By the 18th, this feature was shifting eastward, with upper air high forming there at that time.
The week November 19-25 saw temperatures six degrees cooler than normal and rainfall 300percent of normal. A powerful storm crossed on the 23rd and 24th. This brought heavy rainfall, with amounts of between two and six inches to the area. Otherwise, a high pressure ridge brought cold air early in the week. The rain on the morning of the 24th was heavy enough that US271 in Lamar County was closed due to high water. A rainfall record was set in Tyler on the 24th.
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.
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November 2000, RECORDS AND SUMMARY: