by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
For the second year running, January was an unusually wet and unusually warm month. Precipitation totaled 8.17 inches. This places January 1999 as the third wettest January. January 1932 saw 9.60 inches, and January 1949 8.91 inches. January 1998 precipitation in Tyler was 7.50 inches. The month was warm. Indeed, January 1999 was a typical La Nina January, with an active southern branch of the jet stream. There were three severe weather events during the month--on the nights of the 1st, 21st, and 29th. This is unusual. As was also the case with January 1998, January 1999 was much warmer than normal. January 1999 was 0.6 degrees cooler and 0.67 inch wetter than January 1998. Rainfall over the past twelve months is 118 percent of normal, totalling 53.40 inches. The thirty-day outlook had called for above normal temperatures and near normal precipitation.
The first week in January saw temperatures four degrees below normal and rainfall about 200 percent of normal. Most of the rain fell on the evening of the 1st when a storm system moved through. There were reports of severe weather from some of the counties. The storm ushered in much colder air, which persisted for most of the week.
The second week in January saw near normal temperatures and no rainfall. During the week, winds aloft were northwesterly for most of the period, though a zonal westerly flow aloft set up late in the week. The result was two sharp Arctic air outbreaks, separated by a warm-up at mid-week.
The third week in January saw ... On the morning of the 15th, freezing fog severely restricted visibilities in the Tyler area.
The final ten days of the month were eight degrees warmer than normal, and saw 700 percent of normal rainfall. Strong to severe thunderstorms occurred the night of the 21st- 22nd, and very heavy rains occurred on the 28th-29th. Storm totals with the latter event ranged from three to eight inches in the area. Both storm features were upper air low pressure systems crossing in the southern branch of the jet stream.
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 1999, RECORDS AND SUMMARY: