The month of March 1999 saw near normal temperatures and below normal rainfall. Average temperatures in March 1999 were virtually identical to those in March 1998. March 1999 was 0.45 inch drier. Year-to-date precipitation is 5.29 inches less in 1999 than it had been a year earlier. Precipitation over the twelve-month period ending March 31, 1999 is 47.44 inches--about 104 percent of normal. The thirty-day outlook for March 1999 had called for near normal temperatures and below normal precipitation. The first week in March saw temperatures six degrees warmer than normal and rainfall less than ten percent of normal.
Upper atmospheric high pressure over Central North America was the dominant weather feature. The southern branch of the jet stream, flowing beneath this ridge, was weak. Though two migratory storms crossed, neither produced significant rainfall in Tyler. There was severe weather on the evening of the 5th as a squall line passed to the north of the city as a result of one of these storms. There was some wind damage that evening to structures on the city's northeast side.
The second week in March saw temperatures five degrees cooler than normal, and rainfall about twice normal. A slow-moving storm crossed between the 10th and 14th. It was accompanied by an Arctic air mass, which moved into the region on the 12th. The result was a period of cold rain, which was heavy on the 12th. Severe weather occurred on the 11th as the cold front worked its way into the area, though there were no reports of substantial damage in the immediate Tyler area.
The third week in March saw near normal temperatures and rainfall about one-eighth normal. High pressure dominated the area for much of the week, bringing generally a regime of mild daytime and cool nighttime readings. What may have been the last freeze of the season occurred the morning of the 15th. A weak upper air storm crossed on the 19th, bringing the week's only rainfall. It was followed by a turn back to cooler temperatures as a Polar Maritime air mass built into the region.
The final ten days in March saw temperatures one degree below normal and near normal rainfall. The week's weather pattern was fairly typical for early- Spring. Two upper air storms crossed--one rapidly on the 25th, and a second more slowly between the 28th and 31st. These two features brought the week's rainfall. The first was followed by cooler temperatures, though a Tropical Maritime air mass came over the region on the 30th. The Polar Maritime air mass had held temperatures down until Tropical Maritime air displaced it.
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
March 1999, RECORDS AND SUMMARY: