By Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of April 2003 saw near normal temperatures and below normal rainfall. Compared with the same month in 2002, the month was 3.9 deg. cooler, and 0.45 in. drier. April 2003 is the third consecutive year when rainfall was significantly below normal. In April 2001, rainfall was 14.8 percent of normal, and in 2002 it was 63.8 percent of normal. April 2000 saw normal rainfall; April 1999 was the last "wet" April with 124.4 percent of normal rainfall. The storm track was to the north of the area for most of the month, and upper air high pressure, centered over the Southeastern United States, kept storm systems away. This resulted in the below normal rainfall.
The month continued a pattern of below normal rainfall, which began in late-February. Rainfall through April 30 was 0.51 inch less in 2003 than through the same date in 2002. Twelve-month rainfall is 101.3 percent of normal. The thirty-day outlook for April 2003 had called for below normal temperatures and near normal precipitation.
The week March 30-April 5 saw temperatures two degrees cooler than normal, and rainfall about 15 percent of normal. The week began cold, with a freeze on the 30th. Temperatures warmed through the week, as Tropical Maritime air returned on the night of the 31st. A weak cold front crossed on the night of the 4th, returning northward on the 5th. The week's precipitation occurred on the 4th and 5th as minor disturbances crossed in association with the front. The week's average temperature was 62.0 deg., 2.7 deg. warmer than the previous week. Rainfall was 0.12 inch. Compared with the same week in 2002, the week was 1.0 deg. warmer, and 1.06 inch. drier.
The week April 6-12 was 6 degrees cooler than normal, and had 150 percent of normal rainfall. Severe weather events occurred on the night of the 5th over the northwestern counties, and on the afternoon of the 6th over the southeastern. Three tornadoes over Rusk, Panola, Angelina, and Nacogdoches Counties destroyed homes on the afternoon of the 6th. Large hail caused three injuries in Hopkins County on the night of the 5th.
A Canadian air mass spilled into the region after the storm crossed, lowering temperatures into the 30s on the mornings of the 9th and 10th. A few locations experienced a light freeze. A warming trend began on the afternoon of the 10th, and continued through week's end under surface and upper atmospheric high pressure. The week's average temperature was 59.0 deg., which was 3.0 deg. cooler than the previous week, and 7.8 deg. cooler than the same week in 2002. Rainfall was 0.80 inch less in 2003 than during the same week in 2002.
The week April 13-19 saw temperatures three degrees warmer than normal, and no rainfall reported during the week. Upper air high pressure controlled the area's weather for much of the week. A weak disturbance crossed on the morning of the 16th--bringing a few sprinkles. The upper air ridge went east of the area on the 19th, when an upper air low began crossing. This brought showers and thunderstorms to the area at mid-day, with 0.75 inch hail reported from north of Tyler around noon. Two surface high pressure ridges brought dry air with cool nighttime temperatures during the week. The first was on the 13th and 14th, and the second on the 17th and 18th. Moist air returned from the Gulf of Mexico on the 18th. The week's average temperature was 69.9 deg., which was 10.9 deg. warmer than the previous week. The week was 6.1 deg. cooler than the same week in 2002, and 0.07 inch drier.
The week April 20-26 saw near normal temperatures and rainfall about one-half of normal. Cool air masses were in the area during the early- and late- week periods. At mid-week, an upper air storm crossed, which brought showers and a few severe thunderstorms on the 23rd. Rainfall amounts varied from none to as much as two inches. A dew point front crossed on the afternoon of the 24th, which brought the week's warmest temperatures. The week's average temperature was 67.3 deg., which was 2.6 deg. cooler than the previous week. Precipitation totaled 0.42 inch. Compared with the same week in 2002, the week was 4.3 deg. cooler, and 0.24 inch wetter.
The last four days of the month were warm. A storm system crossed on the night of the 29th-30th, but rainfall was not significant.
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
APRIL 2003, RECORDS AND SUMMARY: