By Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of April 2008 was slightly cooler and slightly wetter than normal. Compared with April 2007, the month was 2.6 deg. Warmer, and 1.25 inches drier. Year-to-date rainfall through month's end was 1.24 inches greater in 2007 than in 2008. The thirty-day outlook had called for above normal temperatures and below normal precipitation.
The week March 30-April 5 saw near normal temperatures, and rainfall about 400 percent of normal. Flooding rains occurred from Hemphill northward to Longview on the 29th and 30th. Another heavy rain event across the central and west came on the 4th, with the flooded areas spared additional downpours. Hemphill received 11.68 inches of rain during the week. The early-week rains were the result of a slow-moving and diffuse warm front interacting with considerable moisture and upper air support. The late-week rains were the result of a cold front and upper air storm system. The week's average temperature was 64.9 deg., and rainfall was 3.39 inches. This was 4.4 deg. Warmer than the previous week. Compared with the same week in 2007, the week was 5.2 deg. Warmer, and 3.74 inches wetter.
The week April 6-12 saw temperatures about 3 degrees above normal, and rainfall about one- half normal Tropical Maritime air was over the region through the 10th, but a strong cold front on the 11th dramatically lowered temperatures. Severe thunderstorms crossed the region on the evening of the 8th and the morning of the 10th. In the first event, a tornado touched down in northern Rusk County near Kilgore. The week's average temperature was 67.9 deg., and rainfall was 0.50 inch. This was 3.0 deg. Warmer than the previous week. Compared with the same week in 2007, the week was 10.7 deg. Warmer, and 0.31 inch drier.
The week April 13-19 saw temperatures about 7 degrees below normal, and rainfall about 150 percent of normal. The week started cool, with frost occurring in Tyler on the morning of the 14th. A few stations observed a light freeze on that and the following morning. A dramatic warm-up began on the 16th, with another storm system and weaker cold front crossing on the 18th. Tyler's only rain of the week fell that morning. Conditions were windy on the 16th, 17th, and behind the front on the 18th. The week's average temperature was 59.7 deg., and rainfall was 1.30 inches. This was 8.2 degrees cooler than the previous week. Compared with the same week in 2007, the week was 2.6 deg. Cooler, and 1.20 inches wetter.
The week April 20-26 saw temperatures about 4 degrees above normal, and rainfall about two-thirds normal. Much of the week was spent under Tropical Maritime air with warm temperatures and high humidities. Three storm systems penetrated the western counties, with severe weather on the evening of the 23rd, and again on the 25th. A weaker system on the 22nd brought only some light showers. Tyler's measurable rain fell with the weak system of the 22nd, and as the first line decayed early on the morning of the 24th. The second line brought only a trace of rain to the city. Neither of the two severe thunderstorm clusters affected Smith County. Cooler air entered the region on the morning of the 26th behind the cold front associated with the previous evening's thunderstorms. The week's average temperature was 72.2 deg., which was 12.5 deg. Warmer than the previous week. Rainfall was 0.58 inch. Compared with the same week in 2007, the week was 3.1 deg. Warmer, and 3.42 inches drier.
The final four days of the month began cool behind a strong cold front which crossed on the morning of the 27th. This front brought the period's rain. Temperatures returned to normal values on the 30th as southerly winds and Gulf moisture return ahead of another storm system.
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 2008, RECORDS AND SUMMARY: