by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of February 1998 was warmer and wetter than normal. The El Nino Southern Oscillation persisted through the month, though its moisture connection to the Southwestern United States abated late in the month. A procession of storms in the active southern branch of the jet stream was responsible for the rainfall. >With the northern branch of the jet along the United States-Canadian border for much of the month, Arctic air was kept bottled up to the north of the international boundary and away from East Texas.
This is the second consecutive wet February, with 1997 being wetter by 2.90 inches. It is also the second consecutive warm February--last year was 1.0 degrees cooler than this. Year-to-date rainfall through month's end is 1.38 inches greater this year than last. Rainfall over the past twelve months is 53.99 inches--about 118 percent of normal. The thirty-day outlook had called for below normal temperatures and above normal precipitation.
The first week in February saw temperatures about two degrees above normal and rainfall about one-fifth normal. A storm feature crossed at mid-week, bringing the week's rainfall. A cool high pressure ridge built in at late-week behind the departing storm. The southern branch of the jet stream remained active early in the month, bowing to the north over the Central Plains late in the first week. The succession of storm features which came onto the California Coast through the week lost much of their energy as they crossed the western mountain ranges. East Texas got very little rainfall from these features.
Temperatures during the second week in February were about five degrees above normal, and rainfall was about 325 percent of normal. A powerful storm crossed on the 10th. This brought general rains of about three inches to the region, and severe weather on that morning. A weaker storm crossed on the 12th with patchy light rain over the southern counties. The last storm was followed by a Polar Maritime air mass, which lowered nighttime temperatures slightly.
The third week in February saw temperatures about two degrees above normal and rainfall near normal. The procession of upper air storms continued, with two crossing during the week. As with earlier in the month, these were followed by weak high pressure features. The result was that most of the week was overcast, though sunshine was present between storm features.
Temperatures during the final week in February were eight degrees above normal and rainfall was about 250 percent of normal. Severe weather occurred in the region on the night of the 25th as a strong upper air storm crossed ahead of a Pacific cold front. Wind damage to roofs, trees, and utility lines occurred in Smith County around midnight the 25th-26th. Another upper air storm had crossed earlier in the week bringing rainfall.
Dry air after the 26th allowed for quite warm daytime temperatures.
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
February 1998, RECORDS AND SUMMARY: