by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of February 2009 was warmer and drier than normal. Compared with February 2008, the month was 3.0 deg. Warmer, and 1.35 inches drier. Year-to-date rainfall through month's end was 2.77 inches less in 2009 than in 2008.
For much of the month, upper air high pressure extended northeastward out of North Mexico. This warmed temperatures, kept the air mass generally dry, and shoved the main storm track to the north of the region for most of the month. The thirty-day outlook had called for above normal temperatures and below normal precipitation.
The week February 1-7 saw temperatures about 3 degrees warmer than normal, and rainfall about 40 percent of normal. Fast-moving Arctic fronts on the 1st and 3rd kept temperatures well below normal through mid-week. Showers and a few thunderstorms accompanied the earlier front. At mid-week, the upper air pattern changed from a northwest flow aloft to a southwest flow aloft. Low pressure, deepening over Western North America, caused strong south winds which transported warm and increasingly moist air into the region beginning on the 6th. The week's average temperature was 52.5 deg., and rainfall was 0.32 inch. This was 5.3 deg. Warmer than the previous week. Compared with the same week in 2008, the week was 4.7 deg. Cooler, and 0.05 inch wetter.
The week February 8-14 saw temperatures about 8 degrees above normal, and rainfall near normal. An upper air storm crossed at mid-week, bringing two rounds of thunderstorms on the 9th and 11th. Severe weather occurred on the evening of the 11th, with a small tornado over northwestern Smith County. Cooler air followed the second disturbance, though the temperature was above normal each day during the week. The week's average temperature was 58.9 deg., which was 6.4 deg. Warmer than the previous week. Rainfall was 0.83 inch. Compared with the same week in 2008, the week was 1.7 deg. Warmer, and 0.56 inch wetter.
The week February 15-21 saw near normal temperatures, and rainfall about one-half normal. Storm systems on the 18th and 21st brought the week's rains, and both were followed by modified Polar Continental air. Warming preceded the front of the 18th, with temperatures well above normal on that day, and near to below normal for the remainder of the week. The week's average temperature was 52.2 deg., which was6.7 deg. Cooler than the previous week. Rainfall was 0.42 inch. Compared with the same week in 2008, the week was 2.3 deg. Warmer, and 1.12 inch drier.
The week February 22-28 saw temperatures about 2 degrees above normal, and on measurable rainfall. The final week of the month began cold, warmed rapidly at mid-week under upper air high pressure, then cooled dramatically at week's end. Upper air high pressure over North Mexico kept the week dry. A tight pressure gradient between high pressure to the east and low pressure over the Plains brought strong winds on the 25th and 26th. Arctic high pressure, building in ton the 28th, brought strong winds on that day. The week's average temperature was 56.8 deg., which was 4.6 deg. Warmer than the previous week. Compared with the same week in 2008, the week was 0.2 deg. Cooler, and 0.15 inch drier.
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 2009, RECORDS AND SUMMARY: