by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of January 2005 was much warmer and slightly drier than normal. Temperatures swung widely during the month, spending most of the month in the much-above normal range. Though the beginning and end of the month was wet, the middle was dry. Compared with January 2004, the month was 2.6 deg. warmer, and 0.17 inch drier. Year-to-date rainfall was 0.17 inch less on the 31st in 2005 than in 2004. The thirty-day outlook for January 2005 had called for near normal temperatures and above normal precipitation.
The week December 26, 2004-January 1, 2005 saw temperatures 10 deg. warmer than normal, and no rainfall. The Arctic air mass, which moved into the area just before Christmas, shifted eastward early in the week. By late-week Tropical Maritime air was in control, as upper air high pressure bulged northward from the Gulf of Mexico. This kept temperatures warm, conditions humid, and the area dry. The week's average temperature was 57.0 deg, 15.2 deg. warmer than the previous week. Compared with the same week in 2003-2004, the week was 1.3 deg. warmer, and 1.78 inches drier.
The week January 2-8 saw temperatures 7 deg. warmer than normal, and precipitation about 130 percent of normal. Tropical Maritime air continued until the 5th, when it was replaced by a sharp Arctic outbreak. Rain fell on the 2nd with a crossing disturbance, and on the 5th with the front. On the 7th, overrunning rain developed behind the front, with a few ice pellets on the evening of the 6th but no accumulation. Temperatures on the 6th averaged about 40 deg. colder than those of the 4th. The week's average temperature was 53.8 deg., and precipitation was 1.18 inches. This was 3.2 deg. colder than the previous week. Compared with the same week in 2004, the week was 12.3 deg. warmer, and 1.09 inches wetter.
The week January 9-15 saw temperatures 10 deg. warmer than normal, and rainfall about 90 percent of normal. The week began as had the previous week, with Tropical Maritime air in control until the arrival of a strong cold front on the night of the 12th. This brought an outbreak of severe weather over parts of the region, with widespread rain. Colder air flowed into the region between the 13th and 15th. The week's average temperature was 56.8 deg., and rainfall was 0.60 inch. This was 3.0 deg. warmer than the previous week. Compared with the same week in 2004, the week was 1.3 deg. warmer, and 0.71 inch drier.
The week January 16-22 saw temperatures about 1 deg. warmer than normal, and no rainfall. The week began with Polar Continental air in control, which held temperatures well below normal. On the 19th, Tropical Continental air replaced it, sending daytime temperatures well above normal, though overnight lows remained cool. Dense fog formed in the area on the 20th and 21st as the warmer air flowed over the damp and cold ground. A strong cold front crossed on the 22nd, bringing very windy conditions to the area. Upper air high pressure, extending into the region from its position over Western North America, kept the region dry. The week's average temperature was 48.0 deg. This was 8.8 deg. cooler than the previous week. Compared with the same week in 2004, the week was 2.4 deg. warmer, and 0.65 inch drier.
The week January 23-29 was one of sharp contrasts, with temperatures averaging about 1 deg. cooler than normal, and rainfall about one-half normal. The week began cold, warmed rapidly at mid-week with record temperatures on the 26th, and cooled sharply beginning the 27th. The week's rain fell with a crossing upper low on the 27th. Amounts of more than two inches were common across the south, with the remainder of the area receiving little or none. A temperature inversion set up on the morning of the 27th, bringing an overcast which trapped the modified Polar Continental air beneath it into the following week. The week's average temperature was 47.2 deg., which was 0.8 deg. cooler than the previous week. Compared with the same week in 2004, the week was 1.7 deg. warmer, and 0.47 inch drier.
The final two days of the month saw the temperature inversion continuing, and another crossing disturbance. The result was cold temperatures and rain from the afternoon of the 30th through the 31st.
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
January 2005, RECORDS AND SUMMARY: