by Robert K. Peters, Ph.D. - National Weather Service Cooperating Observer
The month of January 2002 was warmer and drier than normal. The month was much warmer and much drier than January 2001. Last month was 5.6 degrees warmer and 4.66 inches drier than last year at the same time. The month began cold, and warmed significantly after the first week, with a turn back to colder temperatures at month's end. Precipitation over the past twelve months is 54.24 inches, which is 119.8 percent of normal.
The term "normal" changes with this summary. The 1971-2000 period is now used as the standard climatic period. This replaces the 1961-1990 standard climate, in use since 1992. Under the new standard climate, January is 1.0 deg. warmer and 0.57 inch wetter than under the old one. This standard climate will remain in use until about 2012, when it will be replaced by the 1981-2010 standard climate. The 30-day outlook for January 2002 had called for above normal temperatures and near normal precipitation.
The week December 30, 2001-January 5, 2002 was twelve degrees colder than normal, and precipitation was about twenty percent of normal. Polar Continental air was over the region for most of the week. Disturbances crossing on the 31st, 1st, and 2nd brought snow flurries, which yielded trace amounts of precipitation. An upper air storm, crossing on the 5th, brought the week's only measurable precipitation, which fell as rain. For the entire week, high pressure over Western North America allowed cold air to move into the region from Central Canada. The week's average temperature was 34.7 deg., which was 8.8 deg. colder than the previous week.
The week January 6-12 was four degrees warmer than normal, and precipitation was about two-thirds normal. The flow of Polar Continental air shut off on the 7th, with a sharp warming trend through the 10th. Cold fronts on the evening of the 10th and morning of the 12th lowered temperatures back closer to seasonal normals. The week's rainfall occurred on the 5th with the crossing of another upper air disturbance. The weak disturbances of the 10th and 12th brought only widely scattered and very light precipitation--principally to the southern counties.
Blustery winds blew on the 7th, 9th, 10th, and 12th. With sun on all days except the 10th, the week's average high temperature was 19.7 deg. higher than the previous week. The week's average temperature was 50.4 deg., which was 15.7 deg. warmer than the previous week.
The week January 13-19 was two degrees warmer than normal, and rainfall was about one-third of normal. Systems crossed the area rapidly during the week in a progressive upper air flow pattern. Cool air masses were Polar Maritime in origin. Cold fronts crossed on the 15th, 17th, and 19th. Moist air overrode the shallow cool layer on the 18th, and a crossing upper air disturbance on the 19th brought the week's rainfall. The week's average temperature was 48.4 deg., which was 2.0 deg. cooler than the previous week.
The week January 20-26 saw temperatures about three degrees warmer than normal, and near normal precipitation. The week began chilly, with a sharp warming trend into mid- week, followed by a sharp cooling trend at late-week. The week's precipitation occurred with a crossing upper air storm on the 23rd and 24th, and a cold front on the morning of the 24th. Record high minimum temperatures were equalled or broken in the area on the morning of the 23rd with the presence of a Tropical Maritime air mass. The average temperature was 49.7 deg., which was 1.3 deg. warmer than the previous week.
The last five days of the month saw a sharp warm-up from the 28th-30th, with a record high minimum temperature equalled on the 29th. Record high maximum readings were approached on the 29th and 30th. A strong cold front moved through on the 31st, lowering temperatures and bringing rain, which will be counted in February's total since it fell after 6 a.m.
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 2002, RECORDS AND SUMMARY: