January 2007

Report and Summary

Tyler, Texas
JANUARY 2007
by Robert K. Peters, Ph.D.
National Weather Service Cooperating Observer

January 2007 goes into the record books as the third wettest in Tyler since record-keeping began in 1896. The month was also slightly colder than normal. Compared with January 2006 one of the warmest Januaries on record, the month was 11.1 deg. Colder, and 4.12 inches wetter.

Twelve-month precipitation is approaching normal. Through January 31, more than 93 percent of normal rainfall had occurred during the preceding twelve months. This compares with 57.9 percent of twelve-month normal rainfall through January 31, 2006 at the nadir of the drought. Though drought conditions have improved markedly in East Texas to "waning" in Tyler and moderate at some other locations, drought, severe to extreme conditions persist over parts of South Central and Southwest Texas.

The thirty-day outlook for January 2007 had called for near normal temperatures and above normal precipitation.

The week December 31, 2006-January 6, 2007 saw near normal temperatures and rainfall about 150 percent of normal. Polar Maritime air was over the area during the week, with chilly temperatures until moist air began overriding the surface air mass on the 3rd. An upper air low, crossing on the 4th, brought general rains of one to three inches in the region. Cold fronts on the 4th and 6th lowered temperatures back closer to seasonal normals, after above-normal readings on the 4th and 5th. The week's average temperature was 47.5 deg., which was 2.5 deg. Cooler than the previous week. Precipitation was 1.34 inches. Compared with the same week in the previous year, the week was 11.2 deg. Cooler, and there was no rainfall in 2006.

The week January 7-13 saw temperatures nearly 6 degrees above normal, and rainfall about 300 percent of normal. The week began cool, but ended very warm. A cold front on the 7th was followed by reinforcing fronts on the 8th and 9th. This held down temperatures, and brought rain to the entire area on the 7th. Tropical Maritime air returned rapidly on the 11th ahead of a massive storm which crossed between the 13th and 15th. An Arctic outbreak accompanied the storm system, dramatically lowering temperatures as it eased through the area. On the afternoon of the 13th, there was a 42-degree temperature difference between stations along Red River and those near the East Texas Lakes. This storm brought torrential rains on the 13th and 14th, which averaged between 3 and 7 inches. There were numerous reports of flooding and road closures on the 13th. The week's average temperature was 52.7 deg., and rainfall was 2.56 inches. This was 5.2 deg. Warmer than the previous week. Compared with the same week in 2006, the week was 3.2 deg. Cooler, and 2.04 inches wetter.

The week January 14-20 saw temperatures about 13 degrees below normal, and precipitation about 650 percent of normal. It was a week of long periods of bad weather. Temperatures were below freezing for 74 consecutive hours between 5 a.m. on the 15th and 7 a.m. on the 18th. The 236-hour overcast string included the entire week, having begun at 3 p.m. on the 11th and ending at 11 a.m. on the 21st. Arctic air covered the region during the entire week, with three storm systems affecting the region. The slow-moving storm of the 13th-15th brought more than six inches of rain to the city, and filled Lake Palestine, which had been nearly five feet down in mid-December. Two periods of wintry precipitation occurred: light freezing rain on the 15th, and a freezing rain/sleet mix on the 17th which closed schools, and left a one-tenth inch ice glaze. Reinforcing cold fronts on the 14th, 16th, and 18th held down temperatures. There was slight warming towards the end of the week when the final storm crossed on the 19th and 20th bringing additional rainfall. The week's average temperature was 34.2 deg., which was 18.5 deg. Colder than the previous week. Precipitation was 4.46 inches, of which 0.14 inch was frozen. Compared with the same week in 2006, the week was 20.9 deg. Colder, and 4.42 inches wetter.

The week January 21-27 saw temperatures about 2 degrees cooler than normal, and rainfall less than one-half normal. Cold fronts on the 21st, 24th, and 27th held down temperatures, though the week was not as bitterly cold as was the previous week. Gusty winds followed each front for about eighteen hours, lowering wind chill equivalent values. The fronts of the 21st and 27th caused rain over much of the region. Rain with the front of the 24th was confined mainly to the southern counties. A split upper air flow regime meant that upper air storm systems moved eastward out of the Southwestern United States to cause periods of cloudiness and rainfall. The week's average temperature was 45.9 deg., which was 11.7 deg. Warmer than the previous week. Rainfall was 0.40 inch. Compared with the same week in 2006, the week was 5.7 deg. Cooler, and 3.75 inches drier. Cold air held in the region during the final four days of the month, with a reinforcing cold front and crossing storm on the 30th. Some rain fell over the southeast. A stronger storm began crossing on the 31st, bringing a rain/sleet mix in the Tyler with no ice accumulation.

• KEY TO SYMBOLS:
• A = HAIL
• B = BLOWING
• D = DUST
• F = FOG
• H = HAZE
• IP = SLEET
• K = SMOKE
• L = DRIZZLE
• R = RAIN
• S = SNOW
• T = THUNDERSTORM
• Z = GREENWICH MEAN TIME
• ZL = FREEZING DRIZZLE
• ZR = FREEZING RAIN
• - = LIGHT
• + = HEAVY

R FOLLOWING A TEMPERATURE OR PRECIPITATION VALUE = RECORD

The reporting period for temperatures, precipitation, 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. 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.

JANUARY 2007

• 01 51 31 45
• 02 53 31 45
• 03 56 34 51
• 04 55 47 53 1.34 F, PCPN 0500-1500
• 05 62 46 55 F
• 06 61 44 54
• 07 59 42 52 0.32 PCPN 0200-0900 MN 0000-1200 45
• 08 60 29 50
• 09 63 33 52
• 10 65 32 58
• 11 69 47 65
• 12 72 63 67
• 13 67 37 37 2.24R T, PCPN 0500-2400
• 14 44 34 34 2.71 F, T, PCPN 0000-1600, 2100-2200
• 15 34 26 26 1.41R T, ZR, IP, PCPN 0000-1600; MN 0000-1200 32, MX 1200-2400 32
• 16 29R 25 28
• 17 32 28 32 0.14 ZR, IP, PCPN 1300-1700, 0.1 INCH ICE;
• 18 40 32 39
• 19 41 35 38 0.02 PCPN 2200-2400
• 20 44 35 42 0.18 PCPN 0000-0600, 2200-2400
• 21 62 37 43 0.36 F, PCPN 0000-1200
• 22 48 34 42
• 23 45 32 43
• 24 53 38 48
• 25 62 34 53
• 26 64 30 57
• 27 63 48 41 0.04 PCPN 1100-1200, 2000-2100 MN 0000-2400 48
• 28 45 28 28 MN 0000-1200 30
• 29 48 25 46
• 30 55 33 33
• 31 39 29 37 0.07 PCPN 1800-2000

• 13TH RECORD HIGH PRECIPITATION 2.24, PREVIOUS RECORD 1.72 IN 1951;
• 15TH RECORD HIGH PRECIPITATION 1.41, PREVIOUS RECORD 1.29 IN 1949;
• 15TH, FREEZING RAIN ON TREES AND UTILITY LINES;
• 16TH RECORD LOW MAXIMUM 29, PREVIOUS RECORD 31 IN 1953;
• 18TH, PERIOD OF 74 CONSECUTIVE SUB-FREEZING HOURS ENDED; 1100 01/15/07
• THROUGH 1300 01/18/07;
• 21ST 1700Z, OVERCAST PERIOD ENDED AT 236 CONSECUTIVE HOURS; OVERCAST BEGAN 2100 01/11/07;
• THIRD WETTEST JANUARY ON RECORD, REPLACES 8.17 INCHES IN 1999;
• HIGHEST TEMPERATURE 72 ON THE 12TH,
• LOWEST TEMPERATURE 25 ON THE 16TH AND 29TH;
• AVERAGE MAXIMUM 52.9 F.,
• AVERAGE MINIMUM 35.2 F.,
• AVERAGE TEMPERATURE 44.1 f.;
• 3.4 DEG. COOLER THAN NORMAL.
• HEATING DEGREE DAYS 650,
• 117.5 PERCENT OF NORMAL HEATING DEGREE DAYS.
• COOLING DEGREE DAYS 3,
• 63 PERCENT OF NORMAL COOLING DEGREE-DAYS;
• TOTAL PRECIPITATION 8.83 INCHES.,
• 5.49 IN. GREATER THAN MONTHLY NORMAL.
• 264.4 PERCENT OF NORMAL MONTHLY PRECIPITATION.
• YEAR-TO-DATE PRECIPITATION 8.83 IN.,
• 5.49 IN. GREATER THAN NORMAL YEAR-TO-DATE PRECIPITATION,
• 264.4 PERCENT OF NORMAL YEAR-TO-DATE PRECIPITATION;
• 3 DAYS ON WHICH THUNDERSTORMS OCCURRED;
• 4 DAYS ON WHICH THE VISIBILITY WAS HEAVILY RESTRICTED BY FOG, SMOKE, OR HAZE;
• 0 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED BY DUST OR BLOWING DUST;
• 2 DAYS ON WHICH FROZEN PRECIPITATION WAS OBSERVED;
• 0.1 IN. TOTAL SNOWFALL.
• 11 DAYS ON WHICH MEASURABLE PRECIPITATION OCCURRED.
• 0 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 90 DEG.;
• 0 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 100 DEG.;
• 2 DAYS ON WHICH THE TEMPERATURE FAILED TO RISE ABOVE 32 DEG.
• 13 DAYS ON WHICH THE MINIMUM TEMPERATURE REACHED OR FELL BELOW 32 DEG.
• 1434 SEASON-TO-DATE HEATING DEGREE DAYS,
• PERCENTAGE OF NORMAL SEASON-TO-DATE HEATING DEGREE DAYS:106.0,
• 3 YEAR-TO-DATE COOLING DEGREE DAYS.
• PERCENTAGE OF NORMAL YEAR-TO-DATE COOLING DEGREE DAYS: 62.5
• PRECIPITATION DURING THE PREVIOUS TWELVE MONTHS 42.52 IN.,
• TWELVE-MONTH PRECIPITATION PERCENTAGE 93.9.

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