September 2009

Report and Summary

Tyler, Texas
September 2009
by Robert K. Peters, Ph.D.
National Weather Service Cooperating Observer

The month of September 2009 was cooler and wetter than normal.

Frequent early-season cold fronts along with clouds and rain held down temperatures. The transition to a Fall weather pattern occurred earlier than in the past few years in mid-month. The month began and ended dry, with the mid-month period quite wet. Compared with September 2008, the month was 1.2 deg. Warmer, and 0.05 inch wetter. Year-to-date rainfall through September 30 was 11.23 inches less in 2009 than in 2008. The thirty-day outlook had called for near normal temperatures and near normal precipitation. The week August 30-September 5 saw temperatures about 5 deg. Below normal, and no rainfall. A couple of cold fronts brought Polar Maritime air to the region, holding temperatures below normal each day. A storm system between the 3rd and 5th brought showers to the northeast and southwest, but only a trace of rain fell in Tyler. The week's average temperature was 76.1, 5.0 deg. Cooler than the previous week. Compared with the same week in 2008, the week was 0.1 deg. Warmer, and 1.09 inches drier.

The week September 6-12 saw near normal temperatures and near normal precipitation. The week started warm under Tropical Maritime air. At late-week, an area of low pressure moved ashore over South Texas, and moved gradually northeastward through the weekend and through most of the following week. This brought general rain to East Texas, with flooding rains in parts of Central Texas. Temperatures cooled with clouds and rain late in the week. The week's average temperature was 79.5 deg., and rainfall was 0.67 inch. This was 3.4 deg. Warmer than the previous week. Compared with the same week in 2008, the week was 1.5 deg. Warmer, and 4.39 inches drier.

The week September 13-19 saw temperatures about three degrees below normal, and rainfall about 700 percent of normal. A slow-moving cut-off upper air low combined with a surface low to generate heavy and flooding rains in the area between the 12th and 18th. The most serious flooding was over the central and north, moving from the central counties on the 14th to the northern counties between the 15th and 17th. There was one flooding death in Wood County when a blind woman drowned while attempting to cross a flooded bridge. Storm totals in the area were between 4.0 inches in the south and 10.0 to 13.0 inches in the north, with the Gilmer Forest Service station reporting over 13.0 inches. By late-week, the surface low had moved into Mississippi, and the area dried out. Clouds and rain held down temperatures. The week's average temperature was 74.1, and rainfall was 5.27 inches yielding a storm total for Tyler of 5.94 inches. This was 4.4 deg. Cooler than the previous week. Compared with the same week in 2008, the week was 5.0 deg. Warmer and 4.62 inches wetter.

The week September 20-26 saw temperatures about 4 degrees below normal, and near normal rainfall High pressure controlled the region's weather early in the week, to be replaced by a slow- moving upper air low over the Central Plains at mid-week. The result was periods of mostly light rain between the 22nd and 24th, with much below normal temperatures. Late in the week, the upper air low was replaced by high pressure, which ended the rain and brought warmer temperatures. The week's average temperature was 70.5 deg., and rainfall was 0.91 inch. This was 3.6 deg. Cooler than the previous week. Compared with the same week in 2008, the week was 2.5 deg. Cooler, and no rain fell in 2008.

The final four days of the month were dry, with warm readings until a cold front on the 28th brought lower temperatures.

• 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.

September 2009

• 01 87 65 81
• 02 87 64 78
• 03 84 67 77 tr.
• 04 83 67 80 H
• 05 89 67 84 F
• 06 93 70 87 F
• 07 94 69 88 F
• 08 93 70 89 H
• 09 93 70 87 F
• 10 92 71 84 0.04 F, PCPN 1800-1900
• 11 86 71 80 F, T
• 12 72 69 71 0.63 F, PCPN 1400-2100
• 13 79 68 75 0.80 F, PCPN 0100-0900
• 14 80 71 72 3.24 T, F, PCPN 0000-0900, 1900-2300 MN 0000-1200 72
• 15 81 71 77 0.24 F, PCPN 0000-0400, 0800-0900
• 16 76 68 69 0.12 F, PCPN 1800-2100 MN 0000-1200 70
• 17 79 68 73 0.45 F, PCPN 1500-2400
• 18 81 68 76 0.38 F, PCPN 0000-0600
• 19 80 67 76 F
• 20 88 65 81 F
• 21 90 66 85 F, MN 0000-1200 71
• 22 73 62 67 0.75 T, F, PCPN 0500-1100 MN 0000-1200 66
• 23 69 59 63 0.02 PCPN 2200-2400 MN 0000-1200 61
• 24 69 58 64 0.14 PCPN 0000-0500, 1600-1800
• 25 81 58 75
• 26 87 62 79 F
• 27 90 65 84 F
• 28 83 63 75 MN 0000-1200 71
• 29 78 55 70
• 30 84 57 78

September 2009, RECORDS AND SUMMARY:

1
• 4TH RECORD RAINFALL 3.24 INCHES, PREVIOUS RECORD 1.85 INCHES IN 1982;
• 22ND ASTRONOMICAL ONSET OF AUTUMN AT 2118Z;
• HIGHEST TEMPERATURE 94 ON THE 7TH,
• LOWEST TEMPERATURE 55 ON THE 29TH;
• AVERAGE MAXIMUM 83.4 F.,
• AVERAGE MINIMUM 65.7 F.,
• AVERAGE TEMPERATURE 74.6 F.,
• 2.8 DEG. COOLER THAN NORMAL.
• 2 HEATING DEGREE DAYS,
• 100 PERCENT OF NORMAL HEATING DEGREE DAYS.
• 299 COOLING DEGREE DAYS,
• 79.9 PERCENT OF NORMAL COOLING DEGREE-DAYS;
• TOTAL PRECIPITATION 6.85 IN.,
• 3.57 IN. GREATER THAN MONTHLY NORMAL.
• 208.8 PERCENT OF NORMAL MONTHLY PRECIPITATION.
• YEAR-TO-DATE PRECIPITATION 33.82 IN.,
• 2.93 IN. GREATER THAN NORMAL YEAR-TO-DATE PRECIPITATION,
• 109.5 PERCENT OF NORMAL YEAR-TO-DATE PRECIPITATION;
• 3 DAYS ON WHICH THUNDERSTORMS OCCURRED;
• 21 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED TO BETWEEN 1 AND 7 MILES BY FOG, SMOKE, OR HAZE;
• 0 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED TO 1 MILE OR LESS BY FOG;
• 0 DAYS ON WHICH THE VISIBILITY WAS RESTRICTED BY DUST OR BLOWING DUST;
• 0 DAYS ON WHICH FROZEN PRECIPITATION WAS OBSERVED;
• 0 IN. TOTAL SNOWFALL.
• 10 DAYS ON WHICH MEASURABLE PRECIPITATION OCCURRED.
• 7 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 90 DEG.;
• 0 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 100 DEG.;
• 0 DAYS ON WHICH THE TEMPERATURE FAILED TO RISE ABOVE 32 DEG.
• 0 DAYS ON WHICH THE MINIMUM TEMPERATURE REACHED OR FELL BELOW 32 DEG.
• 2 SEASON-TO-DATE HEATING DEGREE DAYS,
• PERCENTAGE OF NORMAL SEASON-TO-DATE HEATING DEGREE DAYS: 100,
• 2313 YEAR-TO-DATE COOLING DEGREE DAYS.
• PERCENTAGE OF NORMAL YEAR-TO-DATE COOLING DEGREE DAYS: 97.7,
• PRECIPITATION DURING THE PREVIOUS TWELVE MONTHS 46.42 IN.,
• TWELVE-MONTH PRECIPITATION PERCENTAGE 102.5.

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