September 2005

Report and Summary

Tyler, Texas
September 2005
by Robert K. Peters, Ph.D.
National Weather Service Cooperating Observer

The month of September 2005 was much warmer and somewhat drier than normal. In fact, it replaces September 1910 and September 1998 as the fifth warmest September on record.

The four warmer Septembers were all early in the twentieth century: 1911 with 83.6., 1939 with 83.4, 1921 with 83.1, and 1900 with 82.9. The September 1910 and September 1998 monthly average was 81.9, with September 2005 0.1 deg. warmer. Compared with September 2004, the month was 4.3 deg. warmer, and 2.14 inches wetter. Year-to-date rainfall through September 30 is 11.68 inches less in 2005 than in 2004. Much of East Texas remained in extreme drought, though torrential rains from Hurricane Rita on the 24th alleviated some of the moisture deficit across the southeast.

The thirty-day outlook for September 2005--which was wrong--had called for near normal temperatures and near normal precipitation. The week August 28-September 3 saw temperatures about 2 deg. warmer than normal, and rainfall about 10 percent of normal.

Catastrophic Hurricane Katrina came ashore in Southeast Louisiana on the morning of the 29th. East Texas was on the fringe of this circulation, which resulted in very warm temperatures until slightly cooler air arrived on the 1st. Three of the rain bands associated with the hurricane crossed on the 29th and 30th, bringing the week's only rainfall.

Upper air high pressure, which controlled the area's weather otherwise, slid westward late in the week. This permitted lower nighttime temperatures and comfortable daytime relative humidities.

The week's average temperature was 83.1 deg., and precipitation was 0.07 inch. The temperature was 6.1 deg. cooler than the previous week. Compared with the same week in 2004, the week was 6.8 deg. warmer, and rainfall was identical during the comparable weeks in 2004 and 2005.

The week September 4-10 saw near normal temperatures and no rainfall. Upper air high pressure controlled the region's weather through the week. A couple of intrusions of dry air--one on the 4th and a stronger one on the 7th--resulted in cool nighttime temperatures. Daytime high readings in the dry air mass were slightly above normal.

The upper air high and the dry air mass suppressed any shower development until the afternoon of the 10th, when a tropical low pressure feature over Southwest Texas brought widely showers to the southwestern counties. The persistent easterly to northeasterly wind and full sun brought haze to the region at mid-week, with daytime visibilities running in the 4-9 mile range. The week's average temperature was 79.9 deg., which was 3.2 deg. lower than the previous week. Compared with the same week in 2004, the week was 3.1 deg. warmer. There had been no rain in 2004, either.

The week September 11-17 saw temperature about 5 deg. warmer than normal, and rainfall about 40 percent of normal. Heat built through the 15th, with a weak cold front that night lowering temperatures over the following two days. The week's only rain fell on the morning of the 16th as an upper air disturbance crossed.

A record high minimum temperature was set on the 15th. The week's average temperature was 83.2 deg., and rainfall was 0.28 inch. The week was 3.3 deg. warmer than the previous week. Compared with the same week in 2004, the week was 2.1 deg. warmer, and 0.24 inch wetter.

The week September 18-24 saw temperatures about 8 deg. warmer than normal, and rainfall about 225 percent of normal. For most of the week, a very strong upper air high pressure ridge dominated. The center of the ridge shifted from time to time, accounting for the minor day-to-day temperature variations.

The record high maximum temperature was tied on the 18th, 19th, and 21st. A new record high maximum temperature mark was set on the 22nd.

On the 24th, Hurricane Rita came ashore near Port Arthur, and moved north-northeastward through the region. This brought rains of up to 10 inches over Shelby County, and held down temperatures on that day. The week's average temperature was 83.6 deg., and precipitation was 1.89 inches. This was 0.4 deg. warmer than the previous week. Compared with the same week in 2004, the week was 7.8 deg. warmer. There was no rainfall during the week in 2004.

Hurricane Rita, which came ashore near Port Arthur on the morning of the 24th as a Category 3 hurricane, caused massive power failures in the Tyler area between the 24th and 27th.

There was devastation along the Upper Coast in Port Arthur, and considerable damage to structures, utility grids, and blockage of roads in the southeast. Rita moved rapidly northeastward overnight the 24th/25th, and upper air high pressure built back into the region.

Temperatures ran about 10 deg. above normal early in the week until a cold front arrived the night of the 28th.

This lower readings significantly on the 29th and 30th. There were scattered showers and thunderstorms with the front, though no rain fell in the city.

The fourteen days between the 15th and 28th saw seven new daily high temperature records set or tied, and a new record for warmest ever for so late in the season.

• 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 2005

• 01 97 70 90
• 02 95 71 89
• 03 96 70 87
• 04 95 68 90
• 05 93 65 88
• 06 93 69 87 H
• 07 92 67 86 H
• 08 93 65 87 H
• 09 95 64 89
• 10 92 67 87
• 11 93 71 89 H
• 12 92 68 83
• 13 95 74 92
• 14 98 76 87
• 15 98 77 92
• 16 92 72 82 0.28 T, PCPN 1400-1600 MN 0000-1200 73, MX 1200-2400 86
• 17 97 68 89
• 18 100 75 91
• 19 99 75 92
• 20 96 72 89 H
• 21 100 71 93
• 22 100 71 92 H
• 23 92 74 88
• 24 88 71 72 1.89 pcpn 1000-2400, mn 0000-1200 74, mx 1200-2400 74
• 25 97 71 89 0.12 PCPN 0000-0300
• 26 101 75 90
• 27 95 76 87
• 28 95 75 89
• 29 89 66 70 tr. MN 0000-1200 68, MX 1200-2400 76
• 30 79 60 74

SEPTEMBER 2005, RECORDS AND SUMMARY:

• 15TH, RECORD HIGH MINIMUM 77, PREVIOUS RECORD 76 IN 1920;
• 18TH, TIED RECORD HIGH MAXIMUM 100, SET FIRST IN 1911;
• 19TH, TIED RECORD HIGH MAXIMUM 99, SET FIRST IN 1941;
• 21ST, TIED RECORD HIGH MAXIMUM 100, SET FIRST IN 1939;
• 22ND, RECORD HIGH MAXIMUM 100, PREVIOUS RECORD 99 IN 1944;
• 22ND, 2223Z, ASTRONOMICAL ONSET OF AUTUMN;
• 24TH, HURRICANE RITA, PK GST 49 MPH WITH 1.89 INCHES OF RAIN;
• 26TH, RECORD HIGH MAXIMUM 101, PREVIOUS RECORD 100 IN 1939; ALSO WARMEST EVER FOR
• SO LATE IN THE SEASON,PREVIOUS RECORD 102 IN 1956;
• 28TH TIED RECORD HIGH MINIMUM 75, SET 1915 AND 1959;
• HIGHEST TEMPERATURE 101 ON THE 26TH,
• LOWEST TEMPERATURE 60 ON THE 30TH,
• AVERAGE MAXIMUM 93.5 F.,
• AVERAGE MINIMUM 70.5 F.,
• AVERAGE TEMPERATURE 82.0 F..
• 4.6 DEG. WARMER THAN NORMAL.
• HEATING DEGREE DAYS 0
• 0 PERCENT OF NORMAL HEATING DEGREE DAYS.
• COOLING DEGREE DAYS 510,
• 136.4 PERCENT OF NORMAL COOLING DEGREE-DAYS;
• TOTAL PRECIPITATION 2.29 IN.,
• 0.99 IN. LESS THAN MONTHLY NORMAL.
• 69.8 PERCENT OF NORMAL MONTHLY PRECIPITATION.
• YEAR-TO-DATE PRECIPITATION 21.18 IN.,
• 9.71 IN. LESS THAN NORMAL YEAR-TO-DATE PRECIPITATION,
• 68.6 PERCENT OF NORMAL YEAR-TO-DATE PRECIPITATION;
• 1 DAYS ON WHICH THUNDERSTORMS OCCURRED;
• 6 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;
• 0 DAYS ON WHICH FROZEN PRECIPITATION WAS OBSERVED;
• 0 IN. TOTAL SNOWFALL.
• 3 DAYS ON WHICH MEASURABLE PRECIPITATION OCCURRED.
• 26 DAYS ON WHICH THE MAXIMUM TEMPERATURE REACHED OR EXCEEDED 90 DEG.;
• 4 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.
• 0 SEASON-TO-DATE HEATING DEGREE DAYS,
• PERCENTAGE OF NORMAL SEASON-TO-DATE HEATING DEGREE DAYS: 0,
• 2674 YEAR-TO-DATE COOLING DEGREE DAYS.
• PERCENTAGE OF NORMAL YEAR-TO-DATE COOLING DEGREE DAYS: 112.9.
• PRECIPITATION DURING THE PREVIOUS TWELVE MONTHS 33.82 IN.,
• TWELVE-MONTH PRECIPITATION PERCENTAGE 74.7.

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