Tropical Cyclone Report

Tropical Storm Fay

Tropical Storm Fay was a short-lived cyclone that made landfall along the central Texas producing widespread heavy rainfall and inland flooding.

a. Synoptic History

Tropical Storm Fay developed from an area of disturbed weather that included a broad, non-tropical low pressure system over the northwestern Gulf of Mexico. During the first few days of September, a broad mid- to upper-level trough moved southward from the United States and became stationary across the northern Gulf of Mexico. Thunderstorms developed along a surface low pressure trough that hugged the northern Gulf of Mexico coastal areas. Gradually, the trough and a series of weak low pressure systems drifted southward over the warm waters (sea-surface temperatures > 30° C) of the Gulf. A low in the northwestern Gulf of Mexico became the dominant circulation and developed persistent deep convection near the low-level center by 4 September. On 5 September, an Air Force Reserve Reconnaissance aircraft investigated the system when it was centered about 85 n mi southeast of Galveston, Texas. During the flight, a broad, closed circulation and sufficient winds were found to estimate that a tropical depression had formed at 1800 UTC. The "best track" chart of the tropical cyclone's path is given in Figure 1, with the wind and pressure histories shown in Figure 2 and Figure 3, respectively. The best track positions and intensities are listed in Table 1.

The depression moved steadily south-southwestward and strengthened fairly quickly. The depression became Tropical Storm Fay at 0000 UTC 6 September about 110 n mi southeast of Galveston. Fay moved south-southwestward for 12 hours before turning toward the west where it reached a peak intensity of 50 kt by 1200 UTC that day about 125 n mi southeast of Galveston. Shortly thereafter, Fay turned and moved erratically in a general west-northwestward direction and maintained its 50 kt intensity for nearly 24 hours until landfall occurred at 0900 UTC 7 September on the southern Matagorda Peninsula about 10 n mi east of Port O'Connor, Texas. After making landfall, the broad circulation reformed farther north, about 25 n mi northwest of Palacios. Fay then made a sharp turn toward the west and accelerated to about 15 kt. With more of the circulation being over land, the faster forward speed hastened the weakening process and by 0600 UTC 8 September, Fay had degenerated into a remnant low pressure system about 30 n mi southwest of Hondo, Texas. However, the rather tenacious remnant low meandered across southern Texas and northeastern Mexico for another 3 days producing copious amounts of rainfall before finally dissipating about 65 n mi northwest of Monterrey, Mexico.

b. Meteorological Statistics

Observations in Fay (Figure 2 and Figure 3) include satellite-based Dvorak technique intensity estimates from the Tropical Analysis and Forecast Branch (TAFB), the Satellite Analysis Branch (SAB) and the U. S. Air Force Weather Agency (AFWA), as well as flight-level observations from flights of the 53rd Weather Reconnaissance Squadron of the U. S. Air Force Reserve Command.

There were no ship reports of tropical storm force winds associated with Fay. Selected surface observations from land stations and data buoys are given in Table 2.

Fay's peak intensity of 50 kt from 1200 UTC 6 September to 0900 UTC 7 September (near landfall) is based on a blend of a reconnaissance flight-level spot wind report of 68 kt and larger area of 60 kt wind, which convert to surface wind values of 54 kt and 48 kt, respectively, and a pressure-wind relationship surface wind estimate of approximately 43 kt (Figure 2). This lower maximum wind speed is believed to be more representative of Fay's overall circulation since the isolated peak flight-level wind speed of 68 kt was well removed from the circulation center. In addition, after the center of Fay moved inland, the converted flight-level-to-surface wind speed estimate of 62 kt (Figure 2) that was observed over land on 7 September was not considered to be representative since it was associated with a large nocturnal thunderstorm complex and little or no thunderstorm activity existed over water. The minimum pressure of 998 mb at 0000 UTC 7 September was based on a reconnaissance aircraft extrapolated surface pressure from 1500 ft.

The 50 kt surface wind value at landfall along the central Texas coast is consistent with previous flight-level-to surface wind conversions when the center of Fay was still offshore and is close to the pressure-wind relationship value of 47 kt. The interpolated landfall minimum pressure of 999 mb is based on a reconnaissance aircraft extrapolated (from 1500 ft) surface pressure of 999.9 mb that was reported approximately 40 n mi northeast of the center.

Maximum storm surge values were generally around 2 -3 ft all along the Texas coast. Along the Louisiana coast, west of Cameron, storm surge values ranged from 1.5 to 2.5 ft and caused minor beach erosion and coastal highway flooding.

Rainfall totals across the San Antonio metropolitan area ranged from 4 to 8 in with some isolated reports in excess of 11 in. Across the remainder of south-central Texas, rainfall totals exceeded 9 to 12 in at several locations (Figure 4), with a total of 17.29 in reported at Fowlerton.

Twelve tornadoes occurred in association with Tropical Storm Fay. Six of the tornadoes developed across the upper Texas coastal area on 6 and 7 September, while the remaining six tornadoes were reported over the coastal plain of south-central Texas on 8 September. A funnel cloud was also sighted 3 miles west of Belmont, Texas during the early evening of 6 September.

c. Casualty and Damage Statistics

While Fay was only a moderate tropical storm, a combination of the long duration of tropical storm force winds and isolated tornadoes resulted in damage to more than 800 single-family homes, 100 multi-family buildings, and nearly 100 businesses in Brazoria County. Some coastal floods and beach erosion caused $3.5 million in damage to public roads, bridges, and recreational areas along the upper Texas coast, especially in Galveston County. Farther south, though, only minor beach erosion occurred.

Heavy rainfall and widespread inland freshwater flooding occurred across the upper Texas coastal area, north of where the center of Fay passed. Rainfall totals across the Upper Texas coast and in the Houston metropolitan area ranged from 8 to 12 in in many areas, with some estimated rainfall totals of 20 to 24 in near the town of Sweeney. Severe floods occurred across much of the upper Texas coastal area. In Galveston County, 135 residential structures were affected by Fay, with 23 receiving major damage that totaled about $500,000 in losses. In Brazoria county, more than 1500 homes and nearly 500 cars were flooded. In Matagorda County, 130 single-family homes and 32 businesses were damaged by flood waters. In addition, over $1 million in damage was done to public facilities, including roads, bridges, and public buildings. In Wharton County, nearly 200 single-family homes were damaged or destroyed by flood waters.

After moving inland and dissipating as a tropical cyclone, the remnant low generated widespread showers and thunderstorms which, in turn, produced torrential rainfall and widespread flooding across the region. Some homes and businesses across the area were damaged due to the floods. Ten homes were damaged due to floods in La Coste in Medina County, while another 20 homes were damaged in Pearsall in Frio County. Widepread minor damage also occurred to roads and bridges across Bexar, Medina, Wilson, Atascosa, Frio, Comal, and Guadeloupe Counties due to the floods. In contrast, the remnants of Fay brought much needed rainfall to help alleviate water shortage problems in the drought-stricken regions of west-central and south Texas.

Several tornadoes were spawned by Fay before and after the system moved inland. Late on 6 September, the first tornado destroyed a beach house in Surfside; a second tornado damaged a home in Matagorda County near Van Vleck. Shortly after midnight on 7 September, a third tornado hit west Columbia knocking down numerous trees along Highway 36; the fourth tornado touched down in Wharton County and destroyed a mobile home, and damaged 3 other mobile homes and a barn near Boling; the fifth and most significant tornado (F1 intensity) touched down in extreme eastern Fort Bend County destroying one mobile home and injuring 3 people; this same thunderstorm later crossed the San Bernard River into Wharton County and produced a sixth tornado that caused minor damage near Hungerford. During the morning and early afternoon of 8 September, a total of 6 weak tornadoes (all F0) occurred in Jim Wells (2 tornadoes), Bee, Live Oak, and Goliad (2 tornadoes) Counties, but produced no damage.

No deaths were reported in association with Fay. Insured losses did not meet the $25 million threshold in order to be recorded by the American Insurance Services Group and total flood-related damages are not available at this time. No monetary damage figures are available from Mexico.

d. Forecast and Warning Critique

No meaningful track and wind forecast statistics are available due to the limited period for which Fay was a tropical storm. However, a tropical storm warning was issued at 2100 UTC 5 September, which resulted in about 36 hours of lead time.

Table 3 lists the watches and warnings associated with Fay.

Acknowledgments

Some of the data in this report was furnished by National Weather Service Offices in Brownsville, Corpus Christi, Ft. Worth, Houston, San Angelo, and San Antonio, Texas, and Lake Charles, Louisiana.

Figure 1: Best track positions for Tropical Storm Fay, 5-11 September 2002, with minimum central pressure.

Figure 2: Selected wind observations and best track maximum sustained surface wind speed curve for Tropical Storm Fay, 5-11 September 2002. Aircraft observations have been adjusted for elevation using 75% and 80% reduction factors for observations from 925 mb and 1500 ft, respectively.

Figure 3: Selected pressure observations and best track minimum central pressure curve for Tropical Storm Fay, 5-11 September 2002.

Figure 4: South Texas rainfall totals 6-10 September 2002 associated with Tropical Storm Fay and its remnant low pressure system (Map courtesy of WFO San Antonio, TX).