Preliminary Report
Tropical Storm Frances
08 - 13 September 1998

1998 PRELIMINARY REPORTS

Tropical Storm Alex (TS)
Hurricane Bonnie (3)
Tropical Storm Charley (TS)
Hurricane Danielle (2)
Hurricane Earl (2)
Tropical Storm Frances (TS)
Hurricane Georges (4)
Tropical Storm Hermine (TS)
Hurricane Ivan (1)
Hurricane Jeanne (2)
Hurricane Karl (2)
Hurricane Lisa (1)
Hurricane Mitch (5)
Hurricane Nicole (1)

Frances was a tropical storm that brought more than 15 inches of rainfall to portions of east Texas, about ten inches in southern Louisiana, and lesser amounts were spread northward across Oklahoma, Arkansas, Kansas, Missouri, and Iowa.

 

a. Synoptic History

Frances formed within a broad area of low pressure which first showed signs of organization of its associated convective cloudiness on 4 September. The convection was widespread over the western Caribbean and southern Gulf of Mexico, but there was no well-defined low-level center of circulation. This situation persisted for several days as the system moved slowly west-northwestward and during this time three poorly-defined closely-spaced tropical waves moved into the area, perhaps contributing to the development of this system. By the 8th, the system developed a 1000-mb central surface pressure and considerable organized deep convection over a large area of the western Gulf of Mexico. The best track is listed and begins as a tropical depression at this time at a position about 140 nautical miles east of Brownsville, Texas.

The tropical cyclone formation described above, with its large size, loosely organized convection and lack of a distinct center, is known as a "monsoon depression" in the western North Pacific basin.

The tropical depression drifted southward for about a day. By 1800 UTC on the 10th, wind observations from a data buoy, reconnaissance aircraft, and several oil rigs indicated that Frances had strengthened to a 40-mph tropical storm. It began moving north to northwestward at 12 to 17 mph. The center moved inland across the Texas coast just north of Corpus Christi at 0600 UTC on the 11th. By this time, Frances had strengthened to 63 mph under a large anticyclone aloft, weak vertical shear and SST's near 30 degrees Centigrade.

After moving inland, the center moved in a small cyclonic loop for 12 hours between Corpus Christi and Victoria and then moved northward across eastern Texas as a weakening tropical depression. The best track ends at 1800 UTC on the 13th, when the center was near the Texas/Oklahoma border north of Dallas, but the remnant low pressure and rainfall were tracked northward to Iowa during the next 24 hours.

b. Meteorological statistics

Tropical storm force wind speeds were observed at several data buoy and oil rig locations in the western Gulf of Mexico. The CMAN station at Sabine Texas reported a maximum 2-minute wind speed of 51 mph; this is the highest sustained surface wind speed in Table 2(a). Tropical storm force sustained winds were observed over land at Galveston, Victoria, and Jefferson County Airport, Texas. Frances was a large storm and the 39-mph wind speed radius extended approximately 300 nautical miles north and east of the center.

1. Storm Surge Data

Storm surge flooding of up to six to eight feet occurred along the middle and upper Texas coast and up to 5 feet along the Louisiana coast. This flooding persisted for about 48 hours.

2. Rainfall Data

Freshwater flooding from rainfall was the most significant weather effect. Frances dropped copious amounts of rain over east Texas and southern Louisiana. The highest total reported in Texas was over 16 inches in Brazoria County and the highest total from Louisiana was over 11 inches. Undoubtedly, even higher amounts are likely to have accumulated in these areas.

c. Casualty and damage statistics

There was 1 death attributed to Frances; 1 in Louisiana.

The only known fatality directly attributable to Frances was in Lafourche Parish, Louisiana, where a man was killed when his trailer home was destroyed by a tornado spawned by the tropical storm. Six others were injured by this tornado. An indirect death occurred in the New Orleans area where a woman died in an automobile accident.

Moderate beach erosion occurred along much of the upper Texas and western Louisiana coastlines.

Three Texas counties and four Louisiana parishes have been declared as federal disaster areas, primarily due to the rainfall flooding in the wake of Tropical Storm Frances. These include including Brazoria, Galveston, and Harris Counties and the parishes of Cameron, Jefferson, Lafourche and Terrebonne.

The American Insurance Association reports that a total of $110 Million in insured property damage has been claimed in Texas, Louisiana and Mississippi. The Houston Chronicle reported that $256 Million in damage was inflicted in Galveston County. The total NHC damage estimate for Frances is $500 Million.