Tropical Cyclone Report

Tropical Storm Matthew

Matthew made landfall on the Louisiana coast as a tropical storm with 35 kt winds.

a. Synoptic History

The origin of Matthew can be traced to a tropical wave that moved across the west coast of Africa on 19 September. The wave was very difficult to track between Africa and the Lesser Antilles because its close proximity to Tropical Storm Lisa and another large disturbance in the tropical Atlantic. The wave crossed the Lesser Antilles on 29 September and began to interact with a westward moving upper-level low. Cloudiness and showers gradually increased as the wave moved very slowly westward, trailing the upper-level low. The shower activity associated with the wave reached the Bay of Campeche on 5 October and gradually became better organized while moving little. An upper-level ridge became established over the convection and surface pressures began to fall in the area. On 7 October, data from a reconnaissance aircraft indicated a broad area of low pressure had formed just east of Tampico, Mexico, accompanied by light winds. The system continued to become better organized while moving little, and it is estimated that a tropical depression formed at 1200 UTC 8 October about 180 n mi southeast of Brownsville Texas. By 1800 UTC that day the cyclone strengthened into Tropical Storm Matthew. Initially, the cyclone moved toward the east and east-northeast, but then gradually turned to the northeast and north steered by a large mid- to upper-level low over western Texas. It is estimated that Matthew reached its peak intensity of 40 knots and a minimum pressure of 997 mb at 1800 UTC 9 October. Matthew's center made landfall just west of Cocodrie, Louisiana about 1100 UTC 10 October. Maximum estimated winds were then 35 knots. Thereafter, Matthew weakened to a depression and became an extratropical low. It continued moving northward and was absorbed by a frontal system at 1200 UTC 11 October.

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.

b. Meteorological Statistics

Observations in Matthew (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 53^rd Weather Reconnaissance Squadron of the U. S. Air Force Reserve Command. Microwave satellite imagery from NOAA polar-orbiting satellites, the NASA Tropical Rainfall Measuring Mission (TRMM), the NASA QuikSCAT, and Defense Meteorological Satellite Program (DMSP) satellites were also useful in tracking Matthew.

Table 2 shows selected surface observations including reports from southern Louisiana of heavy rainfall. The maximum rainfall was reported at Reserve in St. John Parish with 16.23 inches.

c. Casualty and Damage Statistics

One tornado briefly occurred near Golden Meadow, damaging the roof of a trailer. In Terrebonne Parish about 20 homes were flooded by the combination of rains and storm surge. There was a report of a 5.85 ft surge at Frenier as indicated in Table 2. According to local newspapers, Grand Isle suffered extensive beach front erosion. There were no known deaths or injuries.

d. Forecast and Warning Critique

Matthew was a short-lived tropical cyclone and there were only a few forecasts to verify. The few track forecasts produced errors are comparable to the average official track errors for the 10-yr period 1994-2003. The average official intensity errors were smaller than the average official intensity errors over the same period.

A strong pressure gradient prevailed over the northeastern Gulf of Mexico and produced gale force winds in that area during the formation of Matthew. As the circulation of the tropical cyclone headed for the coast, a tropical storm warning was issued from the Alabama-Florida border westward to Intracoastal City, Louisiana at 2100 UTC 9 October. The tropical storm warning replaced the existing gale warning about 15 hours before the poorly-defined center of Matthew crossed the Louisiana coast. The warning was discontinued at 1500 UTC 10 October.

Figure 1: Best track positions for Tropical Storm Matthew, 8-10 October, 2004.

Figure 2: Selected wind observations and best track maximum sustained surface wind speed curve for Matthew, 8-10 October, 2004. Aircraft observations have been adjusted for elevation using 80%, reduction factors for observations from 1500 ft or less.

Figure 3: Selected pressure observations and best track minimum central pressure curve for Tropical Storm Matthew, 8-10 October, 2004.