Tropical Cyclone Report

Hurricane Fausto

Hurricane Fausto was a long-lived category 4 hurricane (on the Saffir-Simpson Hurricane Scale) that did not affect any land areas. After degenerating to a remnant low in the Central North Pacific basin, Fausto was reborn as a tropical depression and later as a tropical storm.

a. Synoptic History

Fausto developed from a tropical wave that crossed the west-African coast on 11 August and entered the eastern North Pacific basin on 17 August. By late on 18 August the system acquired enough organization to be classified using the Dvorak technique. By the following day a broad closed circulation was present, but the convective pattern had weakened. Early on 21 August the system began to reorganize and at 1200 UTC became a tropical depression about 400 n mi south-southwest of Manzanillo, Mexico.

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 initially moved westward and strengthened, becoming a tropical storm at 0000 UTC 22 August, about 450 n mi south-southwest of Manzanillo. Fausto turned to the west-northwest, a heading it would maintain for the next six days, and steadily strengthened, becoming a hurricane later that day at 1800 UTC, when it was about 565 n mi south-southwest of Cabo San Lucas, Mexico. Steady and significant strengthening continued, with Fausto reaching its peak intensity of 125 kt at 1200 UTC 24 August, roughly 60 hours after becoming a tropical storm. At the time of peak intensity Fausto was located about 800 n mi southwest of Cabo San Lucas.

By 0000 25 August, deep convection in the eyewall of Fausto began to diminish, and a weakening trend began, one that was nearly as steady as the intensification had been. Fausto crossed the 26C SST isotherm near midday on 25 August, and had become a tropical storm again by 1200 UTC the following day. Even though Fausto subsequently failed to generate any more deep convection (and therefore was arguably no longer a tropical cyclone), its large circulation was slow to spin down. Winds did not fall below tropical storm strength until 0000 UTC 28 August, shortly after Fausto crossed 140 W longitude and entered the central Pacific basin. Fausto is considered to have become a remnant low by 1200 UTC 28 August.

The remnant low of Fausto continued on a westward track, passing about 430 n mi north of the Hawaiian Islands on 30 August. During the day the surface circulation passed underneath an upper-level low and redeveloped deep convection. With the redevelopment of convection Fausto became a tropical depression again at 1800 UTC 30 August, although it did have some subtropical characteristics; scatterometer passes and satellite imagery indicated that the strongest winds and convection were located over 120 n mi east of the center. Fausto moved to the west-northwest on 31 August, and during the day the upper-level flow over the center gradually changed from cyclonic to anticyclonic. (A scatterometer pass at 1642 UTC 1 September indicates that the surface wind field was contracting as the upper-level anticyclonic flow developed.) Fausto strengthened and became a tropical storm later on 1 September. On 2 September, Fausto turned north and accelerated ahead of a mid-latitude frontal system, becoming absorbed by an extratropical low shortly after 0000 UTC the next day.

b. Meteorological Statistics

Observations in Fausto (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).

Ship PFEW (Jo Lonn) reported 35 kt winds at 0000 UTC 24 August and again at 0000 UTC 25 August. These observations are given in Table 2.

c. Casualty and Damage Statistics

There were no reports of damage or casualties associated with Fausto.

d. Forecast and Warning Critique

Forecasts on Fausto were issued by both the National Hurricane Center (NHC) and by the Central Pacific Hurricane Center; only the NHC forecast verification is presented here. Average official track errors (with the number of cases in parentheses) for Fausto were 21 (21), 42 (20), 54 (18), 74 (16), and 120 (12) n mi for the 12, 24, 36, 48, and 72 h forecasts, respectively. These errors are substantially lower than the average official track errors for the 10-yr period 1992-2001 (36, 67, 97, 125, and 182 n mi, respectively), (Table 4). The Global Forecast System ensemble mean (AEMI) and the GFDL/UKMET/NOGAPS/GFS consensus (GUNA) were among the best performing of the guidance models.

Average official intensity errors were 8, 13, 16, 19 and 23 kt for the 12, 24, 36, 48, and 72 h forecasts, respectively. These were slightly above the long-term averages (7, 12, 16, 18, and 21 kt, respectively), although mostly smaller than the errors from the SHIPS and GFDI guidance models. Although overall the intensity forecast biases were low, the official forecasts systematically under-forecast intensity changes during both the strengthening and weakening phases.

Figure 1: Best track positions for Hurricane Fausto, 21 August - 03 September 2002.

Figure 2: Selected wind observations and best track maximum sustained surface wind speed curve for Hurricane Fausto, 21 August - 03 September 2002. Objective Dvorak estimates represent linear averages over a three-hour period centered on the nominal observation time.

Figure 3: Selected pressure observations and best track minimum central pressure curve for Hurricane Fausto, 21 August - 03 September 2002. Objective Dvorak estimates represent linear averages over a three-hour period centered on the nominal observation time.