Preliminary Report
Hurricane Gustav
24 August - 03 September 1990

1990 PRELIMINARY REPORTS

Tropical Storm Arthur (TS)
Hurricane Bertha (1)
Tropical Storm Cesar (TS)
Hurricane Diana (2)
Tropical Storm Edouard (TS)
Tropical Storm Fran (TS)
Hurricane Gustav (3)
Tropical Storm Hortense (TS)
Hurricane Isidore (2)
Hurricane Josephine (1)
Hurricane Klaus (1)
Hurricane Lili (1)
Tropical Storm Marco (TS)
Hurricane Nana (1)

a. Synoptic History

The tropical wave that spawned Gustav moved off the northwest coast of Africa on 18 August with some signs of organization. However, the system became embedded within the ITCZ on its westward journey across the tropical Atlantic and didn't gebin strengthening until late on the 23rd and early on the 24th. It is estimated that the system became Tropical Depression Eight 840 nautical miles east of Barbados near 0600 UTC on the 24th.

Tropical Depression Eight gradually strengthened while moving west to west-northwestward at 12 mph and, based on satellite imagery, reached tropical storm strength 620 nautical miles east of Barbados near 0000 UTC on the 25th.

Tropical Storm Gustav continued the same general motion under the influence of weak ridging to the north. There was some concern that a cold low that was located to the northwest of Gustav would inhibit development during the next day or so. However, the low had little impact and Gustav reached hurricane strength 240 nautical miles east-northeast of Barbados near 1200 UTC on the 26th. The first of 53 reconnaissance aircraft fixes in Gustav had 75-mph winds at the 1500-feet flight level with 81-mph winds estimated at the surface at 1217 UTC on the 26th.

A hurricane watch was issued soon thereafter for the northern Lesser Antilles and a prtion of that area was placed under hurricane warnings at 2200 UTC on the 26th. However, the ridge to the north was breaking down and Gustav began responding by taking a gradual northwestward and then northward with the center of the system by-passing the Lesser Antilles 180 nautical miles to the east.

Gustav reached a central pressure of 965 mb near the beginning of its northward trek while centered 200 nautical miles east of Antigua at 1800 UTC on the 27th. Some minor weakening occurred thereafter in response to shearing conditions aloft. Dynamic models indicated a possibility that a ridge would build to the north of Gustav which would impart a northwestward motion to the hurricane thereby posing a threat to Bermuda. That scenario did not verify. Instead, a trough to the west of Bermuda and ridging to the east of Gustav kept the hurricane moving northward nearly along the 58th meridian.

During the next three days while Gustav was moving northward, Tropical Storm Hortense, later Tropical Depression Hortense, was approaching Gustav from the east. While there were some tendency for Hortense to rotate counterclockwise around Gustav, it probably was due to different steering currents rather than an actual Fujiwhara effect. The two centers were seperated by only 400 nautical miles at 0600 UTC on 31 August when reconnaissance reports indicated that Gustav reached its minimum central pressure of 956 mb 390 nautical miles east-southeast of bermuda.

Late on the 31st, the upper trough west of the system imparted a northeastward motion to Gustav and its outflow created shearing over Hortense. As a result, Hortense eventually dissipated. On the 1st of September, Gustav began merging and interacting with a frontal zone to the north which started the weakening process. During the 2nd, the ridge to the east of Gustav strengthened therevy imparting a north-northeast jog to the hurricane's motion just southeast of the Grand Banks. Ship reports indicated that the radius of the 39-mph winds by then had spread out to at least 200 nautical milesin the northwest quadrant over the cold waters of the North Atlantic. Thus, with the center only 240 nautical miles southeast of Cape Race, Newfoundland at 1800 UTC, a more northerly jog would have brought those winds to the extreme southeast coast of Newfoundland. However, a trough moving eastward across the Maritime Provinces accelerated the center in a northeast direction and Gustav was declared extratropical at 0600 UTC on 3 September. METEOSAT satellite imagery showed that the remnants of Gustav passed less than 200 nautical miles to the south of Iceland.

b. Meteorological Statistics

Gustav was primarily of concern to the marine community and at least two ships reported sustained winds of hurricane force. Ship C6BB, "Trinidad and Tobago", a merchant marine ship registered in the Bahamas reported 75-mph winds at 0000 UTC on 27 August 210 nautical miles northeast of Barbados. Ship FNWT, "Galion", a vessel of French registry, appears to have gone through or near the edge of the eye with winds of 030/81 mph at 0000 UTC on 2 September, and 280/81 mph at 1800 UTC on the same data. A pressure of 994.5 mb was reported from the Galion at 1200 UTC on the 2nd. Very likely that ship experienced hurricane conditions for 24 hours except for whatever period it may have been in the eye.

c. Casualty and Damage Statistics

There were no reports of deaths or damage attributed to Gustav. The U.S. Navy Ship "Antares" was potentially threated by both Hortense and Gustav bu the U.S. Navy Tug "Apache" towed the disabled Antares to safety.