Hurricane Edouard Preliminary Report

Excerpts courtesy of the
National Hurricane Center (NHC)
--Written by Richard J. Pasch and Jack Beven

Synoptic History

Edouard originated from a tropical wave that was already well-marked by a spiral-shaped mass of convective clouds while moving across western Africa on 17-18 August. The wave crossed the west coast of Africa early on the 19th, accompanied by a 45-knot mid-tropospheric jet seen in rawinsonde data. Observations from Dakar and nearby stations showed thunderstorms and squalls, along with 24-hour surface pressure falls on the order of 3 to 4 mb as the wave passed. Soon after entering the eastern tropical Atlantic, ship reports showed the presence of a large surface circulation. It is estimated that a tropical depression formed around 1800 UTC on 19 August, centered about 300 n mi southeast of the Cape Verde Islands. This was the first in a series of four tropical cyclones that would form over the eastern Atlantic from waves that moved off the west coast of Africa during a two-week span in late August and early September of 1996. Three of these systems, Edouard, Fran, and Hortense eventually became category three (or stronger) hurricanes.

Initially, it appeared that the westward-moving tropical cyclone would soon take a northwestward turn in response to a weakness in the subtropical ridge over the eastern Atlantic. However, the subtropical ridge remained strong enough to the north of the system to keep it on a generally westward track into the central tropical Atlantic. Higher-level winds favored intensification of the cyclone, as an upper-tropospheric anticyclone became well established over the area. The system became Tropical Storm Edouard early on 22 August, and strengthened into a hurricane around 1200 UTC the following day, when a banding-type eye was noted in satellite pictures.

When the hurricane neared 45W longitude on the 24th, a deep-layer cyclone to the east of Bermuda began to create a weakness in the subtropical ridge. In response to this, Edouard's direction of motion changed from westward to west-northwestward. Meanwhile, intensification continued, and Edouard's winds strengthened to 100 knots on the 24th and to 125 knots on the 25th, making it a category four hurricane. The latter wind speed was the maximum intensity, and a similar wind speed is estimated on the 26th and also around 0000 UTC on the 28th. From the 26th to the 28th, some fluctuations in intensity were noted, apparently as the result of eyewall replacement cycles and occasional doses of stronger vertical shear over the area. Nonetheless, Edouard maintained 115 knot or greater winds throughout the above period . The final deepening episode in Edouard was observed late on 29-30 August. During that event, three concentric eyewalls were indicated by aerial reconnaissance observations. Overall, Edouard remained a powerful, 100-knot or stronger hurricane for a very long time - from 24 August until early on 1 September.

Edouard moved relentlessly towards the west-northwest, at around 12 knots, until the 29th of August. This track kept the hurricane well to the northeast and north of the islands of the northeastern Caribbean Sea. On the 29th, a mid-tropospheric trough became established near the U.S. east coast, creating a more northward steering component for Edouard. Slowing its forward speed slightly, the hurricane turned northwestward, and then northward, while gradually weakening. The cyclone passed about midway between Cape Hatteras and Bermuda on 1 September, and then started moving slightly east of north. Late on the 1st, the hurricane wobbled toward the north, in the general direction of southeastern New England. However, early on the 2nd, Edouard veered sharply toward the northeast, and the center of the hurricane passed about 75 n mi southeast of Nantucket island around 0900 UTC, the closest point of approach to the United States. Maximum winds had diminished to near 70 knots by that time.

Edouard weakened to a tropical storm near 0000 UTC on the 3rd, and became extratropical shortly thereafter. The storm's motion became east-northeastward, keeping the center south of Nova Scotia, and, later, well offshore of Newfoundland. Edouard's remnant low was drawn around and into the circulation of a larger extratropical cyclone on the 6th, and was absorbed by this bigger system by 0000 UTC 7 September.

Meteorological Statistics

Most of the aircraft reconnaissance flights into Edouard were accomplished by the "Hurricane Hunters" of the U.S. Air Force Reserves. The Hurricane Hunters flew 15 missions, and made 66 center fixes. NOAA aircraft provided four additional fixes. The highest wind speed reported was 140 knots (at 700 mb) at 0003 UTC 28 August. Lowest central pressure reported was 934 mb at 1727 UTC 30 August. However, the highest wind reported by aircraft around that time was 134 knots. Subjective and objective Dvorak intensity estimates indicate that Edouard was stronger on 25-26 August, and also at 0000 UTC 28 August, than it was at the time of the minimum aircraft-reported pressure. At the latter time, the hurricane appeared considerably less well-organized on satellite images than on the earlier days.

Since Edouard crossed over the New York shipping channels, there was a large number of encounters by vessels at sea with this hurricane.

The hurricane came close enough to New England to produce sustained winds of tropical storm force at Nantucket Island and the Cape Cod area. Wind gusts to hurricane force were reported at Nantucket. In addition, there were unofficial reports of wind gusts to 90 mph at Nantucket, 80 mph at Martha's Vineyard, and 77 mph on Cape Cod.

Large swells, minor beach erosion, and some coastal flooding, presumably minor as well, occurred along the coast from North Carolina northward through Maine.

Casualty and Damage Statistics

Two deaths have been directly attributed to Edouard. A 71-year old man died when his boat capsized in heavy surf in Great Egg Harbor Inlet, south of Atlantic City, New Jersey. A 28-year old man drowned while surfing at Lavallette, northeast of Tom's River, New Jersey. Additionally, a 44-year old man suffered a broken neck (but survived) while surfing near Atlantic City. Overall, the effects of Edouard on land were apparently minor. Most of the damage was to boats at Martha's Vineyard and Nantucket.