Hortense became the second category four hurricane and the fourth category three hurricane on the Saffir-Simpson Hurricane Scale (SSHS) of the season. Hortense was a wet hurricane and most of the damage was caused by its accompanying torrential rains. Hortense crossed the southwestern tip of Puerto Rico and the eastern top of the Dominican Republic as a category one hurricane and the associated floods killed at least 21 people. Hortense moved northward over the western Atlantic and crossed Nova Scotia as a weakening hurricane.
a. Synoptic History
A broad area of low-pressure associated with a tropical wave
crossed Dakar, Africa on 30 August. The Dakar vertical-time section during
that period showed a well marked cyclonic wind shift below 700 mb and
a 63-mph easterly jet at 550 mb. Surface observations indicated that a
1005 mb low associated with the wave moved just south of the Cape Verde
Islands on the 31st. Although the system had a well defined low- to middle-
level circulation, satellite images indicated that the deep convection
was minimal. The low-pressure area continued moving westward and during
3 September, it crossed an array of NOAA drifting buoys. Data from these
buoys helped to determine that the system had become a tropical depression
at 1200 UTC 3 September.
The depression continued almost due westward around the periphery
of a strong high pressure ridge with no significant change in strength.
Satellite images suggest that for the next couple of days, deep convection
was rather intermittent and not well organized. In fact, on 6 September,
the first reconnaissance flight into the system found a broad circulation
and only a few squalls. As the depression approached the Lesser Antilles,
upper- level winds became more favorable for strengthening and satellite
images showed an increase in deep, organized convection. It is estimated
that the depression reached tropical storm status at 0600 UTC 7 September.
An early reconnaissance flight on that day reported peak winds of 71
mph at flight level and a minimum pressure of 1001 mb confirming
the strengthening of the system.
Hortense moved over Guadeloupe, where the pressure dropped
to 998 mb and produced sustained winds of 53 mph
with gusts to 81 mph. It also produced torrential
rains. The tropical cyclone moved westward into the eastern Caribbean
and encountered a fast eastward moving upper-level short wave. This increased
the vertical wind shear which temporarily inhibited strengthening. In
fact, high resolution visible satellite images clearly showed that the
low-level center of the tropical cyclone became exposed during the morning
of the 8th. A new burst of deep convection developed over the center later
in the afternoon and a gradual intensification began. By then, the short-wave
had moved out of the area and the shear had relaxed. Hortense became a
hurricane at 0600 UTC 9 September.
After slowing down just to the south southeast of Puerto Rico,
Hortense took a jog toward the northwest and the center moved over southwestern
Puerto Rico. Fixes from the San Juan WSR-88D radar indicate that the eyewall
of Hortense reached the coast near Guanica about 0600 UTC on the 10th
and moved over the southwestern tip of the island for about 2 hours.
Hortense moved through the Mona Passage and weakened slightly
while the circulation was interacting with land. The center passed very
close to Punta Cana, on the eastern tip of Dominican Republic where a
calm was felt and the pressure dropped to 988 mb. The hurricane continued
on a northwesterly track and the center moved just east of the Turks and
Caicos Islands. Hurricane conditions were observed in some of these islands.
Thereafter, Hortense briefly reached category four status with a peak
intensity of 138 mph and 935 mb minimum pressure
at 0000 UTC 13 September.
A developing trough along the eastern United States forced
the hurricane to turn northward with an increase in forward speed. A weakened
Hurricane Hortense rapidly crossed eastern Nova Scotia on 15 September
and became extratropical while moving just south of Newfoundland later
on that day.
b. Meteorological Statistics
There are unconfirmed reports of gusts to 109 mph in the southwestern tip of Puerto Rico about
0800 UTC 10 September. These strong winds may have been a local effect
caused by the Venturi effect (acceleration between walls). Residents of
the southwestern portion of Puerto Rico reported calm winds and that the
"stars were out" as the eye crossed the area. Peak winds of hurricane
force were reported over the Dominican Republic, and hurricane force winds
were registered in Grand Turk and Nova Scotia.
Hortense was upgraded to a category four hurricane of 138 mph based on a report from a Hurricane Hunter plane of 141 mph at 700 mb in the northeast quadrant at 2130 UTC followed by 147 mph in the southeast quadrant at 2220 UTC. The plane also reported a minimum pressure of 935 mb, a closed eyewall of 11 nautical miles in diameter and an excellent stadium (outward slope of the convective clouds in the eyewall) effect at 2323 UTC. In addition, satellite objective T-numbers were of the order of 6.5 on the Dvorak scale, corresponding to an intensity 146 mph and a pressure of 935 mb. Visible satellite images revealed a spectacular cloud pattern with a clearly distinct eye during that time.
1. Rainfall DataHortense was a wet hurricane. It produced about 10 inches of rain in Guadeloupe and dumped between 15 and 20 inches of rain over Puerto Rico and the U.S. Virgin Islands with possibly higher amounts in the mountains. Rainfall distribution associated with Hortense is displayed in. The Dominican Republic also experienced torrential rains with a maximum of 19.25 inches in the town of San Rafael de Yuma.
c. Casualty and Damage Statistics
There were 21 deaths attributed to Hortense; 18 in Puerto
Rico and 3 in Dominican Republic.
Three people were killed and 21 reported missing in the Dominican Republic and there was significant damage primarily in the northeastern portion of the country. A school and one church were demolished by winds or falling trees, numerous houses were damaged and several electrical poles went down. There was a 9-foot storm surge along the northeast coast. Roads were blocked due to flooding both from the storm surge and from torrential rains. In Samana, 80 percent of the agriculture was damaged.
Maximum Intensity For Hurricane Hortense