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Preliminary Report
Hurricane Hortense
3-16 September 1996

Lixion A. Avila
National Hurricane Center
23 October 1996

Tropical Storm Arthur
Hurricane Bertha
Hurricane Cesar
Hurricane Dolly
Hurricane Edouard
Hurricane Fran
Tropical Storm Gustav
Hurricane Hortense
Hurricane Isidore
Tropical Storm Josephine
Tropical Storm Kyle
Hurricane Lili
Hurricane Marco


 Colorized infrared image of Hurricane Hortense pounding Puerto Rico. (57K GIF)

[1996 Atlantic Hurricane Season]

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 55-knot 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 (Fig 1 [44K GIF]).

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 62 knots 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 46 knots with gusts to 70 knots. 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 120 knots 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.

Hortense's track is shown in Fig. 2 (73K GIF). Table 1 is a listing, at six-hour intervals, of the "best-track" position, estimated minimum central pressure and maximum 1-minute surface wind speed.

b. Meteorological Statistics

The best track pressure and wind curves as a function of time are shown in Fig. 3 (31K GIF) and 4 (27K GIF) and are based on reconnaissance and surface observations, satellite intensity estimates from the Tropical Analysis and Forecast Branch (TAFB) of the Tropical Prediction Center. It also includes estimates from the Satellite Analysis Branch (SAB) and the Air Force Global Weather Central (AFGWC).

Hortense 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 Fig. 5 (120K GIF). The Dominican Republic also experienced torrential rains with a maximum of 19.25 inches in the town of San Rafael de Yuma.

There are unconfirmed reports of gusts to 95 knots 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. Tables 2 and 3 contain selected surface observations and ships reporting 34-knot winds or higher associated with Hortense.

Hortense was upgraded to a category four hurricane of 120 knots based on a report from a Hurricane Hunter plane of 123 knots at 700 mb in the northeast quadrant at 2130 UTC followed by 128 knots in the southeast quadrant at 2220 UTC. The plane also reported a minimum pressure of 935 mb, a closed eyewall of 11 n mi 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 127 knots and a pressure of 935 mb. Visible satellite images revealed a spectacular cloud pattern with a clearly distinct eye during that time.

c. Casualty and Damage Statistics

Hortense devastated portions of Puerto Rico but most of the damage was not done by winds or storm surge. Instead, torrential rains produced flash floods and mud slides which killed at least 18 people. A preliminary report from FEMA indicates that nearly 11,463 homes were severely damaged by Hortense and agricultural losses were of the order of 127 million dollars. In addition, there was significant inland flooding in the low-lying areas as well as serious coastal flooding in Nagabo, Guayanilla and Ponce.

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.

d. Forecast and Warning Critique

Table 4 summarizes the watches and warnings associated with Hortense. As indicated in Table 4, a hurricane watch and a tropical storm warning were issued for Puerto Rico when Hortense was still in the developing stage over the Leeward Islands. Hortense became sheared and weakened over the eastern Caribbean and the official intensity forecast called for no significant change in strength. Consequently, the hurricane watch for Puerto Rico was discontinued but the tropical storm warning remained in effect. However, it was emphasized in the tropical cyclone discussions issued by the NHC that there was low confidence in the intensity forecast. Hortense reintensified and a hurricane warning was issued for Puerto Rico about 14 hours before landfall.

Hurricane warnings were in place for the entire island because hurricanes can often wobble along the track. These wobbles are in general difficult if not impossible to forecast but are taken into consideration when issuing watches and warnings. Hortense jogged to the north of the main track when it was located just south of Puerto Rico. That wobble or jog brought the center of the hurricane over the extreme southwestern portion of the island.

Figure 6 (a [82K GIF], b [87K GIF]) shows a series of model track forecasts for different periods when Hortense was in the eastern Caribbean. One can notice that most of the model and official forecasts were to the left of the best track. This means that, as expected, neither the models nor the official forecast captured the jog to the north. However, the errors in the forecast, in general, were much smaller than the most recent 10-year average forecast errors. Models and official forecast performance are shown in Table 5.

From the time the tropical cyclone was located over the Lesser Antilles, NHC advisories as well as San Juan Forecast Office statements indicated that 5 to 10 inches of rain, with larger totals over mountains were expected along the path of Hortense. Indeed, most of the damage produced by Hortense was caused by rainfall.


Data was primarily provided by NWS forecast office in San Juan Puerto Rico, the Dominican Republic Weather Service, and by Environmental Canada.

Table 1. Preliminary best track, Hurricane Hortense, 3-16 September 1996.
Position Pressure
Wind Speed
Lat. (°N)Lon. (°W)
120018.367.8989 65 "
180021.670.6970 95"
13/0000 125.971.5935120 "
1200     merged with front
10/0600 218.066.998970 H
15/0300 344.862.597870 H

1 Minimum Pressure.

2 Landfall near Gunica Puerto Rico

3 Landfall Nova Scotia

TD: Tropical Depression

TS: Tropical Storm

H: Hurricane

E: Extratropical

Table 2. Hurricane Hortense selected surface observations, September 1996.
Desirade  46708/0000     
Maison du Volcan        12.5
Saint-Claude Bourg        10.6
Le Raizet998.77/21004670     
U.S. Virgin Islands:
Hamilton Arp.  3445 9/1556   
USDA        12.04
St. Thomas Scott Free        6.2
St.Thomas Univ.        4.85
Hess Oil 9/2130 549/2130    
Puerto Rico:
Carolina Arp.1005.110/06154354 10/0555  9.45
Cupey, Rio Piedras   65 10/0735   
Ceiba, Naval Base  4046 10/2155   
Dominican Rep.:
Punta Cana  80 11/1616    
Punta Cana987.310/1737calm      
El Macao99010 a6174     
Puerto Plata98910/20256574     
San Rafael de Yuma 10/20306178 10/2030   
Turks and Caicos:
Grand Turks  5278 11/1620   
Cape Sable         
St. Paul Island994.415/07426682 15/0742   
Sidney984.815/0900305115/0448   4.02
Forchu Head  435215/0348   2.57
Hart Island978.415/0545324915/0145    
Beaver Island982.815/01444355 15/0144  5.38
Halifax Int'l989.815/0200203915/0200    
Shearwater985.015/0200294215/0200   3.92
Cape Sable  a 63     
Cape Race, Nfld99415/20434049 15/2043    

a time unknown

Table 3. Ship reports of 34 knots or higher wind speed, associated with Hurricane Hortense, September 1996.
ship namelatitude
wind dir/speed
7/1800SVEN OLTMAN13.069.9110/411005.5
9/12003FOA5 *18.063.5110/34 1010.0
8PNI *18.153.6130/361010.3
9/18008PNI *17.264.2100/41 1007.0
SEALAND HAWAII186866.2100/391008.2
ELRI2 *19.164.3110/581006.5
9/21003FOA5 *16.161.9100/37 1008.0
8PNI *16.964.5100/451006.4
10/00008PNI *16.564.7080/45 1008.0
ELRI2 *18.663.7120/581006.5
TROPIC SUN18.665.5090/371008.2
10/0600TROPIC SUN18.564.9080/35 1009.4
SEALAND HAWAII18.666.2070/561005.5
SS NUEVO SAN JUAN20.466.1120/501011.6
12/1200COPACABANA28.468.8110/36 1014.0
12/2100C6QK *24.469.2140/36 1007.5
13/0000COPACABANA26.166.2140/35 1013.0
3FKD6 *26.768.5130/371009.2
13/0600COPACABANA24.964.9120/43 1013.0
14/1200ATLANTIC HURON39.370.0330/40 999.5
14/1500TARANTAU41.982.2250/45 980.0
14/2100ZCBF2 *43.663.5070/41 977.9
15/0000 MV JOSEPH46.759.8090/38 1010.0

* name unknown

Table 4. Watch and warning summary, Hurricane Hortense, September 1996.
7/1500 tropical storm warning issued Martinique northwestward through the British and U.S. Virgin Islands
tropical storm watch issuedPuerto Rico
7/2100hurricane watch and a tropical storm warning issued British and U.S. Virgin Islands and Puerto Rico
8/0300hurricane warning issued British and U.S. Virgin Islands
8/1500hurricane warning replaced by tropical storm warning British and U.S. Virgin Islands
hurricane watch discontinuedPuerto Rico
tropical storm warning discontinued From Anguilla southward
8/1800tropical storm warning discontinued Northeastern Leeward Islands
9/0000tropical storm watch issued Dominican Republic from Cabo Engano to Pedernales of the border of Haiti (south coast)
9/1500hurricane warning issued Puerto Rico
hurricane watch replaces tropical storm watch Dominican Republic from Cabo Engano to the border of Haiti.
9/2330hurricane warning issued Dominican Republic from Bahia de Calderas to Peninsula de Samana
hurricane watch issued Dominican Republic from west of Bahia de Calderas to Pedernales.
10/0900hurricane watch issued Turks and Caicos Islands and southeast Bahama Islands of Mayaguana and Inagua Islands
10/1200hurricane warning extended Dominican Republic from Peninsula de Samana to Cabrera.
hurricane watch discontinued south coast of Dominican Republic
10/1500hurricane warning issued Turks and Caicos, Inagua Islands and Mayaguana
tropical storm warning discontinued U.S. and British Virgin Islands
10/1800hurricane warning discontinued Puerto Rico
10/2100hurricane warning extended north coast of Dominican Republic
hurricane watch issuedcentral Bahamas
tropical storm warning and hurricane watch north coast of Haiti from St. Nicolas eastward.
11/0000hurricane watch discontinued south coast of the Dominican Republic
11/1500hurricane warning discontinued Dominican Republic
12/1500 hurricane warnings and watches discontinuedBahamas

Table 5. Preliminary forecast evaluation Hurricane Hortense. Heterogeneous sample. The number of cases is in parentheses.
Forecast TechniquePeriod (hours)
OFCL48 (34)92 (33)110 (31)140 (29)251 (25)
OFCI47 (33)79 (32)110 (31)152 (29)299 (25)
AVNI51 (31)109 (31)159 (30)176 (28)216 (24)
GFDI46 (31)91 (31)124 (30)156 (29)240 (24)
VBRI37 (33)53 (32)90 (31)126 (29)273 (25)
NGPI53 (26)298 (26)386 (26)193 (26)121 (20)
UKMI60 (24)120 (24)155 (23)188 (21)321 (16)
CLIP61 (34)126 (33)182 (31)233 (29)371 (25)
BAMD37 (34)72 (33)99 (31)140 (29)213 (24)
BAMM51 (34)98 (33)148 (31)182 (29)232 (24)
BAMS66 (34)126 (33)177 (31)211 (29)263( 24)

Brian Maher
Jack Beven

Last updated December 29, 1998