• ARLENE
• BRET
• CINDY
• DENNIS
• EMILY
• FLOYD
• GERT
• HARVEY
• IRENE
• JOSE
• KATRINA
• LENNY

The four tropical depressions that didn’t develop further were number 2, 7, 11, and 12. Depression #2 originated on the evening of 2 July over the Bay of Campeche and dissipated over Mexican territory on the morning of the 3^rd. Number 7 formed on the afternoon of 5 September some 130 Km east southeast of Tampico dissipating on the 7^th over northeastern Mexico.

Table 4. Tropical Storms and Hurricanes of the 1999 cyclone season over the north Atlantic.

*UTC means Universal Coordinated Time, and differs +5 hours from the Local Time for Cuba (Meridian 75° W)

Fig.1 Trajectories of tropical cyclones on 1999.

Depression No. 11 formed on 4 October, also over the Bay of Campeche and degenerated into a broad trough on the afternoon of the 6^th. This system caused torrential rainfall over east Mexico, with significant life and economic loses. Finally depression No. 12 formed eastward and rather far away from the Lesser Antilles on the evening of 5 October and started dissipating on the afternoon of the 8^th as it ran into a highly sheared environment caused by an upper trough.

The main characteristics of each one of the depressions that reached at least the rank of Tropical Storm are introduced next.

ARLENE

11 – 17 June

The first tropical cyclone of the 1999 season originated on the afternoon of 11 June in a low pressure area some 865 Km southeast of Bermuda. The depression started moving northeast and then turned north-northeast and north while increasingly intensifying and organizing, so it reached the rank of tropical storm on the morning of the 12^th. Arlene changed quickly its course to the west, since it became blocked by an anticyclone center to the north.

The storm showed its maximum intensity on the early hours of the 13^th, with wind speed of about 95 Km/h and a minimum central pressure of 1000 hPa. The center of Arlene was at that time embedded in an area of dense overcast and presented a good outflow pattern on the high levels of the troposphere (see Fig. 2). In the morning hours of that same day the cloud pattern associated to the storm started shearing and the center became defined then by low clouds near the northeast edge of the convective clouds. Nevertheless a well-defined band of convective clouds still remained to the east.

The circulation center remained uncovered and since the evening of the 13^th the storm started loosing intensity. It retained its slow course almost to the west until the morning of the 14^th, when it headed near the northwest. During the night it started a small loop that was completed by noon on the 15^th, to follow then a course between the west-northwest and northwest. Winds increased and during the evening that day and the early hours of the 16^th they reached again 95 Km/h, but the minimum pressure was 1010 hPa. On the morning of the 16t^h it headed north-northwest. The storm started weakening gradually and in the early hours of the 17^th, as it was moving north-northeast, it was ranked as a tropical depression, showing on the satellite images as a whirl of low clouds. In the morning it headed closely to the northeast and during the evening the cloud pattern distorted, dissipating over the Atlantic Ocean.

Fig. 2 Tropical storm Arlene. IR Image from satellite GOES-8, 13 June 1999 06:45 UTC.

BRET

18 - 23 August

The first hurricane of the season originated in an area of disturbed weather associated with a tropical wave on the afternoon 18 August. This system formed over the Bay of Campeche 500 Km east-southeast of Tampico, Mexico. At first it remained with little motion and developed over the gulf, ranking as a tropical storm on the afternoon of the 19^th, when the accompanying convective clouds showed still poor organization.

On the early hours of the 20^th it started moving north with a better-organized cloud pattern showing already the development of bands. The intensifying process continued and on the evening it reached the category of hurricane. Since the early hours of the 21^st it bent its course to the north-northwest and in the next day further to the northeast and later to the west-northwest. Bret had a significant decrease of pressure of 34 hPa over 24 hours, and according to the report of a reconnaissance aircraft, the minimum pressure reached 944 hPa on the morning of the 22^nd, with maximum wind speed of about 220 Km/h. The cloud pattern associated to the hurricane at the moment of its maximum intensity can be seen on Fig. 3, showing a well defined eye, embedded into a central dense overcast, typical of intense tropical organisms. Later, moving with course west-northwest and less intensity, it made landfall on the coasts of Texas between Brownsville and Corpus Christi on the afternoon.

Along its trail over the territory of Texas it weakened, and in the morning of the 23^rd it became a tropical storm. On the evening that day it crossed the border with Mexico, getting even weaker and finally dissipating over the state of Coahuila.

Bret produced heavy rains with accumulates above 125 mm over great part of the south of Texas and in the center-north of Mexico. Near Laredo, Texas, it caused four deaths by accident. Damages were relatively scarce, due to its small size and its trajectory mainly over uninhabited coastal zones.

Fig. 3  Hurricane Bret. IR Image from satellite GOES-8, 22 August 1999 13:45 UTC.

CINDY

18 -31 August

Cindy originated over the Atlantic Ocean on the evening of August 18^th within a tropical wave coming from Africa, 460 Km east-southeast of Cape Verde islands. The tropical depression had a sheared cloud pattern, but the 20^th on the afternoon, when its center was more closely linked with the convection zone, it was ranked as a tropical storm. Meanwhile, it was moving in a direction close to the west until it tilted somewhat to the west-northwest on the early hours of the 21^st. The process of organization and intensification continued, so it was classified as a hurricane on the evening that day. It had at that time the center embedded in a small dense overcast.

During the early hours and morning of the 22^nd it moved little while entering again in a highly sheared environment, degrading back to tropical storm later in the day. Since that afternoon it reassumed its course, heading closely to the west-northwest until the 25^th in the early hours, when it turned further to the northwest. Cindy remained in a hostile environment, with its center uncovered until the next day, when the cloud pattern became more symmetrical. By the evening it reached again the category of hurricane.

On the evening of the 26^th it presented bands around the core, indicating that an eye had appeared. The course to the northwest remained until the early hours of the 28^th, when it turned further to the north-northwest. Over the morning and the afternoon it reached its maximum intensity with 220 Km/h and minimum central pressure of 944 hPa. The cloud pattern associated to Cindy at that time is shown on Fig 4. On the evening that day a strong flux from the west started shearing it and the process of weakening started, as it was moving north.

On the early hours of the 29^th, it was moving towards the first quadrant and getting weaker until it lost the category of hurricane early on the 31^st. On the morning that day it started associating to an extratropical low when it was southwest and at some distance from Newfoundland.

Fig. 4 Hurricane Cindy IR image from satellite GOES-8 28 August 1999 19:45 UTC.

DENNIS

23 August - 7 September

This hurricane originated over the Atlantic Ocean on the evening of 23 August, 250 Km north of the eastern end of La Hispaniola. The tropical depression started moving close to the west-northwest and characterized by showing an extensive circulation pattern and a poorly defined center, resembling a monzonic depression. Nevertheless it developed and at noon (16:13 UTC) an aircraft reported a maximum wind speed of 50 knots (95 Km/h) and a minimum pressure of 1009 hPa. The system was classified as a tropical storm and kept the same course, showing a good outflow pattern, but its center was uncovered, located somewhat to the west of the main convection zone, so in the early hours of the next day it lost some intensity.

On the afternoon of the 25^th it started intensifying again showing outflow on every quadrant and the center linked to the deep convection zone. On the early hours of the 26^th the winds reached the strength of hurricane. However, on the satellite images it showed a somewhat ragged pattern, non-representative of the state of the hurricane, due to the high shear that affected its left side.

On the 27^th in the afternoon Dennis presented a very well defined eye and outflow and by the evening it turned its path further to the north-northwest. From the afternoon of the 28^th until the early hours of the 30^th it sustained its maximum intensity of 165 Km/h and the pressure dropped to 962 hPa on the evening of the 29^th. Early on the 30^th it started to loose gradually its organization and intensity, to become a tropical storm on the evening of the 31^st. Fig 5. Shows the nearly circular cloud pattern associated to the hurricane at the moment of its maximum intensity.

On its course to the west-northwest since the 24^th to the morning of the 28^th, Dennis passed very close to the Bahamas. After its course turned further north, it started its recurvature the 29^th on the afternoon and remained moving towards the first quadrant until it stationed easterly and very close to Cape Hatteras. Here it kept an erratic course since the evening of the 30^th until September 2^nd, when it drifted south-southwest till early on the 3^rd, then southeast till noon. From that moment on it headed close to the northwest, as the anticyclone system that blocked its course moved east.

On the morning of the 4^th the storm looked better organized. Crossing over the Gulf Stream became an incentive to increase its intensity, which got near the hurricane level early in the afternoon. In this condition it made landfall on the coasts of North Carolina at the end of the afternoon. It went on moving across the United Stated and, consequently, weakening, so it was degraded to tropical depression early the next day. The remains moved towards Lake Ontario, where they vanished on the 7^th.

Dennis produced rain accumulates of about 200 mm over zones of the states of North Carolina and Virginia. It caused minor damages.

Fig. 5 Hurricane Dennis. IR image from satellite GOES-8, 28 August 1999 19:45 UTC.

EMILY

24 - 28 August

Tropical storm Emily developed within a tropical wave traveling from Africa on the afternoon of 24 August, approximately 600 Km east-southeast of Barbados. The storm presented its maximum intensity at that moment, but it was small and was sheared by a flux from the northeast (see Fig 6). Until the evening of the 25^th, its course remained between west-northwest and northwest, turning later to north-northwest.

After a slight weakening on the evening of the 24^th, Emily remained with little change and its center uncovered. The circulation pattern from Cindy interfered with that of Emily and in the early hours of the 26^th it looked poorly organized showing only sporadic convection. A high shear from the northeast weakened the storm further and during the afternoon it was ranked as a tropical depression, while it started moving definitely north. Early on the 27^th two centers showed up and convection was not organized. However, during the afternoon that day, a reconnaissance aircraft reported wind speed of 50 knots (95 Km/h) and it was again ranked as a tropical storm.

Emily continued to be a small storm and it remained in that category until the morning of the 28^th, when it was finally absorbed by Cindy, that was located approximately 700 Km almost northwest.

Fig. 6 Tropical storm Emily. IR Image from satellite GOES-8, 24 August 1999 20:45 UTC

FLOYD

7 -17 September

The most intense hurricane of the season originated 1,575 Km east of the Lesser Antilles on the afternoon of 7 September, within a tropical wave coming from Africa. The depression characterized by an extensive circulation pattern, it started moving west-northwest and became a tropical storm early the next day. The process of intensification was rather slow and despite the cloud cover pattern resembled that of a hurricane by the morning of the 9^th, the pressure and wind fields did not match this category until the next day in the morning. That day in the afternoon, Floyd showed an eye pattern.

The course of the hurricane remained to the west-northwest until the early hours of the 10^th, when it turned northwest and continued so until the 11^th at noon, when it headed almost west. This movement was kept until the morning of the 13^th, when it turned west-northwest. Floyd was being steered by an anticyclone ridge on the middle troposphere, located to the north, and continued the process of intensification. In the morning of the 13^th a reconnaissance aircraft reported a central pressure of 921 hPa, the lowest for this organism, after a drop of 34 hPa over 24 hours. From the early hours of the 13^th to the morning of the 14^th, the wind speed was of 250 Km/h, placing it on the upper end of category 4. The cloud pattern associated to Floyd is shown on Fig 7 minutes before being reported its aforementioned minimum pressure. It is typical of an intense hurricane.

On the evening of the 13^th, Floyd showed a symmetric cloud pattern, characteristic of a system that has reached its peak intensity. However, early on the 14^th, the pattern became elongated in the direction north-northwest – South-southeast, indicating that the hurricane was being influenced by a trough of the middle levels over the continent. Floyd had some oscillations in intensity on the 14^th due to the interaction of its center with the northwest Bahamas. That day in the afternoon it affected Great Abaco and headed north-northwest, keeping the course until the 15^th at noon when it started the recurvature as it was captured by a flux from the South-southeast on the east of the United States.

As Floyd moved over the seas east of the southeastern coast of the U. S. it lost intensity, and when it made its landfall east of Cape Fear, North Carolina, on the early hours of the 16^th, it was category 2. The system continued to loose intensity as it moved fast along the northeastern coast of the United States, and on the afternoon that day it was classified as a tropical storm. On the evening of the 16^th it started a transition to an extratropical low, that ended by next day.

Floyd was the most damaging hurricane of the season with its direct affectation on the Bahamas and the United States. The islands of Great Abaco, Eleuthera, Cat, San Salvador and Grand Bahama were the most affected and suffered interruptions in communications and water and power supply. Significant damages to the agriculture occurred and at Great Abaco, where the eye crossed, 10% of houses were destroyed and 40% severely damaged.

The approaching of this hurricane to the eastern coast of Florida made more than 1.5 million people to flee inland. The most important highways got crowded with cars and gas stations between Jacksonville and Tallahassee were reported to have run out of fuel. The hurricane, however, turned its course more to the north.

At North Caroline heavy rains caused the greatest natural disaster on that state, with accumulates ranging from 150 to 500 mm over wide areas, causing severe flooding. About 30,000 houses were flooded and 1,600 were destroyed. Animal loss was huge: 100,000 pigs, 500,000 turkeys and 2.4 million poultry fowl perished in the flooding, Economic loss is estimated in 6 billion dollars. In New Jersey, estimated loss was 100 millions with significant flooding at some areas. Thousands of people were left without electric power from South Caroline to New Jersey. Reported death toll was 69, most of them in North Caroline

Fig. 7 Hurricane Floyd. IR Image from satellite GOES-8, 13 September 1999 11:45 UTC.

GERT

11 – 23 September

Hurricane Gert formed within a tropical wave on September 11^th during the morning. It started as a depression 285 Km South of Cape Verde Islands and showed cloud bands with a few convection, a poorly defined center and an outflow limited by a modest shear from the east. As the wind shear weakened in the afternoon, the system improved its structure and by morning the next day it showed a more concentrated convection and a well-established outflow, which allowed it to be classified as a tropical storm.

Gert intensified fast, and by morning on the 13^th, it reached the rank of hurricane. One day later it showed a well developed eye, though the deepest convection zone still didn’t surround it completely. On the afternoon of the 15^th it was at the moment of maximum intensity with a central pressure of 940 hPa and maximum wind speed of 240 Km/h (Category 4). Fig. 8 shows the cloud pattern associated to Gert at that moment, where the eye can be seen already embedded in the almost circular central dense overcast, and an excellent outflow mechanism. Wind speed of 240 Km/h remained until evening.

On the morning of the 17^th, the outgoing flux is restricted northwest of the center due to the approximation of the upper oceanic trough, so it showed a weaker cloud pattern that caused it to be ranked as category 3 that day.

The subtropical anticyclone ridge governed the motion of this intense hurricane, since its formation until the early hours of the 17th, favoring a course between west and west-northwest. Later it continued northwest following the periphery of the subtropical anticyclone.

Gert intensified again and on the 19^th during the early hours it turned category 4 again. This classification remained until early next day, when a gradual weakening process started, signaled by a less organized cloud pattern and a poorly defined eye. On the afternoon of the 20^th its course turned north and from the 21^st on it headed towards the first quadrant, immerse in the flux from the Southwest associated to mid latitude circulation. Meanwhile, deep convection kept decreasing and the system started turning asymmetrical and loosing more and more intensity, classifying as a tropical storm early on the 23^rd. After passing east of St. Johns, Newfoundland early in the morning, it lost its tropical characteristics over the sea close to that peninsula.

Fig. 8 Hurricane Gert. IR image from satellite GOES-8, 15 September 1999 20:45 UTC.

HARVEY

19 - 21 September

Satellite images and surface observations suggested, on September 18^th, the existence of a developing cyclone circulation over the southern central part of the Gulf of Mexico. Early in the morning on the 19^th, the tenth tropical depression of the season originated in that area of perturbed weather, near the center of the Gulf, some 620 Km west-southwest of St. Petersburg, Florida. A few hours later it was located north of the initial position. On the evening of the 19^th the system was upgraded to tropical storm, as it kept a slow course almost east-northeast until early on the 20^th, when it started moving faster.

With little change in organization and a slight increase in intensity (wind speed up to 95 Km/h), it reached its maximum depth on the early hours of the 21^st, when a reconnaissance aircraft reported a minimum pressure of 994 hPa. The course followed on the evening of the 20^th and early hours of the 21^st was Southeast and later east-southeast. This made the storm landfall early in the afternoon to the South and close to Ft. Myers, weakened. Harvey crossed the Florida Peninsula embedded in mid latitudes westerns heading east-northeast, with a poorly defined center, located west-northwest of a deep convection zone that produced rainfall accumulates of near 250 mm at some locations. The storm exited to sea near Palm Beach on the same afternoon and on the evening, as it was close to the northwestern Bahamas, it started being absorbed by a frontal system, until it lost its identity.

It must be pointed that the cloud pattern associated to Harvey was not typical of a tropical storm. This feature can be seen on Fig. 9, where the storm is shown at the moment of maximum intensity.

Fig. 9 Tropical storm Harvey. IR image from satellite GOES-8, September 21^st 1999, 01:45 UTC

IRENE

13 - 19 October

Tropical storm Irene developed on the morning of October 13^th some 255 Km east of Grand Cayman within a broad area of low pressure. Since the early morning the cloud pattern associated to this system matched that of a tropical depression showing signs of development. By the moment of its classification as tropical storm, convection was deep and organized in bands, besides showing a magnificent outflow mechanism on the high levels of the troposphere, but the center was still poorly defined.

As the storm moved on a course close to the north, it gained intensity and organization, with its center located within a very deep convection zone on the early hours of the 14^th. This feature allowed it to be upgraded to hurricane when it was close to the Southwest coast of the Isle of Youth. However, a few hours later in the morning, its cloud pattern became less organized.

Fig. 10 shows the section of Irene’s trajectory over Cuba. The picture shows that, during the morning that day, the course turned temporarily almost east-northeast. This caused Irene to cross over the Isle of Youth, between Nueva Gerona and La Fé, where a minimum pressure of 990.6 hPa was registered at 15:20 UTC. Since early on the afternoon, after undergoing a process of restructuring of the center as it exited to sea, the system reassumed its course to the north making landfall on Havana Province between Cajío Beach and Surgidero de Batabanó, approximately at 19:00 UTC. Irene tilted its course north-northwest and its center crossed over Havana Province, between Bauta and Santiago de las Vegas with a mean speed of 24 Km/h to exit to sea over Baracoa Beach at about 21:00 UTC. The lowest pressure reported was 986.3 hPa at the Baracoa beach airport.

Fig. 10 Trajectory of hurricane Irene over Cuba and nearby sea.

Irene stationed, since the end of the afternoon until evening, over sea, very close to the north coast of Havana, producing heavy rains over Havana provinces and the extreme east of Pinar del Río. Fig 11 shows the deep convection area, about 110 km in diameter, that caused the aforementioned rainfall. Over that period, it drifted almost west and later back east nearing again Casablanca station at the end of the evening, when the barometer registered the second minimum (taking the barometric tide into account) after the one registered on the afternoon (see Fig. 12). At this station, a calm was registered then, of about 30 minutes (03:00 – 03:30 UTC day 15^th).

Fig. 11 IR image from Satellite GOES-8 14 October 1999, 21:45 UTC

Fig. 12 Variation of atmospheric pressure at Casablanca station during Irene’s pass on October 14 1999. Hours stamped at the top of the graphic are referred to meridian 75 W.

Table 5 shows the maximum sustained wind speeds (estimated) and maximum gusts registered at some Cuban stations as Irene passed by and Table 6 shows the greatest rain accumulates over 24 hours on Cuba.

On Table 5 the maximum gust of 122 Km/h registered at Casablanca station stands out, with a maximum sustained wind of 98 Km/h (estimated). Observations from the Havana Province and the Isle of Youth, as well as the configuration of the cloud pattern associated to Irene do not evidence the classification of the cyclone as a hurricane. Furthermore, a reconnaissance aircraft flying over the area didn’t find wind speeds of about 120 Km/h until the early hours of the 15^th, when it was over the Florida Strait. These data allow inferring that Irene actually affected Cuba with the intensity of a tropical storm.

Table 5. Maximum sustained wind speeds (estimated) in Km/h (average over one minute) and maximum gusts registered at some Cuban stations as Irene passed by on October 14^th 1999.

La Jagua and Casablanca, with rain accumulate above 200 mm over 24 hours stand out on Table 6. However, it was on the province of Sancti Spíritus that the greatest accumulates were registered due to the pass of feeding bands, both in short periods of 6 and 12 hours and over 24 hours, in addition to the accumulates of the whole rainy event that lasted almost 5 days (Table 7).

Table 6. Greatest rain accumulates registered over 24 hours after Irene’s pass over Cuba

Table 7. Greatest rain accumulates registered over the province of Sancti Spíritus during the whole rain event associated to the feeding bands of Irene, from October 13^th to the 17^th.

These heavy rains caused rivers to overflow at the province of Sancti-Spiritus, standing out the Agabama on its confluence with the Ay River, where despite the height, it interrupted traffic and communications and affected electric lines in addition to flooding sugar mill "FNLA". Another interesting example was the Zaza River, which reached on October 15^th a historical record level of 13.45 meters at the hydrometer station of Paso Ventura, Cabaiguán. Yayabo River also reached significant levels. In addition, the Zaza dam received a volume of 20 million cubic meters of water within an hour that day. Over the whole event this dam reached a volume of 539 million cubic meters.

Despite all the flooding caused by these heavy rains, Irene caused only four indirect deaths on its pass over Cuba. 106,250 people were evacuated, 3,537 houses were reported as affected and 325 were completely destroyed.

Once hurricane Irene abandoned Cuban territory, it started a course to the north-northeast on the early hours of the 15^th, crossing over Key west by the morning and entering early on the afternoon through Flamingo, Florida. It crossed the Florida Peninsula with the same course and came definitely out to sea, to the north of Palm Beach County early on the 16^th. That day the eye looked large and ragged on the morning satellite images. By the afternoon deep convection turned minimum as dry air entered the circulation. It kept its course almost north while moving over the Charleston Bay and on the morning of the 17^th it turned northeast, moving parallel and close to the southeastern coast of the U. S. with increase of speed. The displacement of the hurricane over the Gulf Stream and the interaction with a trough, caused an increase of convection followed by a drop in central pressure, this allowed the maximum intensity to be obtained on the early hours of the 18^th (central pressure of 958 hPa and maximum wind speed of 175 Km/h). Fig. 13 shows the cloud pattern of Irene at that time, when it was close to the east of Cape Hatteras. Since that morning the hurricane started showing some extratropical characteristics. As it moved northeast over the Atlantic Ocean, it was absorbed by an extratropical low of greater size on the morning of the 19^th, near Newfoundland.

Fig. 13  Hurricane Irene. IR image from satellite GOES-8 on October 18^th 1999, 7:45 UTC.

JOSE

17 - 25 October

Hurricane Jose originated on the afternoon of October 17^th within a tropical wave some 1700 Km almost east of the Windward Islands. By the early hours the next day it had a symmetric appearance with feeding bands and a good outflow mechanism, so the system was rated as tropical storm Jose.

The storm, which remained during its formation stage at about 10 ° north, was located on a latitude somewhat further to the north on the afternoon of the 18^th. The intensification process continued with the band pattern that characterized it and the excellent outflow, until it reached the rank of hurricane on the morning of the 19^th, when it was northeast and close to Barbados.

The hurricane, that kept its course between west-northwest and northwest almost since its earlier stages, crossed over Antigua early on the afternoon of the 20^th, after undergoing its maximum intensity period (central pressure of 978 hPa and maximum wind speed of 160 Km/h) by morning that day. Fig. 14 shows the cloud pattern associated to Jose few hours before reaching its maximum strength.

Fig. 14 Hurricane Jose. IR image from satellite GOES-8, 20 October 1999, 08:45 UTC

Keeping its course, Jose moved into a hostile environment, produced by a strong shear from the Southwest associated to an upper troposphere trough. This caused it to grow weaker as it affected the islands of the Leeward Islands until it became a hurricane of minimal category on the early hours of the 21^st and a tropical storm by morning, while it was north and close to the Virgin Islands. On the afternoon it tilted its course further to the northwest and on the morning the next day it headed north-northwest, while on the 23^rd it was moving north, with its center uncovered Southeast of the deep convection zone.

On the evening of the 23^rd it followed a more defined course towards the first quadrant. By the morning of the 24^th the center of the storm was again embedded in the deep convection zone, so it was classified again as a hurricane. This pattern lasted briefly, since by the afternoon the shear increased, causing a shift of the center to the Southwest of the deep convection zone, so it degraded to tropical storm by evening. At this moment it started joining a frontal zone and definitely lost its tropical characteristics on the 25^th.

KATRINA

28 October - 1 November

Katrina originated on the afternoon of October 28^th in an area of low pressures 320 km east-southeast of Bluefields, Nicaragua. By the early hours of the 29^th the deep convection zone, located west of the center, was still far from it. During the morning, the center was further to the north and an anticyclone on the high levels standing over the Central Caribbean Sea produced a strong shear from the east. Nevertheless, a reconnaissance aircraft found circulation and a minimum pressure of 999 hPa, with wind speed of 65 Km/h (43 knots at the flight height), so it was possible to classify the system as a tropical storm on the afternoon. The cloud pattern, poorly organized, associated to Katrina at the moment of being classified, when it was very close to the northeastern coast of Nicaragua is shown on Fig. 15.

At the beginning of the evening it made landfall on Nicaraguan soil and degraded quickly, turning into a tropical depression. The course remained to the northwest while deep convection was limited to a small area to the west of the center and circulation was turning increasingly diffuse, becoming elongated and showing multiple centers as it moved over the mountainous terrain to the east of Honduras. Late on the afternoon of the 30^th, it came out to the Gulf of Honduras with its center reformed and towards the end of the evening it entered the Yucatan Peninsula, where it kept going until it dissipated on 1 November.

Fig. 15 Tropical storm Katrina. IR image from satellite GOES-8, 29 October 1999, 20:45 UTC

LENNY

13 - 21 November

The last hurricane of the season originated in an extensive area of low pressure on the afternoon of November 13^th some 300 Km south of Grand Cayman. The depression had a deep convection zone associated but was still not organized. The system went on structuring better with its center approaching the convective area and on the 14^th by morning the cloud pattern already showed the characteristics of a tropical storm. Following reports from a reconnaissance aircraft, it was classified as such on the afternoon and after a fast process of intensification, as a hurricane by the evening that same day.

Already a hurricane, it kept intensifying, and on the morning of the 15^th, it had maximum wind speed of 160 km/h and central pressure of 971 hPa. Overnight it suffered a slight weakening, but it gained strength again since the early hours of the 16^th.

Since its origin until the afternoon of the 16^th, Lenny remained embedded in westerns and this forced it to follow a marked course to the east, an unusual trajectory for such low latitudes. From this moment on, it turned its course to the northeast with further gain in intensity. A reconnaissance aircraft reported a minimum central pressure of 929 hPa, while maximum wind speed was 240 Km/h (Category 4). It had a significant decrease in the minimum pressure from the 16^th (21:26 UTC) to the 17^th (21:24 UTC) of 33 hPa. Fig. 16 shows the cloud pattern of Lenny, where a very well defined eye and a very good outflow can be seen.

On the evening of the 17^th, Lenny got trapped in a col, between two anticyclone ridges of the mid troposphere, so it remained almost stationary, drifting east-northeast. By the time it passed over the Island of St. Martin it had a lesser category. It remained as an intense hurricane since the afternoon of the 16^th to the 18^th. It kept an erratic course over the islands of St. Martin, San Barthelemy and Anguilla, weakening further. By the afternoon of the 19^th it was already a tropical storm, showing a less symmetrical cloud pattern and the center uncovered, west of the deep convection zone. From this moment it started heading slowly between east and east-southeast.

Over the 20^th if kept the same course, but its center was every time more diffuse and getting farther from the convective area, due to the presence of a high shear to the west. On the early hours of the 21^st, it was degraded to tropical depression, while it started a course northeast. The circulation center, extensive and disorganized, was defined by low clouds. By the afternoon that day it dissipated over the Atlantic Ocean almost to the east and close to the Leeward Islands.

Fig. 16 Hurricane Lenny, IR image from satellite GOES-8, November 17^th, 1999 17:45 UTC

Lenny caused severe damages over an extensive area of the Lesser Antilles, but it was far less than it would have been if the eye of the cyclone had crossed over any of the islands at the time of its maximum intensity. A death toll of 12 is attributed to Lenny. Most of the damages were caused to infrastructure and the environment: Highways close to the coasts, piers and beaches. In particular, the west coast of the islands was severely affected.

Industries were also severely affected, especially agriculture, tourism and fishing. Barbuda suffered great flooding due to the heavy rains, 65% of the island stood under water and fresh water reserves became contaminated. 95% of agriculture on the island was devastated.