Review of the past hurricane season reports of hurricanes, tropical storms, tropical disturbances and related flooding during



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WORLD METEOROLOGICAL ORGANIZATION

___________________________________________

RA IV HURRICANE COMMITTEE


THIRTY-THIRD SESSION
GRAND CAYMAN, CAYMAN ISLANDS
8 TO 12 MARCH 2011




RA IV/HC-XXXIII/Doc. 4.2(5)

(08.II.2011)

________

ITEM 4.2


Original: ENGLISH


REVIEW OF THE PAST HURRICANE SEASON
REPORTS OF HURRICANES, TROPICAL STORMS, TROPICAL

DISTURBANCES AND RELATED FLOODING DURING 2010

(Submitted by Jamaica )


1. The Hurricane Season
During the 2010 Atlantic Hurricane Season, a total of 18 tropical storms and 11 hurricanes have developed. Of these, the Region was directly impacted by Hurricane Alex (June 25-July 2), Tropical Storm Bonnie (July 22-24), Hurricane Earl (August 25-September 5), Tropical Storm Fiona (August 30-September 4), Hurricane Karl (September 14-18), Tropical Storm Matthew (September 23-26), Tropical Storm Nicole (September 28-29), Hurricane Paula (October 11-15), Hurricane Richard (October 21-26) and Hurricane Tomas (October 26-November 8). This works out to be ten tropical storms and six hurricanes - two major – or close to 50% of the Season’s developments.
2. Area of Low-Pressure


T
Track of T.D. #16/T.S. Nicole


he weather over Jamaica itself was directly affected by only one of these systems… Tomas; however, an area of low-pressure remaining over the central Caribbean after the passage of Tropical Depression #16 and Tropical Storm Nicole created mayhem for the country. T.D. #16 formed in the extreme northwestern Caribbean south of Cuba’s Isle of Youth and moved near-northward over western Cuba, strengthening to a tropical storm while over land. Within six hours of this development, the system dissipated over the Strait of Florida, but Jamaicans continue to associate the devastating flood rains that resulted in the loss of 13 lives with Nicole.
Although the centre of this tropical cyclone was always over 500 kilometres away from Jamaica, a broad area of low pressure extended across the region and over the island. This seemed to have been a complex system of interactions involving a low-level jet stream, a frontal trough, an upper-level anticyclone and a displaced ITCZ or “monsoonal trough”.

T.S. Matthew approaching Nicaragua


On September 23, Tropical Depression Number 15 developed south of Jamaica, near latitude 13.9 degrees North, longitude 76.2 degrees West. The Depression made the transition to Tropical Storm Matthew by 5:00 p.m. that day as it moved towards the west, closer to Nicaragua. As Matthew continued towards and over Nicaragua, its outer bands extended over Jamaica’s southern territorial waters, affecting the cays and banks. The broad area of low-pressure that remained across the region produced light to moderate rainfall over sections of Jamaica’s southern parishes later that night and into the next morning and were forecast to spread across most parishes during the day with the potential of causing dangerous flash flooding.
B
Forecast Track for T.D. #16 at formation
ased on radar reports of continuing showers and thunderstorms over Jamaica on September 26 and into September 27, a Flash Flood Warning was issued at 1:00 p.m. with the low-pressure area drifting northward in the vicinity of the island. Conditions were, at that time, favourable for gradual development into another tropical cyclone and rainfall was expected to continue over the island. Throughout the night, radar reports indicated that periods of heavy showers and thunderstorms affected all western, central and southeastern parishes. These were forecast to continue during the day and for the next 2-3 days as Tropical Depression #16 formed west of the island.
With the Depression moving towards the north on September 28, rainfall continued across the country and was forecast to peak in intensity within the next 24 hours although continuing through to October 1. Strong winds and heavy rains associated with the Depression were expected to occur “a couple hundred miles to the east and southeast of the centre” as it moved across Cuba. The next day, September 29, the centre of the tropical cyclone moved over central Cuba and into the Straits of Florida, becoming Tropical Storm Nicole by 11:00 a.m. while over land and dissipating by 5:00 p.m. over the Straits. The broad band of showers and thunderstorms left behind, continued to produce gusty winds and heavy rainfall across Jamaica, forecast to continue for another two days. The Flash Flood Warning was continued.


On September 30, most parishes continued to experience scattered light to moderate and sometimes heavy showers and thunderstorms. These, however, showed gradual reduction on October 1-3; hence the Flash Flood Warning was lifted at 5:00 p.m. on October 3. The broad area of low-pressure had begun to drift northward and away from Jamaica leaving a trail of destruction with sections of western Jamaica reporting significant damage from winds and waves. The automatic weather station in Negril confirms that winds gusted to tropical storm-force on September 29.


Although, reports indicate that the extent of damage to the country’s infrastructure amounted to about $20b (US$235m), the CCRIF report states that, “the tropical storm wind footprint does not quite touch the extreme eastern end of Jamaica, so Tomas is not a qualifying event here”.
3. Tomas

The experience of this system heightened anticipation for Hurricane Tomas after it wreaked damage over the Eastern Caribbean prior to the start of November. On October 30, the National Hurricane Centre predicted that the tropical storm would become a major hurricane passing east of Jamaica on November 4. As Tomas waxed and waned over the southern Caribbean for the next few days, Bulletins were being issued for the island with the cays and banks being evacuated on November 1 and a Hurricane Watch being put into effect on November 2. This was downgraded to a Tropical Storm Watch on the following day and then elevated to a Tropical Storm Warning by 5:00 a.m. on November 4. At 5:00 p.m., Tropical Storm Tomas passed just 90 kilometres southeast of the island’s east coast before winding its way through the Windward Passage towards the North Atlantic. By this time, it had regained hurricane strength.


The impact over Jamaica was negligible, although a few stations recorded in excess of 75 mm (3 inches) of rainfall and occasional wind gusts to tropical storm force. No lives were lost.
4. Challenges
The Meteorological Service in Jamaica was challenged during the flooding event of September 2010 to accurately define the system affecting the island. What is now being referred to as a persistent area of low-pressure was responsible for the evolution of two tropical depressions, one of which became Tropical Storm Nicole. As the system impacted Jamaica’s weather, an article in the Jamaica Observer quoted tourism interests in the western town of Negril as saying, “The Met Service sent out a flash flood-warning on Tropical Storm Nicole, but we had a Category-One hurricane, with storm surges up to 30ft high, accompanied by waves crashing over them". Data confirm, however, that Negril actually did experience a number of wind gusts that were within the range of tropical storm force on September 29. There is question about whether there was a more significant embedded feature within that low-pressure system.
With the passage of Tomas shortly afterwards eliciting a Hurricane Watch, yet producing very little activity, another newspaper article arose, suggesting that the Meteorological Service operated obsolete equipment and lacked the skill to properly predict the impact of tropical systems. The actions of the organization were, however, stoutly defended by many who paid keen attention to the content of News Releases in the preceding days.
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Directory: pages -> prog -> www -> tcp -> documents
documents -> Review of the ra IV hurricane operational plan
documents -> Cyclone programme
documents -> World meteorological organization technical document
documents -> World meteorological organization ra IV hurricane committee thirty-fourth session
documents -> World meteorological organization ra IV hurricane committee thirty-third session
documents -> Review of the past hurricane season
documents -> Ra IV hurricane committee thirty-fourth session ponte vedra beach, fl, usa
documents -> World meteorological organization ra IV hurricane committee thirty-second session
documents -> World meteorological organization ra IV hurricane committee thirty-fifth session
documents -> English only review of the tropical cyclone operational plan for the south pacific and south-east indian ocean

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