Hurricane Marco (1996) - Meteorological History

Meteorological History

On November 9, a cold front moved into the northwest Caribbean Sea, shortly before an abnormally strong high pressure system entered in the area. The front then became nearly stationary and interacted with several tropical waves over the next week. The Intertropical Convergence Zone became active, causing monsoonal southwesterly flow to enter the system from the eastern Pacific Ocean. On November 13, surface weather analysis indicated a weak low pressure area had developed north of Colombia. Despite a well-defined low-level circulation, the system did not meet the criteria for a tropical cyclone because convective activity was not organized or concentrated within the vicinity of the center. Several small, weak centers of low pressure formed in the general area, and the entire system drifted northward for a couple days. In combination with a high pressure area over the United States, the system produced gale-force winds on Florida, Cuba, the Bahamas and the Gulf of Mexico.

Convection gradually developed over the broad low pressure area, and post-storm analysis indicated that Tropical Depression Thirteen developed at 1800 UTC on November 16, while centered about 160 miles (260 km) southwest of Kingston, Jamaica. Operationally, the National Hurricane Center did not issue advisories until 2100 UTC on November 18. The depression tracked generally southward, soon encountering a more favorable environment for tropical cyclone development. Although environmental conditions were favorable for intensification, the depression initially failed to strengthen further. However, the depression later developed significant amounts of deep convection and intensified into Tropical Storm Marco on November 19. After intensifying into a tropical storm, Marco then headed slowly east-northeastward and continued to strengthen. By early on November 20, Marco was upgraded to a hurricane. Simultaneously, Marco attained its peak intensity with winds of 75 mph (120 km/h) and a minimum barometric pressure of 983 mbar (hPa; 29.03 inHg).

However, shortly thereafter, Marco began to move into a less favorable environment with strong upper-level westerly winds. As a result, it weakened back to a tropical storm later on November 20, after being a hurricane for only twelve hours. Despite the lesser favorable environment, Marco began to re-strengthen starting on the following day. By November 22, it nearly re-gained hurricane status, with winds remaining at 70 mph (110 km/h). However, Marco subsequently weakened to a tropical depression at 1800 UTC on November 23 while south of Jamaica. A mid-level ridge rebuilt over the Bahamas and Florida, which forced Marco westward, and then northwestward. The cyclone re-organized and thus re-intensified into a tropical storm on November 24. Tropical Storm Marco reached a third peak intensity with winds at 60 mph (100 km/h) on November 25 at 1200 UTC, before it weakened again. The storm maintained tropical storm status until 1200 UTC on November 26, when it weakened to a tropical depression once again. Marco then interacted with a cold front, causing it to degenerate into a remnant low pressure system at 1800 UTC on November 26. Three hours later, the National Hurricane Center issued its final advisory on Marco, stating that the storm was merely a low-level swirl devoid of deep convection. After dissipating, the remnants of Marco drifted southward and produced heavy rainfall over Belize and Honduras.