Preliminary Report
Hurricane Marco
13 - 26 November 1996

1996 PRELIMINARY REPORTS

Tropical Storm Arthur (TS)
Hurricane Bertha (3)
Hurricane Cesar (1)
Hurricane Dolly (1)
Hurricane Edouard (4)
Hurricane Fran (3)
Tropical Storm Gustav (TS)
Hurricane Hortense (4)
Hurricane Isidore (3)
Tropical Storm Josephine (TS)
Tropical Storm Kyle (TS)
Hurricane Lili (3)
Hurricane Marco (1)

Hurricane Marco drifted aimlessly over the western Caribbean Sea for about a week threatening several land areas but never making landfall.

 

a. Synoptic History

A cold front moved into the northwestern Caribbean on 9 November, followed by an abnormally strong high pressure system which dominated the eastern United States. The front became nearly stationary and interacted with a series of westward moving tropical waves. The Intertropical Convergence Zone (ITCZ) became active in the southwestern Caribbean as monsoonal southwesterly flow from the eastern Pacific reached the area. As early as 13 November, surface analysis showed a weak low pressure area just north of Colombia and, by the next day, there was a well-defined but broad low-level circulation between Jamaica and Honduras. At that time, the system did not meet the criteria for tropical depression status because the convection was not concentrated nor organized near a center of circulation. In fact, there were several smaller centers of circulation embedded within a much larger system. The broad area of low pressure drifted northward for a couple of days, and in combination with a high pressure system over the United States, produced gale force winds over Florida, Cuba, the Bahamas and the Gulf of Mexico.

The convection gradually became organized south of Jamaica and a post-analysis of the surface and reconnaissance aircraft data indicates that the system became a tropical depression at 1800 UTC November 16. The poorly-defined tropical depression moved generally southward and encountered a much better upper-level environment for strengthening. It became a tropical storm at 0600 UTC 19 November and then moved on a slow east-northeast track. Marco briefly reached hurricane status at 0600 UTC 20 November with maximum winds of 75 mph and a minimum pressure of 983 mb. Thereafter, Marco was hit by strong upper-level westerlies and weakened rapidly to a tropical depression at 1800 UTC 23 November. It was then located just to the southeast of Jamaica.

Once a middle-level ridge rebuilt over the Bahamas and Florida, Marco turned toward the west and west-northwest and regained tropical storm strength. The tropical cyclone was south of the western tip of Cuba when it interacted with a cold front and dissipated by 1800 UTC 26 November. The remnants of Marco drifted southward and produced heavy rains over Honduras and Belize.

Marco was characterized by its numerous intensity fluctuations. For several consecutive days, Marco became disorganized during the afternoon when the low-level center was practically exposed and there was an increase in the central pressure. This was followed by a significant redevelopment of the convection and a drop in pressure during the nights and early mornings. These fluctuations could be attributed to the interaction of Marco with a series of fast moving shortwave troughs and ridges observed on water vapor imagery. These features increased and relaxed the shear while moving through the area.

b. Meteorological Statistics

Marco was upgraded to a hurricane based on a 72-mph 1-min sustained wind reported by a U.S. Navy ship. Shortly thereafter. A reconnaissance plane reported a minimum pressure of 983 mb and 1-sec wind of 102 mph. This was a significant pressure drop of 11 mb in 1 h and 40 minutes. During that flight, the crew reported a volatile center structure with severe turbulence, extreme rainfall and hail. Satellite images showed very cold convective tops at that time. During the early morning flight of 22 November, the reconnaissance plane observed another pressure drop from 996 to 985 mb in about 2 hours, and a 5 nautical mile diameter eye. The vessel PFAS reported sustained winds of 64 mph and a pressure of 1007.5 mb at 1200 UTC 25 November. This observation was used to operationally upgrade Marco to a tropical storm for the second time.

c. Casualty and Damage Statistics

There were 8 deaths attributed to Marco.

Marco never hit land but its large circulation brought heavy rains to Central America and Hispaniola. These rains produced floods and mud slides causing at least eight deaths. The interaction of Marco during its developing stage with a strong high over the U.S. resulted in gale force winds which produced beach erosion along the east coast of Florida.