page_title: Meteorological history of Hurricane Dennis
section_title: Intensification and Cuban landfalls
hierarchical_section_title: Meteorological history of Hurricane Dennis / Intensification and Cuban landfalls
caption_attribution_description: English: Visible satellite image of Hurricane Dennis shortly before making its second landfall in Cuba on July 8, 2005.
context_page_description: The meteorological history of Hurricane Dennis spanned twenty-two days, beginning with its inception as a tropical wave over Africa on June 26, 2005, and terminating with its dissipation on July 18 over the Great Lakes of North America. The incipient wave that became Dennis emerged over the Atlantic Ocean on June 29 and moved briskly to the west. Dry air initially inhibited development, though once this abated the wave was able to consolidate into a tropical depression on July 4. The depression soon crossed Grenada before entering the Caribbean Sea whereupon increasingly favorable environmental factors, such as low wind shear and high sea surface temperatures, fueled intensification. Turning west-northwest, the system achieved tropical storm status on July 5 and hurricane status the following day.
  Formation of a well-defined eye and central dense overcast signaled Dennis's intensification into a major hurricane. The powerful storm soon struck Granma Province, Cuba, as a Category 4 early on July 8; violent winds battered the province and caused extensive damage.
context_section_description: Embedded within deep east-southeasterly flow and along the periphery of a subtropical ridge, the depression moved rapidly along a west-northwest course; it soon made landfall over Grenada at 21:00 UTC on July 4 with maximum sustained winds of 35 mph (55 km/h). Upon entering the Caribbean Sea, deep convection flared over the system. Environmental conditions ahead of the depression favored intensification into a hurricane, with little to no wind shear—analyzed to be roughly 25 mph (35 km/h) below average—and high sea surface temperatures around 84 °F (29 °C) present along its path. Based on satellite intensity estimates obtained through the Dvorak technique, the depression is assessed to have become a tropical storm by 12:00 UTC on July 5. Accordingly, the NHC assigned it the name Dennis at this time. This marked the earliest formation of a season's fourth named storm on record; however, this was later surpassed by Tropical Storm Debby of 2012 which was named on June 23.
  Throughout July 6, convection steadily consolidated as the system acquired a more northerly component to its track. Hurricane Hunters investigating Dennis found steadily falling barometric pressures, indicative of intensification. Around 22:00 UTC, observation from the aircraft indicated that Dennis achieved hurricane-strength; a central pressure of 985 mbar (hPa; 29.09 inHg) and flight-level winds of 91 mph (146 km/h) were measured. A central dense overcast soon blossomed over the hurricane's center while microwave satellite imagery depicted a closed, well-defined mid-level eye. At this point, the only factor inhibiting development was interaction with the mountains of Hispaniola and Jamaica. Dennis developed unusually prominent outflow, especially along its western side, for its location and time of year due in part to an unseasonably weak trough over the mid-Atlantic.
  Rapid intensification ensued throughout July 7, as Dennis turned more northwest and tracked through the Jamaica Channel. A well-defined, 10 mi (16 km) eye formed within the hurricane's central dense overcast that evening. Dennis achieved major hurricane status by 18:00 UTC and Category 4 status by 00:00 UTC on July 8 as it approached southern Cuba. An abbreviated eyewall replacement cycle likely took place during this period as the eye expanded to 18 to 23 mi (29 to 37 km) in diameter. Reconnaissance flying in the storm reported flight-level winds of 154 mph (248 km/h), and based on this Dennis is estimated to have reached its initial peak with surface winds of 140 mph (225 km/h). Around 02:45 UTC, Dennis briefly moved over Granma Province, Cuba, with its center crossing the coast near Punta del Inglés (close to Cabo Cruz). Violent and destructive winds battered the province. A weather station in Cabo Cruz reported sustained winds of 133 mph (214 km/h) and a gust to 148 mph (238 km/h) before being destroyed.
  Interaction with land caused slight weakening; however, Dennis soon emerged over the Gulf of Guacanayabo and the region's shallow, warm waters fueled an abrupt reorganization. The hurricane traveled along the western spine of the Jardines de la Reina archipelago, subjecting the islands to Category 3 and 4 strength winds. Paralleling the coast of Cuba, Dennis attained its peak winds of 150 mph (240 km/h) around 12:00 UTC on July 8. Hurricane Hunters observed flight-level winds of 173 mph (278 km/h) and a pressure of 938 mbar (hPa; 27.70 inHg) around this time. The former value indicated surface winds around Category 5 strength while the latter yielded slightly lower winds, via a pressure-wind relationship method. The aforementioned peak strength was chosen accordingly as a compromise between the conflicting data. Another eyewall replacement cycle took place soon after this peak and slight weakening ensued. Around 18:45 UTC, Dennis made its second landfall in Cuba near Punta Mangles Altos in Matanzas Province with winds of 140 mph (225 km/h); a gust of 149 mph (240 km/h) was reported in Cienfuegos. Despite moving over land, weakening was initially slow due to the hurricane's proximity to
caption: Hurricane Dennis shortly before making landfall in Matanzas Province, Cuba, on July 8 as a Category 4.
exif: {"Image Orientation": "Horizontal (normal)", "Image XResolution": "72", "Image YResolution": "72", "Image ResolutionUnit": "Pixels/Inch", "Image ExifOffset": "90", "EXIF ColorSpace": "sRGB", "EXIF ExifImageWidth": "1024", "EXIF ExifImageLength": "887"}