On October 20, the storm transitioned into an extratropical cyclone and tracked northeastwards along the U.S. East Coast. The system was last distinguishable east of Greenland four days later. The origin of this major hurricane was traced to a tropical disturbance that moved into the western Caribbean Sea by October 11, 1944. The system was initially broad; no observations of strong winds or low pressures indicated a tropical cyclone's presence. Nearby weather reports that day nonetheless suggested tropical cyclogenesis was underway. Based on aerial and surface observations, the Atlantic hurricane reanalysis project determined in 2013 that the system organized into a tropical depression by 12:00 UTC on October 12. Operationally, the first evidence of a developing cyclone was a report of rough seas later that evening by a ship east of the Swan Islands. The incipient system tracked towards the north, quickly intensifying; tropical storm intensity was attained just six hours after the initial tropical depression classification, and it strengthened into a hurricane by 18:00 UTC on October 13. Two days later, the slow-moving hurricane took a more westward trajectory and passed south of Grand Cayman—sustained winds on the island peaked at with a gust to , while the air pressure bottomed out at 984 mbar (hPa; 29.06 inHg). Between October 16–17, the storm made an abrupt turn towards the north along the 83rd meridian west and continued to strengthen, gradually accelerating northwards. It became a major hurricane by 18:00 UTC on October 17 and reached Category 4 intensity six hours later as it passed over the western portion of Isla de la Juventud, Cuba. The following morning, the cyclone reached its peak intensity with winds of , a value extrapolated by the reanalysis project based on a pressure of 937 mbar (hPa; 27.67 inHg) observed on the northern coast of Cuba; this was the lowest pressure measured in connection with the hurricane. Maintaining peak strength, it made landfall on mainland Cuba at around 08:00 UTC on October 18, crossing the narrowest part of the island west of Havana before emerging into the Gulf of Mexico. The hurricane's interaction with Cuba caused the winds to taper slightly, bringing the storm down from its peak intensity to a Category 3 hurricane over the Straits of Florida. At 21:00 UTC on October 18, the eye passed over the Dry Tortugas, producing two hours of calm over the islands.