Hurricane Bob
Hurricane Bob was one of the costliest tropical cyclones in New England history. The second named storm and first hurricane of the 1991 Atlantic hurricane season, Bob developed from an area of low pressure near The Bahamas on August 16. The depression steadily intensified, and became Tropical Storm Bob late on August 16. Bob curved north-northwestward as a tropical storm, but re-curved to the north-northeast after becoming a hurricane on August 17. As such, it brushed the Outer Banks of North Carolina on August 18 and August 19, and subsequently intensified into a major hurricane. After peaking in intensity with maximum sustained winds of, Bob weakened slightly as it approached the coast of New England.
Bob made landfall twice in Rhode Island as a Category 2 hurricane on August 19, first on Block Island and then in Newport. Upon doing so, it became the only hurricane to make landfall in the contiguous United States during the 1991 season. Moving further inland, Bob rapidly weakened, and deteriorated to a tropical storm while emerging into the Gulf of Maine. Shortly thereafter, Bob made landfall in Maine as a strong tropical storm early on August 20. Bob entered the Canadian province of New Brunswick a few hours later, where it transitioned into an extratropical cyclone. By August 21, the remnants of Bob crossed Newfoundland and re-emerged into the open Atlantic Ocean. The remnants traveled a long distance across the northern Atlantic Ocean, and finally dissipated west of Portugal on August 29.
Bob left extensive damage throughout New England in its wake, totaling approximately US$1.5 billion. This made it one of the costliest United States hurricanes at the time; as of 2013, it ranked thirty-second in the category. But some sources say that Bob might have caused as much as US$3 billion in damage. In addition, eighteen fatalities were reported in association with Bob. The loss of life and most of the damage occurred as a result of high winds and rough seas. There were six confirmed tornadoes during its passage. Bob is the most recent hurricane to hit the New England states directly as a hurricane.
Meteorological history
Hurricane Bob originated from the remnants of a frontal trough to the southeast of Bermuda on August 12. The system tracked towards the southwest and later west towards the Bahamas. By August 15th, satellite analysis of the system found a weak low-pressure area a couple hundred miles east of the Bahamas. Operationally, the system was not declared a tropical depression until 0600 UTC on August 16 after a reconnaissance mission into the storm found a closed circulation and flight level winds of. After post-storm analysis, it was determined that the low had developed into a depression around 0000 UTC. Several hours after being designated, the system began to develop convective banding features. Roughly 18 hours after being declared a depression, the National Hurricane Center upgraded it to a tropical storm, giving it the name Bob. At this time, Bob was situated roughly northeast of Nassau, Bahamas. The storm tracked slowly towards the northwest in response to the deep layer mean flow it was embedded within.A deepening trough over the eastern United States was forecast to turn the storm toward the north on August 16. This turn took place earlier than forecasters anticipated. The storm slowly intensified as convection was displaced from the center of circulation; however, upper-level outflow was well-defined and intensification of the storm was expected as it tracked over the Gulf Stream. Later that day, Bob began to consolidate and a reconnaissance plane recorded hurricane-force winds at 1719 UTC, following this reading, the NHC upgraded the storm to a Category 1 hurricane on the Saffir–Simpson Hurricane Scale. Shortly after, the hurricane began to turn towards the north-northeast in response to a subtropical ridge over the Atlantic and the trough over the southeastern United States.
By August 18, the NHC noted that the hurricane was asymmetrical, having uneven distribution of the wind radii. Later that day, deep convection continued to form and an eye later appeared on satellite imagery. Early the next day, the eye became increasingly defined as the center of Bob passed roughly from the North Carolina coastline. By 0600 UTC, hurricane hunters recorded flight level winds of, corresponding to surface winds of. At this time, the barometric pressure of the storm also decreased to 950 mbar, the lowest pressure recorded during the storm. After attaining this intensity, the hurricane tracked quickly northeast at, steered by the trough over the southeastern United States, an upper-level cutoff low over the Great Lakes Region and the subtropical ridge over the Atlantic.
The track of Bob by late August 18 and early August 19 was similar to that of Hurricane Carol in 1954, another major hurricane that impacted New England. Significantly cooler sea surface temperatures in the path of the hurricane resulted in weakening, leading to the eye becoming cloud-filled. Later on August 19, the western portion of the eyewall brushed the eastern tip of Long Island. Around 1800 UTC, the center of Bob made landfall near Newport, Rhode Island, with winds of, making it a Category 2 hurricane. The storm quickly weakened as it tracked through Rhode Island and Massachusetts before entering the Gulf of Maine. Around 0130 UTC on August 20, the now weakened Tropical Storm Bob made another landfall near Rockland, Maine.
Later that day, Bob had crossed through Maine and part of New Brunswick, Canada and entered the Gulf of St. Lawrence. Around 1800 UTC, the former hurricane transitioned into an extratropical cyclone. Early the next day, the storm passed over northern Newfoundland before re-entering the Atlantic Ocean. Rapidly tracking eastward, the storm briefly weakened to the equivalent of a tropical depression on August 22. After restrengthening to tropical storm-force winds, the remnants of Bob turned towards the southeast and slowed. Once more, the extratropical system weakened to the equivalent of a tropical depression; however, it did not re-intensify. The storm slowly tracked towards the east before dissipating off the coast of Portugal on August 29.
Preparations
Watches and warnings
Several hours after the declaration of Tropical Storm Bob on August 16, the Government of the Bahamas issued a tropical storm warning for the northwestern Bahamas, between the islands of Andros and Eleuthera. After the storm turned northward, this warning was discontinued as tropical storm-force winds were no longer expected to affect the islands. Shortly before Bob was upgraded to a hurricane on August 17, the NHC issued a hurricane watch for coastal areas of North Carolina between Little River Inlet northward to Virginia Beach, Virginia. Roughly four hours after this watch, it was upgraded to a hurricane warning. A new hurricane watch was issued late on August 17, encompassing areas between Virginia Beach northward to Cape Henlopen, Delaware. This watch was also upgraded to a warning on August 18 as Bob paralleled the Mid-Atlantic coastline. During the afternoon hours, a tropical storm warning was declared for areas in the lower Chesapeake Bay area, including Norfolk, Virginia.A new, extensive hurricane warning was issued late on August 18 when forecasts showed Bob moving directly over southern New England. The warning covered areas between Cape Henlopen, Delaware, to Plymouth, Massachusetts, including Long Island and Long Island Sound. Early on August 19, all watches and warnings south of Cape Lookout, North Carolina were discontinued and the hurricane warning was extended northward to encompass areas south of Eastport, Maine. The Canadian Hurricane Centre began issuing warnings for Atlantic Canada later that day. Nova Scotia, Prince Edward Island and New Brunswick were placed under wind and heavy rain warnings. By the morning of August 20, all watches and warnings in the United States were discontinued; however, a brief tropical storm warning was declared for coastal Maine between Rockland and Eastport before the remnants of Bob moved through eastern Canada. The advisories for Atlantic Canada were later discontinued after the system moved out of the region.
Mid-Atlantic states and the Carolinas
Following the issuance of a hurricane warning in North Carolina on August 17, mandatory evacuation orders were declared for the outermost islands in the state. Local police assisted significant traffic as an estimated 50,000 to 100,000 people left the region. At the height of the evacuations, delays in some places exceeded three hours. Despite the large number of evacuees, an additional 50,000 people were estimated to have stayed home and wait out the storm. Several bridges in the area were shut down prior to Bob's arrival as hurricane-force winds were likely to create life-threatening conditions on them. The National Park Service in the state also shut down campgrounds across the Outer Banks. An evacuation shelter was also opened in Carteret County.In Virginia, 125 planes were relocated from Langley Air Force Base to Wright-Patterson Air Force Base in Dayton, Ohio. Roughly 400 people evacuated from coastal areas in Maryland, and stores in Ocean City reported a substantial increase in sales related to storm preparation. Further north in New Jersey, casinos prepared sandbags to protect the structures and tape to cover windows.
In Suffolk County, New York, emergency officials were unsure of whether or not to issue evacuation orders for residents along coastal areas. This contemplation led to "mixed messages" on the ability of the government being sent to the public. By the evening of August 19, the evacuation order was not issued; however, the county was placed under a state of emergency and disaster centers were opened. The American Red Cross opened four shelters on Long Island that housed 800 people during the storm.