Hurricane Gonzalo now a Category 3 storm, severe threat to Bermuda

by Artemis on October 15, 2014

Hurricane Gonzalo, the seventh named storm of the 2014 Atlantic Hurricane Season, formed to the east of the Leeward islands at the beginning of this week and has steadily intensified to Category 3 major hurricane status and poses a severe threat to Bermuda.

For the latest on Gonzalo see our new article here.

Update 16th Oct, 16:00 BST, 11:00 EST:

Hurricane Gonzalo has got a little stronger again with maximum sustained winds of 145mph, according to an NOAA hurricane hunter aircraft which investigated the storm. The minimum central pressure has dropped again to 940mb and hurricane forces winds now extend outwards 45 miles and tropical storm force winds 150 miles. Hurricane Gonzalo remains a strong Category 4 storm and poses a significant threat to Bermuda.

Brian Owens, meteorologist and senior director at RMS, told Artemis; “The intensity and long-duration of Gonzalo prior to reaching Bermuda may drive dangerous storm surge towards the island’s southern coastline.”

Owens said that while the forecast still shows the center of Gonzalo tracking slightly to the west of Bermuda, there’s a 50% chance that the entire island will be hit by at least hurricane force winds.

Gonzalo’s forward progress has been slower today, meaning that the storm will likely approach Bermuda a little later on Friday. Tropical storm force conditions are to be expected in Bermuda from early on Friday. The latest forecast path can be seen below.

National Hurricane Center forecast path for hurricane Gonzalo

National Hurricane Center forecast path for hurricane Gonzalo

Update 16th Oct, 10:00 BST, 05:00 EST:

Hurricane Gonzalo has intensified even further, after undergoing an eyewall replacement cycle and is a Category 4 hurricane once again. Gonzalo now has sustained winds of 140mph, according to the latest update from the National Hurricane Center, with higher gusts. The minimum central pressure has dropped further to 945mb.

Hurricane Gonzalo has also grown again, so hurricane force winds now extend outwards up to 40 miles from the center while tropical storm force winds extend 140 miles out. The larger the storm gets the greater the probability that Bermuda experiences severe winds, unfortunately.

The latest forecast path has also worsened the outlook for Bermuda, with the National Hurricane Centers forecast showing the storm making almost a direct hit on the island on Friday. See the forecast path below.

The NHC said in its latest update this morning:

Hurricane conditions are expected to reach Bermuda on friday, with tropical storm conditions beginning late tonight or early friday morning. it should be noted that wind speeds atop and on the windward sides of hilly terrain are often up to 30 percent stronger than at the surface, and in some elevated locations can be even greater.

A dangerous storm surge is expected to produce significant coastal flooding in Bermuda. near the coast, the surge will be accompanied by large and destructive waves.

Gonzalo is expected to produce total rain accumulations of 3 to 6 inches over Bermuda.

Update 15th Oct, 16:00 BST, 11:00 EST:

Hurricane Gonzalo has now reached Category 4 status with maximum sustained winds of 130mph with higher gusts. Hurricane force winds now extend outwards up to 35 miles from the center of Gonzalo and tropical storm force winds up to 115 miles. This indicates that hurricane Gonzalo is growing in size.

Meteorologists suggest that hurricane Gonzalo has just been through an eyewall replacement cycle. After this part of the natural cycle of tropical storm development, hurricanes can become much better organised. The next updates from the NOAA will be telling as to whether the storm has more of a chance of maintaining intensity as it tracks northwards.

The latest forecast track shows hurricane Gonzalo’s eye passing a little to the west of Bermuda, which would at least spare the island the worst of the winds. However it seems very likely that Bermuda will begin to experience strong tropical to hurricane force winds from early on Friday.

The forecast path for the hurricane will be clearer once hurricane Gonzalo has made its northwards and then northeasterly turn. When it makes this turn and how sharply it veers will have a bearing on how close it comes to Bermuda. The tracking maps below will reflect this as they update automatically every few hours.

Interestingly, the forecast models have diverged further and the consensus for Gonzalo’s path is not as clear as before, with some suggesting a path further west. It’s worth watching how this develops and we’ve added a graphic showing the forecast models below the tracking maps.

Original article:

Gonzalo gained tropical storm status very quickly and has occurred at a time when conditions in the Atlantic are conducive to formation and also rapid intensification of hurricanes and tropical storms. Gonzalo reached hurricane status quickly while lashing the Leeward Islands and Virgin Islands, but as soon as it had moved clear and over warm waters it has rapidly intensified.

Currently hurricane Gonzalo is located 1,100km south of Bermuda, the reinsurance and insurance-linked securities (ILS) industry hub. The maximum sustained winds carried by hurricane Gonzalo are reported to be 125mph by the NOAA, while the hurricane is capable of gusts much higher than that. Hurricane force winds extend outwards up to 25 miles from the centre of hurricane Gonzalo, while tropical storm force winds stretch outwards by 115 miles.

At the moment the forecast for hurricane Gonzalo takes it extremely close to Bermuda, as you can see from the tracking maps below. Further intensification to Category 4 is possible as Gonzalo approaches Bermuda. The worst case scenario would be for Gonzalo to track directly over Bermuda and any deviation to east or west will lessen the impact to the island.

Bermuda was struck just last weekend by tropical storm Fay, but this storm will be significantly more powerful when it approaches the island and we would urge all friends and colleagues in Bermuda to take heed and watch Gonzalo’s approach carefully.

Hurricane Gonzalo forecast track or path

Hurricane Gonzalo forecast track or path -Source: Weather Underground

Hurricane Gonzalo forecast models

Hurricane Gonzalo forecast models - Source: Weather Underground

A few lesser followed forecasts continue to have some uncertainty in the intensity that the storm will reach and also the path that hurricane Gonzalo will follow. Model consensus suggests that Gonzalo will reach Category 3 or even 4 as it heads north, perhaps weakening back to Category 3 before making its closest pass to Bermuda. That would be a storm with sustained winds of 111mph to 130mph, potentially very destructive even for an island nation so well-prepared for hurricanes. Should Gonzalo maintain Category 4 strength of over 130mph winds a direct hit on Bermuda would not bear thinking about.

Hurricane Gonzalo is being steered by winds from the east but forced north by the weather patterns pushing out from along the U.S. coastline. Should that weather pattern change and the forces pushing Gonzalo north and east weaken, there would be nothing to stop the path moving further west potentially bringing the storm closer to the U.S. and sparing Bermuda the worst At the moment that is a very outside chance, but something to remain aware of.

At the current rate hurricane Gonzalo is moving northwards it would be expected to come closest to Bermuda on Friday. It is to be hoped that Gonzalo is steered as far offshore from the island as possible and we hope our friends and colleagues there remain safe.

The latest update on hurricane Gonzalo from risk modelling firm AIR Worldwide can be found below:

Hurricane Gonzalo Skirts Caribbean Islands, Threatens Bermuda: AIR

BOSTON, Oct. 14, 2014 – According to catastrophe modeling firm AIR Worldwide, Tropical Storm Gonzalo passed through the eastern Caribbean on a northwest course, further east than initially forecast, delivering heavy wind and rain to Antigua and other close-by islands. Near St. Martin, Gonzalo achieved hurricane-speed winds and continued to strengthen—more quickly than forecast. Now a Category 2 storm with 110 mph maximum sustained winds and a minimum pressure of 973 mb, Gonzalo is expected to take a turn to the northeast by early Thursday and set a course for Bermuda. Hurricane Gonzalo is not expected to reach the U.S. mainland.

“Direct damage from wind thus far has been isolated to roofing, with reports of some structures having complete damage to the roof,” said Scott Stransky, manager and principal scientist at AIR Worldwide. “Additionally, there have been reports of felled trees and power outages, primarily on Antigua. Aside from wind, the storm is expected to produce up to a foot of rainfall in some areas.”

Stransky continued, “Tropical Storm Gonzalo formed over the weekend, just east of the Antilles. As a tropical storm, Gonzalo passed through the northern Antilles. As it moved northwest on Monday, roughly between Antigua and St. Thomas, Gonzalo reached hurricane status. Hurricane Gonzalo has continued to strengthen to a Category 2 storm on the Saffir-Simpson scale, with maximum sustained wind of 110 mph and a minimum pressure of 973 mb. The storm should experience lower wind shear and warm water on its projected track, contributing to its strength and potential for damage should it impact Bermuda.”

As a tropical storm and then hurricane, Gonzalo tore roofs off structures, felled trees, and knocked out power as it passed through the eastern Caribbean, primarily impacting Antigua. Heavy rain from the storm could result in mudslides, particularly in mountainous areas, as well as flash flooding. Gonzalo has also produced large swells, resulting in potentially dangerous surf and rip currents.

According to AIR, at Category 2 wind speeds, it is expected that significant damage will occur to poorly built structures. Structures that are built to the local codes and building standards are not immune from damage, but damage will likely be limited to roof covering, wall cladding, and unprotected windows. Similar damage would also be expected for larger commercial structures. While Bermuda is on track to experience Gonzalo’s significant winds, the high building standards and construction quality will help to mitigate much of the impact.

The potential for structural damage from hurricanes in the Caribbean region varies widely from moderate to high vulnerability, depending both on building codes and building code enforcement. Grenada, Haiti, Trinidad and Tobago, St. Lucia, St. Kitts and Nevis, Jamaica, and Barbados islands, for example, have low building regulation enforcement and thus higher vulnerability to hurricane wind and rain. In contrast, Bermuda (as well as the Bahamas and Puerto Rico), benefits from strong building codes and rigorous enforcement, and thus has lower vulnerability.

According to AIR, reinforced concrete apartments, condominiums, and other structures often are constructed with some level of structural engineering attention, which reduces their vulnerability to moderate winds. However, unprotected windows and openings can pose a risk for possible breaches in the building’s envelope, subsequently allowing for higher wind loads on the building and allowing rain intrusion to damage contents. Structures of masonry construction, however, can exhibit varying vulnerability due to differences in building quality and adherence to building codes.

AIR will continue to monitor Hurricane Gonzalo, as well as a developing storm in the Central Pacific, Tropical Storm Ana, which has the potential to affect Hawaii this weekend. Updates will be provided as warranted by events.

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