Hurricane Dorian sustaining Cat 5, Florida still at-risk as eyewall grows

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Hurricane Dorian is still a very dangerous Category 5 hurricane and is now packing sustained wind speeds of 160 mph as it continues to batter the Bahamas.

Update, Sep 4th: Hurricane Dorian remains a strong hurricane. The U.S. coastline is not yet in the clear, as Dorian is forecast to hug it on the way north, with dangerous winds and storm surge expected. Our latest here.

Last update to this article at 17:20 UTC: Dorian has been downgraded to Cat 4 with 155 mph winds.  But Florida is not out of the woods, with hurricane Dorian still forecast to pass very close to the coast on a northwards path.

But Dorian’s eye also appears to have expanded in recent satellite imagery, which is likely to increase the size of the wind-field carrying hurricane force gusts, which heightens the risk of damage to the Florida coastline should Dorian remain near to it on its northerly path.

Tropical storm or hurricane Dorian forecast path towards Florida

As we explained earlier, the weekend saw hurricane Dorian’s forecast path shifting east away from the Florida coastline, which is where it stays.

It has however edged back a little west again, which if the forecasts are right means the coast of Florida is in for sustained tropical force winds and hurricane force gusts while hurricane Dorian travels north along it.

Any deviation further west in the timing of the turn to the north, or wobbles while on its path up the coast of Florida, could bring hurricane Dorian perilously close and bring hurricane force winds or even a landfall.

The Bahamas have faced a devastating day facing the full force of hurricane Dorian’s winds and when reports emerge it’s likely that the Abaco and Grand Bahamas islands will have experienced very significant damage and tragic loss of life.

Dorian has slowed to a crawl as it passed over these islands, slowing the time of its arrival closest to Florida and also heightening uncertainty over when it will begin its turn to the northwest and then north.

At this time, the forecast still shows hurricane Dorian’s eye remaining offshore of Florida, with the Space Coast likely to see the closest pass.

But the eye has also grown in recent hours, while it underwent an eyewall replacement cycle meteorologists reported, meaning hurricane force winds may now extend further out from the middle of Dorian and the wind-field of the strongest gusts may now be wider than before.

That could mean stronger winds for the Florida coast while the hurricane travels north. It also means the margin for error in a brush with the coast being relatively benign, or more impactful, could have narrowed somewhat.

So it’s still important to understand that the margin between minor impacts and a much more significant loss is very small for Florida (so too for insurance, reinsurance and ILS interests), with just a slight deviation west able to put much stronger winds over the Florida coast or inland and increase the potential for damage to occur.

Dorian’s track needs to be watched very closely over the next 24 hours as it moves closest to Florida. The hurricane continues to move very slowly and it will be at its closest to the Florida coast late Tuesday and early Wednesday.

The NHC continues to warn of “Life-threatening storm surges and dangerous hurricane-force winds” for some of the Florida east coast and now also Georgia coast through the middle of the week.

As we explained above, the NHC also stresses, “Only a slight deviation to the left of the official forecast would bring the core of Dorian near or over the Florida east coast.”

Parts of Florida are very likely to experience some hurricane conditions, akin to Category 1, but any shift in the path west could easily see wind gusts rising significantly.

The NHC also warns that, “The risk of life-threatening storm surge and hurricane-force winds continues to increase along the coasts of South Carolina and North Carolina.”

Georgia, South and North Carolina will all feel the effects of hurricane Dorian as it travels north. Dorian is forecast to come very close to landfall around the Cape Hatteras region of NC.

While the tracking map shows Dorian staying off the coast, again, any deviation west could bring a landfall or more significant impacts to these states.

Finally, it’s worth remembering that as this week progresses an extratropical transition is possible, as hurricane Dorian moves north, which some weather models show as Dorian turning into a major extratropical cyclone that could affect other northeastern U.S. states at the end of the week.

The potential for Dorian to impact much of the U.S. eastern seaboard as it travels north is real.

Of course, the uncertainty over hurricane Dorian’s track and how impactful it will be in Florida and northern states makes modelling a potential insurance and reinsurance market loss challenging at best.

Clearly, risks still exist for the insurance, reinsurance, insurance-linked securities (ILS) and catastrophe bond markets, and the ILS market cannot discount losses from Dorian, as we explained in more detail earlier.

The impacts in the Bahamas will drive a significant insurance loss and reinsurance firms will likely assist in local insurers payments of claims.

But forecasting a loss figure for the industry from Dorian is now incredibly difficult under these circumstances, while the uncertainty over hurricane Dorian’s ability to jog west and hit the coast is so high.

A slight westward shift in the track could result in tens of billions of damages, with resulting reinsurance and ILS market impacts.

Staying completely off the coast could mean a much smaller insurance sector loss, with reinsurance and ILS impacts significantly lower.

The next 48 hours remain key and will require market participants to keep a close watch on hurricane Dorian as it slowly turns and progresses north.

Below is the latest intensity model output from TropicalTidbits.com

Tropical storm or hurricane Dorian intensity forecast

Below are the latest GFS ensemble hurricane forecast model tracks for Dorian, from TropicalTidbits.com.

Tropical storm or hurricane Dorian forecast model tracks

NOAA’s latest full update on hurricane Dorian is below:

At 1100 AM EDT (1500 UTC), the eye of Hurricane Dorian was located near latitude 26.8 North, longitude 78.3 West. Dorian is moving very slowly toward the west near 1 mph (2 km/h). A slow westward to west-northwestward motion is forecast during the next day or so, followed by a gradual turn toward the northwest and north. On this track, the core of extremely dangerous Hurricane Dorian will continue to pound Grand Bahama Island through much of
today and tonight. The hurricane will then move dangerously close to the Florida east coast late tonight through Wednesday evening and then move dangerously close to the Georgia and South Carolina coasts on Wednesday night and Thursday.

Maximum sustained winds are near 155 mph (250 km/h) with higher gusts. Dorian is an extremely dangerous category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Although gradual weakening is forecast, Dorian is expected to remain a powerful hurricane during the next couple of days.

Hurricane-force winds extend outward up to 45 miles (75 km) from the center and tropical-storm-force winds extend outward up to 140 miles (220 km).

The estimated minimum central pressure is 922 mb (27.23 inches).

HAZARDS AFFECTING LAND
———————-
WIND: Catastrophic hurricane conditions continue on Grand Bahama Island. Do not venture out into the eye, as winds will suddenly increase after the eye passes.

Hurricane conditions are expected within the Hurricane Warning area in Florida by late tonight or Tuesday. Hurricane conditions are possible in the Hurricane Watch area on Wednesday.

Tropical storm conditions are expected within the Tropical Storm warning area today and Tuesday, and are possible in the Tropical Storm watch area by tonight.

STORM SURGE: A life-threatening storm surge will raise water levels by as much as 18 to 23 feet above normal tide levels in areas of onshore winds on Grand Bahama Island. Near the coast, the surge will be accompanied by large and destructive waves. Water levels should very slowly subside on the Abaco Islands during the day.

The combination of a dangerous storm surge and the tide will cause normally dry areas near the coast to be flooded by rising waters moving inland from the shoreline. The water could reach the following heights above ground somewhere in the indicated areas if the peak surge occurs at the time of high tide…

Lantana to the Savannah River…4 to 7 ft
North of Deerfield Beach to Lantana…2 to 4 ft

Water levels could begin rise well in advance of the arrival of strong winds. The surge will be accompanied by large and destructive waves. Surge-related flooding depends on the how close the center of Dorian comes to the coast, and can vary greatly over short distances. For information specific to your area, please see products issued by your local National Weather Service forecast office.

RAINFALL: Dorian is expected to produce the following rainfall totals through late this week:

Northwestern Bahamas…12 to 24 inches, isolated 30 inches.
Central Bahamas…Additional 1 to 3 inches, isolated storm totals of 6 inches.
Coastal Carolinas…5 to 10 inches, isolated 15 inches.
Atlantic Coast from the Florida peninsula through Georgia…4 to 8 inches, isolated 10 inches.

This rainfall may cause life-threatening flash floods.

SURF: Large swells are affecting east-facing shores of the Bahamas and the Florida east coast, and will spread northward along the southeastern United States coast during the next few days. These swells are likely to cause life-threatening surf and rip current conditions. Please consult products from your local weather office.

TORNADOES: Isolated tornadoes are possible this afternoon into tonight along the immediate coast of east-central Florida.

We will update you on hurricane Dorian as it proceeds and the threat it could pose to global insurance, reinsurance and ILS market interests.

You can always visit our 2019 Atlantic hurricane season page for the latest and we will update you as new information is reported to us.

For details of every catastrophe bond every issued visit the Artemis Cat Bond Deal Directory.

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