Hurricane Dorian slams Bahamas, Florida risks hurricane winds, surge, rain

Hurricane Dorian remains a monster storm this morning, with sustained winds of 160 mph and higher gusts. The Bahamas felt the full-force of Dorian as a strong Category 5 storm, resulting in significant damage for some islands, while the Florida coast is now at-risk of hurricane force winds, storm surge and torrential rains as Dorian curves northwards.

Update, Sep 5th: 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 and a chance of making landfall. Our latest here.

Last update to this article at 14:00 UTC: Still, the timing of hurricane Dorian’s curve north and how close the eye of the hurricane gets to the Florida coastline is everything, as any movement further west will now increase impacts for Florida.

Hurricane Dorian made landfall in Elbow Cay, Abacos, Bahamas, with sustained wind speeds of 185 mph and gusts of 220 mph, causing significant damage from this major Category 5 status storm. The storm is currently impacting Grand Bahama Island with 200 mph wind gusts and a significant storm surge.

Since then Dorian has weakened slightly to 160 mph winds and the minimum central pressure has risen from its low at 910mb to now 919mb.

However weakening is not forecast to begin in earnest until Dorian has tracked further north, so interests in Florida need to remain alert to hurricane Dorian’s potential to shift its track any further west and come closer to the coast.

The weekend saw hurricane Dorian’s forecast path shifting eastward away from the coastline and then back a little west again. As of this morning, the eye of hurricane Dorian is only forecast to pass tens of miles off the coast of Florida, meaning hurricane force wind conditions are likely for some of the coast, as well as a storm surge and torrential rains.

Again, it’s key to realise that the margin between minor impacts and more significant is very small for Florida, with a slight deviation west able to put much stronger winds over the Florida coast and increase the potential for damage significantly.

Dorian’s track will need to be watched very closely over the coming day or two. The hurricane continues to move very slowly and it will be at its closest to the Florida coast late Tuesday now.

The NHC warns of “Life-threatening storm surges and dangerous hurricane-force winds” for some of the Florida east coast through mid-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.”

Looking further ahead, Georgia, South and North Carolina will all feel the effects of hurricane Dorian as it travels north. While the map shows Dorian staying off the coast, again any deviation further west could bring a landfall or more significant impacts.

Finally, it’s worth noting as the week progresses that 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 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. 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 is incredibly difficult under this circumstance, while the uncertainty over hurricane Dorian’s ability to job west and hit the coast is key. A slight westward shift in the track could result in tens of billions of damages, with resulting reinsurance and ILS market impacts. Staying off the coast could mean a much smaller insurance sector loss, with reinsurance and ILS impacts significantly lower.

The next 48 hours or so will require a close watch on hurricane Dorian as it slowly turns and progresses north.

Below is the latest intensity model output from TropicalTidbits.com

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

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

At 800 AM EDT (1200 UTC), the eye of Hurricane Dorian was located by NOAA Doppler radar near latitude 26.7 North, longitude 78.2 West. Dorian is moving 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 move dangerously close to the Florida east coast tonight through Wednesday evening.

Maximum sustained winds are near 165 mph (270 km/h) with higher gusts. Dorian is a category 5 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 916 mb (27.05 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 Mouth of the St. Mary’s River…4 to 7 ft
North of Deerfield Beach to Lantana…2 to 4 ft

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 Florida east coast, and can vary greatly over short distances.

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

Northwestern Bahamas…12 to 24 inches, isolated 30 inches.
Coastal Carolinas…5 to 10 inches, isolated 15 inches.
Central Bahamas and the Atlantic Coast from the Florida peninsula
through Georgia…2 to 4 inches, isolated 6 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.

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