Laura & Marco challenge Gulf Coast with double storm & hurricane landfall

The Gulf Coast states of Louisiana and Texas are facing a challenging double storm landfall threat this week, with tropical storm Laura expected to be a large and dangerous hurricane when it nears the coast late on Wednesday, while tropical storm Marco is more likely to remain at storm strength but soak the area in advance of Laura’s approach.

For two named tropical storms to be forecast to make landfall within a couple of days of each other, relatively close to each other on the Gulf Coast, is a rarity and it threatens a prolonged spell of potentially dangerous weather for the region, with ramifications for insurance and reinsurance interests assured as a result.

Forecasters currently expect Marco to be the weaker of the two storms at landfall, but with concerns mounting that hurricane Laura, which is much larger, has the greatest chance of becoming a major and potentially damaging threat to the region.

The first storm to make landfall is forecast to be tropical storm Marco, which intensified yesterday once it emerged over the Gulf of Mexico and became the third hurricane of the season, but has now weakened due to wind shear interaction and is heading for a Louisiana landfall, most likely below hurricane strength, later today, Monday.

Marco currently has maximum sustained winds of around 65 mph with higher gusts and is expected to struggle to intensify too much further due to the ongoing interaction with wind shear. It’s angled approach is likely to exacerbate the rainfall issues the coastal areas of Louisiana into Texas now faces.

Tropical storm Marco is a relatively compact storm and conditions are not particularly conducive to it maintaining its intensity all the way to landfall, although the very warm Gulf of Mexico waters could confound the forecasters. Forecasters warn that Marco could fluctuate in intensity, but the most likely scenario seems a strong tropical storm landfall later today.

Tropical-storm-force winds extend outward up to 70 miles from the center of hurricane Marco.

The Louisiana coastline is threatened by a storm surge as high as 6 foot at its peak, more widely a storm surge of 2 to 4 feet is expected, while rainfall totals are expected of 3 to 5 inches widely across the region, with up to 10 inches forecast in isolated maximum amounts.

Modelled intensity guidance for hurricane Marco can be seen below, which shows the models do not expect the storm to intensify again (from TropicalTidbits.com):

Meanwhile, still tropical storm Laura is travelling the length of Cuba which has hindered its development into a hurricane at this time. However Laura is wobbling along the south coast of Cuba, where the warm Caribbean is helping to fuel it and keep up its intensity for now.

Once Laura passes the island nation and emerges into the Gulf of Mexico, likely by late Monday into early Tuesday morning local time, the chances of intensification ramp up significantly.

After that, some of the forecast models show the storm quickly becoming hurricane Laura over the warm Gulf waters and heading for a curving approach to the Texas / Louisiana border region.

How far west into Texas the forecast track moves has ramifications for the intensity of hurricane Laura, as the longer it spends over the warm Gulf of Mexico the more strength and organisation it is likely to gather.

The NHC’s latest forecast suggests a strong category 1 hurricane Laura, to perhaps category 2, will make landfall Wednesday night right near the border between the two states, but perhaps pushing into Louisiana.

The models are undecided on the track though and hurricane Laura could veer further west, providing added time to fuel itself over the Gulf and enabling a stronger landfall further into Texas.

The model consensus currently points towards a Cat 1 to Cat 2 hurricane, but some forecasters warn that hurricane Laura could be stronger than that, so it’s important to watch how Laura makes progress over the coming day and whether wind shear can affect the storms chances of strengthening.

Laura has maximum sustained winds of 65 mph currently, with higher gusts and tropical storm force winds extending outwards up to 150 miles from the center of the storm.

So Laura is a much larger storm and with its curving approach to the U.S. coastline through the Gulf has a greater chance of organisation and as a result intensification than Marco.

In addition the wind shear that is affecting Marco may be less prevalent at the time of Laura’s passage across the Gulf, so a much stronger hurricane near the coast of Texas / Louisiana by Wednesday cannot be discounted at this time.

Laura could be a much more significant wind damage threat to the area of the Gulf Coast where it comes ashore and the much larger storm could also push a higher storm surge ahead of it, as well as bringing more moisture and rainfall.

Coming just a couple of days after Marco, Laura could exacerbate water related impacts as the rainfall effects will overlap from the two storms.

There should be a better picture of Laura’s potential as a hurricane to intensify into a major category storm by Tuesday, once clear of Cuba and into the Gulf proper, at which stage the insurance, reinsurance and insurance-linked securities (ILS) industry will have a better idea of the potential impacts.

Modelled intensity guidance for tropical storm Laura can be seen below (from TropicalTidbits.com):

The situation, with two landfall threatening storms in the water at the same time has put the insurance, reinsurance and insurance-linked securities (ILS) community on alert and that will continue over the next few days.

With two tropical storm systems set to impact regions badly affected by the coronavirus pandemic, within a couple of days of each other, there is the chance of complications and challenges occurring that are unprecedented, but also hard to predict.

Among these, the availability of loss adjusters is a factor that could potentially inflate claims from these storms, as too are the issues of which storm caused damages and the potential for a second, stronger storm to drive damage to structures weakened by the first.

Whether a double-landfall threat could stimulate any live cat trading remains to be seen, but that is possible if either of the storms intensify significantly.

We’ll keep you updated and you can track the tropics over at our dedicated 2020 Atlantic hurricane season page.