Tropical storm Cristobal to intensify, Gulf coast on watch for rain & surge

Tropical storm Cristobal is expected to emerge back over the Gulf of Mexico later today and head generally northwards towards the United States, with strengthening forecast and still a chance that the storm could be named hurricane Cristobal prior to landfall.

In general the warm waters of the Gulf of Mexico are strong enough to support intensification of tropical storm Cristobal, but just how much is uncertain and the forward-speed of the storm may be a factor, as it dictates how long it will have over the warmer seas to gain additional structure and strength.

In addition, some wind shear has been forecast, although most seem to think this won’t significantly hinder the development of Cristobal as it moves north.

With forecasts for the 2020 Atlantic hurricane season still pointing to a particularly active season ahead, Cristobal is the first U.S. landfall prospect, so has alerted insurance, reinsurance and insurance-linked securities (ILS) market participants.

However, at this stage it does look like rainfall and some coastal storm surge are the major threats, although intensification to hurricane force winds cannot be ruled out yet.

Earlier this week, tropical storm Cristobal formed over the Bay of Campeche and headed south for a landfall in Mexico. Since then the storm has weakened back to a depression but has dropped enormous amounts of rainfall in the Central American region, with storm totals as high as 35 inches reported.

Now, Cristobal is ready to regain tropical storm characteristics and expected to head out over the Gulf of Mexico tonight. Tropical storm Cristobal’s current position can be seen below.

Tropical storm Cristobal is still a depression at the moment, with winds just below storm strength, but is expected to regain that status later today then head into the Gulf travelling northwards at around 12 mph.

Cristobal is expected to near the U.S. Gulf Coast by Sunday and could make landfall Sunday night or perhaps into Monday morning.

The National Hurricane Center warns of a storm surge threat quite widely to the Gulf Coast, of 1 to 4 feet:

– Aripeka to Marco Island including Tampa Bay…1-3 ft
– Grand Isle to Ocean Springs including Lake Borgne…2-4 ft
– Indian Pass to Aripeka…2-4 ft
– Ocean Springs to Indian Pass including Mobile Bay and Pensacola Bay…1-3 ft

Tropical storm force winds from Cristobal are expected on the Gulf Coast as of Sunday morning.

Rainfall could be a significant threat, with NOAA forecasting up to 10 inches in some areas of the eastern and central Gulf Coast and the lower Mississippi Valley.

Now, that is nothing compared to the rainfall experienced in some parts of Central America, as Southern Guatemala, coastal portions of Chiapas in Mexico and El have seen isolated storm total amounts of as much as 35 inches dating back to Saturday, May 30th from Cristobal and the Pacific storm Amanda it formed from the remnants of.

So Cristobal is known to carry a lot of moisture and there is every chance it could absorb much more on its way across the Gulf of Mexico, so rainfall totals will be something to watch and localised flooding is certainly possible.

In terms of potential landfall location, Louisiana seems to be the models favourite, but some put the storm closer to the Florida Panhandle by Sunday.

Forecasters at a number of weather monitoring services warn that there is a chance that hurricane Cristobal forms, as they see time for intensification as the storm tracks across the Gulf and believe the waters are warm enough to support that.

But ultimately, with Cristobal, it is rainfall and also the chance of tropical storm force winds extending inland for some distance, with the storm becoming particularly large as it crosses the Gulf, that seem the main threats.

As a result, it shouldn’t pose any significant threat to reinsurance or ILS interests, although insurance carriers could face elevated claims levels due to the storm.

You can view a recent forecast model run showing the GFS predicted track for tropical storm Cristobal below, sourced from TropicalTidbits.com.

You can view a recent forecast model run showing the intensity guidance for tropical storm Cristobal below, sourced from TropicalTidbits.com.

It clearly shows there remains some potential for steady intensification of tropical storm Cristobal’s winds as it moves across the warm waters of the Gulf of Mexico towards the United States.

However, it’s worth reiterating that Cristobal may be a rain bringer, rather than wind. Even if it does manage to gain hurricane status, it is unlikely to pose a significant reinsurance market threat.

Track the 2020 Atlantic tropical storm and hurricane season on our dedicated page and we’ll update you as new information emerges of relevance to insurance, reinsurance and ILS markets.