Early forecasts of Atlantic basin seasonal hurricane and tropical storm activity for 2018 are pointing towards a year with a slightly above average number of named storms and hurricanes, while landfall probabilities are also seen as slightly above normal as well.
After the major hurricane impacts of 2017 a slightly average season will be welcomed by many, however for insurance, reinsurance and insurance-linked securities (ILS) interests it’s vital to remember that a single major storm landfall can create significant losses for the industry.
Once again and for the tenth consecutive year, Artemis will be tracking the hurricane season as it develops, over on our dedicated 2018 Atlantic Hurricane Season page and reporting on any impacts to reinsurance, ILS and catastrophe bond interests.
Today the Colorado State University tropical weather team led by Phil Klotzbach released its first full forecast for the number of storms expected to form.
Phil Klotzbach presented his teams forecast for 2018 Atlantic hurricane activity at the National Tropical Weather Conference today.
The Colorado State forecast team calls for 14 named tropical storms, 7 hurricanes and 3 major hurricanes of Category 3 strength or greater during the 2018 Atlantic tropical weather season.
Klotzbach said that sea surface temperatures would be important and that some of the models point to anomalous warming, which can mean more storms. However it is too early to predict where or how hot sea surface temperatures may get, hence uncertainty remains the order of the day.
The team explained their forecast, “The current weak La Niña event appears likely to transition to neutral ENSO over the next several months, but at this point, we do not anticipate a significant El Niño this summer/fall. The western tropical Atlantic is anomalously warm right now, while portions of the eastern tropical Atlantic and the far North Atlantic are anomalously cool. There is considerably uncertainty as to what the configuration of Atlantic sea surface temperatures will look like for the peak of the Atlantic hurricane season.”
In terms of landfall probabilities, Klotzbach’s team at Colorado State see a 63% probability of a major hurricane making landfall along the entire U.S. coastline (average for last century is 52%), a 39% probability of a major hurricane striking the east coast or Florida (average is 31%) and a 38% probability of a major hurricane striking the Gulf Coast (average is 30%).
So the landfall probability forecasts are currently above average as well as the forecasts for number of storms and hurricanes, hence the overall forecast prediction is erring towards a more active Atlantic tropical storm season than normal in 2018.
The probability for a hurricane tracking into the Caribbean is put at 52%, above the 42% long-term average.
Other forecasts for Atlantic tropical activity already released include the AccuWeather teams, which calls for 12 to 15 named tropical storms, 6 to 8 hurricanes and 3 to 5 major hurricanes during the 2018 season.
“Last year we had 17 tropical storms. This year may not be quite as active, but still probably normal to slightly above normal,” AccuWeather forecaster Dan Kottlowski said.
“Right now, we are in a weakening La Niña pattern, but the climate pattern is expected to go into what’s called a neutral pattern, which promotes near-normal wind shear,” he continued, a factor that could limit development and intensification of hurricanes.
But Kottlowski also discussed sea surface temperature expectations, saying, “The thing that’s causing the balance to tip in one direction [this year] is that sea surface temperatures are warmer than normal.”
Kottlowski also said that conditions are ripe for early season hurricane development in the Gulf of Mexico as waters in that area are already warmer than normal this year.
The Weatherbell team, another forecaster we track, calls for 11 – 15 named storms, 5 – 7 hurricanes and 1 – 3 major hurricanes in 2018.
Weatherbell explained that the team there believes that hurricane patterns will shift this year, “As far as impact, unlike last year when we plainly had the U.S. in the cross-hairs, this year it looks like the U.S. will be on the western edge of the highest ACE area (50% or more). This will extend between 30°N and 40°N from the U.S. coast to 55°W. If I had to draw it today, the centering of the area of greatest activity would not be like last year. Look for storms to be stronger farther to the north and east than 2017.”
Putting those three forecasts alongside the latest forecast from industry supported Tropical Storm Risks (for 12 storms, 6 hurricanes and 2 major hurricanes) gives us an Artemis average forecast for the 2018 Atlantic hurricane season of 13 named storms, 7 hurricanes and 3 major hurricanes, roughly aligned with the Colorado State figures.
Of course it’s still very early to have any idea of the risk of losses to insurance and reinsurance interests from hurricanes, but seasonal forecasts do at least enable companies to have some idea of the levels of preparation that may be required.
As the season nears the forecasts typically increase their confidence levels and so greater certainty in eventual potential impacts will emerge in time. But it must be reiterated that it only takes one landfalling storm to cause major loss of life and significant damage, meaning while forecasts are directionally useful there is no replacement for preparedness and protection.
Update: Forecasters from the Climate Forecast Applications Network (CFAN) said they predict a below average 2018 Atlantic hurricane season, with a 60% chance of a normal season and a 40% chance of a below normal season. They forecast Accumulated Cyclone Energy (ACE) of 73 [range 43 to 97], which is well below the average for the current active period since 1995.
Keep track of our 2018 Atlantic Hurricane Season page where we will update the forecast numbers over the coming months and then track every storm of the season.