Another November hurricane threat is building » Yale Climate Connection

It's November, the final month of the Atlantic hurricane season, and the active 2024 hurricane season appears poised to bring its third named storm this month. This incoming system could become a dangerous hurricane threatening Central America, Jamaica and the Cayman Islands this weekend. Next week, it will likely move into the southeastern Gulf of Mexico, possibly targeting the Florida Gulf Coast, the Florida Keys and western Cuba. The next name on the list of Atlantic storms is Sarah.

The newly named storm is expected to develop from a tropical wave currently approaching eastern Cuba, which will interact with the massive low-pressure system of the Central American Gyre (CAG) currently developing over Central America and the southwestern Caribbean. Panama and Costa Rica could receive more than 10 to 20 inches (250 to 500 millimeters) of rain in the coming week, potentially causing dangerous flash floods and mudslides. If the embryonic system slowly moves into eastern Honduras and northern Nicaragua later this week, as some models suggest it will, a similar situation could develop in eastern Honduras and northern Nicaragua.

Conditions in the region are very favorable for development, especially late in hurricane season, with mild to moderate wind shear, atmospheric moisture, and sea surface temperatures near 29-30 degrees Celsius (84-86°F), which is about warmer than average 1 degree Celsius. A strong ridge of high pressure over the northern Caribbean Sea will allow the developing system to slowly drift northward, potentially bringing heavy rain to Jamaica, the Cayman Islands, Cuba and Haiti this weekend.

The ridge controlling the system will peak early next week, and it appears the most likely path for any emerging system will be to rotate clockwise around it, dip northwest and into the Gulf of Mexico midweek, and then potentially turn northeast toward Southwest Florida ( as predicted by the 12Z Tuesday run of the GFS model) or west of Cuba (as suggested by the 0Z Tuesday run of the European model). West of this developing ridge, where the system may eventually track, the forecast wind shear pattern early next week (Figure 3) is an area of ​​unusually low wind shear in the western Caribbean and southern Gulf of Mexico, more typical of September Or October is the peak of hurricane season.

Although there is strong consensus on the development of ensemble forecast models, it remains an open question which of three pathways development might take:

• Far enough to the east it would be carried away by a cold front moving through the Bahamas, causing the system to branch across Hispaniola and safely out to sea (a scenario not favored in the latest ensemble forecast, see Figure 2);
• Far enough west to force land interaction with Central America, which could lead to catastrophic rainfall there but reduce hurricane threat;
• Just off the coast of Honduras and Nicaragua, this would still result in potentially catastrophic rainfall there, but would also allow for the northwest arc discussed above. This scenario would also maximize the potential for hurricane development, as it would keep the embryonic cyclone above the water.

As of Monday, average sea surface temperatures in the Gulf of Mexico reached record warm levels, and average sea surface temperatures in the Caribbean Sea were close to record warm levels that will not be surpassed until 2023. Strait, the area still has ample deep-sea heat content. Unusually warm waters at the surface and underwater will help support the rapid intensification of any tropical storms or hurricanes fostered by favorable atmospheric conditions that seem likely to form.

According to analysis @BMcNoldyThe Caribbean's deep warm water (“ocean heat content”) appears to be on par with 2023, a record level for this time of year.

This is still well above the average before the 2023 peak #hurricane season. pic.twitter.com/d2b6qK1zG7

— Jonathan Edelman (@wxjerdman) November 12, 2024

The latest operations of GFS and European models predict the system will develop into a dangerous major hurricane in the Western Caribbean by early next week. Severe hurricanes in November are uncommon in the Caribbean and even rarer in the Gulf of Mexico, but they do happen. Just last week, Rafael reached Category 3 intensity in the northwest Caribbean before reaching Cuba, and again reached Category 3 intensity in the southern Gulf of Mexico and northern Yucatan Peninsula. Rafael tied with Hurricane Kate (1985) as the strongest November hurricane ever recorded in the Gulf (with maximum sustained winds of 120 mph or 195 km/h). In mid-November 1985, Kate passed through northern Cuba, passed south of Key West, Florida, and then followed an arcing path through the eastern Gulf, making landfall as a Category 2 (maximum sustained winds of 100 mph or 160 km/h). /hour) near Mexico Beach. Kate's landfall on November 21 – just eight days before Thanksgiving – was the latest recorded landfall in the country.

The potential threat is greater: It's king tide season in South Florida, and with the arrival of the full moon on Friday, Nov. 15, some of the highest tides of the year will occur Friday through next Tuesday. Any landfalling hurricane during this period would cause greater storm surge damage due to higher water levels.

Note that the wind shear pattern forecast for early next week (Figure 3 above) shows higher wind shear in northern Florida, but lower wind shear in southern Florida, so the risk of hurricane landfall is higher in the south than in the north.

Given the current pattern, I think the only thing that might prevent a severe hurricane from forming next week is if the system ends up further south and moves over Honduras/Belize, rather than staying offshore (EC-AIFS and some system members do do) route). If yes… pic.twitter.com/BLjx064AHA

— Andy Hazelton (@AndyHazelton) November 12, 2024

In its Tropical Weather Outlook, released at 7 a.m. ET on Tuesday, the National Hurricane Center (NHC) gave a two-day and seven-day probability of tropical cyclone development in the western Caribbean at 40 percent and 80 percent, respectively. As of Monday, no Hurricane Hunter missions had been scheduled for the system.