On Sunday, the National Hurricane Center initiated advisories on Potential Tropical Cyclone Eighteen, a tropical disturbance in the southwestern Caribbean forecast to develop into a named storm in the coming hours, possibly reaching hurricane status before impacting western Cuba by Wednesday.
The next name on the list is Rafael.
Although soon-to-be Rafael will move into the Gulf of Mexico for late week, as we discussed in newsletters last week, its core will remain south and west of South Florida and increasingly hostile conditions in the central and northern Gulf should pump the breaks on organization if it heads for U.S. shorelines.
Jamaica, Caymans, and western Cuba up first
The most immediate concern is for the islands that lie ahead. Jamaica is under a tropical storm warning for winds of 39 mph or stronger as soon-to-be Rafael tracks near or over the island later today and on Tuesday.
While the system is still organizing, it’s forecast to take advantage of warm waters and light upper-level winds over the next few days to strengthen into a hurricane by late Tuesday or early Wednesday before reaching western Cuba.
A hurricane warning is in effect for the Cayman Islands for the likelihood of hurricane conditions – winds of 74 mph or stronger – by the time it reaches the British Overseas Territory later on Tuesday.
Most of the intensity guidance shows the hurricane peaking at Category 1 strength early Wednesday before crossing western Cuba, but conditions over the next few days will favor strengthening so we’ll need to monitor how quickly it organizes, and a stronger hurricane can’t be ruled out.
A hurricane watch will likely be required for parts of Cuba later today.
In addition to the wind threat, heavy rainfall will also pose a problem for these same areas, with up to 9 inches of rain possible from Jamaica to parts of Cuba which could lead to flooding and mudslides, especially in higher terrain.
Worst stays west of South Florida but wet, windy weather ahead
Although the core of future Rafael is expected to pass safely west of South Florida Wednesday and on Thursday, the difference between high pressure centered east of the Florida peninsula and low-pressure of the storm system entering the Gulf will create a pressure gradient over South Florida that will ramp up winds and seas in our area for much of the week.
Strong rip currents, large breaking waves, and hazardous marine conditions will make for a bad week to plan any beach or boating outings here in South Florida.
Unfortunately, it also means the return of soupier air for the middle to latter part of the workweek, which will bump up rain chances across South Florida beginning tomorrow into Wednesday.
For southwest Florida and the lower Keys, we’ll need to monitor the progress of future Rafael for any coastal flooding issues that could come with the stronger onshore winds on Wednesday and Thursday if it doesn’t take a wider swing into the Gulf.
Will future Rafael threaten the U.S. Gulf Coast?
The terrain of western Cuba may act as a light speed bump, helping to knock down the system’s organization as it enters the Gulf of Mexico on Wednesday. That said, it won’t be enough to weaken it altogether and it could hang on to its hurricane designation as it initially moves into the Gulf.
It’s worth noting that only 4 hurricanes in the modern record (since 1966) have been recorded in the Gulf of Mexico in November, so a hurricane here this late in the season would be an unusual event.
Deeper into the Gulf, however, challenging environmental conditions – including a ramp up in hostile wind shear and drier air wrapping in from the west – may start eating away at the storm system, especially if it takes a more northerly trajectory.
The track forecasts start to diverge later next week, with some models abruptly turning the system westward across the central Gulf with others bending it northward.
The ultimate track will be a big driver in its future intensity. If it does take a more northerly trajectory toward the U.S. coast, it’ll have to jump through some hoops and more likely than not be a much-weakened version of its former self by the time it reaches the coast.
So for now, the risk of a significant U.S. tropical threat is low, but those along the Gulf Coast should continue to monitor the forecasts for any changes this week.
Active start to November
As we previewed back in middle October, the Atlantic is getting a boost from the active phase of an upper-level wind configuration known as the Madden-Julian Oscillation or MJO that’s passing through now and will linger into next week.
The non-tropical low-pressure area we mentioned last week became Patty and affected the Azores in the far northeastern Atlantic over the weekend.
Another area of low pressure could develop east of Florida later this week from a dying cold front draped over the Atlantic. For now, development odds are low but since it’ll be moving westward, we’ll keep an eye to the trends as it could at the very least increase our rain chances by later this upcoming weekend.
