On Friday, forecast models suggested the possibility of low pressure lifting northward out of the southwestern Caribbean for early this week. Instead, a new area of spin took shape to the north of the Caribbean islands – designated Invest 96L on Saturday – not quite gathering enough steam to become a tropical depression but staving off development farther south.
As 96L is cast aside this week by increasingly strong upper-level winds, models once again turn back to the southwestern Caribbean for potential tropical development for later this week into next weekend.
As we’ve described in previous newsletters, the western Caribbean is the place to look this time of year. Roughly a third of all hurricanes that form this late in the season do so in the western Caribbean. Moreover, 9 of the 11 (82%) Category 3 or stronger hurricanes recorded this late or later in the hurricane season have formed in the western Caribbean.
Of the 126 tropical storms and hurricanes to occur during November, only 14 struck the mainland U.S. – a frequency of about once every 12 years – but 11 of those have been Florida storms. Only four hurricanes on record have struck the U.S. mainland in November: the Yankee Hurricane of 1935, Kate in 1985, the Expedition Hurricane of 1861, and Nicole last November.
No Category 3 or stronger U.S. hurricane landfall has been recorded in November or December. So while U.S. hurricanes can happen in November, they’re a rare event we might expect every 30 or 40 years on average.
Nevertheless, South Floridians should stay vigilant into November, especially in this season of record warm waters. The low pressure we’ll be following this week will be moving westward through the Caribbean toward Central America by next weekend. Our major computer models show an environment favoring development, with light upper winds aloft and water temperatures still simmering at 86°F and above throughout the central and western Caribbean, record values for the time of year.
At least through this week, high pressure steering to the north will keep whatever tries to form moving westward toward Honduras and Nicaragua to our south. The big question comes over the weekend and whether high-pressure steering continues to push the low-pressure system inland into Central America or weakens enough for it to lift northward toward the Gulf of Honduras. The European model favors a westward scenario into Central America while the American GFS suggests a northward bend courtesy of a sharp jet stream dip into early next week.
With these details still a week away, we’ll have to be patient to see how the forecast shakes out. Each of our forecast models has their biases, and this far out, they can be greatly exaggerated. The American GFS is known to overcook storms in this part of the Caribbean, especially at longer lead times, but the European model has a history of being too overzealous on the strength of high-pressure steering.
For those of us in South Florida, we’ll have plenty of time to follow the trends this week, but interests in Central America will want to monitor this one more carefully in the days ahead.
Tammy says so long while Invest 96L fades away
Over the weekend, the long saga of Tammy finally came to a close as the regenerated storm lost its organized thunderstorms and turned post-tropical once again. The system is meandering over the central Atlantic and isn’t expected to reform.
Meanwhile, the low-pressure area designated Invest 96L over the weekend is quickly fading east of the Bahamas as upper-level winds ramp up from the west. Development isn’t expected as it scoots northeastward and away from Florida this week.