Bryan Norcross: Another tropical system to watch in the Caribbean that could become a threat to Florida
We never have confidence in forecasts for 8 or 10 days in advance, of course, especially when the system in question hasn’t even begun to organize. But since the computer forecast consensus is so high, we pay some extra attention.
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(FOX Weather / FOX Weather)
Mother Nature is not paying attention to the calendar. The consensus of the computer forecast models is that the robust Tropical Disturbance south of the Dominican Republic will develop into a large low-pressure system in the central Caribbean and eventually organize into a tropical depression or tropical storm.
Satellite imagery shows a Tropical Disturbance in the Caribbean Sea.
(NOAA)
The National Hurricane Center still has the development odds in the medium range. They want to be sure that the computer forecasts continue to show a system developing this week near Nicaragua or Honduras before increasing the official development chances.
The consensus of the various models is unusually strong – freakishly so. At Florida State University, researcher Dr. Bob Hart created a scheme to estimate development potential based on the computer forecasts. The FSU odds are currently at 73% that at least a depression will develop in the Caribbean in the next 7 days. The NHC odds of development will increase closer to the FSU number if the computer-forecast trends continue.
Through next weekend, high pressure over the Southeast U.S. will confine whatever develops in the Caribbean to the waters near Central America. The atmospheric pattern would seem to support the development of Tropical Storm or Hurricane Sara. Whatever develops, it looks to track slowly across the western Caribbean.
It’s the long range – into the middle of next week – that presents annoying possibilities. We never have confidence in forecasts for 8 or 10 days in advance, of course, especially when the system in question hasn’t even begun to organize. But since the computer forecast consensus is so high, we pay some extra attention.
In a normal year, tropical systems get stuck in the Caribbean in November because hostile upper winds and cold fronts control the waters farther north. As recently as yesterday, it looked like we were moving into that typical weather regime.
Now, however, a double-barreled, extremely strong storm is forecast to move out of the Southwest U.S. and trek across the country. If it’s as strong as today’s forecasts indicate, it could push the blocking high-pressure system across the Southeast U.S. out of the way and provide a path north for the potential Caribbean system.
If that happens, the potential storm could track toward Florida around the middle of next week.
The National Hurricane Center has odds in medium range that a Tropical Depression will develop in this area over the next week.
(NOAA)
There are lots of variables here. First, the Caribbean system has to develop and intensify. If it stays weak or goes inland, the jet-stream dip associated with the big U.S. storm system won’t be able to grab it. Also, the long-range forecasts for the Southwest system might be overdoing it. It wouldn’t be the first time. Obviously, any forecasts for the weather pattern more than a week in advance are subject to big changes.
Yesterday, I pointed my finger at the American GFS model for consistently being overzealous in developing any little swirl that comes along. I said we wouldn’t pay attention until and unless other computer forecasts followed along. Well, today, in broad strokes, they are all showing Caribbean development moving north. We’ll see what future forecasts bring. As always, all forecasts for systems that haven’t yet developed are subject to large errors and significant changes.
So heads up in Florida! We’ll see what this week brings. Nothing would happen until next week. Sorry for getting your hopes up yesterday, though the hopes might still be well-founded. We’re all looking forward to an end to this hurricane season.