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Eyeing the disturbance in the distant Atlantic as Hanna and Gonzalo fade

Atlantic satellite image from Sunday, July 26.
Atlantic satellite image from Sunday, July 26. (WPLG)

The chatter is accelerating about the large tropical disturbance in the eastern Atlantic. The system is still closer to Africa than it is to the Caribbean islands, let alone Florida, so rational anxiety is premature.

Though memorably bad hurricanes come from this area, a lot of storms that go out to sea do as well. 

The too-early agitation is caused by the computer forecast models that show storm locations 10 or 15 days in the future. The best hurricane forecasts have average errors of over 200 miles just five days out, and the errors increase precipitously as you try to predict events further in the future. So errors eight or nine days out are too big to measure. And every six hours there is a new solution at the long range.

The bottom line of the current information is that Hurricane Season is here. It’s time to prepare and stay informed. 

Having said that, it is reasonable to think that this system will behave differently than Gonzalo, even though, for now, it’s on the same path. First, the system is a lot bigger, so it has more moisture to fend off the plume of Saharan Dust spread across the Atlantic to the north. That doesn’t mean that the dust can’t have some effect, but big, moist systems sometimes can overcome the drying effects of the dusty air.

Also, it appears that the high-pressure system that blocked Gonzalo from turning north will have some weak spots over the next week or more, which means it’s logical that the disturbance will arc toward the north, at least temporarily, into those weaknesses. 

Tropical Storm Hanna Sunday, July 26 (WPLG)

These are the factors, among others, we’ll be watching as we go through this week into next.

The National Hurricane Center is rating this disturbance as likely to organize into a tropical depression or tropical storm this week. If it develops winds of 40 mph or more, it will be named Isaias – properly pronounced ee-sah-EE-us. And even more properly spelled with an accent – Isaías.  It’s Spanish for Isaiah. As I mentioned yesterday, I’m not going to be surprised if English speakers resort to “Isaiahs”, like multiple Isaiahs. The name doesn’t roll of an English-speaking tongue.

The system is about four days from the Caribbean islands on the current schedule – a long way away from the U.S. Just because 2020 has been a miserable year, don’t assume there’s more to it than we know at the present time. 

In the western Gulf, Hurricane Hanna made landfall yesterday south of Corpus Christi, Texas with top winds estimated at 90 mph. Winds are winding down now that the storm is over land, but flooding rain is still expected, especially in Deep South Texas and northern Mexico. A foot of rain with some areas getting 18 inches is forecast – enough to cause flash flooding.

Hanna was the fourth storm to be named by the National Hurricane Center in July. The record is five.  There’s a decent chance we’ll at least tie it.

Gonzalo is no more. It’s back to being a tropical disturbance. Dry air killed it off yesterday shortly after it passed over the southern Caribbean islands.

Hurricane Douglas - Sunday, July 26 (WPLG)

In the Pacific, the center of Hurricane Douglas is will pass just north of the Big Island of Hawaii and Maui today, though they’ll feel effects from the storm. Dangerous winds and rain are forecast over Oahu, the most populated island where Honolulu is located. Impacts there will increase through the day, and should peak late this afternoon or this evening Hawaii time. The island of Kauai is in line after that. 

Near Africa, another disturbance is just moving into the Atlantic behind the one discussed above.  This is normal – it happens about 60 times a year. But as we head into the heart of hurricane season, it’s wise to take note and be aware.


About the Author:

Bryan Norcross is currently a hurricane specialist at Local 10 News, the station where he began his stretch on television in Miami in 1983.