Hanna is now a hurricane. It is forecast to continue to strengthen until it makes landfall on the lower Texas coast today. Water will be pushed over the coastal beaches and into the bays and waterways near and north of Corpus Christi to dangerous levels. Very strong winds will affect the city, though the core of the storm is forecast t to move into a very unpopulated area between Corpus Christi and Brownsville, which is on the Mexican border.
Hurricane Warnings and Storm Surge Warnings are in effect for the south-central Texas coast.
Heavy rain from Hanna is forecast over the Louisiana and Texas coasts, with flooding rain possible in extreme south Texas. The scary thing there is that the land in the Rio Grande Valley is very flat and prone to flooding, but also there is an extreme COVID-19 outbreak underway. It’s a daunting situation.
In the Atlantic, fortunately Tropical Storm Gonzalo turned out to be the little storm that couldn’t. It was not able to recover from its encounter with dry Saharan air. Tiny storms like Gonzalo need a pristine atmosphere to spin up, but the dry air was just too much. When it moves through the extreme southern Caribbean islands today, it will produce gusty winds and tropical downpours, especially in the mountainous areas, but the small-diameter storm will likely not have widespread effects.
In the Pacific, Hurricane Douglas is heading toward the Hawaiian Islands from the east. Impacts are expected on the Big Island of Hawaii and Maui late today Hawaiian Time, and then spreading across the state tomorrow. The center of the storm is now forecast to pass just north of the Big Island and Maui, which may have the effect of making Douglas stronger when it gets to highly populated Oahu, where Honolulu is because it won’t have run into the tall mountains farther east.
Douglas will be a weaker version of its former self as it moves through the islands, but tropical systems can be much worse on mountainous terrain because the winds are stronger at higher elevations. The mountains can enhance the winds and rainfall causing corridors of damage and mudslides from the torrential rain.
In the far eastern Atlantic, a large tropical disturbance – technically a tropical wave – has moved off Africa. Initially, it will be on a similar track as Gonzalo, but there are differences.
Gonzalo was held south by a strong high-pressure system spread across the Atlantic. The same high that has brought the persistent ocean breeze to South Florida. Over the next week or so, however, gaps of weaker pressure may develop in that blocking high due to strong disturbances moving across the Northeast U.S. and the Atlantic. When they pass by, the high, essentially, develops a weak spot. That weakness causes systems on a southern track to veer farther north.
A big plume of Saharan Dust will be spread north of the disturbance, which may be a limiting factor. But large disturbances sometimes carry enough moisture to counteract the drying of the dust layer, so they in essence plow through it. How those factors play out remains to be seen.
The system is still four or five days from the Caribbean islands, so we have a lot of time to watch it. It’s positioned in a part of the ocean that requires our attention, however.
The National Hurricane Center is giving it a good chance of developing into a tropical depression or tropical storm in the next five days. If it gets a name, it will be Isaias.
The name, Isaias (properly Isaías) is Spanish and Portuguese for the Biblical name “Isaiah” in English. In the list of names, languages of all of the countries in and around the Caribbean and the Atlantic are represented, thus Spanish, Dutch, French, and English names are included.
The pronunciation of Isaias is a bit difficult for English speakers. Properly it’s ee-sah-EE-us. The accent is on the EE. I’m betting we hear “Isaiahs” like a plural of the English name – like more than one Isaiah.
However it’s pronounced, it’s a system to watch. A number of the computer forecast models predict it will fend off the dust layer and reach the Caribbean as a developing storm. But nobody should be paying attention to the details of any computer forecast at this point.
As always, it’s important to remember that forecasts for weak or developing disturbances are generally poor compared to organized systems. Errors are many hundreds of miles 5 days in the future, and the intensity is a crap shoot. So every forecast at this point is subject to drastic changes.
Behind this disturbance, there appear to be others in the pipeline. So stay informed, tropical season seems to be kicking in.