Archive for August 4th, 2012

Ernesto and potential impacts on Texas

Published on Saturday, 04 August 2012 20:42

David Reimer

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[caption id="attachment_8578" align="aligncenter" width="595"]width=”595″ height=”318″ /> Tropical Storm Ernesto – Infrared Image[/caption]

Since visible satellite imagery can only show us what is going on with a storm during the daytime, we revert to infrared imagery after dark. This graphic shows the cloud tops of Ernesto. The colder the cloud tops, the higher the clouds extend into the atmosphere. Thus, we’re able to get some idea on how organized a cluster of thunderstorms or in this case, a tropical system is without the need for daylight. As of 8 PM, a cluster of thunderstorms had cloud tops below -70 Celsius. While that might indicate some form of organized tropical system, the storms are actually displaced from the low level circulation of Ernesto.

That means that the storm has a bark worse than its bite at the moment. Hurricane Hunters confirm that the storm has not strengthened this afternoon and generally remains disorganized. That has a significant role in the eventual track of Ernesto.

[caption id="attachment_8579" align="aligncenter" width="595"]width=”595″ height=”476″ /> National Hurricane Center forecast for TS Ernesto[/caption]

Before I begin to detail the possible scenarios for Ernesto, let us go over the official forecast from the National Hurricane Center. Remember not to focus on the black line, rather the cone of uncertainty in terms of the possible tracks of Ernesto. They have Ernesto moving west/northwest over the next 36 hours, passing just south of Jamaica as a weak hurricane. By Monday, it turns to the northwest and threatens the Yucatán Peninsula as a hurricane. After that, the storm could emerge into the Gulf of Mexico. While there are several scenarios possible, I’m going to focus on the one I believe is the most likely to happen based on current data.

[caption id="attachment_8580" align="aligncenter" width="595"]width=”595″ height=”446″ /> 7 PM CDT Computer Tracks for Tropical Storm Ernesto[/caption]

These are the latest computer  model tracks for Tropical Storm Ernesto, right off the press! Models are in good agreement for the track through Tuesday, but begin to diverge after that. Some take Ernesto further south and west, resulting a weaker system. Other models take Ernesto further north into the Bay of Campeche on a northwest track until it turns west into Mexico south of the TX/MX border.

The eventual track of Ernesto will depend on how strong it becomes. Generally speaking, the stronger systems have a tendency to be influenced by the Coriolis Effect, which would help pull the system on a more northerly track. However, a weak system won’t be affected nearly as much and in the present atmospheric environment, will continue a more westerly track and likely not impact the United States.

Ernesto is quite disorganized at present, so that provides confidence that Ernesto will remain well south of the TX/MX border. Unless it changes considerably in its structure over the coming days, it seems likely Ernesto will remain south of the United States.