The Gulf awakens

10% chance of development in the Gulf this weekend

A spin of moisture off the Louisiana coast has now caught the attention of the National Hurricane Center and this morning they forecasted a 10% chance of development in the next 48 hours (and the next five days, but it will be onshore by then). Expected to move southwest across the Gulf, the system is most likely to impact the Brownsville to Corpus area although a few showers tomorrow and Sunday could get thrown our way!

But why only a 10% chance? The water is well above the 80° threshold needed for tropical development:

The gulf is generally at 86 degrees right now

And no strong winds in the upper atmosphere are present to tear the system apart (note the blue color indicates LOW wind shear):

Wind Shear is Low

So the checklist looks pretty good for something to come of this:

Potential Development Checklist

So why only a 10% chance from the National Hurricane Center? I can’t speak for them, but I will say that neither the American Model nor the European model develops a closed circulation with the system. The key to an upgrade for a tropical cyclone is organization--winds from every direction indicating such a closed system. Here are both models right now and all you see is a disorganized system of rain:

Heavy Rain in South Texas courtesy
Heaviest rain in South Texas courtesy

In fact, the National Hurricane Center forecasts winds below 30mph with wave heights in the 3-5′ range around Corpus on Sunday, so not much of a strong cyclone expected. But as for rain, this could be a soaker for south Texas with as much as 6-8″ of rain in spots and just like us, they need it:

Rainfall Totals through Sunday

Our rain chances will depend on just where this system ends up being located and how strong it becomes --the farther away from us will give us lower rain chances. Whether this really develops into a full tropical depression or storm is to be seen (the next name is DANIELLE), but the bottom line is the tropical season is ramping up now and this is the first evidence of it. Don’t let your guard down!


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About the Author:

KPRC 2's chief meteorologist with three decades of experience forecasting Houston's weather.