Overnight Tropical Update: What Can Louisiana Expect Later This Week

(KMDL-FM) Forecasters with the National Hurricane Center are still suggesting that an area of low pressure currently centered off the east coast of Florida on the Atlantic side of the peninsula will move westward over the next two days. If it does, it will be centered just south of the northern Gulf Coast.

With that proximity to the coast and depending on how far westward the system might travel, interests in New Orleans, Houma, Baton Rouge, and even Lafayette could feel the effects of the system by later this week. The current question on the minds of most forecasters is "What will those effects be"?

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Before we go too far down that road and speculate about what might happen, let's bring you up to speed on the changes the National Hurricane Center has made in its forecast regarding the system. The NHC is now giving the area of disturbed weather a 40% probability for strengthening over the next 48 hours. That same probability holds for the seven-day outlook as well.

Where Is The System in the Gulf Likely to Go?

That is a great question, and it's being made harder to answer because the system is so unorganized at this time. A lot of tropical models are "speculating" that the system will develop a little more than it currently has.

When that happens, it makes it easier for the model guidance to "lock on" to the system and give us a clearer picture. That being said, here's what the tropical forecast models have to say about the projected path of the system, which has been given the working name "Invest 93L".

As you can see, there is a fairly wide separation in the model solutions for where this system might eventually travel. Guidance is fairly clear that a westward move is imminent. However, if and when the system will make a turn toward the coast seems to be the most unsettled part of the forecast guidance.

What Should Coastal Louisiana Expect From the Current System in the Gulf?

The consensus does seem to focus on southeastern Louisiana as the spot where this system, in whatever form it happens to be in the next 48 hours or so, will move very near the mouth of the Mississippi River and the city of New Orleans. But as you can see, the projected paths described by the models show a solution as far east as Mobile, Alabama, and as far west as Terrebonne Parish in Louisiana.

So, there is still a lot of uncertainty in the path of this storm system. What does appear to be quite clear is that it will be a rainmaker of significant proportions. Here's what some of the rainfall projections look like.

That graphic you see above is from the National Weather Service Forecast Office in New Orleans/Baton Rouge, and you can see the greatest concern with this system, at least at this time, is heavy rain. The picture on the left side of the graphic is the most likely scenario, while the right side of the graphic offers a "worst-case" scenario.

Meanwhile, further to the west along I-10 in Lafayette and Lake Charles, the threat of heavy rain won't move into those cities until Thursday, with much of the area under the threat of an Excessive Rainfall Event during the day on Friday.

You can see the graphical representation of what the Weather Prediction Center is forecasting as far as "excessive rain" is concerned in the graphic below.

As of now, the thinking on the tropical weather system that is forecast to move into the Gulf is this. It will be a rainmaker. How much of a rainmaker remains to be seen, but it doesn't appear as though the system will produce flooding rains like some weaker tropical systems have done in the past.

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Residents of southeastern Louisiana can expect conditions to go downhill with an increased threat of heavy rain beginning tomorrow. That rain threat spreads westward toward Lafayette and Lake Charles on Thursday. And there is a good chance that the entire I-10 corridor in South Louisiana will experience tropical rains and downpours during the day on Friday.

Then we start to get back to our regular summertime pattern of heat, humidity, and afternoon pop-up thunderstorms. That should be the rule returning by later this weekend.