Tropical System in the Gulf – How Much Rain for Louisiana?

(KMDL-FM) The National Hurricane Center is officially calling it a "trough of low pressure that is producing a broad area of disorganized showers and thunderstorms." Here, along Louisiana's Gulf Coast, we're calling it our next big rainmaker.

Rain is the most likely effect that coastal Louisiana and Texas will see over the next several days as this system slowly migrates westward along the northern rim of the Gulf.

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And while confidence is high that this system won't develop into something "tropical," we need to worry about it. There is a genuine concern about how much the system could bring to Louisiana between now and Sunday. That rainfall forecast will be very dependent on the actually track the weather system takes.

Where Will The Heaviest Rain Fall in Louisiana This Weekend?

The current thinking based on model guidance is that the heaviest rainfall will fall over the coastal waters and not on land. Rainfall estimates suggest that four to six inches of rain on the offshore platforms will be common between now and Sunday.

However, if the weather system's track shifts a little further to the north, that would mean some of the heavier rain would then fall over coastal Louisiana. The National Weather Service Forecast Office in Lake Charles defines those scenarios quite nicely in this graphic.

As you can see in the "worst case scenario," some parts of Acadiana could receive six to eight inches of rainfall. That would not be a good thing considering how much rain the area has received over the past month or so.

What Is The Risk of Flooding In Louisiana This Weekend?

Over time, the Weather Prediction Center suggests that South Louisiana could be at risk for excessive rainfall events. That's where it rains really hard in a short period of time, and municipal drainage systems can't drain the water away fast enough. It usually results in minor street flooding. But, depending on how much rain and how short the time, there could be serious flooding caused by such a scenario.

In the short term, rain chances along Louisiana's I-10 corridor will ramp up to 80% for this afternoon. Rain chances stay at 60% or more for much of tonight, and then they will increase again on Friday to 90%.

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There is a 60% chance of rain on Friday night, and Saturday's forecast is calling for an 80% chance of even more rain across the region. Rain chances will remain elevated Saturday night and Sunday as well.

Typical summer weather for South Louisiana, hot, humid, with a slight risk of afternoon showers, will return on Monday of next week.