Friday, September 20, 2013

Flash Flood Watch This Weekend

By Jay Grymes & Steve Caparotta

A FLASH FLOOD WATCH is in effect for the entire WAFB viewing area through Sunday evening.

Our wet Friday evening outlook already prompted downtown officials to cancel this evening’s “Live After Five” ... and for the third Friday in a row, at least a few high school games will be dealing with rains and storms this evening.

Although today’s rains and thunderstorms should ease-up later this evening, we’re keeping scattered rains in the WAFB regional forecast tonight with a forecast for a very wet Saturday morning. 

And the rest of Saturday is shaping up to be just plain wet too. 

We’ve got on-and-off rains throughout the day on Saturday with locally-heavy downpours likely, making for standing water and nuisance flooding across the viewing area. As it looks now, 2” to 4” rain totals could be commonplace through Saturday evening for the greater Baton Rouge area. Baton Rouge could then see up to another 1” of rain from Sunday into Monday. And for some areas -- especially closer to the coast -- event totals through Monday could be upwards of something closer to 6” or more!

As for Saturday festivities, we aren’t too concerned about a severe weather outbreak on Saturday but tailgating could be a real mess given the expected rains. And while we think scattered rains will continue into the evening, hopefully the lightning threat will decrease as the LSU-Auburn kick-off (at 6:45PM) approaches and that the game can start without any lightning delays.

Another change to our outlook calls for unsettled weather to extend into the early part of next week. We had hoped that the cool front that will prompt Saturday’s deluges would push out into the northern Gulf, but the latest guidance not only keeps a stalled front draped along our coastline through Tuesday but also hints that a non-tropical low could develop along the stalled front. (Somewhat interestingly, that surface low might be a part of the remnant energy from Invest 95L that we tracked for much of the past week.)

So, sadly, instead of three good looking days to start off next week, were’ keeping scattered rains in the forecast through Tuesday, at least.

Flood threats? As it turns out, our run of unusually dry weather over the past several weeks will work in our favor. Most area rivers and major bayous are running at “base flow” levels, in other words, they are at the lowest end of normal flow, and the environment is ready for a good soaking. So yes, there will be the nuisance street flooding and back-ups that we normally expect after a big rain event, but we don’t expect this to be a news-making flood event.

In the tropics ... Invest 95L just never got its act together, not that anyone is complaining. The National Hurricane Center still shows the poorly-defined disturbance just off the coast of Mexico, with most models allowing it to meander over the western Gulf over the next few days. As just mentioned, whatever is left of 95L could end up tying-in with our stalled front early next week.

Stay dry! And Geaux Tigers and Jaguars!

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