14 August 2016
Catastrophic Flood Event Underway In Louisiana
Posted by Dan Satterfield
Thousands of people have been rescued, and thousands of others are trapped by flood waters in Louisiana tonight, as over 20 inches of rain fell starting early Friday and through the weekend. I’m going to post various images/data to put some context into what/why this is happening. These floods are not yet over, and the threat is now increasing in parts of Missouri and Illinois, where up to 6 inches has fallen, and they may see another 6 inches or more in the next 36 hours. So look at the images, and I’ll note the significance in their captions.
The warm Gulf is not the only culprit here. Look at the water vapor Infrared window on the GOES satellite, The rain in the Eastern U.S. is not just from the Gulf of Mexico. Look at the plume (gray) of wet air in the upper troposphere coming from the Eastern Tropical Pacific. This may play a real factor in the flood threat in Missouri, Illinois, and nearby, tonight through Tuesday.
Another way of measuring how much water vapor is in the air is to add up the amount of water vapor in a column, from the ground to the top of the troposphere. This is called total precipitable water, and when I see values of over 50 mm (or two inches), alarm bells go off. The current analysis (from the latest high-resolution HRRR model) shows extreme moisture levels, and you can also detect that plume of Pacific moisture as well.
This is not good, and gives credibility to model guidance showing more heavy rains to move into Illinois and Missouri tonight and tomorrow. Latest guidance is indicating over 4-6 inches in some spots, and extreme rain events are not handled well by the numerical prediction models,so it could be more, and perhaps a lot more.
Scott Bachmeier (Much more satellite data at the link to the CIMMS twitter page) posted an mp4 movie from the GOES 14, showing the flood event in Louisiana. The GOES 14 spare satellite was in rapid scan mode, and this gives an image every minute.. The gray pixels are cloud tops so high that their temp. is below -70C!
Now, some images from the area, with rain totals from cocorahs gauges/NOAA:
The reason we say “Turn around, don’t drown!” is illustrated well in this video. More amazing images from Twitter below:
Bob Henson (at Weather Underground) has some good perspective on the Amite River flood and who will get hit next there. One last thing to remember: The heating of the planet has loaded the dice, and these kind of events are more likely to happen now. I do not think this one is over yet, and somewhere between Missouri and New York is about to get a lot of water…