The Weather Prediction Center is concerned about flash Flooding today across the western counties of southern Mississippi and the parishes of southeastern Louisiana. The purple outlined area below is the areas of highest concern.
Rain will again drift northward across the area in places that have already seen localized flooding during the last 24-48 hours. More widespread flooding is becoming a concern as rainfall rates may approach up to 3″ per hour in some of the heaviest storms. And training storms may also be possible, leaving some spots with the potential for up to 6″ to 9″ of rain by the time it is all said and done today.
Model gudiance is struggling to resolve the specifics of ‘what areas see the most rain’ but know that today may feature some pretty heavy rain (again) with the potential for more street flooding, creek/stream flooding, and longer lasting flooding in yards.
Currently river flooding is less of a concern, but will need to be monitored.
Here is the latest technical discussion from the WPC:
Pulse to loosely organized convection will maintain itself through the afternoon, enhanced by a weakness in the upper level ridge and within an axis of anomalously high precipitable water. The latest blended TPW product shows values between 2-2.5″, which is between 1-2 standard deviations above normal or near the 90th percentile. Radar imagery this morning already shows slow moving and back-building thunderstorms over south-central Louisiana and this is expected to continue over the next several hours with a gradual increase in coverage through the outlook area as convective temperatures are reached. The available instability and higher PWs will support localized 2-3″ hourly totals (supported by 12Z HREF probabiltiies) and some of the hi-res guidance shows potential for isolated 3-6″ totals through mid/late afternoon.
Parts of the outlook area have seen above normal precipitation and recent heavy rainfall. The latest NASA SPoRT soil moisture saturation product shows 90+ percent saturation in the top 40 cm layer and AHPS 14 day departures are 200-300 percent locally. As a result, the combination of intense rain rates and potential localized higher amounts over more sensitive soil conditions will continue flash flood threat into the afternoon.
