Tropical Depression Isaac, although far away near Joplin, Missouri, reached out and touched portions of central Louisiana Friday morning with flooding rainfall.
As the remnants of Isaac moved away, strong inflow of rich moisture from the Gulf of Mexico became established all across Cenla. This created a narrow corridor called a confluence zone or a "feeder band," where upward motion in the atmosphere is enhanced. This causes thunderstorm development. Once established, these confluent zones move very slowly. As a result, thunderstorms move over the same locations repeatedly in a process termed "training." There is nearly no net motion and the rain accumulates quickly.
The highest totals came from Rapides Parish. Near River View Baptist Church on Highway 1 toward the Poland community, 9.40 inches fell. I measured 6.64 inches in the Tara Subdivision near Kolin. Esler Airport received 5.90 inches. As is customary, if a location is not in the feeder band, little or no rain falls. Hence, Bellwood and Cloutierville both reported no rain Friday.
Moisture from Isaac will linger in central Louisiana this weekend. Rain will be likely Saturday but nothing organized like Friday morning's event. However, because of the deep, rich moisture, any storm that develops will be very efficient at producing rain. Thus, a few rainfall totals may exceed two inches Saturday. Scattered showers and thunderstorms will also occur Sunday, but your chance of getting wet is not as high as it is Saturday.
Have a good weekend!