Heavy storms barged back into southeast Louisiana Monday evening, and forecasters have slapped an Impact Day label on it as the threat of flash flooding ramps up from the North Shore into Baton Rouge and along the I-10 corridor. Radar showed the most intense cells clustered near Interstate 55 around Kentwood, while spotters reported torrential downpours of 2 to 4 inches per hour near Donaldsonville. Several North Shore waterways were already at or above minor flood stage, and the Tangipahoa River had pushed into moderate flood stage and was being monitored to crest on Tuesday near 19.5 feet.
According to WDSU, the station designated Monday as a WDSU First Warning Weather Impact Day after many communities picked up 2 to 5 inches of rain over the past five days, with isolated totals closer to 7 to 10 inches near Baton Rouge. WDSU meteorologists said another 1 to 2 inches is likely for many locations Monday night, with locally higher amounts where storms repeatedly track over the same neighborhoods.
Weather Prediction Center ups the odds
The National Weather Service's Weather Prediction Center placed stretches of the I-10 corridor under a Slight, level 2 of 4, excessive rainfall risk, citing solid model agreement on a training band that could deliver 2 to 4 inches along the main axis, along with intense hourly rates. That outlook heightens the risk for urban and roadway flooding in areas where drainage is already strained, according to the Weather Prediction Center. Forecasters highlighted neighborhood-scale probabilities for rainfall totals topping 2 inches within the shaded corridor.
Rivers to watch
As reported by WDSU, the Tchefuncte and Pearl rivers on the North Shore had reached minor flood stage, while the Tangipahoa River was sitting at moderate flood stage and forecast to crest near 19.5 feet on Tuesday. Those river levels, paired with short-lived but intense bursts of rain, raise the odds of nuisance street flooding and could prompt isolated closures on low-lying roads.
What residents should do
The National Weather Service New Orleans/Baton Rouge office is urging residents to stay plugged into the latest forecasts and to have multiple ways to receive warnings. Their guidance is blunt: do not drive through flooded roadways, and do not drive around barricades. Local forecasts and river-gauge pages remain the best source for pinpoint timing of crests and specific road impacts, so officials recommend checking updated products before heading out, according to the National Weather Service New Orleans/Baton Rouge.
Timing and outlook
Forecast guidance shows the highest flash flood threat arriving Monday evening and persisting into the early overnight hours. After that, a drying trend is expected to begin Tuesday, with rain chances slipping through midweek. The Weather Prediction Center's extended discussion points to a frontal passage that should pull in drier air and reduce the flash flood risk for most locations later in the week, although a few spotty showers may still pop up.
