Rapidly Warming Gulf of Mexico Contributes to Louisiana Storms/Flooding

NOAA Long-lead Forecasts Through The Warm Season
04/15/2021, 9:34 am EDT
Another Rapidly Intensifying Tropical Cyclone That Passed Very Warm Ocean Water
04/19/2021, 2:29 pm EDT
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Discussion: Severe flooding continues to occur across rain-soaked Louisiana. River flooding will expand across most of Louisiana and southern Mississippi today (Fig. 1). Another day of excessive rainfall and severe weather already underway will intensify drifting eastward across Louisiana into southern Mississippi and coastal Alabama today (Fig. 2). So far in April Baton Rouge has received 8.04 in. of rain (2.31 in. is normal) while New Orleans has observed a whopping 11.19 in. of rain (2.26 in. is normal). Each location receives another 1-2 in. of rain today. The catalyst to the flooding rainfall and frequent severe weather events which also created havoc with offshore operations is the sudden warming of the Gulf of Mexico (Fig. 3) increasing considerably the amount of low atmospheric moisture for upper troughs/cold fronts to work with to generate excessive rainfall.

Fig. 1-2: NOAA 5-day river flood forecast and today’s excessive rainfall/flash flood risk area outlook.

Fig. 3: Rapid warm-up of the Gulf of Mexico a catalyst to the Louisiana flooding.