Saturday evening around 8 o'clock, rain began to pick up around the Sanibel area. Heavy rain continued for much of the night as repeated rounds of thunderstorms continued to train over Sanibel Island and into much of coastal Lee county.
Intense rainfall rates in the early morning of over 2 inches per hour overwhelmed drainage in Sanibel leading to street flooding and the flooding sensor in Saint James City showed 1 foot of inundation Sunday morning.
The rain amounts led to alerts from the City of Sanibel to drivers and a flash flood warning from the National Weather Service Sunday morning.
Due to the heavy rain experienced on Sanibel, temporary localized flooding has occurred over certain roadways and drivers are encouraged to use caution and avoid travelling over flooded roads. The National Weather Service has issued a Flash Flood Warning that will currently expire at 9:15 am today (Sunday).
Fortunately, rain slowed down in the late morning hours, but not after leaving some impressive rainfall totals. In just 13 hours, a sensor in Sanibel indicated almost a foot or rain, 11.62."
The majority of Sanibel island picked up over 6 inches of radar estimated rain and in St. James City, a sensor recorded 8.93" of total rain.
Predicting extreme rainfall events can be challenging for meteorologists. For rainfall to accumulate to such extremes, it requires an unusually stable flow of moisture to feed slow moving, training thunderstorms that continue to develop along the moisture stream.
Current models have difficulty reproducing the small scale features needed to accurately depict a localized heavy rain event like Sunday's deluge.
As computing power continues to improve, and weather models become more sophisticated, extreme rain events should be easier for the model to reproduce.
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