DISCUSSION: In light of the recent land-based progress of Tropical Storm Harvey after its first official United States (U.S.) landfall in southeast Texas, it is worthwhile to try to diagnose a possible reason for why this tropical cyclone remained at tropical storm intensity since its initial point of landfall. More than 72 hours after its first U.S. landfall, this tropical cyclone has remained at tropical storm intensity which has beat out several previous all-time records along with the most tropical cyclone event rainfall total in Texas state as well as United States weather history. More details on the theory behind the "Brown Ocean Effect" and how this effect may have influenced the longevity of Tropical Storm Harvey is attached below.
"Tropical cyclones are fueled by warm ocean water and typically peter out over land. Sometimes, however, their lives are extended by something called the “brown ocean effect”.
This is a phenomenon where a storm derives energy from the evaporation of abundant soil moisture deposited by previous rainfall. Essentially, the saturated soil mimics the role of the ocean allowing a tropical cyclone to maintain its strength or even intensify after making landfall.
For the brown ocean effect to occur, according to a NASA funded study by Theresa Andersen and Marshall Shepherd of the University of Georgia, three criteria need to be met:
Storms that are impacted by the brown ocean effect maintain a warm-core and are known as Inland Tropical Cyclone Maintenance and Intensification events (TCMIs). While rare, they are most common in the US, China, and Australia."
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©2017 Meteorologist Jordan Rabinowitz