When Hurricanes Fall Apart: Diagnosing the Rapid Weakening of Tropical Cyclones

Kimberly Wood, Assistant Professor, Department of Geosciences, Mississippi State University

Abstract for Weekly Colloquium on Thursday, March 22, 2018 at 4 pm in Harvill 318

Rapid intensity changes of tropical cyclones (TCs) are known to negatively impact intensity forecasts, and an ever-growing body of research on these rapid changes has driven improvements in the 24-h time frame. Due to the risk posed by intense hurricanes to coastal populations, most of the focus has been on rapid intensification events, at least a 30-kt increase in 1-minute sustained maximum winds in 24 hours. 

However, even the most intense TCs eventually fall apart. Rapid weakening (RW; a 30-kt decrease in 24 hours) over open ocean also contributes to forecast error, and these events can occur near land. This presentation will describe the environmental conditions that generally lead to RW in the eastern North Pacific (ENP) and the North Atlantic, including spatial distribution of moisture and sea surface temperature gradients. RW is much more common in the ENP than the North Atlantic, and in the ENP, RW events often follow periods of rapid intensification. Finally, this presentation will explore the use of GOES ABI data in monitoring RW now that GOES-16 is operational as GOES-East and ahead of GOES-17 becoming the new GOES-West satellite.