Jun 3, 2019

Hurricane stalling along the North American coast and implications for rainfall

by
Timothy M. Hall, James P. Kossin
,
npj Climate and Atmospheric Science
  • States that the average speed of tropical cyclone (TC) translation has slowed since the mid 20th century
  • Reports that North Atlantic (NA) TCs have become increasingly likely to “stall” near the coast, spending many hours in confined regions
  • States that the stalling is driven not only by slower translation, but also by an increase in abrupt changes of direction
  • Computes residence-time distributions for TCs in confined coastal regions, and finds that the tails of these distributions have increased significantly
  • Shows that TCs stalling over a region result in more rain on the region
  • Finds that, together, increased stalling and increased rain during stalls imply increased coastal rainfall from TCs, other factors equal
  • Finds a significant positive trend in coastal annual-mean rainfall 1948–2017 from TCs that stall, and verifies that this is due to increased stalling frequency
  • Makes no attribution to anthropogenic climate forcing for the stalling or rainfall; the trends could be due to low frequency natural variability
  • Regardless of the cause, the significant increases in TC stalling frequency and high potential for associated increases in rainfall have very likely exacerbated TC hazards for coastal populations