A Climatology of the Extratropical Flow Response to Recurving Atlantic Tropical Cyclones

Previous case studies have noted a significant extratropical flow response to recurving Atlantic tropical cyclones (TCs), which is often linked to extreme weather events downstream. This study examines the modification of Rossby waves on the extratropical jet in response to recurving Atlantic TCs fr...

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Bibliographic Details
Published in:Monthly weather review 2020-02, Vol.148 (2), p.541-558
Main Authors: Brannan, Allison Lynn, Chagnon, Jeffrey M.
Format: Article
Language:English
Subjects:
Amplitude
Amplitudes
Case studies
Climate
Climate change
Climatology
Cyclones
Extreme weather
Flow alteration
Hurricanes
Morlet wavelet
Planetary waves
Potential vorticity
Propagation
Rossby waves
Tropical climate
Tropical cyclones
Vorticity
Wave power
Weather
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Summary:Previous case studies have noted a significant extratropical flow response to recurving Atlantic tropical cyclones (TCs), which is often linked to extreme weather events downstream. This study examines the modification of Rossby waves on the extratropical jet in response to recurving Atlantic TCs from a climatological perspective. Changes in amplitude and location of Rossby waves are identified using a wavelet decomposition technique on isentropic potential vorticity. The climatology demonstrates that recurving Atlantic TC events are capable of modifying the amplitude of the extratropical flow. Though the majority of TCs did not produce a significant, systematic modification of the extratropical flow amplitude, a subset of events were associated with a period of significant Rossby wave deamplification occurring from the time of recurvature to 48 h after recurvature, followed by a return of the Rossby wave power beginning around 96 h after recurvature. The characteristics of the TCs were not significantly associated with the resulting extratropical flow modification—a result consistent with previous western North Pacific climatologies. The nature of the extratropical flow response is most strongly tied to the average translation speed of the TC relative to the Rossby wave over the 72 h following recurvature. This study highlights the importance of investigating the extratropical flow response to recurving Atlantic TCs with regards to predictability.
ISSN:0027-0644
1520-0493
DOI:10.1175/MWR-D-19-0216.1