Systematic Precipitation Changes Following a Strong Hurricane Landfall

Authors: Paul Miller*, University of Georgia, Thomas Mote, University of Georgia, Abhishek Kumar, University of Georgia, Deepak Mishra, University of Georgia, Flavia Dias de Souza Moraes, University of Georgia
Topics: Climatology and Meteorology, Earth Science, Marine and Coastal Resources
Keywords: Hurricanes, land-atmosphere interactions, hydroclimate
Session Type: Poster
Day: 4/4/2019
Start / End Time: 8:00 AM / 9:40 AM
Room: Lincoln 2, Marriott, Exhibition Level
Presentation File: No File Uploaded

The 2017 and 2018 Atlantic hurricane seasons were a poignant reminder of the dangers posed by powerful tropical cyclones to residents of the U.S., Central American, and Caribbean coastlines. This study (1) investigated hydrometeorological consequences of Hurricane Maria's mass defoliation in Puerto Rico, and (2) assessed the transferability of these patterns to coastal Georgia using the Weather Research and Forecasting (WRF) model. During the defoliated period in Puerto Rico, the atmosphere’s thermodynamic structure more strongly explained daily cloud activity (R2PRE = 0.02; R2POST = 0.40) and precipitation (R2PRE = 0.19; R2POST = 0.33) than before landfall, indicating that post-Maria land-atmosphere interactions were comparatively muted. Further, similar precipitation patterns were also found following Hurricanes Hugo (1989) and Georges (1998). When adapted to the Georgia coastline in a numerical weather simulation, Maria-scale defoliation reduced precipitation by 15.3% within 25 km of the hypothetical landfall location with a maximum deficit of 20.0% four weeks after the hypothetical landfall. However, precipitation totals were unchanged on the domain scale. Based on the near-surface temperature, humidity, and wind fields, defoliation is hypothesized to enhance 10-m wind speeds upwind of the hypothetical path and retard them downwind by introducing a thermally driven pressure gradient force near the hurricane path. Meanwhile, the sea-breeze front is strengthened as onshore flow is directed more orthogonally and more strongly toward the coast. The near-landfall drying was also evident in three less-severe defoliation simulations.

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