Tyler Green - November 6

Name:     Tyler Green Title:    Impact of Assimilating WSR-88D Radar Observations for the Analysis and Prediction of the Eyewall Replacement Cycle for Hurricane Matthew (2016) using the HWRF hybrid EnVar System Location:  https://meet.google.com/ksh-txvg-kni Date:     2020/11/06 Time:     03:00 PM Series:   Convective Meteorology (Mesoscale Dynamics) Abstract: As hurricane Matthew paralleled the east coast of

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November 6, 2020 - 3:00 pm

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November 6, 2020 - 4:00 pm

Name:     Tyler Green

Title:    Impact of Assimilating WSR-88D Radar Observations for the Analysis and Prediction of the Eyewall Replacement Cycle for Hurricane Matthew (2016) using the HWRF hybrid EnVar System

Location:  https://meet.google.com/ksh-txvg-kni

Date:     2020/11/06

Time:     03:00 PM

Series:   Convective Meteorology (Mesoscale Dynamics)

Abstract: As hurricane Matthew paralleled the east coast of Florida on October 6th-7th, its inner core was continuously sampled by ground-based radar starting at 15Z on the 6th, and by TDR for a shorter period from 19Z to 02Z as it completed an eyewall replacement cycle (ERC).  In this study, WSR-88D radar observations are assimilated into the Hurricane Weather Research and Forecasting (HWRF) model using a rapidly updating Ensemble-Variational system (EnVar) data assimilation system. The primary objectives of this study are to determine if and how assimilating ground-based radar observations can increase the predictability of Matthew’s ERC.

Four different experiments consisting of 12 hours of continuous hourly data assimilation cycling are performed.  Varied types of inner core observations are assimilated to explore added benefits of assimilating ground-based radar observations on top of assimilating the airborne Tail Doppler radar observations.  It was found that additionally assimilating ground-based radar observations can correct an initially weaker storm more quickly than experiments without them. In addition, assimilation of ground-based radar observations improves the analyzed structure and ERC for Matthew.   The predictability of Matthew’s ERC in the free forecasts are investigated using Hovmöler diagrams of azimuthally averaged tangential wind. The results suggest that assimilation of ground-based radar observations aid in the prediction of this ERC process which is known to affect the structure and intensity of TC’s and has been notoriously difficult to forecast.

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