Noah Brauer - April 15

Weather and Climate Seminar

The Inland Maintenance and Re-intensification of Tropical Storm Bill: Tropical Precipitation Microphysics

Noah Brauer

Wednesday, April 15^th

3:00pm Central Time (US and Canada)/Zoom Meeting

Join Zoom Meeting
https://oklahoma.zoom.us/j/505651584

Meeting ID: 505 651 584

Zoom Password: 996546

Tropical Storm Bill produced over 400 mm of rainfall to portions of southern Oklahoma from 16-20 June 2015 which resulted in catastrophic urban and river flooding. Prior to this event, unprecedented excessive precipitation that occurred across Oklahoma and Texas during May and June 2015 resulted in anomalously high soil moisture and latent heat fluxes over the region, acting to increase the available boundary layer moisture. Tropical Storm Bill progressed inland displaying polarimetric radar signatures associated with tropical, warm rain events. Vertical profiles of polarimetric radar variables such as Z_H, Z_DR, K_DP, and r_hv were analyzed along the track of the storm over Texas, southern Oklahoma, Missouri, and southern Illinois. The profiles suggest that Tropical Storm Bill maintained warm rain features and specifically collision-coalescence process signatures in the liquid phase as it tracked hundreds of kilometers inland away from the landfall point. Ground-based radar data were complemented with spaceborne radar observations with vertical profiles of Ku-band reflectivity, mass-weighted mean drop diameter, and drop number concentration from the NASA Global Precipitation Measurement Mission (GPM) Dual Frequency Precipitation Radar (DPR). These high-resolution profiles were analyzed during the periods of tropical cyclone maintenance and reintensification and showed similar signatures of collision-coalescence and/or drop breakup while Bill moved progressed inland.