Deffi Putri:
Meteorological Causes and Atmospheric Conditions Associated with Extreme Precipitation Events in Southeast Michigan
Flooding is a hydrological phenomenon influenced by extreme precipitation generating storms with destructive impacts on various sectors, including infrastructure. The temporal and spatial features of storms are based on storm types. The objective of this study is to understand the meteorological causes of extreme precipitation by studying historical cases that exceed geographically varying thresholds, specifically percentile and number of extreme grid points, using the ECMWF Reanalysis v5 (ERA5) precipitation in Southeast Michigan. Analyzing data from 1991-2023, we found that extreme precipitation dominantly occurs during the warm season (June to September). Furthermore, we categorized identified cases based on meteorological phenomena, including Fronts (FRT), Extratropical Cyclones (ETC), Tropical Cyclones (TC), and Mesoscale Convective Systems (MCS). The HURDAT2 and CNECT Extratropical Cyclone project databases were used to detect TC and ETC. To identify FRT and MCS, we employed the Thermal Front Parameter and the Python FLEXible object TRacKeR (PyFLEXTRKR) objective identification methods. Our preliminary results indicate that the primary mechanisms responsible for extreme precipitation are FRTs, followed by ETCs, TCs, and MCSs. Storm types show differences in spatiotemporal distributions where FRT, ETC with FRT, and TC pose a higher risk of generating extreme conditions.
Zach Solecki:
Characteristics of Cold Air Outbreaks Effecting the Eastern United States
Cold air outbreaks (CAOs) continue to effect North America in a changing climate. We develop a gridpoint-based definition for CAOs in the Eastern United States using ERA5 reanalysis 2-meter temperature data. A CAO climatology is developed, and the circulation patterns associated with CAOs are investigated. A novel K-means approach allows for the categorization of these events based on characteristics relating to their evolution in space and time, as well as an analysis of the synoptic patterns involved in the resultant CAO composites. Parcel back-trajectories associated with these airmasses are calculated using the LAGRANTO analysis tool, and time series construction of meteorological variables along the parcel paths are used to explore airmass maintenance and evolution prior to CAO onset.