Connecting Urban Areas and Flood Risk: Forecasting Hydrometeorological Conditions that can Fuel Flood Events Around the Dallas-Fort Worth Area and the Influence of the Local Urban Heat Island Effect

During the days of August 21st and 22nd, 2022, widespread river and flash flooding occurred in the North Central Texas region. The bouts of heavy rainfall that spurred this event were difficult to forecast, especially due to an uncertainty of the overall range of accumulation and the location of heaviest precipitation within the area. The overperformance of the rainfall event may have seen some influence from the Urban Heat Island effect given off by Dallas-Fort Worth, as well as the synoptic pattern. Although previous studies have analyzed Urban Heat Island (UHI)-based impacts on heavy rainfall and subsequent flooding conditions, few have focused on the region surrounding Dallas-Fort Worth (DFW). It is vital that forecasters draw the best predictions possible for such events, especially as flooding is the deadliest among severe weather events. However, disseminating life-saving predictions can sometimes prove difficult, as the above story illustrated.

In order to foster such forecasts with increased confidence and better understanding, this study aims to find the link between the meteorological and hydrological conditions as well as the influences held by the UHI that would be most conducive to flooding of the DFW area. The analysis will acquire data from a number of flood events which took place during the years of 2002-2022 within an approximately 100-mile radius encapsulating the DFW region. Some examples of data utilized in this study include radar reflectivity products, daily rainfall totals, as well as relative humidity. Each data type from the selected flooding cases will then be combined together to generate an ensemble. This ensemble will display the common traits from all the events to pinpoint a combination of conditions which increase the likelihood of flooding impacts to the area. Afterwards, the same steps will be taken to construct a similar ensemble to investigate the influence of the local UHI on the hydrometeorological conditions within the same region. Overall, further research is necessary to truly grasp the impacts of urban areas on the meteorology of surrounding regions.