Identification of Intraurban Summer Precipitation Hotspots

Heavy rainfall events in cities can affect a variety of socioeconomic activities. Urban climate
literature has shown hydrometeorological phenomena, specifically summer season convection,
can be influenced and/or initiated by altered surface budgets and surface roughness in and near
cities. There are also several documented focal points of enhanced precipitation such as the La
Porte (downwind Chicago, Illinois) and Norcross (Atlanta, Georgia) anomalies. Systematic
quantification of intraurban heavy precipitation intensity is necessary to determine the true
nature of precipitation hotspots in specific locales.
This study uses daily, 6-hour, 4-km NCEP Stage IV Multisensor Precipitation Estimates dataset
over 20 years (2002 to 2022) to determine precisely how precipitation varies across three cities
in the southern United States (Atlanta, Georgia, Houston, Texas, and Raleigh, North Carolina).
By assessing daily summer precipitation with respect to sectors surrounding each city’s urban
core, representations of convective precipitation and its internal (by sector) and intraurban
(across each urban area) variabilities are derived. The background synoptic conditions
corresponding to levels of precipitation intensity variation provide practical information for
forecasters and decision-makers.