A Hydrologic Climatology for Hazard Simplification

From wildfires and drought to outbreaks of severe storms and flooding, Oklahoma is prone to a wide range of natural hazards. Communicating risks posed by these phenomena via a system of watches, warnings and advisories is often a challenge for meteorologists at the National Weather Service’s Weather Forecast Office in Norman, Oklahoma (WFO Norman). The spring of 2015 brought record rainfall and widespread flooding to Oklahoma. During this extended rain and flood episode, the complexity and ambiguity of headlines issued by WFO’s to address various modes of flooding was highly evident. Following this high-impact flood season, improvement of hydrologic-related services became a priority at WFO Norman. This helped WFO Norman recognize the need to establish a hydrologic climatology which will serve to establish a historical database for flash flood and flood reports, rainfall, and rainfall rates using NOAA’s Storm Events Database and the Oklahoma Mesonet. Based on these analyses, WFO Norman forecasters will have a better understanding of hydrologic events that will aid in more informed and simplified warning decisions. This climatology will incorporate an analysis of case studies, such as 6-8 May 2015, in order to accentuate the overly complex hydrologic headlines issued during these particular events. Comparisons between the present-day practices and hydrologic hazard simplification proposals will be included. These proposals are based upon “Flash Flood Services for the Future: Flash Flood Summit and Focus Group Findings” which was drafted by the 2014/2015 Flash Flood Summit and Focus Groups in addition to findings from WFO Norman’s May/June 2015 After Action Review. Results of this work will help WFO Norman, and other offices, implement simplified hazardous weather headlines in its hydrologic warning services and recognize the importance of having a hydrologic climatology for each WFO’s county warning area (CWA). This will aid in community preparedness as part of the ongoing Weather-Ready Nation and StormReady initiatives.