Thoughts on the Use of Probabilistic and Deterministic Weather Data for Incident Command Support and Decision Support Services

The heavy rainfall/flooding events during May 2015 generated historic flash flooding and river flooding across the Southern Plains into Texas. In total, several large impact events followed a rapid succession from May 2015 into late June 2015 that created significant activations of the Incident Command Support (ICS) and Decision Support Services (DSS) of the National Weather Service. This presentation will focus on the use of probabilistic and deterministic forecast data, specifically in context of decision making for strategic and tactical DSS. A brief outline of events will be presented for reference along with a variety of operational levels ranging from local decision makers to regional and national coordination. Next, a brief overview of some basic ICS tenets will be reviewed and compared with the NWS best practices for delivering a unified weather message at each operational level. Finally, some best practices for using probabilistic and deterministic forecast data for operational decision making will be discussed. Some of the practices include: ● Establishing a high trust working relationship with partners for operations in critical events ● Using “worst case” scenario briefings appropriately ● Balancing the “worst case” with the “most likely” forecast event outcome ● When to forecast a record event with confidence ● Coordinating weather intel with hydrologic intel ● Returning to normal operations…and what can cause a resurgence of hazards/impacts