Overhaul of MDL's Extra-Tropical Storm Surge Post-Processing and Web Dissemination

The National Weather Service's Meteorological Development Lab (MDL), in furtherance of its mission to help protect life and property from disastrous storms, developed an Extra-Tropical Storm Surge post-processing methodology and website (http://www.nws.noaa.gov/mdl/etsurge) in the late 1990's to provide forecasters, emergency managers, and the general public total water level guidance for extra-tropical storms. Both the post-processing methodology and website have recently undergone an overhaul to improve communication and interpretation of storm surge and total water level guidance. Information displayed on the website is now prepared on the National Center for Environmental Prediction's (NCEP) operational system. Water level observations are retrieved from NCEP's collection of Binary Universal Format for the Representation of meteorological data (BUFR) files. The Degrib utility is used to access gridded surge output, allowing greater flexibility in adding water level observation stations. Calculation of primary and subordinate tides is completed using harmonic constituents from the Center of Operational Oceanographic Products and Services (COOPS). Data are then combined to calculate anomalies and predict total water level guidance. Post-processing extra-tropical surge data on NCEP's operational system means the process is more robust, results are immediately available on operational machines (allowing for direct communication with river forecast offices), and computations are completed quickly using NCEP's load sharing facility (LSF) system.

Open source tools (JQuery, D3, Google Maps, and COOPS's API along with Beautiful Soup), which allow for interactive plotting, clear visualization, and real-time mapping of flood status and water level observations, were used to build the new website front end. Users can readily navigate stations, view maps of gridded results and multiple model outputs, and have access to better utilities for interacting with current and historic data.

A lesson learned during the post-processing overhaul, was that raw storm surge and total water level data, only available to the public in printed text or gridded binary format, were difficult to interpret. Offices like COOPS make data publically available in standard, downloadable formats through an application programming interface (API). Using that and similar tools, as well as the White House's Open Data Initiative for guidance, the new website seeks to provide improved access to extra-tropical storm surge and total water level data along with relevant tools and documentation.