Welcome to the repository for the Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model.

Please note, if you make a copy of this repository, the following files are required for defining the Intellectual Property (IP) protection:

1. INTENT.md describing the intent of the IP protection.
2. LICENSE.md providing the Apache 2.0 licensing information.
3. NOTICE.md providing required copyright attribution.

ABOUT SLOSH

The SLOSH model Jelesnianski, et al is a numerical model developed by the National Weather Service (NWS) to estimate storm surge heights resulting from historical, hypothetical, or predicted hurricanes.

It is a “diagnostic” hydrodynamic model, meaning it does not forecast a storm’s evolution. Instead, it relies on a set of driving forces provided by a wind and pressure model (including the storm’s location, central pressure, size, and forward speed) to compute the resulting water level responses. SLOSH solves the Navier-Stokes equations of motion across a finite-difference grid mesh (polar, elliptical, or hyperbolic) to simulate how water reacts to wind stress and pressure gradients, accounting for coastal features, barriers (e.g., levees and roads), and sub-grid hydraulic structures.

SLOSH is the foundational model used by the National Hurricane Center (NHC) to generate storm surge guidance and evacuation planning products, such as Maximum Envelopes of Water (MEOWs) and Maximum of the MEOWs (MOMs).

For a deeper dive into the model’s core physics, grid architecture, tidal coupling, and operational forecast products, please see the About SLOSH page.

ABOUT THIS REPOSITORY

This repository contains the source code to build and run the SLOSH model, along with a suite of utility programs, a Graphical User Interface (GUI), and regression testing assets.

It is designed to help researchers, students, and developers compile the SLOSH model on both MS-Windows (via MSYS) and Linux environments.

Included Utilities

• stm2trk: Converts a 6-hourly storm parameter file (stm-file) into a 1-hourly track file (trk-file) used by the parametric wind model.
• rexout: Extracts and converts data from SLOSH rex-files (time-series snapshots of wind and water heights at specific grid cells).
• envutil: Extracts and converts data from SLOSH env-files (maximum water heights attained at each grid cell during a run).

DOCUMENTATION & GUIDES

To get started with building, running, and understanding the model, please refer to the following documentation:

1. About SLOSH: A detailed overview of the model’s physics, meteorological driving forces, tidal coupling, and operational products.
2. Set up MSYS: A pre-requisite guide for Windows users detailing how to install, update, and configure the MSYS environment needed to compile SLOSH.
3. Installation Guide: Step-by-step instructions for downloading the required assets, building the SLOSH model using gcc, running regression tests, and testing the SLOSH-GUI.
4. stm-file Specification: Detailed documentation on how to format, run, and interact with 6-hourly stm-file storm inputs.

DISCLAIMER

“As Is” Software: The code, visualization tools, and regression storm inputs provided in this repository are for educational and development purposes and are provided “as is” without warranties of any kind.

No Technical Support: Due to limited resources, NOAA/NWS will not provide technical support, troubleshooting, or training for this software unless a separate formal agreement is in place.

Not Official Guidance: The storm inputs provided as part of the regression tests are not official SLOSH inputs of record, nor have their results been calibrated against observations. Generating an official SLOSH forecast requires an expert human-in-the-loop to adjust inputs to better match observations.

For official storm surge forecasts and warnings, always rely on the National Hurricane Center (NHC) and your local NWS forecast office.