Probabilistic Storm Surge (P-Surge) Upgraded to Version 3.1

May 20, 2025

P-Surge simulation from September 10-12, 1992 during Hurricane Iniki

Probabilistic Storm Surge (P-Surge) Upgraded to Version 3.1

On May 20, 2025, NOAA NWS upgraded its operational Probabilistic storm Surge (P-Surge) model to version 3.1. P-Surge brings a probabilistic approach to the modeling of storm surge, and is run on a case-by-case basis in advance of hurricanes and tropical storms that may impact the Atlantic and Gulf coastlines of the contiguous U.S., Puerto Rico, the U.S. Virgin Islands, and now, with the most recent upgrade, the coastlines of Hawaii. This upgrade represents the first time that P-Surge will provide guidance for the coastlines of the Hawaiian Islands, and accounts for surge, tide, and waves.

Ian Morrison, Pacific Region Warning Coordination Meteorologist, sums up how valuable the addition of P-Surge for Hawaii is: “For the first time in NWS Honolulu history, we will be able to focus Emergency Managers on specific coastlines that are under imminent threat from storm surge.  The new P-Surge guidance will be a critical component to our ability to issue Storm Surge Watches and Warnings to that regard.”
 

Screenshot of P-Surge simulation from September 10-12, 1992 during Hurricane Iniki
Figure 1: P-Surge simulation from September 10-12, 1992 during Hurricane Iniki, showing the probabilistic guidance that would have been available to forecasters to aid with the Storm Surge Watch/Warning process.

 
An Animation of P-Surge output from Hawaii into the Nearshore Wave Prediction System
Figure 2: The incorporation of P-Surge output from Hawaii into the Nearshore Wave Prediction System has also been included, which has an impact on wave heights as shown in the far right animation.
 

In addition to the new Hawaii products and code optimizations, version 3.1 also includes a more efficient calculation of waves which reduces the processing time for Puerto Rico and the U.S. Virgin Islands.  Version 3.1 also discontinues the probability of > 0 feet above ground level products as they were of limited use due to the water being initialized around 1 foot.

This upgrade was made possible through a collaboration between the NOAA NWS Meteorological Development Laboratory Storm Surge Team, the National Hurricane Center Storm Surge Unit, and the Central Pacific Hurricane Center.

For more information on P-Surge V3.1, please see the corresponding Service Change Notice [PDF].