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Nearshore Wave Prediction System

The Nearshore Wave Prediction System (NWPS) is currently being developed at NCEP's Environmental Modeling Center (EMC) and a number of participating Weather Forecast Offices (WFOs), in particular WFO Miami, WFO Eureka and Southern Region HQ. NWPS is designed to provide on-demand, high-resolution nearshore wave model guidance to all US coastal WFOs, triggered in real time by forecast wind grids prepared and submitted by the individual offices. The system was implemented on NCEP's operational supercomputer for NWS's Southern and Eastern Regions in February 2016, with the remaining US regions following in September 2016.

NWPS system structure

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NWPS is driven by forecaster-developed wind grids produced in AWIPS 2, and offshore wave boundary conditions from the operational WAVEWATCH III model. The nested nearshore wave model used is SWAN. Wave-current interaction is included using surface current fields from the Real-Time Ocean Forecast System (RTOFS-Global). The influence of tides and storm surge is accounted for by using output from the Extratropical Surge and Tide Operational Forecast System (ESTOFS, extratropical conditions), or the probabilistic model P-SURGE (tropical conditions). The computational grids have a nominal resolution of 1.8 km, with further nesting down to 500 m or less in high-impact areas. NWPS produces fields of integral wave parameters, wave spectra and individually tracked wave systems (Gerling-Hanson plots). These, together with real-time and 30-day retrospective validation graphics can be viewed in the model validation interface below.

Access the NWPS Model Validation Viewer
NWPS interactive interface

Monthly Validation

Below are the combined monthly validation statistics at all coastal data buoys in the NWS Southern and Eastern Regions respectively, computed as a 30-day, moving-window retrospective. For real-time validation, as well as buoy-specific validation statistics, please see the model validation viewer above.

SR NDBC buoy validation
Southern Region Validation Statistics
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key west example forecast
Eastern Region Validation Statistics
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SR NDBC buoy validation
Southern Region Statistics History
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key west example forecast
Eastern Region Statistics History
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Follow Us

Sign up for the NWPS mailing list for updates and information on this system.

Follow the system development on our Wiki Page (authorization required).


Van der Westhuysen, A. J., R. Padilla-Hernandez, P. Santos, A. Gibbs, D. Gaer, T. Nicolini, S. Tjaden, E. M. Devaliere and H. L. Tolman. Development and validation of the Nearshore Wave Prediction System. Proc. 93rd AMS Annual Meeting, Am. Meteor. Soc., Austin, 2013. Available here

Gibbs, A., P. Santos, A. J. van der Westhuysen and R. Padilla-Hernandez. NWS Southern Region Numerical Optimization and Sensitivity Evaluation in Non-Stationary SWAN Simulations. Proc. 92nd AMS Annual Meeting, Am. Meteor. Soc., New Orleans, 2012. Available here

Settelmaier, J. B., A. Gibbs, P. Santos, T. Freeman, D. Gaer. Simulating Waves Nearshore (SWAN) Modeling Efforts at the National Weather Service (NWS) Southern Region (SR) Coastal Weather Forecast Offices (WFOs). Proc. 91st AMS Annual Meeting, Am. Meteor. Soc., Seattle, 2011. Available here

Upcoming features

Unstructured mesh implementation

SWAN and WW3's unstructured grid functionality is currently being incorporated into NWPS. With flexible unstructured grids, computational time can be optimized by concentrating computational grid points only in those nearshore regions where it is required to adequately resolve physical processes at small spatial scales. This is demonstrated below for WFO Key West:

key west mesh
Unstructured mesh over WFO Key West domain.
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key west example forecast
Forecast guidance produced using NWPS (with SWAN wave model).
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key west mesh zoom
Zoom of unstructured mesh over Key West.
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key west example forecast zoom
Forecast guidance over zoomed-in domain.
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Inclusion of time-dependent P-Surge water levels during hurricane events

Tropical cyclone events are characterized by a high uncertainty in the atmospheric forcing. As a result, a probabilistic approach is followed by NWS's National Hurricane Center (NHC) to produce cyclone-related coastal surge forecasts during tropical cyclone events using the P-Surge system, based on the highly-efficient Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model. One type of output from P-Surge is the composite surge level fields associated with a given exceedance level (e.g. 10-50%). Since these exceedance fields represent a single water level surface, they can be applied in a single deterministic NWPS run at a given exceedance level. Since the P-Surge fields include inundation of overland regions, it enables the computation of overland waves in flooded areas in NWPS, as shown below for WFO New Orleans during Hurricane Isaac (2012).

water depth
Total water depth from P-Surge surge levels (20% exceeedance) and ESTOFS tides.
Click to animate
surge forecast
Forecast guidance produced using NWPS (SWAN).
Click to animate

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Page last modified: Friday, 18-Mar-2016 21:25:32 UTC