Storm watch helps safe management

Forecasts of wind and wave conditions are vital for effective and safe management of near- and offshore operations. MetOcean Solutions has developed a warning system based on ensemble forecasting, which allows us to provide warning of upcoming severe wind and wave conditions for up to 7-day horizons, thereby helping operators plan for safe and efficient management.

Accurate high-resolution forecasts of wave conditions at local scales can be done using nested or grid-refining models such as SWAN (Simulating WAves Nearshore). Such forecasts capture local wave transformation and dissipation, and can be done at a reasonable computational cost. However, at horizons beyond 2-3 days a forecast inevitably suffers from the onset of chaotic uncertainty that is a physical characteristic of the atmosphere-ocean system. 

Ensemble forecasting is a method that quantifies this uncertainty in longer-range forecasts, providing probabilistic guidance for management decisions. MetOcean Solutions can customise a forecast warning system for any offshore or nearshore location based on the 7-day forecast wind speed, significant wave height (Hs) and maximum individual wave height (Hmax). The method used to estimate extreme Hmax accounts for the long-term uncertainty of the severity of the environment and the short-term uncertainty of the severity of the maximum wave of a given sea state, complying with the International Organization for Standardization (ISO standards).

Example of Storm Watch programme. T indicates present time.

Example of Storm Watch programme. T indicates present time.

We use such ensemble forecasts to provide the best possible site-specific warning to clients of upcoming severe conditions, using pre-set thresholds to define the level of alert. 

Up to 60 wind and wave ensemble forecasts can be used to support a storm watch programme.  

An example of email alert is illustrated below. All components of the email can be customised upon request.
 

Example of Storm Watch alert email. 

Example of Storm Watch alert email. 

Storm watch guidance. Orange shading indicates when the alerting thresholds are exceeded. Wsp: windspeed. Hmax: maximum wave height. Hs: significant wave height. 90 PCTL: 90th percentile. 

Storm watch guidance. Orange shading indicates when the alerting thresholds are exceeded. Wsp: windspeed. Hmax: maximum wave height. Hs: significant wave height. 90 PCTL: 90th percentile. 

Wave height warnings. Red shaded area represents the incoming wave direction for which thresholds are exceeded.

Wave height warnings. Red shaded area represents the incoming wave direction for which thresholds are exceeded.

MetOcean Solutions can set up a storm watch programme for any location. For more information, or to discuss your site, contact us at enquiries@metocean.co.nz.