These are theoretical values. Actual sea size and period can vary.
Blue cells are what is 'typically' experienced in a storm. The others are provided for informational purposes.

Instructions
If you want to try an alternative to using the wave models (a good idea) to estimate sea heights where the seas are still under the influence of a storms winds, use this table. Often the wave models have difficulty detecting and resolving seas in tight gradient/small fetch areas. This is particularly true in extratropical systems. Though NOAA produces a hurricane wave model product for the Southeast and Southwest US coasts, the rest of the globe remains unscanned.

To estimate significant sea height (highest 1/3 of all waves) and period within a storm, first obtain QuikSCAT imagery to confirm wind speeds and wind duration within a storm. (QuikSCAT imagery can be obtained from links provided off our maproom page under "Current Weather".) Capture this data for the life of the storm, or during it's peak. Then select the best combination of wind speed and wind duration (from the outer edges of the table) and navigate inward to the cell located at the intersection of those values. If the actual fetch area is less than the what is indicated in that cell, proceed one cell to the left (along the same row) until the actual fetch area best matches that found in a cell. Interpolate between cells as necessary.

Cells indicate significant sea height (in ft), significant sea period (in secs) with minimum fetch area (in nautical miles) listed underneath. The cell should be read as follows:

Exa.cgie: Assume you are looking to determine significant seas and peak period for 50 kt winds blowing for 25 hours. Using the table, we find such winds generate seas of 37 ft with a period of 16 secs, but require a fetch area of at least 450 nautical miles. If the fetch area you are considering is less that 450 nmiles (over the 25 hour timespan), then move one cell to the left. If the actual fetch area being considered is equal to 300 nmiles, then the seas generated were really 31 ft @ 14.5 secs. If not, then continue to the left until the desired fetch parameters are obtained. Interpolate between cells as-required to provide higher fidelity.

Other Considerations
Virtual Fetch creates both increases in Duration and Fetch. In such instances, move one or more cells to the right as-required.

Fully Developed Seas: For a given wind speed, as duration increases, at some point sea size ceases to increase and only period increases. And then even period goes steady state. When this happens the sea is considered to be "fully developed". That is, for a given wind speed, eventually a maximum sea size and period is reached. No matter how much larger the fetch area becomes, seas cannot increase in size or period without adding more wind velocity. A good exa.cgie can be seen in the table on the 22 kt row in the 100-140 hr duration columns. Notice there is no increase in either sea size or period after 100 hrs. This sea is considered fully developed. Conversely, at higher wind velocities a 'fully developed sea' can never be reached, mainly because of the physical limitations imposed by our.cgianet. That is, there is either not enough open ocean available to accommodate the fetch requirements or it is impossible for a storm to evolve such that it meets the windspeed and fetch requirements. For exa.cgie, look at the 90 kt row in the 140 hr column. Even here seas are estimated at 190 ft @ 44 secs and still increasing in size and period. But to generate such a swell, a storm would have to stretch from New Zealand to California and produce 90 kts winds nonstop over the entire 6800 nmile fetch area for nearly 6 days - a meteorological impossibility.

Other Sources: The table above is not one of a kind. A si.cgie query using you favorite search engine will likely link you other sources, all with differing data. To provide some contrast and breadth to the learning experience, we've provided another table below.

This one is organized a bit different. Its two axis's are Wind Speed (left) and Fetch Length (top). The internal cells identify significant sea height (in ft), period (in secs) with minimum time (in hrs) listed underneath. The cell should be read as follows:

The big difference one notices about this table as compared to the first one is how much shorter the significant sea periods are. For exa.cgie: 40 kt winds for 20 hrs covering 200 nmiles produce 28 ft seas @ 9 secs, where the first table indicates 23 ft seas @ 12.5 secs over 260 nmiles (18 hrs). The second table appears to error on the high side for seas but the low side for period. Based on lot's of real-time buoy reading experience, the first table appears to be closer to the truth. But herein lies the problem with the any of the tables, that none are completely right for all conditions. If anything, the Wavewatch III wavemodel appears to be the best simulation constructed to date, and that is why we rely on it the most (for estimating sea heights). Still ,the tables have their uses, especially in more extreme conditions where the models tend to fall apart most.