Trace - Noticeable swells but in the toe tocalf range.
Tiny - Ankle to knee high. For most folks this is flat.
Small - Knee to chest.
Medium - Waist to head.
Large - Chest to overhead.
Extra Large - Overhead to double overhead.
Giant - Double overhead plus.
Light - Winds up to 15 mph.
Moderate - Winds from 15 to 25 mph.
Strong - Winds in excess of 25 mph.
Light Yellow - Surf, but winds might not be good and waves won't have much size.
Bright Yellow - Surf, but winds probably not good but waves have some size.
Light Green - Surf, winds are probably good but waves won't have much size.
Bright Green - Surf, winds are probably good and waves have some size.
Simplified -Swells and Winds are provided for each day with some locale mentioned within the notes.
Detailed - 5 geographical sections from Watch Hill, Rhode Island to Schoodic Point, Maine.
Approach - The forecast is based on actual data from buoys, ship reports, satellite data from geostationary and polar orbitting satellites. Guidance about future events incorporates the actual data into manual forecast of future conditions along with input from numerous atmospheric numerical models. This results in a set of expected conditions for the atmosphere which are in turn used to derive corresponding future conditions of the ocean and the results are transformed into sensible surf forecasts for the New England region. Typically surf in New England forms based on the local weather (mid-latitude) which presently inherent high variability and low confidence in all forecasts. However, a general approach of explaining the forecast and updating the forecast each day provides continuity such that the forecast can be used as a guide for expected surf conditions.
Additional Wind Terminology:
During times of strong weather patterns (cold offshore flow, warm onshore flow) the winds in New England are usually the same across the entire region, however as weather systems approach or stall in our vicinity, it usually is the case that local winds change on an hourly basis. This is also true during the non-winter time of the year when atmospheric heating causes light winds to shift to seabreezes.
Shifting winds is a term used to describe a complete rotation of winds within a short period of time, a common example would be ESE/SE winds in the morning with a storm system moving right over the region and winds shift to the S, then SW and then WNW and eventually NW. Rather than listing that out, the forecst will just say "shifting winds".
Three ranges are used for winds. Light winds are exactly that, anything from 5mph to 15mph. Moderate Winds start in the high-teens and approach 30mph. Usually surf can be good with light or moderate winds. Strong winds are in excess of 35mph and usually this is a little too much intensity and can compromise a swell.
Additional Forecast Considerations
It is very important to keep in mind that the NESURF forecast is for a zone as opposed to a spot. On a day that the surf is forecasted to be medium (Waist to Head) you may find some spots are actually waist to chest, other spots are chest to head and there is also the chance that some spots are knee to chest, and others are actually chest to a little overhead. This type of surgical precision would only be possible if the forecast were for 'spots' rather than 'zones' so the forecast tends to generalize and remain in the middle of the road in terms as opposed to being pessimistic (calling it based on the smallest spot) or optimistic (calling it based on the biggest spot). For inquiries or suggestions, pleaes open a thread within the forecast discussion section of the forums.