I bet it's really easy for the sites to get solid info for Wilmington--we have a National Weather Service division here. One thing to check if your spot is constantly mis-predicted is how close you are to an NWS office/station--I'd bet you get more variation in the wind forecast the further you are away from one.
Another thing to look out for is the number of buoys near your area that report wind data.
Emass: I don't chest-bump with little girls. Sorry.
Y'all realize, Mr. Yankee wasn't axing how winds come to be, he was axing where all of these surf predictin' sites get their wind info.
It was funny watching which of the responders got that and which did not. Frank the Tank (aka BCN) luckily blacked out again and told us about warm and cold air masses and how they get, well, er..."inverted" [places one hand upside-down over the other while describing].
I often find the difference in wind forecasts is simply because they are updated at different times. Wait till the next forecast update and see if they line up more.
I think most US based sites use GFS models for wind, but I wonder if MSW uses ECMWF. (Probably not since it looks like their wind forecast is the same as SI's)
Yes. Wind forecasts are based off of model predictions, so updates in the model(s) can make a wind forecast shift. If one source shifts drastically, then it may just be due to the forecast update where model shifts the track or location of a weather system. Yes, everyone is updating their data at differently.
Swellinfo doesn't just use raw model data. Other sources may just output GFS data, but Swellinfo tries to be more intelligent then that. Every model has biases and strengths and weaknesses, and understanding these biases is what makes a good forecaster.
Let me add - In general, wind forecasts will be more accurate as you get closer to the present time.
The biggest sources of error for the current day forecast will come with the sea breezes, which are present often in the summer time. This occurs from large temperatures between the land/ocean that create onshore/sideshroe breezes that develop and strengthen during the day. Swellinfo has made some strides with sea breezes, but its not such an easy problem. The large scale grid models are too course in resolution to handle the microscale weather physics.
FYI - On the Surf Forecast pages, under the wind map tab, you can view the wind field for both GFS and NAM models wind forecasts.
Last edited by Swellinfo; Jul 11, 2013 at 08:17 PM.