The NAM model is intended to be more accurate - it calculates the weather at a higher resolution than the GFS model. Let's check the forecast map for tomorrow at 1 pm. Here is the NAM map from iWindsurf.com:
- 19 mph is barely worth rigging; any less, and we'd need huge sails; but 29 mph is prefect
- We can't wait until 4 pm, when both models predict wind - it gets dark at 3:30.
- It will be warm (50ºF, 10ºC) and sunny tomorrow after noon.
- It has not been windy for a while.
So, which model will turn out to be right? Often when we see such discrepancies, the GFS model is closer to the truth, especially in the fall. Sometimes, the wind comes in even stronger than the GFS model predicts. But sometimes, the "light wind bubble" that the NAM model predicts actually happens. For tomorrow, my bet is on the GFS - but windsurfers have to be optimists. So watch the meters!