Temp in Caribbean
The temperatures displayed for most of the Caribbean islands has been a bit off all spring and summer. Example: The past week has shown temps around 82 degrees in Grenada but it is actually 87-90 degrees most days. Not sure how the info is derived but it is not quite correct.
its truth and it has to do with the size of an island.
Forecast models compute temp. (and other variables) in places called grid points with resolution of 9 km for ECMWF (22 km for GFS). Some small islands are "invisible" by the model and the temperature given is that of the air above the sea.
Thank you for your help to understand this better.
If you could see the temp. on grid point, it looks like that:
Small islands (like St. Croix) are represended by only one grid point and the temp. at this grid point is "smoothed" with the other nearby points.
Biger islands (like Jamaica) have more reliable data.
Meteorologists try to improve the accuracy by makings models with finest grid but it needs more (much more) computing power
especialy if you want a model with global coverage.