The Eurasian QuarterSpheric Window runs in latitude from the Equator to the North Pole, and in longitude from 90 West to 90 East (large map, small map).
Two grids are used:
For Pressure Data and Surface Data, a regular 2.5 by 2.5 degree grid is used. | For Surface Flux (Surface Gauss) Data, a T62 Gaussian grid is used. |
As far as I've been able to ascertain, (interpret that how you will!), the grid point locations are notionally at the centres of the grid cells (rather than, say, at the intersections).