Many thanks, @Paul. A max. difference of 7 Kelvin across the grid doesn't strike you as high? I thought it seemed high for differences between two "identical" initial conditions, but I have zero experience with this. But the std. dev. of differences is only about 0.2 Kelvin.
If I could piggyback with one more question about the analysis vs. the 000 hour forecast... in a 12z forecast, for example, what time does the 000 hour forecast refer to? Is it referring to conditions at 12z (i.e., noon UTC)? I'm puzzled because that forecast gets dumped on the FTP site after 12z, so it's more of a hindcast by then. I guess the analysis describes conditions assimilated prior to 12z?
Thanks again.