The default ForecastBuilder code lists Superblend as the primary model and NationalBlend as secondary. However, since the last NationalBlend update (3.0), the model only comes in through so many hours depending on the run. For example, the 00z NBM goes through 264 hours but the 01z run only comes in through 18 hours - see attached graphic from the NBM Vlab. This is by design, and NIC 7.x has a fix wherein the "NationalBlend" model will vary in length but an "NBM" model will always go out through 10 days and update with the latest NationalBlend guidance at each time-step. (The NIC 7.x update is apparently coming to CR by way of a tech note some time this month along with a FB update.)
I say all this because I wonder if the reason for this problem is that NationalBlend does not always come in through the same time range, and thus the dirunal curve that gets built is messed up? I have no idea if that's possible, but as a work-around I would recommend manually running Diurnal with Superblend selected for both primary and secondary models to see if that solves the issue.
