Dear Mike,
You can use the NSRDB API to download weather files from the database. The example they provide is written in a version of LK for the SAM SDK, but it should work from the SAM user interface too. Please try that and let me know if you run into any trouble:
https://nsrdb.nrel.gov/api-instructions
Note that to use the API, you need to request an API key, which you can do by following the link at the top of those instructions.
Best regards,
Paul.