Updates needed for RRFS and REFS #557

A few issues, following #555:

1. REFS template is missing ensprod in the AWS url

• Herbie/src/herbie/models/refs.py

  Lines 45 to 50 in c5e480c

  	self.SOURCES = {
  	"aws": (
  	f"https://noaa-rrfs-ops-pds.s3.amazonaws.com/"
  	f"refs.{self.date:%Y%m%d/%H}/"
  	f"refs.t{self.date:%H}z.{self.product}.f{self.fxx:02d}.{self.domain}.grib2"
  	),

  

2. the NOMADS url goes to RRFSENS, not REFS. Looks like REFS is at, e.g., https://nomads.ncep.noaa.gov/pub/data/nccf/com/refs/v1.0/refs.20260915/

• Current URL example:
  

• Correct URL example:
  

3. REFS does not include f00, just f01-f60, but Herbie defaults to looking for f00.
4. RRFS Ensemble ("rrfsens") is not included

For item 4, it could make sense to add "rrfsens" as a separate (3rd) model, but it seems that NOAA clearly describes only 2 distinct models, with "rrfsens" simply being an output of RRFS. https://www.weather.gov/media/notification/pdf_2026/scn26-048_Updated_RRFS_and_REFS_Implementation_aad.pdf. So, I'm proposing that we stick with two models, and that the member input can be used to differentiate between RRFS deterministic and ensemble outputs.