Update model template for ECMWF IFS

[blaylockbk]

Discussed in #538

^{Originally posted by williamhobbs May 7, 2026}
I managed to miss this until today, so maybe others missed it as well.

From https://www.linkedin.com/posts/ifs50r1-opendata-aifs-share-7458166864892968961-5Tp7:

📢 𝗜𝗺𝗽𝗼𝗿𝘁𝗮𝗻𝘁 𝗻𝗮𝗺𝗶𝗻𝗴 𝗰𝗵𝗮𝗻𝗴𝗲𝘀 𝗮𝗵𝗲𝗮𝗱 𝗳𝗼𝗿 𝗮𝗹𝗹 𝗘𝗖𝗠𝗪𝗙 𝗱𝗮𝘁𝗮 👇
IFS Cycle 50r1 goes live from the 06 UTC run on 12 May 2026, and it comes with naming changes that affect anyone with hard-coded stream or type values in their code.

𝗧𝗵𝗲 𝗰𝗵𝗮𝗻𝗴𝗲𝘀:
📌 stream=scda → stream=oper (the 06 and 18 UTC runs join the main stream)
📌 stream=enfo, type=cf → stream=oper, type=fc (ENS Control and ex-HRES become one forecast)
📌 For waves: stream=scwv → stream=wave, and stream=waef, type=cf → stream=wave, type=fc

To make sure I’m understanding correctly, for init dates 2026-05-12 06:00 and later, where we would have used product=‘scda’, we now use oper, right?

[blaylockbk]

Good find @williamhobbs!

Probably should update the template to only accept the new naming convention for selecting the product, then let the template automatically convert it to the legacy naming for dates older than May 12.

[blaylockbk]

Looks like there is test data that exists for testing
https://data.ecmwf.int/forecasts/testdata/

I won't be able to get to this myself, but would be happy to approve a pull request and make a new Herbie release when someone updates the ECMWF templates.