Documentation additions

[williamhobbs]

• Consider adding something in docs about possible firewall/certificate issues. pip install pip_system_certs is one option that could be suggested.
• Info about disk space and the data/save_dir, with reference to https://herbie.readthedocs.io/en/stable/user_guide/configure.html
• organized description of examples folder (bullet list of files/descriptions)
• other troubleshooting tips (eccodes and the latest version of python, issues with AWS and IFS, upgrading urllib3)
• notebook (or ipynb-to-md file) with overview of forecast definitions (get_fcast_definition), time delay calcs (adjust_forecast_datetimes), and observed delays from https://gist.github.com/williamhobbs/9585ff5d1248ab5de4d9e8665d7c8ea6 and http://dynamical.org/status

[williamhobbs]

On firewall/cert issues: certifi, like @etsmith14 used in the example in #37, looks like another good option

[williamhobbs]

Upgrading urllib3 (pip install --upgrade urllib3) fixed intermittent errors I was getting with IFS via google, like:

Exception has occured : Processing failed: HTTPSConnectionPool(host='storage.googleapis.com', port=443): Max retries exceeded with url: /ecmwf-open-data/20250905/12z/ifs/0p25/enfo/20250905120000-27h-enfo-ef.grib2 (Caused by SSLError(SSLEOFError(8, '[SSL: UNEXPECTED_EOF_WHILE_READING] EOF occurred in violation of protocol (_ssl.c:1032)')))

I went from urllib3 2.5.0 to 2.6.3.

[williamhobbs]

Errors like

TypeError: objects must be an iterable containing only DataTree(s), Dataset(s), DataArray(s), and dictionaries: ['t2m']

can come from partial .grib files. I've found that navigating to the corresponding ~\data folder, e.g., C:\Users\[username]\data\ifs\20240605, and deleting the contents can fix this.