SUJET :

The GFS GRIB server has been down for 48 plus hours. Do we know what the issue is or when it may be up again?

Checking the github server and David's remark, apparently the server has been down since September 1st, now 17 days

I found this additional info re the GitHub server issue.
There’s a fair amount of discussion online re the server issue, mostly on GitHub. The short version: the outage is a lost backend machine, not a temporary glitch, and no fix from the maintainers has appeared yet.

What happened

The main thread is GitHub issue #326 (“can’t download issue”), opened Sept 5. It now has 89 comments.
github
The server itself still answers requests. It returns a message dated 5 September 2026 saying the server that prepares and serves the GRIB datasets is no longer available to them. The cause is that the broker at grbsrv.opengribs.org lost the machine that built the datasets. The front-end PHP host is still running, but the backend that fetched and prepared the data is gone.
Remove the broker dependency: downloads are dead because grbsrv.opengribs.org lost its backend, and upstream can now do that work client-side · Issue #329 · opengribs/XyGrib · GitHub
+2
This is why the client can look hung instead of plainly failing. The status page keeps replaying its last successful output from 2026-09-07, so XyGrib’s Server Status dialog shows an old forecast date and “Waiting” with no end.
github

Will it come back?
Nothing official suggests it will soon.

Issue #329, a detailed analysis posted Sept 29, says the machine won’t come back on its own, and the client has no way to download that avoids it.
github
A maintainer said in #326 on Sept 15 that the server scripts would be uploaded the following week, but nothing had appeared in the repository as of Sept 29.
github
Even if the scripts do get published, the project’s last commit was 2022-05-16, and an open issue already describes XyGrib as unmaintained.
github

Community workarounds

Issue #327: a standalone script, grib_downloader.sh, that pulls data directly from NOAA/NOMADS, HYCOM, DWD and ECMWF, does the conversion locally, and doesn’t depend on the XyGrib server.
github
DrCalambre’s GitHub script: downloads GFS 0.25° straight from NOAA NOMADS and builds a GRIB2 that XyGrib can open. It also has optional WW3 wave data.
github
Issue #329’s proposal: have XyGrib fetch directly from NOMADS. A contributor, frfa, has already built a first version in a fork, with providers for GFS, DWD ICON, ECMWF and Météo-France.
github

Limits of the direct-download approach

ICON-EU and ECMWF can’t be cropped to an arbitrary area at the source. You either download the full grid (about 50 MB for 24 hours at 3-hour steps) or need a broker server.
github
Arpege and Arome (issue #328) have the same problem.
github
GFS, NAM and WW3 through NOMADS are the clean path.

There are also outage threads in English and French on the OpenGribs forum (opengribs.org/en/forum/xygrib-support), but GitHub #326 and #329 have the substance.

Sources:

Issue #329 – Remove the broker dependency
Issue #327 – Download issue workaround
XyGrib issues list (incl. #326)
GFS NOAA NOMADS Downloader for XyGrib
OpenGribs forum – XyGrib Support