Better UI

Reorganization of panels.
Release of the unsigned dmg image.

Double‑click the DMG in Finder and drag Gribview.app into your Applications folder.
Try to launch gribview once from Applications (or Spotlight). macOS will warn that the app is from an unidentified developer and block it.
Open System Settings → Privacy & Security. Scroll down until you see the message saying that “gribview was blocked from use”.
Click Open Anyway, then confirm by clicking Open in the dialog that appears.
From now on you can launch gribview normally, or just double‑click .grib/.grib2 files to open them in the app.