GEFS ensemble forecast charts

The GEFS is an ensemble forecasting system. Instead of just a single forecast the computer model is run an additional 20 times with the starting conditions varied slightly in each instance.

The key thing to look for on these charts is consistency. For example, if most of the individual runs for a selected time show snow then confidence in this outcome is high.

Chart type

  • Alps snow (C)

Hours ahead

  • 6
  • 12
  • 18
  • 24
  • 30
  • 36
  • 42
  • 48
  • 54
  • 60
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  • 372
  • 378
  • 384

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Pink shading indicates snow fall.

Darker shades of pink indicate more heavier snow.