Sunday, October 17, 2010

The 10-day wishcast

This morning's GEFS is showing remarkable spread at 10 days, which allows for great "wishcasting".  Wishcasting is all about introducing bias into your forecast based on what you want to happen.  The 240 hour GEFS forecast has something for everyone (image below courtesy of PSU E-wall).

If you want a deep trough, go with member P002.  If you want a good snowstorm, perhaps C001 is your member of choice.  Or, if you want the nice weather to continue, maybe P007 instead.

Of course the real question when the ensemble looks like this is what do you communicate to your customer.  The ensemble mean is probably close to climatology, but you have members that show a major change in the weather for Utah that could be important.  A difficult challenge, but one that savvy meteorological communicators can address.


  1. I choose C001. Any idea what could be causing this pattern change? The pattern change we saw in September was likely due to typhoon malakas, but I can't find anything too out of the ordinary for the next 10 days.

  2. A good question. may let you dig in further.