Another slightly unusual thing about the GFS 06z 850hPa ensembles is that
there is, after taking out a few extreme ouliers, more agreement for 6 days
out than for 3 days out. Shows the uncertainty, even in the short term.
Dave

On Wed, 31 Dec 2008 17:44:27 -0000, Dave Cornwell wrote in


Another slightly unusual thing about the GFS 06z 850hPa ensembles is that
there is, after taking out a few extreme ouliers, more agreement for 6 days
out than for 3 days out. Shows the uncertainty, even in the short term.
Dave

I've often noticed that behaviour as well. The upper long waves (useful in
medium range forecasts) are sometimes easier to predict than the embedded
short waves associated with the moving highs and lows affecting day to day
weather.

The best example I can recall was the farming forecast before the big storm
of 1987. This signalled a severe storm in 4 or 5 days, but then the
shorter range forecasts backed away, until very close to the event.

--
Mike Tullett - Coleraine 55.13°N 6.69°W posted 31/12/2008 18:55:08 GMT