The weather model GFS (Global Forecasting System) has, for years, teased weather anoraks with mouthwatering possibilities of what the weather could be like 5 to 10 days away. Many ‘coldies’, that unexplained breed of weather anorak whom lust after extreme cold and snow every winter, often look at the end of the run, out to 384 hours, and cherry pick these charts, taking as gospel that the synoptics will come to pass, especially if there is high pressure plonked over Scandinavia.
But 16 days is an eternity in weather forecasting and what happens on the day is, more often than not, a world away from what was modelled a fortnight before. But it doesn’t stop the blizzard of toys and dummies being thrown out of prams, often by grown men who really should know better that the weather they really want is always 10 days away.
Is this about to change? Probably not but the improved resolution, from 27km to 13km, will massively improve accuracy at short-range.
In the meantime it is perhaps ironic that the final 18z operational run of the GFS 27km resolution model had some of the most mouthwatering solutions for classic cold and snowy winter weather for nearly two years. But, just for a change, the operational is backed up by the ensemble.
Here are most of the 500hPa charts from that last run