[Model output discussion - winter proper underway]

4 minutes ago, Broadmayne blizzard said:

Because as Tamara and GP pointed out the other day there will be a transition period from the end of the current Atlantic ridge driven cold spell to another cold spell come xmas/new year driven by hieght rises to our north and northeast. This was always on the cards and it is no surprise to see it in the modelling.

Yes, but the question is whether those atmospheric drivers are still present.

Today's output is about as flat and vile as we've seen for a couple of years, going back to December 15's horror show.

[Model output discussion - 1st December onwards]

1 hour ago, fergieweather said:

Quite so. Presently, the E/SE'ly cold solutions courtesy of the diffluent block out east - as offered by some recent deterministic output across various suites - is rated as 10% PROB. Whilst a mobile/zonal pattern remains the stronger and thus more favoured signal out beyond d10-15, clearly any mean fields will be skewed by these energetic ENS members (& with inevitable tendency to lean back towards climatology) versus those stamps (presently a minority) showing the opposite. I know we hammer on about this, but inspection of individual stamps is critical, rather than pronouncements based solely on ENS mean.  As it stands, indication of an eventual change to the pattern has bolstered slightly, rather than diminished. But it's clearly all highly tentative for now.

Those of you who like to base analysis primarily on ensemble means might like to remember Ian's well made point a little more often.

 

 

[Model Output Discussion - The final stretch to Christmas]

This forum has a mix of excellence and schizophrenics  . 

 

 

This morning some were euphorically trumpeting an easterly and explaining how it was really all so predictable based on Alaskan ridging, shortwaves off Philadelphia, and a shattered PV.

 

This evening some (often the same people) are in a state of gloom due to a return of a zonal flow, and explaining how it was really all so predictable based on Alaskan troughing, shortwaves off Greenland, and a strong PV. 

 

 

As a casual reader I'm just giving my opinion on a thread which generally seems long on over-reactions and short on rational consideration ........... and again I stress that there are some excellent posts in amongst it all.