Clustering Is Your FriendAdded : Wednesday at 9:56 Latest GFS ► model for start of November is here :-
Oh! Blummin 'eck Metcheck! What are you trying to do to me? You can see that the GFS ► is resolute in this cold Northerly outbreak for the UK for the end of next week, but... and it's a rather big but laden in salt and honey when it comes to these sort of scenarios.
When you see these scenarios appear on the charts there should always be three basic questions you ask before you take too much notice :-
1. Are the other global models in agreement?
2. Do the ensembles support this?
3. Does the model have an inherent weakness in promoting ridges/troughs in the Atlantic?
So, the first question is agreement with other models. The ECMWF ► has this for the same period :-
It's certainly showing a colder Northerly yep, but the GEM?
Similar, but the flow is what we call "disturbed" and cooler, but not quite as cold as the GFS.
To the second question... Do the ensembles support this? Here is the spread :-
You can see the colder period at the end of the ensembles. Note that the control run is to the bottom of the ensemble spread. There is definitely a cool down, you can see this in the trend from the start of November, but the run which you are seeing in the model at the top of the page is at the lower end of the spectrum. Without any sort of clustering it's difficult to add much confidence to the latest GFS ► run and our thinking errs more towards the GEM solution which is a little more "middle of the road".
If you look at the super ensemble with 60 members for Manchester then things become a little clearer :-
You can see a cold shot coming in on Sunday and certainly a cool down as we enter November which is sort of expected for the UK believe it or not...
As for the white stuff? Perhaps a risk, but Northerlies are one of those wind directions which everyone seems to think will bring snow, but rarely does away from coastal areas or across high ground, worth remembering that before you dust down the sledge. But that said, it might be worth checking ice scraper and anti-freeze in the car over the next few days as colder weather is likely for the start of next month, but probably not quite as cold as the GFS ► suggesting.
Oh, and to answer the third question... The GFS ► is a wily old fox for over amplification of mid Atlantic ridges, but then you knew that anyway.
METEOROLOGIST : MARSH |