Interesting to see on the 6z GEFS that the mean 850s for London have dropped by 4 degrees at the end of the mild blip (and the one lonely straggler shows up well).

It's also interesting that beyond the mild blip the mean 850s hover around the -5C mark, much as with the EPS. From the 31st to the 3rd the majority have winds from a NE'ly quarter, too, but of course that's very much subject to change.

Mild blip aside the GFS ens do seem to be gradually reverting back to less scatter with reasonable grouping around the -4 to -8 area right to the end of the run.

 

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GEFS 06z does seem to have firmed up on longer term cold. On the subject of ensemble "blips" I started to notice an increased frequency of them after the SSW last winter. The same thing happened several times during the summer when 850s bulged upwards at relatively short notice. Obviously at longer range the scatter means colder and milder outcomes cancel each other out to a degree. However, I think there is more than that going on. An increased incidence of high pressure blocking is the key I think, because it means the potential for significant deviations from the norm are often only a few hundred miles away. 

 

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GEFS 06z does seem to have firmed up on longer term cold. On the subject of ensemble "blips" I started to notice an increased frequency of them after the SSW last winter. The same thing happened several times during the summer when 850s bulged upwards at relatively short notice. Obviously at longer range the scatter means colder and milder outcomes cancel each other out to a degree. However, I think there is more than that going on. An increased incidence of high pressure blocking is the key I think, because it means the potential for significant deviations from the norm are often only a few hundred miles away. 

 

 

I tend to agree. Often you can find a very different ensemble profile if you select a location even a hundred miles away - particularly if you choose the locations carefully having regard to the prevailing synoptic pattern.

The ECM 00z ensemble suite for London carries an identical message to the GEFS, i.e. long-term signal for cold weather beyond a very brief blip next Saturday. Most of the variants bring in the warm sector at some point that day but a reasonable cluster delays it until the evening. It's noticeable that there's a near-total absence of mild outcomes and very few offering normal temperatures.

Of course we know that ensemble suite can also flip but as it stands the outlook remains a cold to very cold one - and I expect the Met Office forecast to remain largely unaltered.

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I tend to agree. Often you can find a very different ensemble profile if you select a location even a hundred miles away - particularly if you choose the locations carefully having regard to the prevailing synoptic pattern.

The ECM 00z ensemble suite for London carries an identical message to the GEFS, i.e. long-term signal for cold weather beyond a very brief blip next Saturday. Most of the variants bring in the warm sector at some point that day but a reasonable cluster delays it until the evening. It's noticeable that there's a near-total absence of mild outcomes and very few offering normal temperatures.

Of course we know that ensemble suite can also flip but as it stands the outlook remains a cold to very cold one - and I expect the Met Office forecast to remain largely unaltered.

definit slight trend in the clustering for next weekend to stay below average which might not make everyone happy but any slight dip in that cluster could make it interesting 

It still looks cold to cool to cold to me, nothing warm at all on offer!!

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I wouldn't be at all surprised to see more stuborn heights persist to the north east than what the models have been showing since the flip. The full blown east/north easterly may be gone for the time being but a slightly more watered down continental feed with -8c 850's and some snow instead of -12c may still be possible until further trough disruption pulls in colder uppers and a greater snow risk threat.
There has been signs of this happening on the ICON, GFS op and the ECM 0z runs.

I'm quite confident that the end of Jan and into Feb could be quite wintry , the LR Models went for this and we are starting to see this on some of the charts , get this very tiny hiccup of mild out the way and we could well be in business 

UK in general - not an IMBY post 

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Just noticed the Met Office HAVE ditched the northeasterly later this week, although they mention a low possibility of it remaining cold. In the longer term their outlook doesn't appear to fully marry up with the GEFS. However it wouldn't surprise me if milder incursions appeared in he GEFS at relatively short notice - as I mentioned earlier - and that would fit in with the latest Met Office output.

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It will be interesting to see how many of the models still show the north or northeasterly flow on Thursday/Friday. Generally though if the last couple of days are anything to go by cold will remain the key theme with that less cold 2 day blip towards the end of the coming week.

However, anything is possible and we will find out what treats the models have for us in the next 3 or 4 hours.

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It will be interesting to see how many of the models still show the north or northeasterly flow on Thursday/Friday. Generally though if the last couple of days are anything to go by cold will remain the key theme with that less cold 2 day blip towards the end of the coming week.

However, anything is possible and we will find out what treats the models have for us in the next 3 or 4 hours.

For the South it's above average - not less cold - and is potentially longer than 2 days.

 

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10hpa 60N zonal mean wind is back so the PV is starting to reform

 

Lag time and what not but if it set's up shop over Greenland that could bring a milder 2nd half to Feb if things set up right or wrong depending on your POV

10hpa 60N zonal mean wind is back so the PV is starting to reform

 

Lag time and what not but if it set's up shop over Greenland that could bring a milder 2nd half to Feb if things set up right or wrong depending on your POV

The reformation of positive u values higher up and cooling are inevitable and actually serve to push the current reversal down to the surface.

A large portion of Feb will be influenced by the reversed or close to zero u-wind vector hence the higher probability of much colder conditions than normal 

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For the South it's above average - not less cold - and is potentially longer than 2 days.

 

Above average is less cold.

As for longevity it may be longer, shorter or not at all but this is what the latest GEFS ensembles show.

 

Yes, Gavin the SSW timescale is as it has been with the tropospheric response usually following the 10hPa stratospheric effects and not stopping immediately when the 10hPa zonal flow reverseal ends.

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For the South it's above average - not less cold - and is potentially longer than 2 days.

 

The average maximum and minimum for the South (away from the south-west) for late January are around 8c and 2c.  In the far south-west peninsula around 9c and 4c.

so, in fact, based on the latest GFS (06z) run the maxiumum temperature in the south on Saturday will be close to the average.  On Sunday it slips bakc below.  Overnight minimum is also close to average overnight Friday/Saturday and back below overnigth Saturday/Sunday.

If we look at the ensemble mean for Saturday and Sunday the temperatures remain below average throughout.

 

 

 

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Just noticed the Met Office HAVE ditched the northeasterly later this week, although they mention a low possibility of it remaining cold. In the longer term their outlook doesn't appear to fully marry up with the GEFS. However it wouldn't surprise me if milder incursions appeared in he GEFS at relatively short notice - as I mentioned earlier - and that would fit in with the latest Met Office output.

At least that puts to bed the suggestion that there's nobody competent around at the Met Office at the weekend to update the forecast.

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Big change from ICON early doors

12z                                                             06z

Icon was looking more amped to the n/east up to t96 or so before going off on a tangent to its earlier run. Hoping the gfs 12z will continue this theme. Won't be long till we find out.

Eyes down, I would think it will be busy this evening in here

Big change from ICON early doors

12z                                                             06z

Yes, it keeps things from a northerly quarter for most of the run making the milder blip even less pronounced in northern parts than earlier runs. I’m not convinced we will see a consensus on the 12z suite beyond 4 days or so.

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Well I've been away for a couple of days and things have taken a turn for the worse in terms of the forecasts of severe cold and an easterly but a gap in ensemble watching can be quite useful. There is obviously the big mild blip that some of us feared but were warned off about but generally the ensembles are pretty much where they were with still a generally cold outlook. We've been here before though and the older members may recall the old Jim Reeves record "I hear the sound of distant runs" ! 

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