Model Output Discussion 29th December - Into mid-Winter.

[IDO]

The GFS and GEFS have been very consistent with the forecast in FI, a zonal period as the PV moves back towards our NW, though they underestimated the euro high viz the PV movement currently so we have stalled the UK HP pattern for a week, with pretty much no chance of a snowy period ever developing from that high. For the SE the temps have been underplayed by the models as we have seen over 7.5c, 6.5c and 6.5c highs the last three days in the warm feeling sun, so very pleasant compared to some of the cloudier area further up the UK.

The D16 mean has been instructive as to the pattern and remains as of late:

That's a solid mean and a very poor starting position as of Feb 5 in what is a short month in any case. Not a lot to say other than from experience when a period of zonality is predicted the confidence is very high for that signal and although we missed the initial surge, the return of the lower heights over the UK is nailed this time due to the synchronicity with the negative EPO during the same period; forcing of the PV to be corralled to NE Canada/Greenland.  

The EPO ridge initiates around D6 so early days as to how that develops, so the mean although a guide is probably not helpful re surface conditions as variations within the long wave theme may improve our chances as to less unsettled weather. Certainly a milder and wetter period upcoming:

I am not expecting a winter killer zonal period, as this winter has not trended that way. With the GFS bias for overkill when the Atlantic is the driver we may have to wait a few days till we see the return of the Azores high into the game. What is apparent is that the pattern this winter is unlikely to bring the UK anything but a transient snowy spell so we need to start to see the SSW propagate down this week or we will have to rely on trop forcing, and my hopes are poor for snow in that instance.

[Weather-history]

47 minutes ago, IDO said:

That's a solid mean and a very poor starting position as of Feb 5 in what is a short month in any case.

Not sure what the relevancy of the length of the month has got to do with it? Climatic means, sun strength etc would be exactly the same if the first 3 days of March were added to February instead.

Edited January 21, 2017 by Weather-history

[Captain Shortwave]

Looking at the mid-range I do wonder whether we have a big connection between the tropospheric and stratospheric patterns with a major warming on the Siberian side coming up with also the appearance of a very large anticyclone in the same region.

   

Looking at the GEFs in particular I do take note that this anticyclone will persist and slow back west, so I suspect any zonal westerlies will be limited potentially with a west vs east battle ground beginning to shape up further on as the Russian high backs west as the tropospheric vortex remains to our north west but with potial to weaken significantly as we close out January.

So what to look for in the coming week would be in my opinion another shot at a blocking high to our north east, yeah I think everyone is sick of them but something tells me this is the more likely cold scenario that could develop in the coming weeks.

      

Increasing height anomalies to our north east suggesting that slowly a westerly/unsettled pattern could be replaced with something drier for the south and east with systems struggling to push eastwards through the UK. Temperatures would however remain mild until we develop a flow which is east of south, looks possible but of course a flow between the south and west is favoured at this point in time.

 

[northwestsnow]

Looks like any hope of undercutting have disappeared this morning...

Have to hope the SSW has some kind of impact and blocking highs replace the horrid blues and purples to north, not sure what to make of the strat, the warming over western Russia does look like it will spill west towards Greenland but it weakens very quickly and signs of a recovery in 10hpa temps towards the end of the run..

[stodge]

Morning all

I'd forgotten how sub-tropical Reigate Hill was - in my part of East London, we've managed 5c a couple of days, 4c one day and crawled up to 7c briefly yesterday.

As to the models this morning, well,yes.

The spell of long fetch SW'lies looks to be fairly short as the jet eases south and we get plenty of weather coming in off the Atlantic.

I don't see an undercut but a strong possibility of secondary features developing and deepening rapidly in the flow so something to be aware of in what has been a quiet winter thus year in terms of storms. Not only that but they offer the possibility of a transient NW'ly which offers snow to altitude.

To offer some "hope", quite a lot of the GEFS members in far FI sniffing at height rises to the N or NE - very early days but a clear trend there worth keeping an eye on.

IF the Atlantic train can be slowed as the PV weakens from the warming, there is a "chance" for heights in our vicinity.

[Summer Sun]

UKMO extended has the high a bit further north at D7 compared to ECM, therefore, more areas would stay dry

[karyo]

1 hour ago, northwestsnow said:

Looks like any hope of undercutting have disappeared this morning...

Have to hope the SSW has some kind of impact and blocking highs replace the horrid blues and purples to north, not sure what to make of the strat, the warming over western Russia does look like it will spill west towards Greenland but it weakens very quickly and signs of a recovery in 10hpa temps towards the end of the run..

I am keeping an eye on what is happening in the stratosphere but not hoping for much. We had a SSW this time last year and we still got a mild February. Also, there is no consistency, with some runs showing a SSW and others just a warming.

[bluearmy]

ECM 00z suite isn't so interesting for cold surprises as the southerly dig of the jet reverts back across us by day 14/15. The axis of the Atlantic more sw/ne than w/e. in general the mean /anomolies look less interesting. The trop  vortex seems to split and the question is then 'can the N Pacific ridge split the trop vortex'? The standard answer is no and the next building ridge will send some of the Siberian vortex towards ne Canada and the jet will be 'streaked' again. There are two straws for coldies to clutch - we continue to see a cluster of runs building ridging to our north/northeast in two weeks and there is always the possibility that the upcoming SSW drives a quick trop response (which the ec control looks as though it could be doing) 

[Great Plum]

Well, that's an unfortunately shaped high pressure...

[Woldsedge]

10 minutes ago, Great Plum said:

Well, that's an unfortunately shaped high pressure...

Quite apt for the sort of winter we've had I thought. 

[stratty]

21 minutes ago, Great Plum said:

Well, that's an unfortunately shaped high pressure...

.....to go with your 'great plums'!

[fromey]

47 minutes ago, Great Plum said:

Well, that's an unfortunately shaped high pressure...

what would the 850hpa temps be on that  chart, looks like a very long drawn southwesterly. 

Edited January 21, 2017 by fromey

[blizzard81]

I am not too disheartened with the runs as the 00z are often the least amplified. I will postpone any judgement until I see the 12z runs tonight. 

[Timmytour]

21 minutes ago, fromey said:

what would the 850hpa temps be on that  chart, looks like a very long drawn southwesterly. 

I think a whiff of air from the Baltic region is more likely

[Coopsy]

1 hour ago, Great Plum said:

Well, that's an unfortunately shaped high pressure...

I said exactly the same about a similar chart a few weeks back and a mod deleted my message. That's the nature of this place. I appreciate the humour :-)

Chart related (in case big brother is watching) those SW's are from almost off the chart 

[Singularity]

We can't look to the strat warming alone IMO - it may not make it t SSW status anyway.

What I do see is strat developments being good for setting up another big block to our E/NE by about the end of Jan, at which point we'll need tropical forcing to force amplification upstream, buckling the jet.

EC ens have lost interest in the MJO behaving nicely while GEFS have emergence in phase 7 which is great, but not until nearly two weeks from now, with impacts in the 14+ day range so barely within range of the runs.

When I get on the laptop later I'm going to seek out the tropical hazards outlook to see if they're still expecting the MJO to remain more active as it propagates east. Continued significant amplification in phase 3 would at least stir the pot a bit.

[Iceaxecrampon]

06z  - the search continues

Best on offer - even this is clutching at straws TBH

   

Winds increasing  next weekend  - one to keep a watch on.

How long till "winter over"?

[bluearmy]

8 minutes ago, Singularity said:

We can't look to the strat warming alone IMO - it may not make it t SSW status anyway.

What I do see is strat developments being good for setting up another big block to our E/NE by about the end of Jan, at which point we'll need tropical forcing to force amplification upstream, buckling the jet.

EC ens have lost interest in the MJO behaving nicely while GEFS have emergence in phase 7 which is great, but not until nearly two weeks from now, with impacts in the 14+ day range so barely within range of the runs.

When I get on the laptop later I'm going to seek out the tropical hazards outlook to see if they're still expecting the MJO to remain more active as it propagates east. Continued significant amplification in phase 3 would at least stir the pot a bit.

I'm still intrigued by your fascination with the MJO - given that the difficulty in obtaining a coherent and convincing forecast for it all winter  I fear for your sanity

[Ali1977]

SSW response may come in this form. A few interesting ENS again

Edited January 21, 2017 by Ali1977

[sebastiaan1973]

10 minutes ago, Ali1977 said:

SSW response may come in this form. A few interesting ENS again

Too early. Ian Fergusson tweeted about half februar.

[bluearmy]

6 minutes ago, sebastiaan1973 said:

Too early. Ian Fergusson tweeted about half februar.

That's according to glosea (and probably eps ).  However, individual ens members will drive a QTR and it's fun to see them - as long as you realise they are the much less likely direction of travel.

[MR EXTREMES]

i wouldnt bank on a strat warming id also say uptick in solar activity will have plenty to say.

im not happy with the model outputs its shame just waist of all that cold air ironic that the med have had better winter than us.

i just dont feel the strat warming will be enough.

[bobbydog]

18 minutes ago, MR EXTREMES said:

i wouldnt bank on a strat warming id also say uptick in solar activity will have plenty to say.

im not happy with the model outputs its shame just waist of all that cold air ironic that the med have had better winter than us.

i just dont feel the strat warming will be enough.

The solar "uptick" is a minor blip. If you've given up on this winter, the next few could be interesting due to just that. Solar minimum before next winter?.....

[nick sussex]

I think the lack of posts highlights the fatigue now setting in. Theres only so many ways you can say the outlook is underwhelming from a cold standpoint.

I think its clear this season that any amplification shown tends to get watered down and we have been in an almost constant chasing potential which has had a low strike rate.

The outputs of a few days back which showed more energy heading se have moved away from that and we're back to chasing outputs at day ten for signs of change.

The MJO seems to have hit the buffers depending on which forecast you look at and its been difficult to nail down exactly where this is given the discrepancies.

Currently its looking like a few more coldish days before the Atlantic returns and a milder spell of weather. The ECM only shows some improvements in the NH pattern towards days 9 and 10 but will they still be there this evening and move forward?

Edited January 21, 2017 by nick sussex

[The Weather Dragon]

Well the models produce proper cold today 2C max - feels like winter - much better than the last transient northerly attempt