polar vortex

I think -QBO works well with low solar and moderate Nino however if the QBO like this winter is to negative this can have a detrimental effect towards northern blocking. Just my opinion of course. One other point that may or may not be of relevance regarding the winter of 62/63 during the October of 1961 the largest detonated nuclear bomb (the Tzar bomba or king of bombs) was dropped over Novaya Zemlya with a yeild measurement of 50 megatons. This would have surely had a impact on the stratosphere remembering of course that the March of 62 was very cold with extensive northern blocking. Maybe this had repercussions for the following winter as well.

Phase 1 is not a high amplified phased state rather the reverse. I see though you have succumbed to the idea of a more amplified state going forward rather than the rinse and repeat that you were forecasting. To much faith in one teleconnect can lead to failure.

I think there is enough evidence in the model output post t120 to suggest a more amplified pattern in the Atlantic. Could be quite a potent affair should this happen. Role on the 12z

The UKMO model this morning suggests that it may not flatten out.The t144 chart screams north Atlantic ridging and a much more meridonal pattern. Something to watch perhaps.

The UKMO t144 chart is loaded with potential this morning. Certainly the pick of the bunch from a coldies perspective but with it being the t144 chart maybe should not put to much faith in it just yet.

Ridge building on the pacific side is more in line with tropical convection around the date line and the weakish phase 8 MJO. Agree with Cohen's lastest thoughts of a trop split of vortex to what was seen in the strat early January. Also I do not buy into what NOAA and the met and its forecasting tools say as gospel. Cold before February is out and then on into March is my bet. The strat has been a thorn in the backside.

Still confident of a pattern change last third of the month with much more in the way of northern blocking as we go into March. This due to tropical convection and MJO signal although the models are struggling with this. The strat has ruled the roost this winter with very little in the way of northern blocking ( possibly due to very strong - QBO ) but hopefully we will see a change over the coming days and weeks.

The strong convection near the date line is obviously being modelled to interact with the polar westerlies (PFJ) in the mid to long range to produce significant ridging up over Alaska and into the Arctic which will amplify (hopefully ) the ridge in the Atlantic. I remember American meteorologist L. Cosgrove who often spoke of this when he forecast a plus PNA and meridonal pattern setting up over the states and the UK. The GFS 18z run is again locking onto this synoptic outcome.

Strong influences from the MJO showing up in the models now with more amplified patterns in the mid range and beyond. I have been banging this drum for a few days now of perhaps a MJO related pattern change last third of February. Clueless as to whether it would be from the east or north or indeed something in between but IF it does transpire then the chances are it could be a very potent affair. There is an abundance of deep cold in the Arctic and should a dropping AO send some of that our way then we could easily still be looking at possible ice days, severe frosts and powder snow.The ECM tonight had it gone on another 48 hours would have covered the country in -10 to -12c uppers at least. Fun times ahead perhaps.

Personally I do not think the model is worthy of band width it takes up, but it shows the effects that MJO forcing could have on the pattern that has been dominated most of the winter by the strat. I am still for thinking pattern change last week of Feb but I would not take any notice of GEM, JMA etc even if they show day after tomorrow scenarios.

I am still hopeful that with continued MJO forcing and ridging on the pacific side we will see a fairly dramatic switch in the mid to longer range output over the coming days. The strat forecasts are showing a split of sorts from 10mb on down around t240 mark. If the MJO forcing is stronger than modeled then the likely hood of a full blown split and HLB's is greatly increased. There is strong tropical convection about 170 degrees west, ideally we would like to see this move further east into a more favorably phase 8 position ( if anything it has moved a little west the last couple of days though it has kept its intensity). This is the key I feel to the AO turning negative and producing the pattern change that most on here are looking for.

ECM 12z t240 is a horrid chart for coldies but I am more interested in the greater amplitude shown over Alaska and north west Canada, again a signal of a stronger MJO wave. Should this continue to increase then we will hopefully see a more amplified pattern take hold over the Arctic (-AO). The models are showing no real signs of this at the moment though it has to be said.

Another poor run from the gfs 12z for those of us wanting a real taste of winter. The strong ridging shown on the run up the western side of America into Alaska made no real impact into the Arctic and thus no real impact in our weather not if your looking for a more blocked and amplified pattern. The reason for this I believe has nothing to do with the GWO and GLAMM tendency or Enso etc but has everything to do with the stratosphere in not allowing heights to build into the Arctic. The 12z does suggest a bigger forcing from the MJO what with the much stronger ridging and although this op run has not shown much of an interest in northern blocking that is not to say that this run is correct or that this will not change.

With the much stronger ridging up into Alaska on 12z run we hopefully will see a much better outcome in FI. This could turn into a very good run for us.

Positive signs on the gfs 12z with stronger ridging over on the Pacific side of north America. This could be very beneficial down the line.

Despite what some say the reason for another poor winter (so far) has been the strength and orientation of the vortex which again has been underestimated. last year the vortex was stretched from Siberia to Hudsons bay area and actually allowed a negative AO anomaly of almost 1 SD compared to +1 this january. I am wondering what with the Jan QBO coming in at -26.70 by far the lowest reading for January since 1979 whether this would have the effect of strengthening the easterly winds around the equator but by being so strong not allowing them to expand further north as seen below from the 30 hpa mean zonal wind. Apart from 1 or 2 very brief easterly transitions you can clearly see the dominance of strong westerly zonal winds.

I think any chance of a potent and newsworthy cold spell in mid to long range depends on the strength of the MJO signal. If we see a strong signal which pushes heights well into Alaska and the Arctic then we are likely to see a trop response with a much more amplified pattern over the Arctic and a much greater chance of a very cold Arctic outbreak. The 06z gfs run coming out at the moment for instance shows much stronger ridging into these areas so it wil be interesting to see where this run takes us. My money would be on for a stronger MJO response to what the models are showing and thus a greater likelyhood of a very cold spell in the last week of Feb.

Good to see the 06z gfs run really amplifing the pattern admittedly in the far far reaches of FI but certainly in keeping with my thoughts for the last week of the month. The forcing from the MJO slowly taking effect on the northern hemispheric tropospheric pattern although a forcing of the magnitude seen on the 06z would reach well into the strat I would of thought. Hoping to see this becoming a regular theme over the coming model runs and ens.

From my experience the anomaly charts are not always first to the party when it comes to pattern changes. Taking them in isolation is not a good practise. Expecting to see a growing trend in mid to long range for more amplified and much colder northerly incursions.

Cracking run and looks like our most potent easterly since 91. I must admit for me when you see a 1040 mb high orientated in such a way as to allow the bitterly cold east/ northeasterly air to push west over the UK there are very few better winter synoptic patterns.

Not sure this is the reason at all.At the present time we have strong westerly wind burst near the date line with strong convection. Easterly trade winds are weaker than they have been plus you can see quite easily on the synoptic models the amplification over western north America and into the Arctic on the opposite side of the pole. Stratospheric forcings are probably very much involved but with what I believe will be a increasingly strong MJO signal this may help to override the lower strat signals and we see a tropospheric response perhaps into the lower strat. Overall I remain very optimistic for the last 8 or 9 days of the month.

The GFS has in my opinion trumped the Euro's again this time with the MJO signal. I would not be at all surprised to see a much more amplified pattern going forward from mid month onwards with the risk of some really potent Arctic outbreaks. Having said this I would expect the models especially the GFS to be picking this up in its longer output. No reason what so ever to feel disheartened by the Meto update. Although they have been fairly good this winter they can and do get it wrong. Below are the last 3 days OLR anomalies. Certainly looking quite impressive.

This is the strongest signal I think this winter from the MJO and with the strong convection around the date line hopefully this will work its magic. The strat lower down looks susceptible for ridging to amplify remembering of course the more the strat is affected so any northern blocking will be that much stronger. I have a feeling that we should see more amplified northern hemispheric synoptic patterns in future runs with perhaps the potential for something much colder than we have seen so far this winter post the second half of February.

Runs this afternoon and evening have definitely toned down the amount of northern amplification that they were showing yesterday. Only had a quick flip through the GFS ens but they look no where near as amplified either. I did say that they could be over reacting to a MJO signal and that may well have been the case but the MJO signal remains strong and the models could well have been to progressive with this. Best to see how the models behave over the next few days rather than speculate on rinse and repeat cycles etc.

The GFS has consistently shown an area of snow moving down from the wash around 4 am in a south westerly direction giving roughly 3 to 4 hours of snow with west cambridge, bedfordshire and hertfordshire in prime location before the snow continues to weaken as it moves further south and west. You can see this quite cleary on the high res 0.25 degrees on meteociel. Temps, dew points and 850's all look conducive for lying snow. If this proves accurate then I could see some places getting 5 or 6cm before it peters out.