swilliam

I agree with this - we may not get the roaring easterly that most of us would like but the model watching is fascinating. One point though is that whichever scenario plays out do not slate the losing model for the next few weeks. The differences at t72-96 are quite small but the effect us massive.

The GFS is finding its own way to scupper the easterly (to be fair several of these options were showing on the ensembles)

That is not what his post says at all - a short extract first Models providing extremely poor guidance at the moment, most probably related to changes in the upper atmosphere and how fast warming propagates down. The time scales for this are not well defined so no surprise that blocking appears, disappears and reappeares then Before that, the GWO composites suggest the potential for trough disruption in the Atlantic and retrogression of highs to the North, as well as ridges pusing into the UK from the south-west (as per previous posting). A trough (or possible cut off upper low) to our east continues to look probable, as does some attempt for colder air to establish in from the NE during the second week of Feb. and finally So pressure building in from the south-west and slow evolution (mild to start) towards heights building across our north then north west delivering a cold snap looks the favourite before a return to high pressure over the UK towards mid month. All he said was the effects of Strat warming would not be felt for few weeks.

The block is stronger on this run but we need the residual Scandi trough to fill. Good Atlantic trough alignment

Thanks NSSC - I just thought that it takes 2 to Tango and that the details of the block are just as important as what is happening in the Atlantic

Concerning the UKMO 144 chart people are concentrating on the energy going into the N jet but I think more attention should be paid to the size, intensity and position of the block to the NE. Looking at the UK first you can see that the block is small, 'only' 1045 and quite a way east. The result is that the Atlantic LP just drifts and expands across the UK with a poor SW/NE alignment. It is difficult to get the Easterly from this position (although people should remember that 8th Feb is till over 70 hours away from this chart - small changes could still allow an Easterly of some description by then) Looking at the ECMF the block is bigger, more intense (1050) and crucially further N and a bit further W. It is now less easy for the Atlantic lows to move over us and they are further W and S. The alignment is now N/S and the easterly is easier to achieve although it takes till the famed 8th Feb at 216 to get there For the 06Z GFS the block is much bigger (even extending to Greenland), more intense again (1055) and well North and West. The result is that the Atlantic LPs are even further S and link up the LPs further East over Europe. The result is the troiugh is now aligned SE/NW and from here it is easyt o get an Easterly occurring within the next couple of days. It is interesting to see why the differences occur. Looking the GFS there is WAA from Russia towards the pole. This then links up with WA already near the pole and this then grows into the large block shown previously. Compare this to the UKMO there is the same WAA from Russia and the pool of warm air near the pole. However by +96 they fail to link up. The result at 120 is a much smaller, less intense block further S and E So I think we need to pay attention to how the block develops to our N&E

Yes a definite shift to many more mildsolutions. The GEFS ensembles are interesting in that they are split into two groups. Between 3-6 feb there are a group of cold solutions - presmably due the early start of an Easterly - and a group of milder ones - probaly indicative of a S/SW flow. Then again between 7-11 Feb there a group of v.cold solutions and some not so cold. Interstingly I think I can only see one that at no stage bring v.cold air in.

but a much more inspiring GEFS control run but unfortunately still in very much in FI

A less than inspiring 120 fax - looks like we will have to wait for the possible easterly.

GEM is not so good today only just making the Easterly and the NOGAPS shows how it can still all go wrong. I would say the chances of a good Easterly have reduced from SMs 70% to about 50% based on this mornings output.

GEM not as good this morning and if you want to see how it could all go wrong have a look at the NOGAPS.

They were similar in that they were shown in FI but the actual evolution here is quite different. Before Xmas it was a brief easterly into a Northerly but is shown here is the exact opposite and on a grander scale. It seems likely that we will get some very cold weather after the what looks like the very good Northerly this weekend. This can be gauged by the maor change in the ECMF ensembles which all now show cold solutions with almost none of the 50 showing temps above 0C in Holland for the next 15 days. Also the GEFS ensemble mean is near or below -5 throughout although there is a wider spread (it will be interesting to see what the 18Z shows). But the main issues are around the details and intensity of the cold - but as NS said earlier it is probably whether it is v. cold or bitterly cold. As for snow do not bother looking until 48 hrs beforehand.

Very poor run for FI - we only get to this!

120 fax has a nice snow streamer for the Irish Sea - could be good for West Wales and SW England

Similar thoughts from the MetO as well based on their medium term update 'Over this weekend occasional sleet or snow showers, heavy at times, are likely to affect eastern and northern parts but also some exposed western areas at times. It is expected to be cold or rather cold with widespread overnight frosts and a risk of icy patches. Elsewhere, there should be a good deal of drier and brighter conditions but rather windy for most. During next week the general trend is for a less cold period to develop with spells of rain, turning to sleet and snow over hills, mainly across northern areas. Drier and brighter in southern parts with a risk of overnight frosts. There is chance of drier and colder conditions developing towards the end of the period but confidence in this aspect is low.'

The run is quite similar to the 0Z if you compare the +240 to the one I posted earlier. You can see the general pattern is the same but in this case the Atlantic HP just fails to link up with the Russian high which wanders off eastwards this time. Result is no easterly in deep FI as was shown on the 0Z. Probably the angle of the Russian high is as important as anything in determining whether the link up happens or not - you see the difference below. 0Z 6Z

Actually if you look at the bigger picture the +240 GFS and ECMF are quite similar. Both show the link between the the Atlantic HP and the developing mega Siberian block which has been showing for several days now. The only difference is that the ECMF link is not quite so well established (probably just a timing thing) but more importantly is further South.

It is the parallel of the GEFS ensembles

15 day extended ensemble don't really support the easterly after the northerly - many more go for the NOAA idea of a flattened mild solution

It was in response to Barb saying the models were currently uninteresting i.e the weather predicted by the models is going to be uninteresting - weather and models are linked. Perhaps I should have said peoples expectations of the model output. Sorry I do not understand the last comment - why is it strange - the last cold spell was supposed to be the worst for nearly 20 years (i.e 81/82) - so if this is the only thing that you find exciting you might have to wait another 20 years - seems fairly simple?

I think peoples expectations have got way to high. Most years we would have been really excited by the possibilities of the projected Easterly with maybe ice days, severe frost and possibly some snow. The last cold spell was exceptional in that it was v.cold and was dominated by low pressure bring plenty of ppn events. This was most unusual. More commonly we might expect v.cold weather to be anticyclonic dominated (as currently forecast) with perhaps some snow flurries or showers and then maybe one major ppn event as the breakdown happens. If you are only going to be interested in v.cold with daily snow events then you might haved to wait another 20 years for your next exciting winter weather.

GEM is sticking with it - slightly different set up from this morning as expected but same general pattern

yes - an outstanding run - 1060mb block in S.Norway and 1040 in Greenland - then the high retrogresses to Greenland - this would be the absolute best we could hope for out of the current set up. Seems fairly unlikely but not impossible.

Still showing the decrease in the mean towards the end of the month