Model Output Discussion

[cooling climate]

lol cant dissagree with that from thease charts would you you think that the cold enriched would provide southern england with a chance?

In one word yes. The trend is east and imo the models will keep trending east.

This is just my opinion mind, but fun could be had by all next week.

I have gone for a very low cet for February but I must admit I thought the very cold

weather would have arrived already.

[J10]

If it was mid January and not heading into towards the end of February then I'd be happier with tonights ECM as there could be alot more surface cold developing.

For northern areas I'd say its still a decent run, for the south more marginal, it would be a shame to see all that very cold air spilling into the Atlantic.

I think it is a decent run for all areas, perhaps better the further north and west you are.

[full_frontal_occlusion]

This is where the Kalman filters in the models will influence trajectory of larger scale dynamic features such as those lows - increasing rates of change in position resulting in overshoot then undershoot and finally stable between runs.

If I'm right, expect the lows to progressively appear further E/SE before back-tracking and finally settling somwhere between the two.

But as NS mentions, it remains to be seen how much the reverse zonals modify the evolution.

ffO.

Edited February 9, 2010 by full_frontal_occlusion

[January Snowstorm]

If it was mid January and not heading into towards the end of February then I'd be happier with tonights ECM as there could be alot more surface cold developing.

For northern areas I'd say its still a decent run, for the south more marginal, it would be a shame to see all that very cold air spilling into the Atlantic.

And Ireland

Looks very promising for us as we are that bit further West.

Don't forget GROUND temps which have yet to recover after Jan's freeze up will help in snow lying.

[cooling climate]

I could be way off the mark here but the way I see this heading is troughing over Denmark,

the low countries and Germany with the block sitting over eastern Greenland, Svalbard and

northern Scandinavia with a bitter unstable northeasterly feed over the UK.

This is the way I expect to see the models heading over the next three or four days.

[Frosty.]

Have to say the models next week are favouring scotland more than anywhere else, definately more chance of low ground snowfalls up north next week if the current trend continues but at least that will compensate for the dry mainly benign conditions up there until sunday, then it gets very interesting.

[azores92]

And Ireland

Looks very promising for us as we are that bit further West.

Don't forget GROUND temps which have yet to recover after Jan's freeze up will help in snow lying.

nah mate ireland will miss out on all the fun, too close to the milder stuff . very promising model runs again tonight, ecm perhaps borderline for those away from higher ground.

[MR EXTREMES]

I could be way off the mark here but the way I see this heading is troughing over Denmark,

the low countries and Germany with the block sitting over eastern Greenland, Svalbard and

northern Scandinavia with a bitter unstable northeasterly feed over the UK.

This is the way I expect to see the models heading over the next three or four days.

this would by the mother and father of all outputs i see where your heading with your thoughts and its always possible i think theres more twists to come and to start its heading in the right,sh direction.

to be very honest i think your on to something flicking through the ecm it does look like the high pushes out ridges whether thease would be strong enough for a slight eastward shift then that where more outputs are needed.

but i can tell you right now im 70/40 that it wont pan out this way,

i think better runs are to come.

i dont think it will center over the uk,

northsea down near holland into germany sounds very possible.

Edited February 9, 2010 by badboy657

[The Weather Dragon]

We need the greenland high about 500 miles south east, if were to be guaranteed blizzards. that aint guna happen

...

Most people though that the current cold spell 'weren't guna happen'....but it did. 500 miles isn't much when looking at a Global scale.

Edited February 9, 2010 by Jonathan Evans

[KTtom]

I think it is a decent run for all areas, perhaps better the further north and west you are.

Must admit I was getting a little concerned with the upper temps, there always seems to be the old warm sectors with lows that move south, strangely enough you seem to get better chances of widespread snow with lows moving north!

Good old Derek on BBC Wales 'I know some of you are looking for more snow, I don't think there will be much this week, but next week could be entirely different'

[nick sussex]

Some of the most memorable snow events have occurred with HP over Greenland and very low heights over the UK, if the pattern is shifted much further East it could just end up a standard northerly. Let's have some excitement, of course there would be marginality involved and you need to be on the right side of the Lows. Would people have moaned if the models had produced this tonight :-

http://www.wzkarten3.de/pics/archive/ra/1968/Rrea00119680206.gif

Can you remind me what happened in that archive chart?, i was still crawling around the floor in nappies at that point! Don't get me wrong they're not bad charts but theres not alot of margin for error. The JMA tonight looks a slightly better way of that set up developing, yes its cannon fodder! but a good example of how things might develop slightly more favourably even with the sw movement of the Scandi trough.

Edited February 9, 2010 by nick sussex

[Optimus Prime]

Can you remind me what happened in that archive chart?,

From TAHARLEY;

"February 1968. (CET 1.9c) Cold and largely dry but with some heavy snowfalls. There was a paticularly heavy snowstorm over the west Midlands on the 5th. Heavy snow fell at Keele for 12 hours, giving 37 cm. Crewe station was blocked. Many roads blocked, particularly in Staffs. Up to 45 cm of snow in some places. There was widespread disruption to traffic in Birmingham; but only a little way away, in Nottingham, the precipitation fell as rain. I don't remember these events at all - nor do I remember snow from the following February. Apparently it wasn't that cold, and not really predicted. In fact, rather oddly, I can't remember any snow in the 60s other than 1963."

Edited February 9, 2010 by Optimus Prime

[nick sussex]

From TAHARLEY;

"February 1968. (CET 1.9c) Cold and largely dry but with some heavy snowfalls. There was a paticularly heavy snowstorm over the west Midlands on the 5th. Heavy snow fell at Keele for 12 hours, giving 37 cm. Crewe station was blocked. Many roads blocked, particularly in Staffs. Up to 45 cm of snow in some places. There was widespread disruption to traffic in Birmingham; but only a little way away, in Nottingham, the precipitation fell as rain. I don't remember these events at all - nor do I remember snow from the following February. Apparently it wasn't that cold, and not really predicted. In fact, rather oddly, I can't remember any snow in the 60s other than 1963."

Thanks for that

Reading the report though it seemed marginal, thats why i'd still like to see the low slightly further east, or something close to the JMA would be an improvement.

[remymartin]

Thanks for that

Reading the report though it seemed marginal, thats why i'd still like to see the low slightly further east, or something close to the JMA would be an improvement.

Be carefull what you wish for!

[nick sussex]

Be carefull what you wish for!

Its unlikely the low will be shunted hundreds of miles further east than tonights ECM output because we're not dealing with a northerly toppler, the reverse zonal winds if anything are going to lock the trough into Scandi.

If you look at the mean height comparisons the ECM and GFS are similar but the ECM has an Omega block further east.

http://www.meteo.psu.edu/~gadomski/ECMWF_12z/hgtcomp.html

Its a slow moving pattern, thats why its important that any phasing of lows near the UK is done with these further to the east, this will then see troughs thrown sw into the UK on the western flank of the low rather than slack low pressure stuck over the UK with the cold air slowly lifting out. We need help from the eastern USA trough to align favourably and block any further retrogression of the pattern.

Edited February 9, 2010 by nick sussex

[ITSY]

Be carefull what you wish for!

Exactly...

It looks good for a Cold and Snowy notherly blast based soley off of today's ouputs. I'd say that the week or so comencing tommorow and ending next wednesday or Thursday is the best (and probably the last great) window of opportunity to see any significant snowfall this winter.

I'll be away; sods law.

Anyway, it WILL be very interesting to see what GFS brings out in the next run...if it maintains this theme, then I think that you guys can expect something almost anywhere in the country during the next week or so.

[tinybill]

Be carefull what you wish for!

all i say wishers could be answerd next week

[grab my graupel]

Too many posts being moved folks. Can we try to use the relevant threads please?

Thanks

Brian

[swilliam]

Some of the most memorable snow events have occurred with HP over Greenland and very low heights over the UK, if the pattern is shifted much further East it could just end up a standard northerly. Let's have some excitement, of course there would be marginality involved and you need to be on the right side of the Lows. Would people have moaned if the models had produced this tonight :-

http://www.wzkarten3...00119680206.gif

I agree with this - I think the currently prognosed evolution would produce some very interesting weather. We do not want a bog standard Northerly or Northwesterly with quite cold weather, showers round the coats and dry inland. Looking at the +192 charts on both the ECM and the GFS the first thing that strikes you is how remarkably similar they are

You can see the North Pole HP ridging all the way down to the mid Atlantic and linking up to WAA from the Azores. The PV is distributed round the hemisphere in very similar fashion on each chart. Next you can see the position size and depth of the LP over the UK is very similar. The heights are remarkably low (510 on the ECM and 500 on the GFS)

Looking at the temps at 850 you can see they are about -7/-8 over most of the country. The depth of the cold is shown by the low temps at 500HPa.

Looking at the predicted surface temps from the GFS (I know how we all love and believe those) we can see that it is close to freezing with significant overnight frost

Finally we can see of course plenty of precipitation about with it all predicted to be snow.

So for me this looks very interesting and I hope it verifies something like this. It would be quite an unusual set up for us -does anybody know of any more analogues other than the one Ian posted?

[Weathizard]

all i say wishers could be answerd next week

Interesting, these charts seem to bring more of an NE/ENE flow to my part of the world which would presumably mean possibility for snow in the south as well as the north?

[Duane S.]

Some of the most memorable snow events have occurred with HP over Greenland and very low heights over the UK, if the pattern is shifted much further East it could just end up a standard northerly. Let's have some excitement, of course there would be marginality involved and you need to be on the right side of the Lows. Would people have moaned if the models had produced this tonight :-

http://www.wzkarten3.de/pics/archive/ra/1968/Rrea00119680206.gif

I'm glad someone else said what I was thinking. Not that I think it will, but if it ends up too far East it could be as poor as staying too far West. FWIW, I think the models are not far off showing where the troughing will be, longitude wise. Hugely risky for me but I'm up for it. After missing out of our single dumping of 1cm a month ago, why not I say!?

[damianslaw]

Alot is hinging on just how far west the high will retrogress next week in terms of likelihood of widespread low level snow. If it retrogresses too far west we will be left with a slow moving low pressure over the country which will eventually mix out the cold uppers, however, it stays further east we will be locked into a potentially very snowy set up, with troughs from the NE filtering south around the low heights - a classic locked in cold snowy pattern from the north, a true cold pattern and one we haven't seen in a long while. Uppers and dew points would be certainly conducive to low level snow.

Its encouraging that the models are beginning to move away from retrogression heading too far west, probably won't be until Friday when we can call for certain whether we are heading for a sustained snowy cold period or not. The signs are good but as ever caution is the word.

[Bobby]

Wow, JMA is Hollywood stuff

Artic blasts, freezing Elys, polar lows (or not but don't spoil my ramp), Atlantic attacks, the whole kitchen sink. Plausible though if it goes a bit further East but the GFS and ECM look OK as it is, maybe a little marginal but mainly snow I would think. GEM is better too, so a nice trend emerging, let's see what the pub run throws up.

[I remember Atlantic 252]

the low seems further west on the 18Z, dont want that, no use cold going into the Atlantic

[swfc]

Why wont the low slide sse.???.Pressure not that high to the south.