Model Output Discussion

[TEITS]

The reason I say boring is quiet simple. At the moment the models in the medium range suggest HP being centred near to the UK or just to the S. Let me use the GFS +240 as an example.

http://www.wetterzentrale.de/pics/Rtavn2401.png

With this chart there wouldn't be any snow, frost, gales, rain but you would have relatively mild temps. Im sorry but that to me sounds boring. The only positive is it would decrease my fuel bills!

I will add that I haven't been spoilt. Seen many days of lying snow but for actual snowfalls then Feb 09 was actually better for my location.

Edited January 21, 2010 by THE EYE IN THE SKY

[MisfitDog3]

Interesting positioning of the dominant 'High' by some of the models. Doesn't look right to me in any of them! Instinct again. I suspect the Atlantic is going to have much more of a say, middle of next week and beyond, than is shown at present.

Either that or we are going to be faced by one mother of an Easterly which is going to appear out of the model gloom with very little warning. I prefer the Atlantic scenario at present!

[Rollo]

Given what most of us have enjoyed thus far this winter I agree with the posters who think the current weather situation is becoming boring. If the 6z is to be believed then we will have to wait some time for any meaningful cold. looking on the brighter side this often do change quickly but we snow lovers have been spoilt so far this winter.

[Bobby]

Heh people were laughing off the 12z ECM after this morning's runs and now the GFS is showing something very similar. I think we can now be confident we aren't going to get much of an Easterly. After that, who knows.

[bluearmy]

The reason I say boring is quiet simple. At the moment the models in the medium range suggest HP being centred near to the UK or just to the S. Let me use the GFS +240 as an example.

http://www.wetterzentrale.de/pics/Rtavn2401.png

With this chart there wouldn't be any snow, frost, gales, rain but you would have relatively mild temps. Im sorry but that to me sounds boring. The only positive is it would decrease my fuel bills!

I will add that I haven't been spoilt. Seen many days of lying snow but for actual snowfalls then Feb 09 was actually better for my location.

you may well be right Dave, but i have a feeling your spirits will be lifted in the medium term within a couple of days. more WAA on the agenda.

[karyo]

I'm afraid the 6z ensembles highlight the departure from the easterly scenario!

http://www.netweather.tv/index.cgi?action=ensviewer;sess=

The mean only touches -5c upper air for a short time, and that's for London! Not much support for a northerly of any substance either. However, at least the outlook doesn't look diabolically mild!

Let's hope the stratospheric warming will make it's effects felt sometime next month.

Karyo

[Glacier Point]

Not sure if there's even much of an easterly at the surface on the 06z GFS run, briefly perhaps across the far south on Monday with some cold air around in the east, but winds look light and variable across England and Wales Saturday onwards into early next week with slack pressure gradients under HP. A brisk or strong SW'erly developing across Scotland and N. Ireland early next week as deep lows track NE across Iceland.

Certainly a growing signal from NWP for HP to build to the W and NW in the longer term towards early Feb with perhaps the PV dropping down into Scandi.

Indeed Nick.

Quite a good example of tropical forcing right now. Strong convection is centred just west of the Dateline which equates to a strong MJO Phase 7 projection for end January into February.

http://cawcr.gov.au/bmrc/clfor/cfstaff/matw/maproom/OLR/m.3d.html

Compare the composites for this phase:

http://raleighwx.easternuswx.com/MJO/FebruaryPhase7500mb.gif

(remember this is a composite of just 16 days - how can the weather be chaotic and generate composites like this ?)

.... with GFS and GEM ensemble means day centred on day 8:

http://raleighwx.easternuswx.com/models/gfsensemble/00zGFSEnsembles500mbHeightAnomalyNH192.gif

http://raleighwx.easternuswx.com/models/cmcensemble/00zGGEMEnsembles500mbHeightAnomalyNH192.gif

The Global Wind Oscillation orbiting phases 1-4 is also reasonably supportive of this longwave pattern.

The northern-most extension of the ridge will be defined by (a) how far the tropical convective signal moves east across the Dateline and ( the immediate impacts of sharply downwelling waves associated with warming of the atmopshere.

Both the tropical convection and downwelling waves have limited shelf lives so we should expect to see the core of the high shift towards the UK and then Europe in time. Both GFS and GEM ensembles agree and want to bring the high towards the UK days 11-15. Whether this is a touch progressive remains to be seen, but a lot of dry and more settled weather to come I think.

[Kentish Man]

The 06z ensembles are now suggesting a prominent mild spike around the 27/28th backed by a majority of members, presumably as the high gets sucked to the west of the UK with mildish air flowing round the top over the UK. This is a big contrast to last night (bar the ECM) which were suggesting cold high scenarios and cold ground temperatures well into next week. The operational is on the mild side into FI but right now we seem to be at the moment when the pattern for much of the rest of the winter is being decided. Tonights runs will be significant.

Edited January 21, 2010 by Kentish Man

[Bottesford]

The reason I say boring is quiet simple. At the moment the models in the medium range suggest HP being centred near to the UK or just to the S. Let me use the GFS +240 as an example.

http://www.wetterzentrale.de/pics/Rtavn2401.png

With this chart there wouldn't be any snow, frost, gales, rain but you would have relatively mild temps. Im sorry but that to me sounds boring. The only positive is it would decrease my fuel bills!

I will add that I haven't been spoilt. Seen many days of lying snow but for actual snowfalls then Feb 09 was actually better for my location.

True it does look fairly uninteresting... but still I'd rather have dull with temps 8-10c rather than dull with temps 2-4c. So from my point of view it would be an improvement on the recent weather albeit still nothing exciting nor special.

[karyo]

The northern-most extension of the ridge will be defined by (a) how far the tropical convective signal moves east across the Dateline and ( the immediate impacts of sharply downwelling waves associated with warming of the atmopshere.

Both the tropical convection and downwelling waves have limited shelf lives so we should expect to see the core of the high shift towards the UK and then Europe in time. Both GFS and GEM ensembles agree and want to bring the high towards the UK days 11-15. Whether this is a touch progressive remains to be seen, but a lot of dry and more settled weather to come I think.

GP, it sounds mild and dry to me! Any chance for the high to ridge northwards, or a renewed spell of northern blocking in February, with the help of a warm stratosphere?

Give us some hope however slight please...

Failing that, promise we'll get a cold March! lol

Karyo

Edited January 21, 2010 by karyo

[Glacier Point]

Give us some hope however slight please...

Karyo

If tropical convection shifts just east of its current position, then there is more inclination towards the high being shifted further north allowing more a north-easterly component. Beyond that, when the convective signal retreats towards the Indian Ocean (or fades), on current analysis, there is a strong signal for high pressure being dominant and gradually drifting south and eastwards which is not conducive to upper cold.

The return of stratospheric temps to above normal should only be felt in the longer term well into February, probably more so March such are the timescales for these things beyond immediate fast propagation. We have the legacy of a lagged impact of a sustained cold stratosphere to work through just yet, allied to a low angular momentum which are not going to help with high latitude blocking in February.

[Duane S.]

For a couple of days the ensembles for Dorset were consistently showing 3-4 members around -13 on the 850s around the 27th of Jan, now the vast majority don't even hit sub -5. In fact the 06z Operational sits pretty well with the mean and they (the ensembles in general) have been showing better agreement in the short-mid term of late than they have for a while.

AO on the way back down again and NAO staying neutral for a while but after that>>? It's up in the air! (these are yesterday's though still, today's reflections are due soon I think)

Short term trend is for a ridge from the azores to link with the faltering block to our East, build over us then sink as a result of the energy to our N. Initially any Easterly looks like it wil be reserved for the far South and will be nothing to write home about to put it mildly! Later on the Northerly blast out of the Arctic still looking on, IMO, but the threat has shifted way past the Meridian towards Eastern Scandinavia and beyond (if the current charts are to be believed of course). If heights to our NW can be promoted later (as should hopefully be the case come about the end of Jan when there should be an opportunity) then this could very easily advect this cold air back Westwards.

Overall though, not exactly what I would class as a classic morning of charts!

[Lewis]

Rather mixed signals with the models, nothing really certain in regards to the pattern. Some lovely runs in FI, but that's FI.

Short to medium turn looks like drier interludes inbetween more unsettled weather, not exactly warm, with temps still below average for N areas, with some wintry showers possible for higher parts of N England, Scotland.

I'm more than certain they will be a lot of changes.

Edited January 21, 2010 by Storm Force Lewis

[karyo]

If tropical convection shifts just east of its current position, then there is more inclination towards the high being shifted further north allowing more a north-easterly component. Beyond that, when the convective signal retreats towards the Indian Ocean (or fades), on current analysis, there is a strong signal for high pressure being dominant and gradually drifting south and eastwards which is not conducive to upper cold.

The return of stratospheric temps to above normal should only be felt in the longer term well into February, probably more so March such are the timescales for these things beyond immediate fast propagation. We have the legacy of a lagged impact of a sustained cold stratosphere to work through just yet, allied to a low angular momentum which are not going to help with high latitude blocking in February.

Thank you GP, I appreciate your response!

This gives us something to look out for.

Karyo

The Met Office further outlook doesn't sound too bad! Around average for the west and north, below average for the east and south. The uncertainty is highlighted once again!

Karyo

[Snowyowl9]

Gem is probably the best run for next weeks easterly,it does collapse in the end but still it would be cold with HP .

http://www.wzkarten.de/pics/Rgem1201.gif

http://www.wzkarten.de/pics/Rgem1441.gif

http://www.wzkarten.de/pics/Rgem1681.gif

No comment as far as GFS is showing.

[ghrud]

Funny how the gfs 06z resembles the ecm yesterday, swings and roundabouts really. As for this weekend, dull, dry and boring with near average temps sums it up.

I've just look at this and thought exactly the same thing. So everything still confused a the moment hopefully we can get some concensus in the next couple of runs.

[snowmadchrisuk]

Gem is probably the best run for next weeks easterly,it does collapse in the end but still it would be cold with HP .

http://www.wzkarten.de/pics/Rgem1201.gif

http://www.wzkarten.de/pics/Rgem1441.gif

http://www.wzkarten.de/pics/Rgem1681.gif

No comment as far as GFS is showing.

And by the 12Z'S The Easterly and then Northerly could be back on . I really can not find any consistency in the models currently .

Nice to see the MJO zooming through phase 6 and heading for phase 7 on todays update , this may give the models more confidence in a Greenland High.

[Nick F]

Both the tropical convection and downwelling waves have limited shelf lives so we should expect to see the core of the high shift towards the UK and then Europe in time. Both GFS and GEM ensembles agree and want to bring the high towards the UK days 11-15. Whether this is a touch progressive remains to be seen, but a lot of dry and more settled weather to come I think.

Thanks for the analysis Stewart.

So from that teleconnection signal, one would assume the broad trend is for high pressure to build N to the W of the UK into the medium term - as the trough over the NW Atlantic disrupts and retreats back a little across NE N America - while heights fall to the NE over Scandinavia as the PV shifts E and SE at higher lattitudes. Then longer-term the mid-Atlantic ridge shifting E and SE across the UK as the wave pattern begins to shift east again upstream.

Best scenario for any cold and snow from this pattern would probably be a N'erly toppler, unless the Atlantic ridge can build further north to allow a cold arctic flow from the N to last a few days or more, this would rely on a more amplified upper flow pattern though.

[summer blizzard]

Personally i do not see why everybody is downbeat, the GFS6z run looks a nice run with plenty of frost, and sunny skies for most of the run, what is more, the ECWMF is in agreement with the GFS until next weekend, so while it may not be the snowy senario people wanted, it could be far worse.

[Southender]

Personally i do not see why everybody is downbeat, the GFS6z run looks a nice run with plenty of frost, and sunny skies for most of the run, what is more, the ECWMF is in agreement with the GFS until next weekend, so while it may not be the snowy senario people wanted, it could be far worse.

You think?

Screams cloudy HP to me.

Either way, it aint a great end to Jan for coldies.

Edited January 21, 2010 by LeighShrimper

[karyo]

As snowmanchris already mentioned, nice MJO progress towards the more favourable phases: http://cawcr.gov.au/bmrc/clfor/cfstaff/matw/maproom/RMM/phase.Last40days.gif

We need to see it strengthen and hopefully enter phase 7 and 8, for the high to edge further north!

Karyo

[mushymanrob]

You think?

Screams cloudy HP to me.

Either way, it aint a great end to Jan for coldies.

..... but great for those of us who dont want any more cold!

[weather eater]

I will add that I haven't been spoilt. Seen many days of lying snow but for actual snowfalls then Feb 09 was actually better for my location.

Hi Dave the opposite for me, snowfall was minimal and it didn't hang around for very long, this year it’s been much better.

In terms of the models I tend to get more interested when there's no clear picture, most of the time charts with a screaming easterly at 144hr rather suggest to me that although something similar may come off, the likelihood is that 95% of the time we end up with something not quite as good. This happened in both the cold spell before Christmas and the one after. Before anyone jumps on me, I'm not for an instant trying to suggest that either spell was rubbish only that some of the projections prior to the events were out of this world, and what we ended up with was somewhat watered down. So I prefer it when, things are a little more up in the air.

[karyo]

Hi Dave the opposite for me, snowfall was minimal and it didn't hang around for very long, this year its been much better.

Same here! In fact for the Manchester area, you need to go many decades back to match the cold and snow we've experienced since December!

I liked last winter also, but not much snow!

I think the 12z's should meet somewhere in the middle, with high pressure the main theme. The further north you are, the more Atlantic influence you will see...

Karyo

Edited January 21, 2010 by karyo

[sebastiaan1973]

As snowmanchris already mentioned, nice MJO progress towards the more favourable phases: http://cawcr.gov.au/....Last40days.gif

We need to see it strengthen and hopefully enter phase 7 and 8, for the high to edge further north!

Karyo

Hey Karyo

very interesting what you and some others post over here in this topic

where can I find some more information for the correlation between the phases of MJO and positioning of high pressure in our neighbourhood?

thanks!!

sebastiaan