Model output discussion - mid-winter

[Nick F]

Broad scale pattern looks fairly set between the models for next week, a strong 200mph  WNWly  jet stream running from New Foundland across the Atlantic, S Ireland and far S of England with UK staying on the cold polar side under a strong Pm WNW flow, occasionally veering NWly behind any waves moving through. 

However, more mesoscale features are far off being resolved, for sample 00z EC blows up a deep low while crossing central parts next Tuesday (Storm Fionn?), GFS doesn’t,

so little point looking at too much detail such as snow, suffice to say upland areas of northern and western areas will likely see good snow accumulations from wintry showers. Snow may fall to lower levels too in north and west, but too far off to say when.

By the weekend following next week, too far off for forecasting with any great confidence, as would be expected, but some trends emerging from the 00z ENS and ops over buckling the jet over the Atlantic enough to allow a northerly to develop, though whether this gets quickly toppled from the W/NW or enough ridging to the west is maintained to allow a NEly develop remains to be seen.

But there is little sign of mild weather on the horizon after next week commences and plenty of wintry potential, albeit transitory in nature ... for now

Edited January 11, 2018 by Nick F

[swfc]

Yet again the deep cold 850s head south into eastern europe be it day ten ete.still good looking nhp and pv destroyed! !!

 

[tight isobar]

6 minutes ago, mulzy said:

Not so sure, think with the Azores High lurking with intent, we need to look west again after 10 days.  If we can take the Azores High out of the equation then there is some potential...

Tbf, i like the thought of the AZHP, IN the equastion at this point of possibilities!!..

As russian warmth good easily exact with az-high..and again the form feed would be siberian, element inflow..

Its a million miles away as it stands.. but mass potential quite a bit before that.  

However- evolutions are of much to ponder over!..and for all the correct reasons...if cold/winter weather is your forte..

Edited January 11, 2018 by tight isobar

[Singularity]

We're now seeing some GFS runs in which the tropospheric wave action and stratospheric warming are making for a pleasingly disorganised polar vortex, but the insistence of the model in finding further bouts of Nina-like forcing instead of taking GLAAM on an upward trend is resulting in the subtropical ridges attempting to build into places like Europe when, if the anticipated GLAAM rise does kick in, they should go elsewhere.

Hopefully we're barking up the right tree and GFS the wrong one. The tropical signal propagation is still uncertain enough to keep me from becoming complacent. 

p.s. as we see in offerman's post just now, it is amusing how a certain word for the rear gets turned into 'weeble' 

Edited January 11, 2018 by Singularity

[offerman]

6 minutes ago, mulzy said:

Not so sure, think with the Azores High lurking with intent, we need to look west again after 10 days.  If we can take the Azores High out of the equation then there is some potential...

Absoloutely spot on post. I have been banging on about this Azores high problem for ages. 

Unless that moves south or westward it is so strong a feature nothing will happen from the East or North. Attacks from the North are feable when up against Azores high. It’s a pain in the weeble really apart from summer of course when we want it:-) 

 

at best sny attacks will be slanted zonal or northwesterlies which could produce some wet white stuff . 

[Man With Beard]

ECM clusters: Once again, the op run cluster is the weakest/latest on mid-Atlantic height rises around 19th January. A short Nly/NWly still a reasonable bet on the other clusters.

Still lacking a clear way forward after D10.

 

[ArHu3]

6 minutes ago, Singularity said:

We're now seeing some GFS runs in which the tropospheric wave action and stratospheric warming are making for a pleasingly disorganised polar vortex, but the insistence of the model in finding further bouts of Nina-like forcing instead of taking GLAAM on an upward trend is resulting in the subtropical ridges attempting to build into places like Europe when, if the anticipated GLAAM rise does kick in, they should go elsewhere.

Hopefully we're barking up the right tree and GFS the wrong one. The tropical signal propagation is still uncertain enough to keep me from becoming complacent. 

Do you have any idea why BOM and NOAA have such a different observed mjo over the recent months? 

http://www.bom.gov.au/climate/mjo/

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

[TEITS]

Looking at the models for snowfall is pointless and I shall explain why.

At the moment the max temps during this oncoming cold W/WNW,ly look to be between 2-5C with mins around -1C to 1C. However this doesn't tell the whole story because a cluster of heavy showers is likely to drop the temp. So for low lying areas whether you see snow or rain could depend on timing and intensity of showers. For example a light shower during the day may only bring rain. If however an organised band of heavy showers moved into say NW Wales and extended into the midlands during the overnight period then this could give some accumlations of snow.

Currently the models are no use for this level of detail at the moment and you're going to be better off viewing models such as the Euro 4 and even at +48 will be subject to change.

Beyond this and im clueless at the moment. The difference between the 0Z & 06Z GFS FI clearly shows this and so does comparing the 0Z ECM with last nights. The combination of the blocking to the NE and N forcing the trough SE is likely to cause huge problems. I am fairly confident that the W,ly will veer towards a NW/N,ly as the trough begins to sink S. My confusion is what happens beyond this?

 

[ACCOUNT DELETED]

9 minutes ago, offerman said:

Absoloutely spot on post. I have been banging on about this Azores high problem for ages. 

Unless that moves south or westward it is so strong a feature nothing will happen from the East or North. Attacks from the North are feable when up against Azores high. It’s a pain in the weeble really apart from summer of course when we want it:-) 

 

at best sny attacks will be slanted zonal or northwesterlies which could produce some wet white stuff . 

Yes indeed let's hope that Azores high can stay close by through June, July & August or is that going to be the time it'll be nowhere near us to allow another cool, wet Summer? Lol 

[nick sussex]

I think what marks this winter out as different to some recent ones is the models when dropping the teases don't revert to some horror show for coldies.

Often its been the case of the teases verifying or bust for coldies in recent years so although the expected outlook doesn't shout ice days and crunchy snow and the depth of cold isn't great it's a lot better than could have been the case.

Concerns over the Azores high shouldn't be uppermost at this point because whilst blocking remains over western Russia this blocks the Euro troughing from edging too far east.

So its not what some might call typical zonal or typical UK winter fare because that wouldn't include the Euro trough.

There are certain robust correlations with the UK in winter, so Euro trough normally keeps the UK on the colder side, the Azores high might be desperate to move ne into southern Europe but hits a brick wall with the trough in place.

What happens past day ten seems more uncertain. Much depends on what happens upstream and the outlook to a large degree will be governed by the amplification.

Because we have the Euro trough solidly agreed on then more amplification upstream will develop a better cut back in the jet towards the UK and develop ridging to the north.

Flatter upstream and then we have to rely on the Russian block continuing to trap the Euro trough.

So whilst of course we'd love to see some much colder upper air modelled the pattern does give chances for the odd snow surprise via a shortwave running east and of course if you're on higher ground especially to the north a better chance of seeing some decent coverings.

 

 

 

 

[Alexis]

22 minutes ago, mulzy said:

Not so sure, think with the Azores High lurking with intent, we need to look west again after 10 days.  If we can take the Azores High out of the equation then there is some potential...

Don't make me dig out the post pointing out the permanence of the Azores high and how it has no bearing on cold spells!

[bluearmy]

If only we could get an anomoly chart like this in January .....

[andymusic]

9 minutes ago, TEITS said:

Looking at the models for snowfall is pointless and I shall explain why.

At the moment the max temps during this oncoming cold W/WNW,ly look to be between 2-5C with mins around -1C to 1C. However this doesn't tell the whole story because a cluster of heavy showers is likely to drop the temp. So for low lying areas whether you see snow or rain could depend on timing and intensity of showers. For example a light shower during the day may only bring rain. If however an organised band of heavy showers moved into say NW Wales and extended into the midlands during the overnight period then this could give some accumlations of snow.

Currently the models are no use for this level of detail at the moment and you're going to be better off viewing models such as the Euro 4 and even at +48 will be subject to change.

Beyond this and im clueless at the moment. The difference between the 0Z & 06Z GFS FI clearly shows this and so does comparing the 0Z ECM with last nights. The combination of the blocking to the NE and N forcing the trough SE is likely to cause huge problems. I am fairly confident that the W,ly will veer towards a NW/N,ly as the trough begins to sink S. My confusion is what happens beyond this?

 

would have thought you'd have the crystal ball out for beyond current modelling, come on Teits, your the master

[karyo]

3 minutes ago, bluearmy said:

If only we could get an anomoly chart like this in January .....

When is this chart for?

[nick sussex]

1 minute ago, karyo said:

When is this chart for?

BA was being cheeky, you can't see the date but I think that's for next week.

[shaky]

8 minutes ago, bluearmy said:

If only we could get an anomoly chart like this in January .....

Even that anomaly will most probably bring warm air from the mediterranean knowing our luck mate!!

[karyo]

11 minutes ago, TEITS said:

Looking at the models for snowfall is pointless and I shall explain why.

At the moment the max temps during this oncoming cold W/WNW,ly look to be between 2-5C with mins around -1C to 1C. However this doesn't tell the whole story because a cluster of heavy showers is likely to drop the temp. So for low lying areas whether you see snow or rain could depend on timing and intensity of showers. For example a light shower during the day may only bring rain. If however an organised band of heavy showers moved into say NW Wales and extended into the midlands during the overnight period then this could give some accumlations of snow.

Currently the models are no use for this level of detail at the moment and you're going to be better off viewing models such as the Euro 4 and even at +48 will be subject to change.

Agreed! In marginal situations intensity is key! A few weeks back I had a day of frequent showers of rain/sleet/hail and snow on the nearby hills. A more organised afternoon band turned everything white for a couple of hours. Further showers that followed in the evening were mostly of rain as they were a lot lighter. This event happened with uppers around -6.

[bluearmy]

THAT CHART IS TODAY’S PEOPLE !!

Surely we are the unluckiest country in the world for wintry conditions !!

Edited January 11, 2018 by bluearmy

[nick sussex]

3 minutes ago, bluearmy said:

THAT CHART IS TODAY’S PEOPLE !!

Surely we are the unluckiest country in the world for wintry conditions !!

Oh!

Yes bad luck that there was no cold air to the east to tap into but its always the same. When theres lots of cold air there the pattern won't allow that west and when the flow manages to come in from the east se theres no cold air.

However given some of the horror weather we've seen globally the UK at least doesn't have to contend  with that.

 

[Singularity]

45 minutes ago, ArHu3 said:

Do you have any idea why BOM and NOAA have such a different observed mjo over the recent months? 

http://www.bom.gov.au/climate/mjo/

 

http://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/CLIVAR/clivar_wh.shtml

When I visit the BOM site and choose anything other than Jan-Mar last year for the phase plots, I get blank diagrams. True, that does make for a different picture... 
Are you referring to one of the other plots on the BOM site?

[ArHu3]

3 minutes ago, Singularity said:

When I visit the BOM site and choose anything other than Jan-Mar last year for the phase plots, I get blank diagrams. True, that does make for a different picture... 
Are you referring to one of the other plots on the BOM site?

 

This one, it's not blank for me, all points are about - 0.5 on the rmm1 axis (everything is shifted left( or west?)) 

[bluearmy]

21 minutes ago, nick sussex said:

Oh!

Yes bad luck that there was no cold air to the east to tap into but its always the same. When theres lots of cold air there the pattern won't allow that west and when the flow manages to come in from the east se theres no cold air.

However given some of the horror weather we've seen globally the UK at least doesn't have to contend  with that.

 

Day three is even worse 

[Singularity]

2 minutes ago, ArHu3 said:

 

This one, it's not blank for me, all points are about - 0.5 on the rmm1 axis (everything is shifted left( or west?)) 

Looks like a case of not pressing any buttons for me; with a refresh I then get to see it

Interesting difference given both use the Wheeler and Hendon RMM methodology... either it's a systematic error by one of the sites, or one version has more updated methodology than the other. 

[beefy201]

A wet and windy week for majority of uk next week is my interpretation ......

[feb1991blizzard]

45 minutes ago, bluearmy said:

THAT CHART IS TODAY’S PEOPLE !!

Surely we are the unluckiest country in the world for wintry conditions !!

YES, but that's why I hate anomaly charts for specific dates on op runs, they just don't tell the story, give me generic charts any day, anoms ok(ish) for monthlies and weeklies and perhaps ensemble means.