Model Output Discussion - 05/01/2016 18z onwards

[nick sussex]

The UKMO T96hrs fax chart:

Quite complicated in terms of snow!

 

 

[Mark Neal.]

Well whenever we have snow chances coming i get the Weather Online Expert charts out..

So we have two systems on Thurs & Fri which could give a mix of RainSleet/Snow which many have posted above what we need in places for a more wintry mix.

       

GFS Precip charts to make be taken with huge pinch of salt. let alone with snow with so many parameters known to have to be on side, John Holmes guides worth a read and the post a few up by Perfect Storm a great post! 

 

Edited January 9, 2016 by Mark N

[Yorlum11]

Really love this forum. Next week now looking more promising with models mostly showing a better ridge and more cold for longer. Just on a side note its snowing in many parts of Ireland this evening and the cold hasn't got going. I hope all ye smowbies get your fix!! 

Edited January 9, 2016 by Yorlum11

[feb1991blizzard]

Something interesting is going to happen on the last few frames of GFS 18z, anyone guess?  I will reveal all in a few minutes.

[northwestsnow]

4 minutes ago, nick sussex said:

The UKMO T96hrs fax chart:

Quite complicated in terms of snow!

 

 

Yes i think elevation is going to play a part nick, further north even.

[bluearmy]

going back to the AO/NAO posts from earlier, I don't see a sustained period of westerlies if at all for nw Europe. Im thinking areas of high heights and I have a feel for retrogression of the blocking. Maybe the oscillations will trend neutral or weakly positive for a time but I don't think it will be long before they are headed negative again.  

Proper winter never lasts for week after week in the UK, though if we get a mid lat high to follow the cold, then even less than impressive uppers can return cold surface T2's. 

No no need for pessimism from coldies.  

[Ali1977]

1 minute ago, feb1991blizzard said:

Something interesting is going to happen on the last few frames of GFS 18z, anyone guess?  I will reveal all in a few minutes.

SSW

[bobbydog]

27 minutes ago, bobbydog said:

troughing into the Med- 

scandi high coming........?

 

i'll get me coat....

[ALL ABOARD]

1 hour ago, feb1991blizzard said:

Something interesting is going to happen on the last few frames of GFS 18z, anyone guess?  I will reveal all in a few minutes.

 

Strat warming up? In all seriousness 18z is a much better run. Keep an eye on the strat temps over the next couple of days apparently its supposed to get quite toasty.

 

[bluearmy]

1 minute ago, Ali1977 said:

SSW

Not exactly Ali but an impressive 10hpa temp profile (though not for the first time at this range I hasten to add)

[nick sussex]

7 minutes ago, gottolovethisweather said:

Was it your shortwave which I saw riding over the top of the mid Atlantic ridge heading towards Iceland Nick, as that would indicate a different Jetstream profile at D6/D7 which is to be expected I guess. This now being one which favours prolonging the cold. What I'm looking at is on the chart on this post by Karlos.

No theres two shortwaves, the first the GFS makes less of an issue than in previous outputs this is ahead of the main trough upstream around T96hrs. The other it doesn't have which is the one the ECM phased with the PV lobe between T144 and T168hrs.

[Nouska]

8 minutes ago, phil nw. said:

It may be Nouska but a similar path is being shown on the ECM mean at day 10

Yes it's a mean chart but the weakening polar heights and the reformation of the Greenland /Canadian vortex is apparent on that.

I admit that it was not what i anticipated from the ECM especially after the morning suite.Hopefully this changes and maybe someone with access to later ECM output can say this is a blip.

In any event we still look like seeing around a week of cold with snow possibiliies whatever happens beyond and for that i guess we would all be happy enough.

Mr Fergusson has written some thoughts on why the mean may be of less value in the extended outlook - see the SW thread.

[carinthian]

6 minutes ago, nick sussex said:

The UKMO T96hrs fax chart:

Quite complicated in terms of snow!

 

 

Nick, that's a crazy chart, could be anything between London and Glasgow, rain , sleet or snow. All very marginal, hard to pin point, but great viewing tonight.

[feb1991blizzard]

Just now, Ali1977 said:

SSW

Well not an SSW, it would take a lot more after that but it isn't as good as I thought tbh.

 

It looked about 5 or 6 frames before the end to be far ahead of previous runs, I expected to see red near to the North pole, still very decent though but probably not worthy of my original post, more runs needed.

[Frosty.]

Let it snow let it snow let it snow..the Gfs 18z certainly does next week hello winter, where have you been hiding?

[gottolovethisweather]

1 minute ago, nick sussex said:

No theres two shortwaves, the first the GFS makes less of an issue than in previous outputs this is ahead of the main trough upstream around T96hrs. The other it doesn't have which is the one the ECM phased with the PV lobe between T144 and T168hrs.

Yeah, the latter one is the one I think I am still seeing on Karlos's chart. Whatever, its vastly removed from the 12z and proves to me we need to sort t96 firstly before worrying about t168hrs. Heck, there could be a widespread covering of snow UK wide before then. Next seven days nailed broadly speaking though and that is a cold to colder trend past Monday for all.

[Mark Neal.]

Using the latest GFS 18z data as a location forecast, you can see there is plenty of heavy precip asscoiated with the Thurs night,fri am low moving through. Midlands could see quite a bit? but obviously alot of water to flow under before we get there! Just the potential though!

http://www.xcweather.co.uk/forecast/ 

[nick sussex]

2 minutes ago, carinthian said:

Nick, that's a crazy chart, could be anything between London and Glasgow, rain , sleet or snow. All very marginal, hard to pin point, but great viewing tonight.

The positive is that this low is dropping se out of Iceland and not one coming east from the Atlantic. The 850's are really quite cold, surprisingly so.

[Daniel*]

To add some contrast in here not to be taken seriously It really does turn very ugly, as blocking wanes and dissolves, with PV wanting to reconsolidate into a scary sight, giving way to very mild conditions, with long fetch SW'lies from Azores with the return of the fat Euro Slug, RIP the rest of January, although Knocker wouldn't mind he might pop out his woodshed. A lot of water to go under the bridge, oh I do hate cliches. 

[Hotspur62]

2 minutes ago, nick sussex said:

The positive is that this low is dropping se out of Iceland and not one coming east from the Atlantic. The 850's are really quite cold, surprisingly so.

Are maybe the cooler than normal temps of that part of the North Atlantic going to make a positive difference I wonder from making a marginal event to a snow event ??

[P-M]

3 minutes ago, Earnest Easterly* said:

To add some contrast in here not to be taken seriously It really does turn very ugly, as blocking wanes and dissolves, with PV wanting to reconsolidate into a scary sight, giving way to very mild conditions, with long fetch SW'lies from Azores with the return of the fat Euro Slug, RIP the rest of January, although Knocker wouldn't mind he might pop out his woodshed. A lot of water to go under the bridge, oh I do hate cliches. 

 

Good thing this is far reaches of FI at the minute but you never know do you!

[northwestsnow]

Well we couldnt have timed this out break any better- mid Jan and all that.

Very marginal stuff next week and im still thinking decent altitude is going to make the difference for many.

Insofar as the north and the midlands are concerned i feel 200m will be a massive bonus.

There is for sure going to be the dreaded mild sector involved with the flow coming off the irish sea, i dont know what the temps are in that locale but ive heard it named the irish bath before now, further away from that the better

[nick sussex]

1 minute ago, Hotspur61 said:

Are maybe the cooler than normal temps of that part of the North Atlantic going to make a positive difference I wonder from making a marginal event to a snow event ??

If it was just down to the 850's it would be an easier forecast, alas its never that simple. The T120hrs fax chart just slightly less complicated.

 

[carinthian]

9 minutes ago, nick sussex said:

The positive is that this low is dropping se out of Iceland and not one coming east from the Atlantic. The 850's are really quite cold, surprisingly so.

Well Nick, its getting late for me in Central Euro Time, looking out the window snow coming down, so I will sleep just dandy after a nice rum and coke. Just seen this latest fax, seems to send the wave down over Ireland with much of the British Isles under 528 snow dam line. The potential Channel Low now heading into mainland Europe. So the cold looks like holding further south and west, which must be a good thing. Let hope tomorrow continues with a more prolonged colder spell for all. Guten Nacht.

 C

Edited January 9, 2016 by carinthian

[Nick F]

Time to wheel out the 12z ECM ENS for London, GFS (NCEP) bit of mild outlier from the 18th to say the least ...

So we have bad guy GFS (aka Dr. Evil) in one corner ...

And the good guys of the Euros in the other ...

The way the jet buckles towards Norwegian Sea and moves down into Europe next w/e onwards is crucial to going pear-shaped al la Dr. Evil GFS or like the good guy ECM.

This jet configuration from 18z GFS ain't what you want to get and easterly, equatorbound jet going south into Europe not SW

This is what you want .. from the 12z EC, note: SW bound over mainland Europe ...