Model Output Discussion - cold spell to end Autumn

[SMU]

21 minutes ago, bluearmy said:

You actually force me to check the archive charts for the past week. Not surprisingly ukmo has done best with the northerly as ecm and gfs had it before day 6 although gfs got the trigger low badly wrong for quite a few runs. As far as the diving trough thereafter, gfs and ecm have both been trailing it with ecm actually making a decent fist if it at day 10 (though it went arwy in its days 8/10 output for a coiled, runs thereafter). Gfs has made a poor call on the diving trough the past couple, days although we can't be sure that the 12z are right on this just yet. Ecm was right to call the accelerated  demise of the Atlantic ridging. 

No model is right but to say that gfs is the model to follow is just plain wrong ! 

Got to call you a wrong there mate based on the last Northerly evolution & this evolution that ECM has been poor again being very progressive always at the eastern point of the envelope..

Also the ECM especially in the 12z has been the run 2-3 days where I have gone through it & thought - thats not going to happen!

However they have probably had some elements that have been wrong...

Anyway who really cares - UKMO coming out well again...

onward & upward with the sliders they need to be as shallow as possible to minimise warm air mixing...

S

[MattStoke]

4 minutes ago, northwestsnow said:

18Z goes for the cheshire gap streamer ..BIG TIME!!

As rain though. Uppers too high at that stage.

[Ice Day]

Nothing marginal anywhere in the UK at 96!

[I remember Atlantic 252]

Just now, MattStoke said:

As rain though. Uppers too high at that stage.

yes, 1am Fri, not cold enough

[*Stormforce~beka*]

27 minutes ago, bartlett high said:

Fantastic news!! the local council have just replaced the light bulb for the lamp-post outside my house!

Sorry but this IS Post of the day for me!!! Pahahahahhaa!

[shaky]

Gfs could be about to slide!!!looking good at 114 hours!!

[That ECM]

Now that's some thin air!! Couple that with wind direction and strength.

[Ice Day]

Here's one for the North Wales/North West England Massive!  Just 96 hours away now.

[Singularity]

I have a suspicion that ECM tends to over-accelerate the jet stream where cold airmasses are plunging well south and coming up against much warmer ones resulting in tight thermal gradients. I've seen this produce insane plume breakdown storms in the summer and it appears to have been a factor of late with the big cold plunge in the U.S.

That's far from the whole story though; issues with the MJO propagation being underestimated have also played a role.

ECM has gained a bit of ground over the past day though in that it's idea of a wider Pacific ridge that shoves the Canadian trough a bit far east for comfort has been explored more by GFS. Perhaps a little concerning for our prospects longer-term? I know it's picking a dud thread out of a fine jumper (it's that time of year...) but, you see, I'm doing my very best to keep my feet on the ground .

[Derecho]

Interesting..... the 18z appears to be stepping back to this mornings 06z

Channel low?

PS I think the conditions late on Thursday to Saturday will be cold enough for many, uppers below -5C and dew points below 0C.

Impressive to see a substantial portion of the Eastern UK under -10C uppers during Friday

[karlos1983]

This could well be a dry slider!!

[Mokidugway]

If you like cold ,sit back and enjoy 

[winterof79]

3 minutes ago, I remember Atlantic 252 said:

yes, 1am Fri, not cold enough

It is by 7am

 

[A.J]

don't get carried away by precip charts that are several days away folks.....purely for trends only, and for accuracy they're about as much use as t*ts on fish IMHO.....the where and how much snowfall is hard enough to be accurate at T24 let alone T-Godknowswhat 

[tight isobar]

Its aligned v-decently..

And uppers/850s are also v-decent..

Lets see where the 18z take things!!!

[Allseasons-Si]

Slider a lot further SE,now i don't mind that as we will all be on the colder side of the jet

 

 

[karlos1983]

Just now, Allseasons-si said:

Slider a lot further SE,now i don't mind that as we will all be on the colder side of the jet

 

 

You mean south west Allseasons 

[Spah1]

What do we make of this little guy???

[weirpig]

2 minutes ago, Ice Day said:

Here's one for the North Wales/North West England Massive!  Just 96 hours away now.

Yes this could turn into an event acrss Wales North England  and the West Midlands And across Parts of the South West    The strength of the wind will really blow these showers through.  Not long before it comes into High Res on the Euro 4 etc    seems every run at the moment is an upgrade for these areas.

[radiohead]

3 minutes ago, karlos1983 said:

This could well be a dry slider!!

Indeed it is.

 

[I remember Atlantic 252]

3 minutes ago, tight isobar said:

Its aligned v-decently..

And uppers/850s are also v-decent..

Lets see where the 18z take things!!!

Ay, further west on this run, most miss snow from slider, except for Scillies perhaps

[Allseasons-Si]

10 minutes ago, karlos1983 said:

You mean south west Allseasons 

No!!

sorry should of been more clear,sliding more SE(as in timing)

120 18z/126 12z

Edited December 4, 2017 by Allseasons-si

[Singularity]

Well this is most unreasonable, GFS adjusting so strongly away from the other models again and indeed so far that we end up with shades of March 2013 (not quite such a burying for the Channel Islands this time though!) 

In truth, it's absolutely fascinating that such an extreme difference can be resurrected within the 5-day range and with the key sliding setup evolving late on day 4...!

[tight isobar]

7 minutes ago, I remember Atlantic 252 said:

Ay, further west on this run, most miss snow from slider, except for Scillies perhaps

It looked primed'..

But theres a whole lot more scope for movement/alignment...

Slider/chanel low.

Going to be interesting watching this one unfold.. 

Coming suites...

Edited December 4, 2017 by tight isobar

[captaincroc]

1 minute ago, Singularity said:

Well this is most unreasonable, GFS adjusting so strongly away from the other models again and indeed so far that we end up with shades of March 2013 (not quite such a burying for the Channel Islands this time though!) 

In truth, it's absolutely fascinating that such an extreme difference can be resurrected within the 5-day range and with the key sliding setup evolving late on day 4...!

For me I feel it is more advantageous for all if the trends are more SW moving than the other way as it keeps us in the cold air for a lot longer. Definitely exciting times!