Model Output Discussion - The Start Of Winter

[Barry12]

The Russian high is moving more west on the 12z, and better ridging towards Greenland at day 7

 

[Geordiesnow]

The deep low that some models hinted at yesterday which formed in the warmer waters off the coast of Newfoundland is now a lot more shallower although a more normal Atlantic deep low does however form, quite a long way off in worrying about the detail of this yet. 

 

I still think the output is interesting with a couple of polar maritime blasts(which lets be honest have lacked during Autumn) and there is the risk of some lower level snowfall for some Sunday night into Monday in particular but Sunday does look an interesting day convective wise in areas exposed to that cold WNW'ly wind. 

 

Another encouraging thing is the models are hinting the PV is to weaken somewhat across Canada so that might help increase a more amplified outlook later on in the month, long way off mind though but overall, its not the worse outlook for a cold enthusiast. 

[Barry12]

Wouldn't rule out snow to lower levels in the North on Sunday with -6 uppers for many of us

 

 

[shaky]

Yup not a bad set of 12zs o far! ! Ukmo looks very interesting pretty much cold right till the end of the run!!! Russian high looks like advancing westwards aswell!!

[LomondSnowstorm]

UKMO is particularly interesting, amplifying the temporary ridge thrown up to the west of Sunday's low which not only brings in a northerly but also looks like drawing in colder uppers on the second low and squeezing the warm sector too:

   

[Nick F]

The ECM solution could be disastrous, not just in terms of this month but also further ahead into Jan.

 

Fortunately the MJO state won't always make or break our prospects, plenty of examples where we've had DJF months that have incorporated cold wintry weather for the UK where there's been a weak or absent MJO. Nov/Dec 2010 and Jan/Feb 1987 to name but a few. There are other atmospheric variables that can have an impact towards tropsheric circulations for better or worse wrt to cold/wintry weather. Though atm, ENSO state and strat have yet to have much of an impact.

 

Back to the near future, the models already firming up with little change on next Tues/Weds deep low passing north of Scotland, even though we are a good 6-7 days away. Come along way since the 1980s with regards to accuracy with modelling low development at such timescales. That's not to say the model confidence can always be relied on this far out!

Edited December 3, 2014 by Nick F

[knocker]

I see the P is running a double low scenario

Chart courtesy weatherbell

 

[IDO]

I see the P is running a double low scenario

Chart courtesy weatherbell

Yes that's the 0z run though. No Parallel till next week due to the super computer being serviced.

GEM and GFS are pretty uninspiring at D10 and the GFS op is rather flat throughout FI. So no real change.

[knocker]

Yes that's the 0z run though. No Parallel till next week due to the super computer being serviced.

GEM and GFS are pretty uninspiring at D10 and the GFS op is rather flat throughout FI. So no real change.

 

Oops. Didn't notice. Ta.

[johnholmes]

Are you serious with this comment?

 

 

The ECM solution could be disastrous, not just in terms of this month but also further ahead into Jan.

 

 

On the 3rd December?

 

Edited December 3, 2014 by Polar Maritime
There you go John.

[Nouska]

Fortunately the MJO state won't always make or break our prospects, plenty of examples where we've had DJF months that have incorporated cold wintry weather for the UK where there's been a weak or absent MJO. Nov/Dec 2010 and Jan/Feb 1987 to name but a few. There are other atmospheric variables that can have an impact towards tropsheric circulations for better or worse wrt to cold/wintry weather. Though atm, ENSO state and strat have yet to have much of an impact.

 

Back to the near future, the models already firming up with little change on next Tues/Weds deep low passing north of Scotland, even though we are a good 6-7 days away. Come along way since the 1980s with regards to accuracy with modelling low development at such timescales. That's not to say the model confidence can always be relied on this far out!

 

I think it is also important to point out that a highly amplified phase six, seven and eight did nothing for our prospects in January and February of 2011.

 

As you will know too well, it is a tool, a guide and not an exact science - definitely not something to be making 'winter is over' pronouncements on!

 

Winter 2010/2011 MJO phases.  

[Ali1977]

The GEFS mean for FI shows the PV moving off Greenland with pressure rising ....no cold charts yet but surely a start , and this ties in with some ideas from the budding forecasters amongst you. (Positive ones)

[Paul]

Latest forecast from Jo - staying chilly this week, increasing cloud, increasing wind and the risk of some wintry showers too..

 

https://vimeo.com/113514885

[Mucka]

I'm still looking tot he east for the first signs of the next pattern change to a more amplified pattern and after a few runs that moved away from a Russian high becoming influential it seems GFS ensembles are starting to sniff the air at least.

I hope ECM anomalies suggest something better in the 10 day time frame with a more elongated trough pushing deeper into Europe rather than the rounded rather flat trough it has been moving toward of late.

 

I still think something along the lines of GEM is the most likely synoptic pattern to develop which would hopefully be the first building blocks toward some decent HLB 

 

 

Increasingly influential Russian high causing the trough to undercut and amplify the pattern. Unfortunately upstream there are still lots of low heights around Greenland so any Atlantic ridge would likely topple if we saw this run progress. Of course a toppling ridge isn't necessarily always a bad thing if there is significant low pressure in Europe to prop it up and a backdoor Easterly can form.

Still all a bit crystal ball I'm afraid as the first steps toward a more blocked pattern are 10 days + away but at least we can watch and see if this develops or if we get a flatter pattern suppressing any heights pushing North and West.

If it is the latter which GFS has been keen on (it does have a bias in this regard though) then I'm afraid even the cold polar maritime air incursions will slowly fade as the jet would slowly align SW/NE, that would be depressing wet, windy and generally mild gunk.

 

But let's end on an optimistic note and hope ECM shows something a little better than GEM.

Edited December 3, 2014 by Mucka

[Barry12]

Much better at 96 hours on the ECM 12z, the Atlantic HP is further south, and the Polar Vortex is an much more disorganised state, with a large chunk moving East. Where also in a colder NW flow.

 

[Captain Shortwave]

The UKMO yet again has gone against other output at day 5 with a much more northerly element to the winds, this actually brings a second pulse of cold air with the -8C isotherm getting into Scotland

Alas like last time it is an outsider with the most likely option still being a transient polar maritime flow. The predicted temperatures by Sunday look to be around 4-8C so a mix of rain, sleet and hail at low levels with snow at modest altitude.

Beyond that, it looks pretty zonal at the moment with bands of rain and strong winds pushing from west to east. Temperatures near normal. The one change today has been a movement away from a potentially damaging storm during the middle of next week as the low seems to get held back a little which spares Scotland. 

That said.....

Watch the small low just east of Greenland, that will swing around the main trough later on. Luckily it comes to nothing this time.

Edited December 3, 2014 by Captain shortwave

[karyo]

Much better at 96 hours on the ECM 12z, the Atlantic HP is further south, and the Polar Vortex is an much more disorganised state, with a large chunk moving East. Where also in a colder NW flow.

 

This only looks marginally better to me and the uppers are not as cold as the UKMO or the GFS at the same time.

[snowice]

http://www.meteociel.fr/modeles/ecmwf/runs/2014120312/ECM0-168.GIF?03-Well much better run from ecm colder air pushing further south

[Polar Maritime]

An even more unsettled run from the ECMWF this evening, With the low Model'd further South around the 10th. Very unsettled and cold from a pure Pm flow. Giving snow with blizzards on Northern hills and Mountains and down to lower levels at times where heavy rain could bring flooding. There's a growing trend for some severe weather to come for the UK, Especially the North.

 

Edited December 3, 2014 by Polar Maritime

[nick sussex]

I wonder if theres something up with the UKMO. Once again it has the most amplified upstream solution compared to the others, we saw with the recent will it won't it northerly that it was too amplified and then had to backtrack.

 

Theres also a divergence across the NWP upstream with low pressure development at T144hrs, with the UKMO having a very weak feature compared to the ECM and GFS.

[Barry12]

At day 8 the Polar Vortex is in a very weak affair, especially compared to the ECM 00z

 

 

At day 9 it's pathetic - much weaker than the 00z

 

Edited December 3, 2014 by Barry95

[Winter Cold]

Yes its great to see a smashed polar vortex still modeled at the end of runs. It has to be a help going forward.

 

Tonights final frame of the ECM literaly shows the PV looking like a sad face (purple bits)

 

[Snowman.]

 

 

At day 9 it's pathetic - much weaker than the 00z

 

But there is a lot of energy still lingering in NE Canada.

[Barry12]

It's also a cold run with day 4,5,8,9,10 all having -4 uppers for many of us. The Polar Vortex is almost completely destroyed. Not a bad run at all!

 

Edited December 3, 2014 by Barry95

[Bristawl Si]

Yes its great to see a smashed polar vortex still modeled at the end of runs. It has to be a help going forward.

 

Tonights final frame of the ECM literaly shows the PV looking like a sad face (purple bits)

 

The azores high seems to be playing its part, as well though, stopping any systems coming in on a more southerly track.

Seems like a watered down version of last Winter, at the mo for next week and beyond, possibly, another week.