Model output discussion - mid January

[damianslaw]

Sorry to have to post this - but lots of winter over posts this eve, these should be put into the bin box - it makes for very irritating reading. I actually think we are in the best position all season so far of seeing a more pronounced non atlantic colder set up; not saying it will happen, but the pacific height development nosing into the Pole coinciding with a weakened PV and atlantic, and propensity of mid atlantic height development is a good foundation point. Traditionally February sees a weakening of the jetstream and we are more likely to see northerly and easterly airstreams take hold especially the further we go into the month - history shows this.

[Summer Snow]

yes and GFS at just 168 hours has UK and Ireland in cold NE flow and risk of snow.....long way to go for winter yet 

Edited January 25, 2018 by Polar Maritime

[bluearmy]

Eps Clusters are back and not surprisingly, given the wide spread,  show 5 pre day 10 and 6 thereafter 

[Bottled Snow]

168 hours from GFS ties in with latest BBC forecast 

[damianslaw]

Not often I comment on GFS 18z runs especially past 144 hr timeframe, but in the not too distant future - tonight's ties in with my more of my thinking, rather than ECM output, a sinking of low heights from the NW on a more NW-SE aligned jet allowing heights to ridge NE behind, but further low heights to the NW will for the time being prevent any significant build to our NW but perhaps only a matter of time come second week Feb this happens.

[Catacol]

On 23/01/2018 at 20:06, nick sussex said:

The above certainly indicates the MJO will play a role and won't be muted out by La Nina.

So if that verifies its inevitable that we will see changes downstream in Europe.

Lets hope we get some luck with a Euro trough and high pressure developing to the n or ne.

 

Hope so - but those looking at the MJO (and it has been modelled to progress through with decent amplitude to phase 7/8 for a while now) need to understand the global atmospheric momentum context. Currently we have the global budget in significantly negative territory

and while the gradient is now on the up it has quite a long way to go to reach neutral before we can start contemplating positive impacts of higher momentum at the tropics disrupting the easterlies that prop up the sub tropical ridge pattern, and reducing momentum impacts at higher latitudes allowing a more meridional flow and high latitude blocking. MJO action is certainly going to help - but it needs to spike the pattern a long way up before we get the subsequent extra-tropical impacts to produce a pattern supportive of continental cold.

Not to say it wont happen - but we need to look at more than just the MJO on its own. The earth is spinning faster than the atmosphere right now, and much MJO energy will be absorbed just bringing the two back to parity. Once this happens - if it happens - then any sustained MJO forcing will bring benefits. However it is also possible that all the energy contained in the MJO convection progression will be used up in cancelling out the current negative budget... and then a mid lat block pattern looks about the best we could hope for.

It is still a question of watch and wait. It's going to need to be a really significant MJO phase progression to rebalance the budget and force an additional Nino-style spike on top. Goggles on and fingers crossed....

Edited January 24, 2018 by Catacol

[Daniel*]

58 minutes ago, More Snow said:

The latest week ahead BBC forecast just said High Pressure moving up the western side of the UK bringing in North East winds, so I'm guessing that high could get up to Greenland.??

Something like this possibly ECM 00z of 2 days ago unsure whether it would be sutained though think we will need to rely on Pacific forcing going right to get a sustained block / cold spell.

[Man With Beard]

36 minutes ago, bluearmy said:

Eps Clusters are back and not surprisingly, given the wide spread,  show 5 pre day 10 and 6 thereafter 

Bit flatter on that Atlantic height rise D8-D10, I thought?

[Froze were the Days]

VERY blocked cfs 12z run - I wouldn't bother mentioning it if it was 1 run in isolation but it's about the 4th run which brings cold to very cold weather in from the east over the last few days.

[feb1991blizzard]

Northerlies prevalent in the GEFS suite with a few Easterlies thrown in, they might look pretty spectacular in graph form although not checked the uppers.

[feb1991blizzard]

Check the graph out for SE England, still wouldn't be getting the champagne corks out until more defined support from EPS, but there is an example of what a good signal for a proper cold spell looks like from the halcyon days between feb 09 and Dec 10, needs those flatliners to stay there gradually adding one by one from the milder cluster as we get into the mid range.

[Duane S.]

51 minutes ago, Catacol said:

Hope so - but those looking at the MJO (and it has been modelled to progress through with decent amplitude to phase 7/8 for a while now) need to understand the global atmospheric momentum context. Currently we have the global budget in significantly negative territory

and while the gradient is now on the up it has quite a long way to go to reach neutral before we can start contemplating positive impacts of higher momentum at the tropics disrupting the easterlies that prop up the sub tropical ridge pattern, and reducing momentum impacts at higher latitudes allowing a more meridional flow and high latitude blocking. MJO action is certainly going to help - but it needs to spike the pattern a long way up before we get the subsequent extra-tropical impacts to produce a pattern supportive of continental cold.

Not to say it wont happen - but we need to look at more than just the MJO on its own. The earth is spinning faster than the atmosphere right now, and much MJO energy will be absorbed just bringing the two back to parity. Once this happens - if it happens - then any sustained MJO forcing will bring benefits. However it is also possible that all the energy contained in the MJO convection progression will be used up in cancelling out the current negative budget... and then a mid lat block pattern looks about the best we could hope for.

It is still a question of watch and wait. It's going to need to be a really significant MJO phase progression to rebalance the budget and force an additional Nino-style spike on top. Goggles on and fingers crossed....

This is where I struggle. Getting my head around the relationship between the MJO and the GWO / mountain &  friction torques. Feedbacks and chicken and egg. Both evidently influence the other. In Excel it would error as a circular reference!

When the convection makes it to the dateline and goes into decline, global AAM is often at its greatest. So are we to expect a big uptick in net AAM to start showing up soon, as the MJO forecasts look promising in that respect?

 

Edited January 24, 2018 by s4lancia

[weathermadbarnsleylad]

25 minutes ago, feb1991blizzard said:

Northerlies prevalent in the GEFS suite with a few Easterlies thrown in, they might look pretty spectacular in graph form although not checked the uppers.

850s looking good on most at 192 apart from one or 2.  Some are absolute crackers. 

[weathermadbarnsleylad]

1 minute ago, weathermadbarnsleylad said:

850s looking good on most at 192 apart from one or 2.  Some are absolute crackers. 

 

[weathermadbarnsleylad]

Just now, weathermadbarnsleylad said:

 

Perb 13 850s - 8 plus off the continent

[feb1991blizzard]

12 minutes ago, weathermadbarnsleylad said:

850s looking good on most at 192 apart from one or 2.  Some are absolute crackers. 

Yes - as I posted above - they definitely do look great - here is a selection of them.

Edited January 25, 2018 by feb1991blizzard

[weathermadbarnsleylad]

1 minute ago, feb1991blizzard said:

Yes - as I posted above - they definitely do look great - here is a selection of them.

When's Ens come out in graph form on here?  still showing 12z graphs. 

[feb1991blizzard]

1 minute ago, weathermadbarnsleylad said:

When's Ens come out in graph form on here?  still showing 12z graphs. 

Use meteociel.https://www.meteociel.fr/modeles/gefs.php click on where you want.

[tight isobar]

Heres some data...take note!!!

.  

[weathermadbarnsleylad]

3 minutes ago, feb1991blizzard said:

Use meteociel.https://www.meteociel.fr/modeles/gefs.php click on where you want.

Thanks feb

[Daniel*]

4 minutes ago, tight isobar said:

Heres some data...take note!!!

.  

Impressive GEFS back at it again! Some truly fantastic cold wintry members. 

[tight isobar]

5 minutes ago, Daniel* said:

Impressive GEFS back at it again! Some truly fantastic cold wintry members. 

Indeed pal..

And the clusters are momumental..

A, whiffed/notable spell is assured imo..

And the ooz ops/suites should engage such synop's..

[feb1991blizzard]

JMA ensembles a t264 not too bad, not as extreme as the GEFS but you cant really tell from a mean.

Trough dropping into Mainland Europe nicely.

Edited January 25, 2018 by feb1991blizzard

[feb1991blizzard]

GEM ens are rubbish though.

[FENDER.]

3 hours ago, tight isobar said:

Indeed pal..

And the clusters are momumental..

A, whiffed/notable spell is assured imo..

And the ooz ops/suites should engage such synop's..

Too far out to be assured of anything.   Lets see if its still looking as good at the end of the weekend, before getting excited