Model output discussion 25th Jan onwards

[Dean E]

It seems some have picked up on what I've seen too. 

Now I know I'm one that has said to look west for Feb and rest of winter proper but I'm certainly not writing off winter weather.  I think we are in a climate phase now where we will see more extreme weather patterns in all shapes not just cold......but I think cold will become more prevalent.

For now t159 caught my eye, I'm looking at the trough coming off Eastern Seaboard of US.  Look at the temp gradient, I think this may develop into a serious LP as it crosses the Atlantic.

 

So with this occurring I won't be surprised to see this. 

 

Jet stream near full steam as well just ahead of the system too..

 

 

Something to keep an eye on

[pointswest]

can I ask is -4 upper air enough for snow to fall I just wondered sorry if of topic but the models are showing the -4 upper air across a lot of the uk.

I think it's more to do with the dew points. Sorry if that's wrong.

[BLAST FROM THE PAST]

Jet stream near full steam as well just ahead of the system too..

 

gfs4image (1).png

 

Something to keep an eye on

Yep and look how it goes ouch!...where do I go from here? as it hits that invisible wall. I know dump it all on the UK and Ireland

 

BFTP

[Severe Siberian icy blast]

Looking through GFS ensembles things aren't quite as cut and dried as we might imagine regarding standard zonal conditions establishing themselves through the first week of February. Yes that is still the most favoured route but already lots of possible diversions appearing including the trough being moved West, diving lows and even some undercut of the block.

Samples.

JMA 12 has quite a large correction back west from yesterday evenings run albeit with a much feistier Atlantic in line with other output.

The thing is I always notice once the models pick up on something (ie Atlantic influence , or indeed easterly elements , aka last 5 days ) models always over react to a trend , the last 2 days is no different , they blow the block away for fun , only to settle on something more reasonable a few days on , even the last 3 wks with a trough disrupting 100 miles east of us , although it hadn't benefitted us as a country , it's still reminded us how strong the blocking has been , now bring that west 100 miles , (exactly what's happening this week) then that brings the possibility of much more interesting weather , surely that's always been a very realistic idea? Why people believe model output that's over t144 away is beyond me what ever signals may appear to offer. How about the fact that the weather is changing all the time , especially now with decent wave activity this next week, that at least gives optimism ? It does with me anyway , I personally think that disruption and energy heading southeast is a good bet , especially given the deep cold over Europe . That's in my opinion where we need to be looking . Edited January 27, 2014 by Severe Siberian icy blast

[fergieweather]

For someone like myself who tries but cannot always understand all the complicated factors at work in creating long term weather patterns, one of the most reassuring changes of the last few weeks has been the persistence of the models to show warmings in the stratosphere. Though not in the dramatic way of an SSW, it is the continuous gradual warming that has happened and is forecast to continue that is giving me cause for optimism in the long run. This particular chart is at the very end of the GFS 12z, but warmings are shown for pretty much the entire run before this. I honestly wouldn't have understood any of that without guidance from posters such as Nick and Tamara, as well as many others, so thank you

 

I think a cautionary note on the strat warming.... it's something UKMO's M-R folk have been watching closely all winter (as you'd imagine). I just asked about this, i.e. re their views on the NCEP signals of late. They tell me: "GLOSEA5, the UKMO seasonal model, doesn't seem to support this event all that much and since it hasn't been working so far this season in terms of getting the warmer air down in reality, this signal isn't being used in relation to forecasting a change to colder periods." 

There was a much more pronounced signal emerging back in earlier Jan (modelled for later Jan and into early Feb, as some on this forum are aware), but that was lost.

[egret]

Jet stream near full steam as well just ahead of the system too..

 

gfs4image (1).png

 

Something to keep an eye on

Just lose the Dodo's head off the eastern end of that Jet Steam and we would be in an interesting spot - I just wonder if the Jet might flick South rather than North given the changes up aloft? I have seen bigger changes a week out. Certainly that big low has the power to make a dramatic change.

 

Another excellent and well explained post Tamara earlier- fully consistent with her other posts. Patience required!  

Edited January 27, 2014 by egret

[mulzy]

Dream-like profile over the arctic.  Shame it's only shown in one ensemble memeber that's 12 days away!

 

Edited January 27, 2014 by mulzy

[Thundery wintry showers]

Some are talking about how a Bartlett high would bring drier conditions, but how far the drier conditions would extend would depend on the positioning of the high.  During the notoriously mild winter of 1988/89, and in February 1998, the high often extended as far north/west as central and southern parts of England, and above-average rainfall ended up mostly confined to northern and western Scotland and Cumbria, but we've had other setups where the high gets no further north than the English Channel and most parts of western Britain end up very wet, e.g. early February 2004, which would aggravate conditions in some of the areas that are currently most at risk of flooding.

 

I am not expecting the polar maritime incursions to come to much- the usual issue is too much secondary low development, periodically cutting off the polar flow and also forcing it to "return" a larger distance over the Atlantic Ocean.

[bluearmy]

I think a cautionary note on the strat warming.... it's something UKMO's M-R folk have been watching closely all winter (as you'd imagine). I just asked about this, i.e. re their views on the NCEP signals of late. They tell me: "GLOSEA5, the UKMO seasonal model, doesn't seem to support this event all that much and since it hasn't been working so far this season in terms of getting the warmer air down in reality, this signal isn't being used in relation to forecasting a change to colder periods." 

There was a much more pronounced signal emerging back in earlier Jan (modelled for later Jan and into early Feb, as some on this forum are aware), but that was lost.

 

indeed ian, it seems very difficult to get consistemcy on the ncep strat modelling. just having a decent temp profile isnt enough to have any confidence. we need to see the same pattern repeating, day by day. at 10hpa, the modelling should be more reliable and differing forecasts for that level are probably indicative of the strat reacting to inconsistent waves sent out of the trop some days earlier. we dotn need reminding how poor the trop modelling can be !!

 

good to know that those 'colder later in the month' forecasts issued earlier in jan were  Glosea 5 induced . i appreciate that you couldnt conirm that at the time.  in respect of the strat, we may not get a SSW and see a consequential strong neg AO response but the winds high up have dropped down to levels where they should not inhibit the establishment of HLB so we are in a different place to a couple of weeks ago.  factors continue to conspire against us re drawing the russian block west. to simply state that the canadian vortex is the be all and end all is too simplistic. tamara is valiantly trying to put things into perspective.  it might end up being 'one of those winters'.  it may not.  i wonder if teh ecm run will be so progressive to our ne or if we will continue to see the trend whereby the systems really cant get past the meridian in our latitude.

[fergieweather]

That'll do me....Meto says "No". The top performers this Winter.

 

Ah - but don't interpret that as saying 'no colder periods - what they mean is they aren't anticipating a major change courtesy of an SSW. But that's not to rule-out 'tricky' phases of colder weather such as were modelled into this week. No-one can discount those, especially if the pattern becomes more amplified again and/or we see any lows running to the S/SE with easterly wrap-around over the top, as per this coming Thursday.

[Panayiotis]

NASA model @120hrs has a low very similar to the low of yesterday bringing colder air (-6C uppers) from the Atlantic/NW (you dont say that every winter,do you? ). Reason is as it stalls against the block over Russia, giving a constant feed of NW winds. Now after, would it dive SE or go over the block? It has a slight negative tilt, and this could promote heights back into Scandi giving another block over that region, something I will be looking for over next few days.

Edited January 27, 2014 by Panayiotis

[Stuie]

Ah - but don't interpret that as saying 'no colder periods - what they mean is they aren't anticipating a major change courtesy of an SSW. But that's not to rule-out 'tricky' phases of colder weather such as were modelled into this week. No-one can discount those, especially if the pattern becomes more amplified again and/or we see any lows running to the S/SE with easterly wrap-around over the top, as per this coming Thursday.

ECM has nothing to wrap around on Thursday Ian unlike the GFS.  I presume the ECM is not in the equation?

[shaky]

ECM has nothing to wrap around on Thursday Ian unlike the GFS.  I presume the ECM is not in the equation?

very interesting ecm at 48 hours and 72 hours!!at 48 hours as the low engages with cold air coming from the continent could turn snowy for some!!and at 72 hours the low west of ireland seems to be undercutting a bit more!!

[Panayiotis]

ECM much better tonight, compared to this morning, look at the tilt of the low, trying to go under instead of over...

Just for comparison:

[nick sussex]

Some marked differences between the ECM and GFS/UKMO over the USA, looks like another ECM tease maybe brewing here, as that lady said in Total Recall, Get Ready For A Surprise!

[SMU]

Well whilst the game is up for the SE in the short term, the ECM looks VERY snowy for Scotland....

 

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=0&archive=0

 

S

[Panayiotis]

ECM seems to be listening (check my post above!) Look at the height rise over Scandi! Low has been pushed back, by an UNDERESTIMATED block...

Edited January 27, 2014 by Panayiotis

[fergieweather]

Well whilst the game is up for the SE in the short term, the ECM looks VERY snowy for Scotland....

 

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=0&archive=0

 

S

Indeed - this sort of variance shows exactly why we can't be too clever/prescriptive (yet) on the exact manner of the return to mobility through Friday. The EC clusters will be interesting in this regard.

[warrenb]

At 144 the low literally bounces off the block back into the atlantic.

[nick sussex]

At 144 the low literally bounces off the block back into the atlantic.

Yes same trend as the GFS/UKMO but everything further west and pressure rising quickly over western Scandi, could be an interesting T168hrs!

 

The more dig south of that small low in the Atlantic the better the following output will be, also its more amplified.

Edited January 27, 2014 by nick sussex

[Panayiotis]

Yes same trend as the GFS/UKMO but everything further west and pressure rising quickly over western Scandi, could be an interesting T168hrs!

 

The more dig south of that small low in the Atlantic the better the following output will be, also its more amplified.

Hi Nick, 168hrs will be interesting! Do you think the block is being underestimated once again? 

PS Great call on the ECM!

Edited January 27, 2014 by Panayiotis

[warrenb]

At 168, that is close, slight se drift into the SE

[Stuie]

Well whilst the game is up for the SE in the short term, the ECM looks VERY snowy for Scotland....

 

http://www.meteociel.fr/modeles/ecmwf.php?ech=72&mode=1&map=1&type=0&archive=0

 

S

Steve, being a fellow SE`ster, this could be our best shot this week, with the wrap around that Ian mentioned. If it could pull in colder air, who knows. It is your broken model though..

[Eskimo]

A much better ECM at 168h!!

[Summer Sun]

850's cold enough for some hill snow in the north at t168

 

Edited January 27, 2014 by Summer Sun