Model Output Discussion; into 2015

[Banbury]

GFS still hinting at something colder mid month

 

3c 3c 7c 9c 7c 7c 10c 12c 9c 6c 3c 1c 1c 1c 0c -1c

 

Double digit days are very few, blink and you miss them

Can i ask 2 questions,

 

What exactly is a more MERIDIONAL pattern as apposed to a zonal pattern and secondly,why would such pattern be poor for cold in the south?

Cheers.

http://www.theweatherprediction.com/habyhints/159/

[Severe Siberian icy blast]

Can i ask 2 questions,

 

What exactly is a more MERIDIONAL pattern as apposed to a zonal pattern and secondly,why would such pattern be poor for cold in the south?

Cheers.

A more meridional pattern , really means amplification upstream , sounds like a midatlantic high , not a greeny block , so a northwest flow maybe , not the holy grail by any means b up plenty of time for these hints to gather pace and develop .

Who's mentioned poor set up for the South ? Naturally the South will always be warmer than the North generally , and apart from an easterly wind , the South will always get a more tempered version of events when winds are from the north , really depends on how much cold air we can get South and for how long. Obviously the South can get snow in feb of March given the right Synoptics .

[KTtom]

Can i ask 2 questions,

 

What exactly is a more MERIDIONAL pattern as apposed to a zonal pattern and secondly,why would such pattern be poor for cold in the south?

Cheers.

meridional pattern = air flow north to south

[Frosty.]

Much more of this please, ecm 0z much better than last night, 522 dam digging SE..overall I see more positives in the outlook on latest models.

[nick sussex]

I had altered my original post but I take it you are saying it's inappropriate to use the mean anomalies  such as NOAA, GEFS and the ECM for indicators of longwave pattern changes, albeit not in isolation?

No I'm not saying that but the mean can give a distorted picture especially at longer range.I'd rather look at the clusters and then compare those to the background signals as in which cluster is most likely to be in tune with that.

 

So for example if the MJO is forecast to remain at decent amplitude and enter phase 7 then I'd edge towards the more amplified cluster.

 

If for example the ensembles then switch to the more amplified solutions and this gets into the T240hrs mark then the mean could be useful.

[cornish snow]

GFS still hinting at something colder mid month

 

3c 3c 7c 9c 7c 7c 10c 12c 9c 6c 3c 1c 1c 1c 0c -1c

 

Double digit days are very few, blink and you miss them

http://www.theweatherprediction.com/habyhints/159/

 

A more meridional pattern , really means amplification upstream , sounds like a midatlantic high , not a greeny block , so a northwest flow maybe , not the holy grail by any means b up plenty of time for these hints to gather pace and develop .

Who's mentioned poor set up for the South ? Naturally the South will always be warmer than the North generally , and apart from an easterly wind , the South will always get a more tempered version of events when winds are from the north , really depends on how much cold air we can get South and for how long. Obviously the South can get snow in feb of March given the right Synoptics .

Thanks ssib Understand the pattern just wasn't aware of the term.

JH implied when responding to Ian's post last night that such a pattern may not be good for the south.

[IDO]

Nice to see that despite differences between the GFS op and P in the more reliable as to the ebb and flow of PM/TM air, the GFS P mimics the op mid month:

 

 

A caveat as to FI GFS charts. When they spot a change they have a habit of over egging the amplification and tend to tone down the heights as we close in on the more reliable. Too early to make conclusions just yet though.

[cornish snow]

Sorry JH. Just looked back and it was someone else who replied to Ian.

[Nick F]

meridional pattern = air flow north to south

 

Or, south to north, depending on what side of the ridge/trough one is.

 

Interesting to see GFS op and para continue on the 06z to force the jet further south, then amplify the flow upstream over the Atlantic as tropospheric PV splits - to carve a trough deep into Europe. Shame it's so far off, but if this signal remains consistent then the GFS maybe on to something.

[Gowon]

ooh la la!! :smiliz23:  :smiliz39:  nice to see these fantasy charts appearing again. 

 

[Captain Shortwave]

GFS still hinting at something colder mid month

 

3c 3c 7c 9c 7c 7c 10c 12c 9c 6c 3c 1c 1c 1c 0c -1c

 

Double digit days are very few, blink and you miss them

http://www.theweatherprediction.com/habyhints/159/

It only turns colder though by day 11 onwards so how much can we trust this. Given the average for January is around 6/7C that means outside of this weekend temperatures will be at or above average. I suspect by mid-month we will be running at between 1 and 2C above average (strong winds will make frosts pretty fleeting beyond this weekend).

The main interest weather wise will be the potential for very strong winds, most notably around day 6 again on the parallel

Gales, perhaps severe for Scotland.

So there is still potential for the strong westerly jet to ease during the second half of week 2, but that is all at the moment. Like IDO, I feel rather sceptical about any potent Arctic blasts, and as we have seen we can't just assume the the positive drivers for this winter will be enough to get these cold charts over the line.

Edited January 3, 2015 by Captain shortwave

[Buxton Codge]

Both the GFSP 6z and the ECM control run are going for a proper cold spell from mid month.

 

Worth keeping an eye on developments

[halny]

Morning all,

IMHO we can never rule out a cold outbreak regardless of what the NWP show,many a cold spell has cropped up at short notice take this one for instance a seemingly dire chart below,

Fast forward ten days to this,

Aythings possible.

 

The strats warming as we speak,

 

 

Notable now is the absence of any sort of strong Siberian High.  In the 1986 chart you posted, we had a 1050mb Siberian High centred over Mongolia that later retrogressed to Scandinavia.  The Siberian High is very weak this year and that is unlikely to change in the next 10 days or so.  It therefore looks unlikely that we get a surprise attack from the East in the next week or so.

Edited January 3, 2015 by halny

[legritter]

Very nice to see today a swing in the Gfs runs out past 10 days .there are some who wont trust these charts at this range but somewhere in the models predictions i,m pretty sure that it has reasons to produce charts like this. Touching on the subject of Meridional flow across the British isles ,if synoptics are right all parts of the uk can get in on the act of colder wintry weather ,but of course the further you are located north the better chance you will get of a bite of the cherry ,but there again If a weather feature runs across to our south or a low comes s/east across our west us snow starved southeners could be sitting comfortably .this is by no means a ramp ,so today i,m certainly feeling a bit more up beat with the charts .I would surely want to see further runs from today firming up on any possible cold shot ,but i do feel that we are approaching a very interesting stormy spell of weather with any vortex moving away from its usual place of residence and atlast some higher pressure showing over variouse parts of the Arctic ,lets hope we can get the Dice to fall in our favour ,cheers all   

[knocker]

Interesting chart at the end of the P run. No I'm not attempting a serious  point.

http://weather.graphics/gsm/ygfs_t1534_global.php

Edited January 3, 2015 by knocker

[Frosty.]

GFS 06z op is a cracker in Fi..Much more like some of those peachy perturbations I posted yesterday, a complete reversal of the current pattern with cold becoming entrenched and an increasing risk of snow. I hope we see much more of this. :-)

[Jonathan Lang]

GFS op continues the theme from the last couple of days with FI potential:  gfs-0-372.png

 

At that range details are not a concern. The pattern change continuing is the main upbeat theme.

 

For those of you who criticized what I said yesterday regarding the high linkup. The chart IDO posted clearly shows what would happen if the high wins. The fact the charts are showing this (and have been for a fair few runs now) shows it isn't impossible. Still unlikely to happen but relatively speaking the chances have increased drastically for it to in my opinion.

[shotski]

Interesting chart at the end of the P run. No I'm not attempting a serious  point.

http://weather.graphics/gsm/ygfs_t1534_global.php

Why ?

[Man With Beard]

The immediate focus of the weather is how stormy / wet it will get in the next ten days. GFS(P) 06Z is similar to other output, suggesting the influence of the Azores High will limit the most stormy weather to northern areas - though still too far away to rule out occasional storminess further south. Accompanying fronts would surely bring rain for all at times regardless.

Longer term and, as with the December cool "snap", the GFS has picked up on a signal of rising heights in the North Atlantic and is sticking rigidly to it:

The repetitiveness of this signal makes me think there is something in it, but, given the timeframe, the eventual outcome could take on many shapes; either the chart displayed above (very wintry) or perhaps the pattern being shifted slightly east i.e. a UK high (cold but dry) are two very possible results. We're 5 or 6 days away from getting nearer to the detail on this.

[snowblues]

Having a look through the N Hemisphere charts in the medium term to the end run, its all one sided with lots of high pressure over Siberia ect.You can see some of them heights being drawn in to the pole enhancing the spilt from the high in the Atlantic.Not sure if it's just the normal pole movement or some stat warming?

[Summer Sun]

Why ?

 

If I'm looking at the first chart correctly its showing a north easterly flow with northern blocking?

[knocker]

If I'm looking at the first chart correctly its showing a north easterly flow with northern blocking?

 

[shotski]

Cheers, sorry I was seeing a chart of North America.

[Cloud 10]

Plenty of support in the 06z GEFS ensembles for the operational run with its FI shenanigans,including this "vortex pays a visit" solution from number 11

 

[BLAST FROM THE PAST]

Cheers, sorry I was seeing a chart of North America.

Shotski, when I opened the link I saw the same as you and thought the same.  Looking at Knocker's post though on previous page then I could see what he meant and obviously you can now.

 

 

Cloud, that is my LRF idea come end of the month into Feb...... :w00t:  For me period 20-25 is pivotal point of winter, even moreso now that December was disappointingly mild overall.  My new moon and perigee 20/21 dates and [if there is one] SSW then effects should be showing or putting into place around then.  My general idea is very deep depressions from Atlantic on possibly more southerly position with a block nearby and a negative tilt to trough..... general thoughts

 

 

BFTP

Edited January 3, 2015 by BLAST FROM THE PAST