Model Output Discussion 1200 hrs 15/11/14

[johnholmes]

Good ECM tonight if you are looking for a dry December. Probably fairly mild too with little in the way of frost

 

http://www.wetterzentrale.de/pics/Recm2402.html

 

cherry picking to the ultimate-you really are a comic BC; best to look at all the frames on any one run, better still to equate past 120-144h with checking the current 12z with previous outputs, even better than that use the anomaly charts for a less knee jerk reaction to what MIGHT happen.

Edited November 27, 2014 by johnholmes

[nick sussex]

The optimist in me hopes that this upstream might give us a bit more dig downstream around the T144hrs mark.

 

From the NCEP discussions:

 

IN THE NRN STREAM...DEEP EXTRATROPICAL LOW DEVELOPMENT FROM THE
BERING SEA INTO GULF OF ALASKA SHOULD ACT TO BUILD AN AMPLIFIED
MID-UPPER LEVEL RIDGE OVER WRN CANADA. THIS SHOULD BETTER ALLOW
ENERGY AND LOWER ATMOSPHERIC COLD AIR TO DIG TO THE LEE OF THE
RIDGE TO CARVE OUT A GRADUALLY PROGRESSIVE AND AMPLIFYING NWRN TO
N-CENTRAL TO ERN US MID-UPPER LEVEL TROUGH NEXT WEEK

 

 

 

Circled red over the USA that troughing, the amplification there will dictate the dig of the jet in the mid Atlantic, the more this digs south the further ne any high will get.

 

It does seem I might be scratching around to find some interest and you'd be right ! but just perhaps a small chance of more interest around the T144hrs to 168hrs timeframe.

 

Much depends on how much more amplification we can squeeze out of that USA troughing.

 

 

 

 

 

[knocker]

To digress but this may be of interest.

 

 

Want to see how the MJO influences the pattern? MJO convectn o/Indian Ocean accelerates jet o/Asia, weakens o/ N. Pac http://www.atmos.albany.edu/student/ventrice/real_time/maps/mjo/global_analyses.html 

[ANYWEATHER]

A rather benign period of weather coming up from now to over the weekend, then during Monday we see a rather strong cold front moving southeast over the uk ushering in some rain, perhaps a squall line, then much colder air pushing right across the country by early Tuesday. I would think there is likely to be some wintry precip in the north and west for a time, before pressure builds .It looks like some folks will get some frost and fog during next week and then a second renewed swave of cold air from the northwest late week. All in all , not a mild outlook, very seasonal as we enter the first Winter month.....

[blizzard81]

The optimist in me hopes that this upstream might give us a bit more dig downstream around the T144hrs mark.

 

From the NCEP discussions:

 

IN THE NRN STREAM...DEEP EXTRATROPICAL LOW DEVELOPMENT FROM THE

BERING SEA INTO GULF OF ALASKA SHOULD ACT TO BUILD AN AMPLIFIED

MID-UPPER LEVEL RIDGE OVER WRN CANADA. THIS SHOULD BETTER ALLOW

ENERGY AND LOWER ATMOSPHERIC COLD AIR TO DIG TO THE LEE OF THE

RIDGE TO CARVE OUT A GRADUALLY PROGRESSIVE AND AMPLIFYING NWRN TO

N-CENTRAL TO ERN US MID-UPPER LEVEL TROUGH NEXT WEEK

 

 

ECH1-144.gif

 

Circled red over the USA that troughing, the amplification there will dictate the dig of the jet in the mid Atlantic, the more this digs south the further ne any high will get.

 

It does seem I might be scratching around to find some interest and you'd be right ! but just perhaps a small chance of more interest around the T144hrs to 168hrs timeframe.

 

Much depends on how much more amplification we can squeeze out of that USA troughing.

I must admit Nick, and I don't know if this in part just wishful thinking but there is a wiff of the famous 1947 spell about the charts at the moment. The models are looking very much like the run up to that famous spell. The illustration you have given above, if it came to pass, would be almost a carbon copy of the run up to that 47 spell.

[heath]

Both GFSP and ECM are consistent in shifting the Greenland vortex eastwards, and both at different times suggestions of cold air heading south just to the east of the UK.  This indicates to me that the Azores ridge may struggle to maintain a benign influence in the second week in December when the eastward progression of the vortex stops.  Would the lower heights over the western Med on the ECM allow a route for colder air from central Europe in due course?  Any thoughts from the more knowledgeable?

[blizzard81]

I wonder what the control (blue) run looks like towards the end ?

 

 

High pressure parked over the low countries ?

Edited November 27, 2014 by blizzard81

[ANYWEATHER]

I must admit Nick, and I don't know if this in part just wishful thinking but there is a wiff of the famous 1947 spell about the charts at the moment. The models are looking very much like the run up to that famous spell. The illustration you have given above, if it came to pass, would be almost a carbon copy of the run up to that 47 spell.

Unfortunately, you cannot compare past years with the output from today. Certainly nice to think so , but the weather machine is so complicated that even the good Lord above does not understand it.....

[bluearmy]

I wonder what the control (blue) run looks like towards the end ?

 

PLUIM_06260_NWT.png

 

High pressure parked over the low countries ?

Parked over most of Europe actually. Uninspiring

[ANYWEATHER]

Those are really quite poor with temperatures on the way up in December rather than down!

Well. Im looking at the Ops and no way is the first week in December going to see warmer temperatures

[Captain Shortwave]

ECM/ens pretty much say the same story really, ridge/trough repeat. We might see some wintry precipitation is enough amplification is achieved. We just have to wait until the pole vortex (or polar doughnut now) hopefully disintegrates later in December. 

[Barry12]

Hopefully the ECM is more like the UKMO tomorrow, much better amplification

 

[Frosty.]

Nice to see the colder outlook is on track with nothing mild from the MO update today either. This is miles better than a year ago synoptically and we are all likely to see increasing amounts of frost and freezing fog once the high builds in next week with only the far northwestern corner of the UK probably more unsettled throughout...for all the coldies it's a welcome change from all the mild mush so far this autumn..thank god we are now on the cusp of winter. :- )

Edited November 27, 2014 by Frosty.

[Polar Maritime]

Okay, Can we please get back on topic to discussing what the Models are showing. More posts have had to be moved or deleted.

Edited November 27, 2014 by Polar Maritime

[A.J]

and to echo PM, please use the report function for any 'questionable' posts so that the site team can take a look at them.  Whilst we do appreciate that some posts can cause annoyance to individuals from time to time, replying to them in the thread simply takes the thread further off topic......thanks 

[fergieweather]

A rather benign period of weather coming up from now to over the weekend, then during Monday we see a rather strong cold front moving southeast over the uk ushering in some rain, perhaps a squall line, then much colder air pushing right across the country by early Tuesday. I would think there is likely to be some wintry precip in the north and west for a time, before pressure builds .

Indeed so - with WBFL's down to between 200-600m, a few cm's of snow expected over NW Scottish uplands (above 400-500m), with temporary blizzard conditions possible from lively CB's migrating inland, fuelled by SST.

[bluearmy]

Extended ens from ECM and naefs are broadly around the same solution. there looks to be a decent chance of a trough in nw Europe as week 2 progresses (dropping in from the nw). Mid Atlantic high anomoly south of greeny stretching back to Eastern Canada. Weakfish nw Russian high anomoly. Aleutian low anomoly. Naefs keener on digging the euro trough to our se - ECM not as keen to get it too far south into Europe. Certainly interesting and plenty of optimism for cold regarding what this pattern could evolve to. The Siberian vortex again looks to weaken on both models with an Eastern Siberian/Alaskan centre establishing. The Canadian centre becoming smaller and looking less threatening. the high upper anomolys are all long gone from Europe.

[Barry12]

The block is fighting back a bit more and a stronger arctic high on the 18z

 

Day 4:

 

 

Day 5:

 

[johnholmes]

Extended ens from ECM and naefs are broadly around the same solution. there looks to be a decent chance of a trough in nw Europe as week 2 progresses (dropping in from the nw). Mid Atlantic high anomoly south of greeny stretching back to Eastern Canada. Weakfish nw Russian high anomoly. Aleutian low anomoly. Naefs keener on digging the euro trough to our se - ECM not as keen to get it too far south into Europe. Certainly interesting and plenty of optimism for cold regarding what this pattern could evolve to. The Siberian vortex again looks to weaken on both models with an Eastern Siberian/Alaskan centre establishing. The Canadian centre becoming smaller and looking less threatening. the high upper anomolys are all long gone from Europe.

 

It might be helpful ba if you gave links to the sites you quote giving your view of what they show-please?

[damianslaw]

Models showing a very quiet start to December, with high pressure anchored to our southwest once we see a cold front move through on 1st December (very timely) introducing colder uppers. With a strong jetstreak to our north, we will be at the mercy of these heights for the rest of the week it seems, its position will be crucial in terms of where cloud will develop. NW parts will see the most of any precipitation with weak frontal activity/influences.

 

Longer term - tentative signs the atlantic trough will dig further SE from the NW combined with mid atlantic height rises moving NW setting up exposure to a colder feed from the NW as we move towards the middle of December.

 

So whilst we are certainly not staring at an imminent cold spell, we do have a set up highly conducive to something resembling colder weather as we move into the middle of month with plenty of cold promise thereafter.

[Cloud 10]

Indeed so - with WBFL's down to between 200-600m, a few cm's of snow expected over NW Scottish uplands (above 400-500m), with temporary blizzard conditions possible from lively CB's migrating inland, fuelled by SST.

 

Almost perfect timing for the first day of winter,and would be a lot different to what we have experienced this autumn.

 

[Duane S.]

The charts show a continued interest in 2 pertinent factors (albeit in FI land) a far eastern pacific wave which could aid strong ridging of the Atlantic high into Greenland and a gradually weakening vortex to our NW. Subtle but there.

Here is something else to add to the well placed optimism about a cold spell evolving mid-end December...

When very cold air establishes itself in west Europe well before Christmas, i.e. November, it very rarely lasts beyond mid January. 81/82 and 10/11 started early but went mild and stayed mild as we headed through January. The two most famous recent winters of 62/63 and 46/47 began on December 22 and January 22 respectively. Not just these, there is a definite correlation.

Talking of 62/63, it is worth watching the evolution of the commencement of that winter through December in the archives. Not a million miles different to where we are. I am of course not saying I think we will have a repeat of that winter but watch through early-mid December the couple of half hearted attempts to ridge northwards by the mid Atlantic high, unable to because of the jet. Then the transfer of the vortex eastwards away from GL and voila, we have lift off...

[Barry12]

Looks like Shannon is still with us, quite big changes at day 6 on the 18z

 

 

Much better for coldies!

Edited November 27, 2014 by Barry95

[knocker]

NOAA 6-10  has Canadian low stretching the colder air into Scandinavia with the Atlantic HP north America to UK, HP over the pole and weak trough Pacific The 8-14 has the Canadian trough weakening and develops a weak low north of the UK and realignes the Atlantic HP more SE. opening the door to possible incursion of colder air from the NW.

 

The GEFS and ECM are pretty much in agreement with this and both have a trough eastern Europe. One difference being the ECM has the trough eastern Greenland and more amplification upstream, It rather depends on how this pattern evolves.

 

Charts courtesy weathebell

Edited November 27, 2014 by knocker

[bluearmy]

It might be helpful ba if you gave links to the sites you quote giving your view of what they show-please?

 

not allowed to post ecm ens charts post T240 JH. evidently, ecmwf must have complained to weatherbell.  the naefs charts are freely available on meteociel. 

 

incidentally, NOAA cpc have a 1/5 confidence in their 2 week output this evening.