Model Output Discussion - 16th Jan 12z onwards - Smile While You Post!

[IDO]

Looks another step forward from the GEFS towards prolonging the cold spell beyond D8.  A selection of the 06z ensemble output at T180:

 

 

 

 

 

Only the 06z of course but what we want to start seeing from now I think.

[Duane S.]

Ref mobility, I can fully see why it is being touted as the formhorse for next weekend. A glance at upstream signals would confirm that the cold spell has got its work cut out to cling on but even if we do pull in a more mobile regime, I would be surprised to see it hanging around for long. The waxing waning ridging of the Azores High looks set to continue, watch an increased ridging northwards signal grow in the models as we get into the final week of the month. There will likely be a period of opportunity here for some more interesting looking heights to grow into Greenland.

[Jason M]

Quite a few of the GEFS have us under an easterly flow out to 180. Coupled with the GEM ensembles it's an interesting little trend.

Edited January 17, 2015 by Jason M

[IDO]

The GFS op is the most progressive run within the ensembles and at the top end of the warmest solutions at D8:

 

 

So best to ignore till it gets support, possibly along with the control.

Edited January 17, 2015 by i'm dreaming of...

[weather eater]

It is interesting that fergieweather notes there is a clear signal for a return to a westerly regime- I hope this is noted.

   

Sort of but not exactly, likely is the word here.

 

"A gradual transition to a more mobile pattern across the Atlantic is likely to gradually take place, through may take until later next weekend to become fully established."       

[Snowman.]

The GFS op is the most progressive run within the ensembles and at the top end of the warmest solutions at D8:

 

graphe3_1000_306_141___Londres (9).gif

 

So best to ignore till it gets support, possibly along with the control.

 

285% chance of snow.

 

Nice

[kev238]

Sort of but not exactly, likely is the word here.

 

"A gradual transition to a more mobile pattern across the Atlantic is likely to gradually take place, through may take until later next weekend to become fully established."

Being pedantic but likely suggests around 75% chance which in my book denotes a clear signal. Not certain granted

[bluearmy]

This is a good illustration of where we will probably be by day 8

Azores ridge to our sw

Euro trough to our se

Both of these features showing within a low spread

Between the two and across our north (all the light blues, greens and yellows) - that's the size of the envelope !!

Apparently though, the pattern next weekend is already assured ...................

We'll call the week 2 evolution of the GEFS 'interesting'. No more at the moment but some members beginning to reflect the mid/upper strat profile shown on the ops in a week/ten days time.

Edited January 17, 2015 by bluearmy

[kiddydaz]

Being pedantic but likely suggests around 75% chance which in my book denotes a clear signal. Not certain granted

 

But we have no idea what will happen Tuesday yet ?

[EML Network]

Interesting Fax chart for Monday looks like a possible Thames streamer, but a very weak feature will probably be gone on the next update, one to watch though. 

 

[Jason M]

GEFS prtb 19 is a developing cobra run.

Not seen many of these over the last two years so rude not to post a chart :-)

http://www.meteociel.fr/modeles/gefs_cartes.php?code=19&ech=252&mode=0&carte=0

[Snowman.]

GEFS prtb 19 is a developing cobra run.

Not seen many of these over the last two years so rude not to post a chart :-)

http://www.meteociel.fr/modeles/gefs_cartes.php?code=19&ech=252&mode=0&carte=0

 

18z CFS.

 

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=894&mode=0&carte=0&run=4

 

It would be on par with 2010...

[weather eater]

Being pedantic but likely suggests around 75% chance which in my book denotes a clear signal. Not certain granted

Maybe but clear signals change  if they didn't do so then this thread would be consternation free, Clear signals have a habit of becoming unclear although I would allow its less so when it comes to the UK default pattern.. Still I'm not sure I would put it at 75% just yet and I suspect we will see some other options on display that don't back a return to a westerly regime, synoptic patterns are a constant evolution.

[Paul_1978]

18z CFS.

 

http://www.meteociel.fr/modeles/cfse_cartes.php?ech=894&mode=0&carte=0&run=4

 

It would be on par with 2010...

894 hours, are you having a laugh?

[IDO]

Maybe but clear signals change  if they didn't do so then this thread would be consternation free, Clear signals have a habit of becoming unclear although I would allow its less so when it comes to the UK default pattern.. Still I'm not sure I would put it at 75% just yet and I suspect we will see some other options on display that don't back a return to a westerly regime, synoptic patterns are a constant evolution.

 

Yes there is no clear signal, just one of several possibilities. If we look at the GEFS at T120 we have 7 members who are outliers ( I am assuming the first slider is now the most likely scenario). We can therefore discount the signal at D8 from them (mostly zonal, one bucks the trend). So when you take the rest as a collective only 33% at D8 are now zonal. The rest at least draw another 2-3 days of colder synoptics. Thats why the mean is not of great use at the moment as it has high clusterings of members that are completely wrong, be it the sliders or non-sliders.

 

This is of course only one run (and the 06z to boot) so we need to see that trending, but as more members join the sliding cluster the trend will become more apparent.

 

The ECM on Tuesday is modelling a short wave in the SW that travels east, it mixes out the uppers but with its own precipitation signal; so would be very interesting if it verified and if other conditions allowed it to fall as snow:

 

 

Edited January 17, 2015 by i'm dreaming of...

[summer blizzard]

GFS and GEM are both progressive this morning and have the Atlantic winning by day 8.

 

Euro is however interesting. At day 6 it has the same front losing to the high to the east, while the Atlantic does win (due to reinforcement from a shortwave), the flow is once again amplifying and looks like the low would have to dive east down Scandinavia and even by then, the Atlantic air is sub-5C hpa. 

 

Moral of the story, the Euro does not back a progressive solution. 

 

Of more more interest perhaps is the day 7 Euro mean.. not exactly a ringing endorsement for the Atlantic..

 

[legritter]

Yes there is no clear signal, just one of several possibilities. If we look at the GEFS at T120 we have 7 members who are outliers ( I am assuming the first slider is now the most likely scenario). We can therefore discount the signal at D8 from them (mostly zonal, one bucks the trend). So when you take the rest as a collective only 33% at D8 are now zonal. The rest at least draw another 2-3 days of colder synoptics. Thats why the mean is not of great use at the moment as it has high clusterings of members that are completely wrong, be it the sliders or non-sliders.

 

This is of course only one run (and the 06z to boot) so we need to see that trending, but as more members join the sliding cluster the trend will become more apparent.

 

The ECM on Tuesday is modelling a short wave in the SW that travels east, it mixes out the uppers but with its own precipitation signal; so would be very interesting if it verified and if other conditions allowed it to fall as snow:

 

150117_0000_90.png 150117_0000_96.png

The sattelite low sounded fine ,thought it was a new weather terminology ,but good that we can Edit our posts .the fun on here certainly makes up for some of the let downs i,m sure .looking at all output next weeks weather looks very interesting and still i feel will pop up a few surprises ,perhaps a russian high backing west ,not completely out of the question ,patience is the key as always ,great forum cheers gang 

[Snowman.]

894 hours, are you having a laugh?

 

He was talking about eye candy.

 

Not reliability.

 

It's just nice to look at.

[mushymanrob]

The return of a SW/W airmass by the end of the week is a high probability now - with the current consistent output

 

this suggests that the cold spell wont last, only the timings in doubt

 

 

it to me suggests the mean upper flow north of west, pretty much like what we have had recently, so cold pm incursions and mild tm sectors , and thats pretty much what the gfs suggests into fi.

is cold hard to shift?... yes, thats a salient point made earlier, so a return to the atlantic isnt nailed, but going off current model outputs its looking likely... only the timings in question, tbh i suspect the gfs 06z is being abit too progressive.

 

But we have no idea what will happen Tuesday yet ?

 

yes we do..... its the detail we dont know. we know it will be cold, we know there will be potential for some areas to get snow, we know it wont be mild. we know we have around a week of predominantly cold weather and we suspect that it wont last longer then about a week going off current outputs.

Edited January 17, 2015 by Paul
Removed un-needed bits

[Cleeve Hill]

Really good post by Phil NW a couple of pages back. Both GFS 06 & ECM 00 have troughs going south east next week which will keep things cold. With daytime highs now at 4 - 5c and cold nights to come the cold will dig in. If the troughs head further west (as per GFS) then more easterlies follow and cold prolonged.

Experience tells us the models are usually to quick to bring the Atlantic back.

So 7 days of below average temps to come and really looking forward to Tues/weds.

Beyond that, who knows but Cohen has talked up negative AO and blocking for NW Europe with a couple of subjectivities and the strat thread may throw up some more winter ideas. Love the comments of Lorenzo in there.

[IDO]

this suggests that the cold spell wont last, only the timings in doubt

 

814day.03.gif

 

 

 

The problem with that chart was that it was based on runs over 24 hours ago and in such a dynamic situation it is not of much use. Also the discussion was " LOOKING AHEAD TO THE WEEK 3/4 PERIOD, THINGS ARE DECIDEDLY UNCERTAIN." & "FORECAST CONFIDENCE FOR THE 8-14 DAY PERIOD IS: BELOW AVERAGE, 2 OUT OF 5".

 

So it is a time when even these anomaly charts are superfluous, especially for D8-14. Though I agree that a return to a zonal flow is one of the main cluster solutions. 

Edited January 17, 2015 by Paul

[Biggin]

285% chance of snow.

 

Nice

lol first time I have seen that.

[Snowy L]

better 00Z's snow likely for all the east, but for my location GFS is modelling a mild sector, so at best snow to rain, then to snow, I need a correction SW

 

The already cold surface temps should help keep the precipitation as snow in inland areas at least I should think?

[I remember Atlantic 252]

The already cold surface temps should help keep the precipitation as snow in inland areas at least I should think?

 

What I am hoping for, boxing day mild sector was dry, then a bit of freezing rain, or ordinary spitty drizzle, temp remained at 0.0C, no damage was done to snow cover

[sunnijim]

Being pedantic but likely suggests around 75% chance which in my book denotes a clear signal. Not certain granted

Hmm that 'signal' is for more atlantic mobility,it does not equate to Westerlys across the UK,a block maybe in place that halts that 'signal' for mobility down the spine of England and a battleground cold vs milder takes place with a snowfest!