Model Output Discussion; into 2015

[Jason M]

It's correct upto T+48 hrs then goes faulty until T+96 hrs where it corrects itself.

 

Yup, agree with that. Does beg the question of where the 48 to 72 charts have come from though??

[fergieweather]

Hi Tamara, fully concur with most of your post. I'd only take issue re: "Despite things not going to plan, so far..."

I'd instead argue it's all gone wholly in line with expectation: the +NAO-driven and essentially unexceptional but slightly milder than average December forecast was borne-out; ditto the early signal for *possible* stratospheric warming complexities emerging turn-of-year; the less clear +ve versus -ve NAO polarisation as January-Feb continues (still tbc through 2nd half of month).. worth remembering no 'deep cold' or 'cold-hearted' winter was ever forecast (Madden hyperventilation aside), hence my view being one of actually a broadly successful seasonal forecast *so far*, in keeping with general expectation, but with the obvious caveat, of course, that we've still a distance to go before any final lap and final judgement!

Cheers

Ian

[MR EXTREMES]

Gfs is certainly trying to higher heights to our East North East.

But not enough yet in some ways I'd like Azores heights to build over the uk perhaps just to let the rest of the northern hemisphere fight it out then have a set pattern!.

Looking at that pv it's a blinking pain in the butt.

[Mucka]

Hi Tamara, fully concur with most of your post. I'd only take issue re: "Despite things not going to plan, so far..."

I'd instead argue it's all gone wholly in line with expectation: the +NAO-driven and essentially unexceptional but slightly milder than average December forecast was borne-out; ditto the early signal for *possible* stratospheric warming complexities emerging turn-of-year; the less clear +ve versus -ve NAO polarisation as January-Feb continues (still tbc through 2nd half of month).. worth remembering no 'deep cold' or 'cold-hearted' winter was ever forecast (Madden hyperventilation aside), hence my view being one of actually a broadly successful seasonal forecast *so far*, in keeping with general expectation, but with the obvious caveat, of course, that we've still a distance to go before any final lap and final judgement!

Cheers

Ian

 

I doubt MetO will be bringing the seasonal forecasts back just yet though.  :smiliz64:

Fair play this year though, they have been spot on thus far.   

[Harsh Climate]

Gfs is certainly trying to higher heights to our East North East.

But not enough yet in some ways I'd like Azores heights to build over the uk perhaps just to let the rest of the northern hemisphere fight it out then have a set pattern!.

Looking at that pv it's a blinking pain in the butt.

 

Doesn't look good to me

 

 

Blacks over greenland/svalbard 

[Buxton Codge]

I think the issue today isn't so much what the pattern will be but whether its zonal mild or cooler zonal weather.

 

 

If you are south of the Peak District, cool/cold zonal does not mean much. I have yet to see London suffering from snow in a cool zonal flow.

[john mac]

Not much talk of events for Saturday, especially as the low is further south!!!

[Matty23]

Yea what's happening about Saturday. We're is the snow most likely now?? Is it a repeat of last weekend

[john mac]

Yea what's happening about Saturday. We're is the snow most likely now?? Is it a repeat of last weekend

If the gfs is to believed I think it will be further south than last week!!

[whiskers]

It's my sons birthday Saturday,would love a bit of snow plzzzzz,sorry if off topic!

[picog]

Not much talk of events for Saturday, especially as the low is further south!!!

If the low is further south, does that mean that any potential snow will be further south too?

[john mac]

If the low is further south, does that mean that any potential snow will be further south too?

Yes I think so but could do with an update from nick s.

[fergieweather]

Yea what's happening about Saturday. We're is the snow most likely now?? Is it a repeat of last weekend

Awaiting EC. As of earlier today, transient leading edge snow for lowland northern areas (bigger problem trans-pennines) but rate of transition W-E mitigated pronounced cold advection phasing with PPN for very long. In any event, generally 10-15mm PPN for most (event total 30mm for some) with rapid GPH build behind it, so as it stands we are cautiously hopeful it won't prove to be a big deal. However, we await full analysis later this evening.

[Cheese Rice]

If the low is further south, does that mean that any potential snow will be further south too?

Yes I think so but could do with an update from nick s.

Unlikely.

All the short range high resolution models don't toy with snowfall, snow risk amplified if front is further north only.

Edited January 1, 2015 by Cheese Rice

[Cheese Rice]

Awaiting EC. As of earlier today, transient leading edge snow for lowland northern areas (bigger problem trans-pennines) but rate of transition W-E mitigated pronounced cold advection phasing with PPN for very long. In any event, generally 10-15mm PPN for most (event total 30mm for some) with rapid GPH build behind it, so as it stands we are cautiously hopeful it won't prove to be a big deal. However, we await full analysis later this evening.

I'm hopeful I'll be in prime position on Saturday.

Eagerly awaiting your update

Edited January 1, 2015 by Cheese Rice

[shaky]

Awaiting EC. As of earlier today, transient leading edge snow for lowland northern areas (bigger problem trans-pennines) but rate of transition W-E mitigated pronounced cold advection phasing with PPN for very long. In any event, generally 10-15mm PPN for most (event total 30mm for some) with rapid GPH build behind it, so as it stands we are cautiously hopeful it won't prove to be a big deal. However, we await full analysis later this evening.

if we go according to gfs ian does that mean the snow line will be further south instead of northern england! !

[Ali1977]

Another bleak outlook for coldies, I feel another year with no snow coming in my part of the UK...Seems that the only glimmer of hope at the minute is the strat warming to change things, it's still looking promising on that front.

[Carlrg]

Middle Diddle according to the GEM.

 

 

 

[stewfox]

For those into statistics, Tamaras post is currently rated at exactly one' like' per paragraph - keep up the good work Tams!

 

Fav post I would like to see now is one from Ian Browns saying  'I don't believe it' .

 

Models tonight should hopefully firm up any transient snow for Saturday.

[IDO]

GEFS at D10 sniffing another possible baby ridge dragging a plume from N.Africa: 

 

No real change to the overall zonal pattern but some drier and warmer interludes. This seems a reasonable development bearing in mind the upcoming 3 day transient ridge next week. So a slight shift to TM>PM but all subject to change as we head closer to D10. Some changes after D12 with a small cluster keeping a MLB over the UK and by mid-month signs that this is becoming a larger cluster as the mean suggests:

 

 

This hopefully ties in with my hope that the PV will become less of a driver as other variables factor into the synoptics around mid-month. Just need it to trend now.

[Jason M]

GEFS fully out now. Nothing much to report really.

 

Perhaps a relaxation of the pattern by the very end and maybe some possibility of a northerly topple scenario out towards mid month.

[reef]

There's quite a few one-liners and off topic posts slipping in here, a few posts have been removed.

 

Please keep on topic and discuss the models.

 

Thanks

[SMU]

Evening All-

 

Its been a low ebb in the 14/15 season here since Xmas day, when the models align into this this type of chart at day 7

 

http://www.meteociel.fr/modeles/ecmwf/runs/2015010100/ECH1-168.GIF?01-12 A deep vortex in the worst possible place over Eastern Canada. With the AO indexing significantly positive.

 

In terms of references to the Winter forecasts, the success of those -  (which as it stands is heading for a fairly successful METO insight ) hinges on how long the vortex stays intact through January.

 The background signals for this Winter have all been in favour of blocking in the mid part of Winter & we are now at that juncture & will remain in that situ for 4 weeks, so in terms of forecast accuracy the 'pit stop window' if you like is now open.

Caution abound though as generally the first third of jan is already forecast to be wiped out by the strong westerly index.

 

Post that the ECM in the 192 arena & to a larger extent the GEM signal a more structured deceleration of the Westerlies & increase the polar heights. 

However being at day 10 its highly volatile

.http://modeles.meteociel.fr/modeles/gem/runs/2015010112/gemnh-0-240.png?12

 

In terms of the feedbacks from the snowcover figures they have been almost absent which has been very disappointing & has certainly denting MY optimism with regards to the effects it will now have in the rest of the winter

Heres the first month of this Winters anomaly chart

 

 

As we can see the MAIN feature is a slightly displaced azores high to the North, which kept the UK in PM air for longer supporting a month near normal, however looking east its pretty weak in terms of any signal.

 

My 'take' on where we are today is as follows.

 

The Winter forecasts ( certainly any going for any form of cold month of Jan ) are at 'risk'. It is however early doors & after day 7 we still have 7 weeks of Winter proper left so there is time for the blocking to develop over the pole & we know from experience it doesn't take long to get there if the wheels start to roll into motion.

 

I guess at this stage I am just raising the marker to say that as it stands we aren't in the right place in terms of expectations for what we are seeing over the pole V the analogues ( especially ones painted by the OPI ).

 

14 - 23 days to go of modelling OF jan where we will then be almost reliable into Feb.

 

We need to see significant changes soon.....

 

S

Edited January 1, 2015 by Steve Murr

[Cheese Rice]

ECM 12z ppn chart shows a more southerly track. Heavy rain for all.

IF a more northward trajectory then snow for southern central northern England on high ground.

[mulzy]

Evening All-

 

Thanks Steve - superb post.  You have called a spade a spade.

 

Do you think the Strat warming may have an impact going forward?

Edited January 1, 2015 by Polar Maritime
To move discussion on.