Model output discussion - 1st December onwards

[damianslaw]

Oh dear this thread is degenerating again...

ECM continues to suggest a colder theme mid month with signs of height rises to the NE. GFS showing the opposite.

What we really don't want to see for simple reasons that it will mean further flooding is the current pattern locked in place for any more real length of time. The behaviour of our weather these past few weeks has been very reminiscent of the exceptional unprecedented 3 month period Dec 13-Feb 14 when it felt like we were on constant repeat.

I'm staying upbeat, and believe a balancing out pattern will occur in the not too distant future.

[johnholmes]

1 hour ago, BLAST FROM THE PAST said:

Many 'get it' and all one has to do is look at it really KTom.  It ain't benign, it's trouble if that comes off with potential quite wintry weather adding in the mix.  So pointless if u really want to say pointless

 

BFTP

Fred is it really too much trouble to post a link if you do not want to post a chart to illustrate your point? I think that would satisfy the great majority on here and be helpful for those new to model watching. Not asking much am I?

Edited December 7, 2015 by johnholmes

[ukpaul]

GFS 06z pushing the rain further south for this time next week. For the sake of my parents up in the affected area I hope this happens instead of the horrific 12z.

[cheshire snow]

The pub run shows a cool NW at Day eight (FI)with temperatures 

Returning more to the seasonal norm

C.S

[feb1991blizzard]

1 minute ago, cheshire snow said:

The pub run shows a cool NW at Day eight (FI)with temperatures 

Returning more to the seasonal norm

C.S

And by day 9 in the genuine cold category, albeit with supressed PPN.

[damianslaw]

I commented yesterday on the Jetstream profile forecast showing an increasingly strong yet very southerly flat jet.. we could well see low pressure digging further south across the country with the heaviest rain reserved more for the south next week and colder conditions in the north - indeed as a theme this is quite possibly the most likely scenario for the middle of the month (would love to see an anticylonic influence). So yes likely to stay unsettled for the foreseeable but temperatures back down closer to the seasonal average, with some quite chilly conditions in the north. From a Cumbria perspective, its a positive as we should be spared the monsoon rains of recent days, and balmy air, replaced with faster moving shorter though probably still just as intense rainfall with colder outbreaks behind.

We shall see..

[cheshire snow]

By day nine most people will be using an ice scraper as overnight

Temperatures dip close or just below freezing. 

Very interesting watching at the moment,and whilst no big freeze

Is on the cards (at the moment ) the weather looks like been more

Seasonal,hopefully giving the chance for my fellow north west

Members to dry out.

C.S

 

 

 

 

[bryan629]

Pv at 192 not looking too shabby

Pv at 384  

 

[chionomaniac]

6 minutes ago, bryan629 said:

Pv at 192 not looking too shabby

Pv at 384  

 

Hi Bryan - it's probably worth just pointing out that those charts are of the temperatures experienced at 10hPa - not of potential vorticity or geopotential height at this level. What they do show is that yet again by the end of the run, the GFS is suggesting a slight warming at this level and, for those who can deduce the PV shape from this warming, then you would be right in thinking that it would be displaced from a central position slightly by T+384. 

[Singularity]

Well, one good thing about the 18z is that it's a lot more like I've been looking out for in terms of the El Nino background working in conjunction with the SAI feedback process. 

The other main positive is that shift south in the weekend rains, the large totals falling across areas which have had near or even below average rainfall over the past 2-3 months.

[marksiwnc]

Just now, Singularity said:

Well, one good thing about the 18z is that it's a lot more like I've been looking out for in terms of the El Nino background working in conjunction with the SAI feedback process. 

The other main positive is that shift south in the weekend rains, the large totals falling across areas which have had near or even below average rainfall over the past 2-3 months.

But it seems to be over my area in nw Wales and we have had copious amounts of rain and flooding too with more to come by the looks of it 

[knocker]

 

Broad overview of the latest EC32 update

The anomaly on the 17th. HP eastern Pacific with LP Alaska and California. HP N. Canada and a trough running a fair way south mid Atlantic. and ridging to the east of the UK. So although LP is dominating the Atlantic the HP is still influencing the UK bringing a warm SW flow. Soon to change.

During the next week the ridge soon collapses and the trough moves east to be be over the UK by the 25th with a familiar story upstream with LP Alaska, trough western N. America and HP NE Canada. Surface analysis for the UK very unsettled at first with some wintry outbreaks, particularly in the north but perhaps improving later nearer the 25th.  Temps generally a little above average.

This scenario holds good until about the 29th when the trough begins to lose it’s influence and HP pushes a little north from the SW and S. Still a flow from a westerly quadrant but a tad more benign so longer periods of settled weather with temps around average or a little above.

Summary

Broadly speaking from the 18th until the 8th January The UK will be in a flow from a westerly quadrant bringing some wet and windy weather at times, particularly in the north, interspersed with some calmer ridging conditions in the wake of the latter as HP edges up from the SW/S.  Temps initially above average but becoming average but they will vary a fair bit around the norm,

Keep in mind this is very broad brush and not taken from the full ecm suite but it gives a pretty good general idea.

The NAO and AO are positive throughout the period except the latter does slip negative at the end.

And remember Oedipus

Edited December 8, 2015 by knocker

[knocker]

Regarding the weekend the gfs has a succession of lows swinging in from the SW. How much rain they will bring to the already drenched areas is problematic at the moment but hopefully not that much as the ridge from the SW nudges them east. The ecm has a different scenario bring the low up west of Ireland before nipping it ESE bringins wet and very windy weather up north. This is not a good scenario rain wise.

Charts weatherbell and http://www.tropicaltidbits.com/

 

Edited December 8, 2015 by knocker

[shaky]

Big differences at just 96 hours between ecm and gfs!!gfs slides the lows over southern england whereas ecm takes it up the west of ireland and then across the uk!!hmm whose gone be right?

[Ali1977]

GFS, GEFS, ECM all going with a block of sorts and E or SE winds at day 10 - Great news, maybe some cooler, dryer and frosty weather on the way.

[MPG]

3 minutes ago, Ali1977 said:

GFS, GEFS, ECM all going with a block of sorts and E or SE winds at day 10 - Great news, maybe some cooler, dryer and frosty weather on the way.

Where's the block at day 10 on the GFS?

[Ali1977]

1 minute ago, MPG said:

Where's the block at day 10 on the GFS?

My bad, I was on the GFS control run....still too early!! Doh

[Paul_1978]

3 minutes ago, MPG said:

Where's the block at day 10 on the GFS?

In the North Sea - but looks a bit lightweight to to termed a "block". If there was a 268h ECM I suspect it would be gone. 

But still, an Easterly of sorts, but probably not one that's got any longevity.

[Frosty.]

As a coldie. sick of looking at bbc weather maps showing 12/13/14c temps every day across england and wales, the Ecm 00z T+240 chart made me smile seeing the mild sw'ly mush being held at bay and even pushed back...hope the ecm continues to build on this idea on subsequent runs..time we had some proper cold weather!! 

[Ravelin]

16 minutes ago, shaky said:

Big differences at just 96 hours between ecm and gfs!!gfs slides the lows over southern england whereas ecm takes it up the west of ireland and then across the uk!!hmm whose gone be right?

Well the UKMO is similar to the ECM but slower in developing the low ie it's position and size at t144 on the UKMO is similar to on the ECM t120 chart.  

The GEM,  well the GEM isn't much help in deciding because it just stalls the low over the azores for 3 days before merging it with another. 

The GEFS doesn't really make anything of the low at all. 

So between t96 and t144 we have 5 different solutions from 5 different models. 

[Frosty.]

Nice to see polar maritime air sweeping across the uk later this week and into the weekend on the Ecm 00z op run with a more seasonal feel to our weather for a change!

[Iceberg]

Looking at the general bigger picture i posted this from the ECM, yesterday evening. This is taken from the GFS this morning. GFS (upto T200-240) shows some consistence with the broad JS pattern, with the energy going into the far southern JET. It rather losses it after that though.

 

[feb1991blizzard]

No wonder there have been a wide spread of ECM London temperature ensembles in FI lately with such uncertainty over scandi.

 

[johnholmes]

Sadly for those looking for the elusive cold spell it remains just that, elusive.

Nothing in the 6-15 day outputs from whatever source show any consistent indication of the major change needed to give a cold spell.

The anomaly charts show the major pattern is a marked trough somewhere west even SW at times of the UK with no indication that this is going to change markedly. What may be of some comfort to those so badly affected by high rainfall totals is that the 500mb flow is showing signs of decreasing. This should have the effect of decreasing the number of deep surface features and the rainfall totals over the 6-15 day period. It terms of any cold then behind each surface feature as the surface and upper flow switches to a more west to NW for a short period then colder air briefly more especially for the northern half. No signal at all so far of any major cold burst.

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

http://mp1.met.psu.edu/~fxg1/ECMWF_0z/hgtcomp.html

[JOPRO]

Models all over the place again, every run I look at seems to be different, expect GFS 06Hrs run to take a different track again from the 00Hrs. As a cold lover confusion breeds opportunity!