Model Output Discussion - January 11th.

[Frosty.]

The Ecm 00z is showing the pattern change that all coldies are waiting for and it arrives in nw britain in 7 days time and then takes over the whole of the uk in the following days with the PFJ ending up across spain, much colder and very unsettled by the end of next week with snow and strong winds, ice and frost and beyond T+240 hours would promises even colder weather from north east europe. The Gfs 00z takes a lot longer to get there and needs several bites of the cherry to strike cold gold but the trend is for a much colder and unsettled pattern evolving during the second half of the month, the ecm is currently leading the way, before then we also have some interest with high pressure building over the uk in the next few days with widespread frosts and according to the gfs 00z, temps don't recover from that until the middle of next week when it eventually turns a bit milder but it could just be a mild blip before the weather pattern takes on a very wintry look.

Edited January 12, 2012 by Frosty039

[nick sussex]

Regarding the GFS operational run, the poor things been abandoned by NOAA today!

PREFER TO ABANDON THE GFS STARTING DAY

4...AND INSTEAD USE AN INTERMEDIATE SOLUTION INVOLVING THE 00Z

OPERATIONAL ECMWF AND ITS OWN ENSEMBLE MEAN FOR THE REMAINDER OF

THE PERIOD.

Thats up to day 7.

Some other interest from that

MODELS AND THEIR ENSEMBLES AGREE THAT THE LONGWAVE PATTERN

CONSISTING OF A DEEP VORTEX OVER NUNAVUT EXTENDING SOUTHWESTWARD

INTO THE PACIFIC NORTHWEST WILL ROTATE SLOWLY EASTWARD THROUGH THE

PERIOD...TAKING ABOUT 4 DAYS TO REACH THE NORTHEAST/NEW ENGLAND.

Look at the ECM from 72hrs in the NH perspective, you can see the PV rotating as that heads east the piece over eastern Greenland backs west.

Full discusssions here:

http://www.hpc.ncep.noaa.gov/preepd/preepd.html

Edited January 12, 2012 by nick sussex

[Radiating Dendrite]

Can I just ask, and this is for the benefit of members who are still learning....not myself; lots of talk of the polar vortex and what it might do. What do we want it to do if we want to se an increased risk of cold?

It needs to move west away from Greenland and over to Canada.

This will allow Northern Blocking to establish.

The PV is the mass of blue and purple over Greenland at the moment.

Regarding the GFS operational run, the poor things been abandoned by NOAA today!

PREFER TO ABANDON THE GFS STARTING DAY

4...AND INSTEAD USE AN INTERMEDIATE SOLUTION INVOLVING THE 00Z

OPERATIONAL ECMWF AND ITS OWN ENSEMBLE MEAN FOR THE REMAINDER OF

THE PERIOD.

Thats up to day 7.

Some other interest from that

MODELS AND THEIR ENSEMBLES AGREE THAT THE LONGWAVE PATTERN

CONSISTING OF A DEEP VORTEX OVER NUNAVUT EXTENDING SOUTHWESTWARD

INTO THE PACIFIC NORTHWEST WILL ROTATE SLOWLY EASTWARD THROUGH THE

PERIOD...TAKING ABOUT 4 DAYS TO REACH THE NORTHEAST/NEW ENGLAND.

Look at the ECM from 72hrs in the NH perspective, you can see the PV rotating as that heads east the piece over eastern Greenland backs west.

Full discusssions here:

http://www.hpc.ncep....epd/preepd.html

So is the rotation good?

NOAA obviously think the GFS is being to progressive with the jet and PV then? A failing the model has always had in these situations?

Stick with the ECM, far less moody.

[SMU]

http://www.knmi.nl/exp/pluim/vijftiendaagse/index.html

Extended ECM-

A very simple ISH evolution- Cold into Europe & getting Cut off, Low in the atlantic squeezes under the block-

Whats the final key.. for fear of repeating myself- the ridge to greenland to enforce the undercut...

I will take the control please...

S

[Radiating Dendrite]

http://www.knmi.nl/e...agse/index.html

Extended ECM-

A very simple ISH evolution- Cold into Europe & getting Cut off, Low in the atlantic squeezes under the block-

Whats the final key.. for fear of repeating myself- the ridge to greenland to enforce the undercut...

I will take the control please...

S

What is the control ECM?

Is that just like the parallel GFS? Run out to day 17 for the ECM, with the op only going to 240 hours?

Is it at a lower resolution? Can it be viewed??

[cooling climate]

http://www.knmi.nl/e...agse/index.html

Extended ECM-

A very simple ISH evolution- Cold into Europe & getting Cut off, Low in the atlantic squeezes under the block-

Whats the final key.. for fear of repeating myself- the ridge to greenland to enforce the undercut...

I will take the control please...

S

Looking at the t240 ECM chart it was looking as if the high to the east may possibly drift south which would not be good news but looking at the the control and other ensembly members suggest that this this may not be the case with as you say the low being squeezed south with higher pressure to the north bringing in a continental flow.

Lets hope the model runs today reinforce what the ECM is showing.

Edited January 12, 2012 by cooling climate

[Tim Bland]

Fantastic 00z ECM if it is snow you are looking for. I would much rather have this than the dry easterly. The evolution starts at T+168 as the allutian ridge pushes north and the low pushes south. Would be bags of snow starting this time next week puishing south . Lets hope this theme continues and the GFS falls in line. Over the weekend we can watch the T+120 fax to see what the experts think. Will also be interesting to see if the extended outlook from the Meto mentio wintry conditions pushing south later next week, I suspect they will stay on the fence for another day or so though.

[TEITS]

Rather than paying too much attention to what the Ops are showing im just glad the ECM ensembles continue to show a drop in the 2m mean and the PV backing W. The control run is bitterly cold.

http://www.knmi.nl/exp/pluim/vijftiendaagse/Data/15DAAGSE_06260_NWT.png

Still say that the undercutting of the trough might occur slightly earlier than predicted i.e 48hrs. Im basing this on the fact that when we have such blocking to our NE the models do have a tendancy of underestimating the blocking and how this affects LP systems coming up against it. Sometimes this can only be seen once inside the +96 timeframe though.

[Paul]

Just wanted to copy this in here..

For those who like the follow the strat temps, we've added a few new charts to our GFS viewers today:

For our extra subscribers we have stratospheric temperatures at 10hpa, 30hpa and 100hpa:

http://www.netweather.tv/secure/cgi-bin/premium.pl?action=gfs3;sess=

For those who don't subscribe we also have the 30hpa temperatures in the datacentre:

http://www.netweather.tv/index.cgi?action=nwdc;sess=

Following along later today or tommorrow we have a tutorial about the stratosphere and it's affects.

[KTtom]

As its quiet, anyone going to take a punt at where this run is going? Hard to imagine the PV can go anywhere but west?

[Downburst]

Rather than paying too much attention to what the Ops are showing im just glad the ECM ensembles continue to show a drop in the 2m mean and the PV backing W. The control run is bitterly cold.

http://www.knmi.nl/e...E_06260_NWT.png

Still say that the undercutting of the trough might occur slightly earlier than predicted i.e 48hrs. Im basing this on the fact that when we have such blocking to our NE the models do have a tendancy of underestimating the blocking and how this affects LP systems coming up against it. Sometimes this can only be seen once inside the +96 timeframe though.

I can't figure where this is for, can you tell me what city this is for? thanks as ever.

[Radiating Dendrite]

I can't figure where this is for, can you tell me what city this is for? thanks as ever.

De Bilt.

The Netherlands.

Edited January 12, 2012 by Radiating Dendrite

[IDO]

As its quiet, anyone going to take a punt at where this run is going? Hard to imagine the PV can go anywhere but west?

Looks like as we nearer the high res the output gets worse for snow. Not good at the moment in the reliable time frame but keeping coldish.

Edited January 12, 2012 by i'm dreaming of...

[Radiating Dendrite]

As its quiet, anyone going to take a punt at where this run is going? Hard to imagine the PV can go anywhere but west?

This is the GFS we are talking about.

It seems to want to follow the ECM lead but is much slower in getting there.

I imagine that it will continue to overplay the PV and keep it over Greenland. We shall see.

[TEITS]

I can't figure where this is for, can you tell me what city this is for? thanks as ever.

Debilt is in Holland in the province of Utrecht

[Radiating Dendrite]

Interestingly, this run is a bit more reluctant to sink the high that will be over us this weekend.

The low over Iberia is not pushed through as quick, supporting the high over us.

Edited January 12, 2012 by Radiating Dendrite

[KTtom]

This is the GFS we are talking about.

It seems to want to follow the ECM lead but is much slower in getting there.

I imagine that it will continue to overplay the PV and keep it over Greenland. We shall see.

http://www.wetterzentrale.de/pics/Rtavn1621.png

Looks like a link up of all 3 high pressure cells, not that its a wonderful set up for snow but you just can't see the Altlantic getting through that block!

[IDO]

GFS keeping us under the influence of HP next week. Just moving around blocking anything wintry. Still cold till Thursday but dry. HP over Eastern Europe is promising, so not sure where this is going in FI.

[Harsh Climate]

All eyes on the gfs 6z soon

But once again looking for specifics regarding any possible easterly is near impossible at this range, so I will be taking this run with a pinch of salt!

I will be looking for perhaps more runs heading below -10 and maybe some clustering of something much colder.

Also very important will be the pressure over scandianvia, look at how many perpetrations have higher pressure over oslo than the operational, that tells me that 'that run' perhaps wasn't quite correct in it's efforts in modeling the pressure to the north east.

The last AO forecast is very good, we have it forecast to plummet to around -2/3 in 10 days time, that is good but we really need the NAO to do likewise, but currently not so good. I think more runs like what the ECM has been showing and it might do so.

.

If we are to have a long lasting cold spell with a good atlantic block, I usually find having the NAO below -1 and the AO below -3 as a very good starting point.

I think the latest output is good and this chart would probably lead to some sort of easterly down the line, as the high to the north eventually flattens as the low over us begins to weaken (probably due to the high squeezing the life out of it from all sides lol.)

Anyways I still think the ECM is main player at the moment, what the ECM begins to show is what I would go along with.

[TEITS]

http://www.wetterzen...s/Rtavn1621.png

Looks like a link up of all 3 high pressure cells, not that its a wonderful set up for snow but you just can't see the Altlantic getting through that block!

Problem with the 06Z is we aren't seeing the trough undercutting the block as does the ECM & the 0Z GFS.

[Nick F]

A cold and dry 4-5 days ahead, as high pressure builds in across the UK behind the cold front clearing south today, the 00z operationals were keen on cloudy and damp southwesterlies returning mid-week next week. Any return to milder conditions next week maybe short-lived, if ECM op is correct, but this is reliant on the PV over Greenland fragmenting, as a deepening trough over NE N America sends WAA towards Greenland - which sees a cold vortex break away southeast on 00z ECM op towards the North Sea.

However, 06z GFS still not keen at all so far on this PV split, prefering to keep the trough over NE N America much less amplified and thus the flow flatter downstream across the Atlantic, though the small positive on this run is that high pressure remains close by over the UK, so milder southwesterlies don't encroach mid-week as suggested by the 00z runs.

[nick sussex]

Is everyone still awake?

The worst of halfway houses from the GFS 06hrs run so far, the main PV does edge west but the upstream pattern is flat and as we can see high pressure remains elongated to the south.

This really takes boredom to a new level, its cold at the surface as the flow is generally off the continent. But without that upstream amplification you won't get troughing to dig se into Europe.

The early GFS was shelved after day 4 by NOAA lets hope this meets the same fate!

[KTtom]

Problem with the 06Z is we aren't seeing the trough undercutting the block as does the ECM & the 0Z GFS.

We also don't have the trough exiting the US heading NE up the western flank of Greenland as in ECM below...important to inject some amplification into the flow.

http://www.wetterzentrale.de/pics/Recm1681.gif

[bluearmy]

re nicks post NOAA thoughts. there will be renewed energy coming out of newfoundland and steve is right - the best thing for us will be enough of a height rise around greenland to send this energy se. prosmising although naefs continues to support a much slower evolution to the trough dropping into our vicinity. (T300+). if the parallel GEFS are better than the normal, this will probably be too slow as the mean jet on the normal GEFS was stronger than on the parallel. promising but not yet a 'done deal'. the ecm ens have not really moved from where they were yesterday. we need more members joining the op/control to give us complete confidence.

[Radiating Dendrite]

Is everyone still awake?

The worst of halfway houses from the GFS 06hrs run so far, the main PV does edge west but the upstream pattern is flat and as we can see high pressure remains elongated to the south.

This really takes boredom to a new level, its cold at the surface as the flow is generally off the continent. But without that upstream amplification you won't get troughing to dig se into Europe.

The early GFS was shelved after day 4 by NOAA lets hope this meets the same fate!

To be honest Nick, the GFS seems to be chucking the kitchen sink in now. Is there any scenario it has not explored in the last few days?

It does seem a little all at see at the moment and surely cannot be trusted?