Winter Model Discussion - Cold Hunting -12Z 30/12/12

[Dampdorset82]

They were going by what the models were suggesting at the time? I'm sure most here would agree placing hopes on a LRF is pretty dodgy. It's a shame the media will go for it though and blast it out in the headlines as if its certain to happen. No wonder the text forecasts now are more vague and broad - its to cover their backsides from criticism for somehow saying "they got it all wrong".

The only one to blame in my view is the that sneaky mistress Mother Nature.

Id have to disagree with "No wonder the text forecasts now are more vague and broad - its to cover their backsides from criticism for somehow saying "they got it all wrong"

They have been so broad because the models have been so inconsistant with medium to long range forecasts recently they have actually just been forecasting what signals they have been observing..

[Zenarcher]

Models are still all undecided at 96 hours on the Atlantic low, the GFS, ECM and GEM show a low forming just as it enters the Atlantic but UKMO and NOGAPS don't. As we move to 120 hours the models show even more disagreement, GFS and NOGAPS show something similar and have 3 different lows all in one small area a very messy idea from them. The ECM and GEM show something that most models have shown for a few days and send just one low up to the South of Greenland. The UKMO is in the middle it has just one low but places it where the GFS and NOGAPS have theirs.

At 144 hours the GFS and NOGAPS send the lows over our North which is not pleasing to see we don't want much energy or no energy going over there at all but they have a messy idea of things at the moment so wouldn't take them too serious. The UKMO sends a low up to the South of Greenland a day later than what the ECM and GEM show. As for the ECM and GEM at 144 hours a deep low sits to the South of Greenland but they form a secondary low the ECM sends this over our North but the GEM doesn't send it over our North but back up over Greenland that's why GEM has more high pressure around us later in the run and the Atlantic looking a bit more weak compared to the other runs this morning.

Remember that things change all the time in the models for those new to this go to the archives on Meteociel from their you can look at different runs from different days all the way back to 2010 and relive history of downgrades/upgrades.

Also Happy New Year Everyone!

Edited January 1, 2013 by weathermaster

[cooling climate]

HAPPY NEW YEAR EVERYONE.

I just posted this in the strat thread and it may or may not be worth repeating in here

but maybe whats needed is a good mountain torque event or MJO wave induced response

(some type of tropospheric forcing) that will couple with the warming higher up.

Without this the models are floundering around unsure what to do with the strat warming.

It could of course also be that until the warming is actually underway in the Arctic

stratosphere the models will continue to struggle to pick up the correct signal.

A strong MJO +PNA ridge would certainly get the ball rolling,although personaly I think it

will be an Atlantic ridge that will build north from the western Atlantic.Or High pressure

building to the north of the UK.

Edited January 1, 2013 by cooling climate

[fergieweather]

HAPPY NEW YEAR EVERYONE.

I just posted this in the strat thread and it may or may not be worth repeating in here

but maybe whats needed is a good mountain torque event or MJO wave induced response

(some type of tropospheric forcing) that will couple with the warming higher up.

Without this the models are floundering around unsure what to do with the strat warming.

It could of course also be that until the warming is actually underway in the Arctic

stratosphere the models will continue to struggle to pick up the correct signal.

A strong MJO +PNA ridge would certainly get the ball rolling,although personaly I think it

will be an Atlantic ridge that will build north from the western Atlantic.Or High pressure

building to the north of the UK.

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

[AWD]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

Sorry Ian, what's MOS mean/stand for?

Nice to hear some positive Wintery thoughts from Exeter for later in the month.

[weathersupremacy]

Is the 12Z showing an upgrade in strat warming? Looks like it to my untrained eye, but could obviously be very wrong.

[snowmadchrisuk]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

Happy New Year Ian , I think your comments there will cheer up most of this forum . The best Cold spells in the 80's that I remember were in Feb , Look forwards to following the coming weeks in the SW thread .

[Rocheydub]

Well out to 168, and not a lot different synoptically on this run, HP centred to our SE and low pressures north of us. No sign of height rises, but not expected to see them yet, hopefully GFS later on in the low res keep up their recent trend of HL blocking deep in FI...

Interesting to hear that Ian, very encouraging, strat changes I presume? ... I know you cannot talk of exactly what is being said and why, but can you point us where to start watching for changes?

[phil nw.]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

Thanks for that Ian.It`s encouraging to hear that you professionals are considering the possibility of a cold pattern later this month.

Does including a SSW in met discussions something new or is it simply based around later ens data that the met use which are trending cold.?

[SLEETY]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

wow,that screams a very cold 2nd half to winter to me.

[fergieweather]

Thanks for that Ian.It`s encouraging to hear that you professionals are considering the possibility of a cold pattern later this month.

Does including a SSW in met discussions something new or is it simply based around later ens data that the met use which are trending cold.?

It's the major SSW event that catches the collective eye.... we're now entering a fascinating phase of a real-world test of the combined published research on this phenomenon versus outcome. The model flip-flop in solutions as they play catch-up further down the line on some highly complex dynamics will become a characteristic (if frustrating for some!) scenario now and this point needs stressing on the forum.

[chionomaniac]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

I suspect that the excitement may be coming from the longer range modelling of the secondary strat warming that occurs in between the displaced and split vortices. This imo is perfectly placed to deliver cold down the line. No doubt that since the GLOSEA2 model has improved stratospherically, the capabilities of the forecasts have improved in this respect.

Edit just seen your answer thanks Ian.

Also Are there any clues to how the strat behaves following day 10 - is it similar say at 10 hPa to the GFS solutions offered such as this:

Edited January 1, 2013 by chionomaniac

[Rocheydub]

Thanks Ian and Chiono, but it must also be stressed that we do not know that this will deliver cold for our Isles, just increases the probability of it happening. I think that all newbies should keep this in mind.

[Bobby]

The 12z UKMO flatten things by Monday with rain moving in from the West

The GFS is similar too bands of rain crossing the country next week before a piece of the PV gets ejected out from Greenland, continuing the trend mentioned earlier, turning things very unsettled and cooler with snow on hills up North, rain most else places.

There is a definite trend to something like this now.

There is a major sudden stratospheric warming event taking place, these can bring the UK very cold weather - maybe the 2nd half of January?

- Chris Fawkes BBC

- "can" and "maybe" being the operative words I think, I'm retaining a healthy scepticism until it something concrete starts showing in the models.

Edited January 1, 2013 by Bobby

[fergieweather]

Thanks Ian and Chiono, but it must also be stressed that we do not know that this will deliver cold for our Isles, just increases the probability of it happening. I think that all newbies should keep this in mind.

Absolutely: and with this in mind, at least a fighting chance of some reward on this particular forum, but not a done deal..... yet!!

[on the coast]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

What ever weather you like this is going to be a fascinating time coming up. Really looking forward to seeing how this pans out and how all models show it and which one comes the closest to show the eventual outcome.

Edited January 1, 2013 by on the coast

[Summer Sun]

Some snow showing in FI tonight around mid month could turn interesting if you want cold and snow

The Jet Stream looks like heading south again

[Ian Brown]

Absolutely. This is a crucial posting and everyone new to model-watching needs to appreciate the inevitable level of flux we'll now see in MOS into the longer medium-range/trend period. It's a fascinating time developing and trust me - the more I hear about what could happen later January from UKMO colleagues, the more exciting it becomes. There's a real buzz in discussions about this one.... (and I'm not normally drawn by such things!!)

Thanks Ian, any sea change in the pattern will be beginning from the worst possible synoptics so I think we all look forward to how the NWP will handle these possible changes.

[bobbydog]

as ian has said, we could see some wild variations in the output soon, however, at the moment the output is fairly consistent. if we do get a change to cold weather, it could be heralded by quite a nasty winter storm-

Edited January 1, 2013 by bobbydog

[Snowmad79]

Nice post by Fergie as quoted a number of times. Who said professionals don't ramp and straw clutch heh ?

Most of us may not see much in the way of Dry and Settled weather as fronts are still able to penetrate the West and North western areas. We will be lucky to get the odd respite in between which is fairly common in a NW - SE split weather pattern which looks the best bet for quite a while. Even height anoms from last week backed this up despite us being led up the garden path to the anoms over the pole!

As always, the SE escaping most of the wet stuff but eventually these fronts will push right across the country again so all in all the settled outlook is looking more and more like a blip.

Happy New Year all.

[HotCuppa]

BBC very bullish today saying for england and wales at least no real rain for 2 weeks or so... for the foreseeable future quite unusually a dry mild spell of weather looks on the cards... early Jan is not renowned for such synoptics...

All interest in the coming days will be on where the high decides to position itself as we move into the second week of January, my own hunch is that it will attempt to ridge northeast towards scandi but be forced to retreat back south thanks to lower heights moving in from the NW heradling a significant pattern change with heights building strongly to the NW. Signs of such developments in the

GFS

output. Its all about trends at the moment as day to day changes are likely to be very small in the coming days. Suspect all the models by this weekend will begin to show these colder trends just beginning to creep into the reliable timeframe.

the BBC forecast is produced and provided by the meto and their staff..to my knowledge the BBC have and will never produce their own forecasts. That said, ITV use exactly the same setup, using the meto, but with wildly different forecasts lol

[Tim Bland]

Some consistency from GFS in FI now. We are possibly looking at pressure rising around the pole and then towards Greenland. The net effect is to push the pv south with a chunk potentially over us. After this hopefully this low pressure can dig south while heights continue to rise over Greenland.

[Grimsby Snow Lover]

Some consistency from GFS in FI now. We are possibly looking at pressure rising around the pole and then towards Greenland. The net effect is to push the pv south with a chunk potentially over us. After this hopefully this low pressure can dig south while heights continue to rise over Greenland.

Could someone explain to me whether having a chunk of the PV over us is a good thing if we want cold and snow. The reason I ask is that the uppers didn't look that cold to me when FI finished on the 12z run. Thanks GSL

[Froze were the Days]

Some consistency from GFS in FI now. We are possibly looking at pressure rising around the pole and then towards Greenland. The net effect is to push the pv south with a chunk potentially over us. After this hopefully this low pressure can dig south while heights continue to rise over Greenland.

Yep a very similar run towards FI and no point putting detail on it as this is the lo-resolution part of the run but with a secondary SSW event occurring I believe some time after this. So this timescale around mid-month is the period to watch.

[snowice]

I suspect that the excitement may be coming from the longer range modelling of the secondary strat warming that occurs in between the displaced and split vortices. This imo is perfectly placed to deliver cold down the line. No doubt that since the GLOSEA2 model has improved stratospherically, the capabilities of the forecasts have improved in this respect.

Edit just seen your answer thanks Ian.

Also Are there any clues to how the strat behaves following day 10 - is it similar say at 10 hPa to the GFS solutions offered such as this:

IS this due to the warming of the stratospher over the artic and the cold is displaced south to the Uk.I think this last happened in 2009 and it became very snowy early February but the signs were there mid January?