Model Output Discussion - The final stretch to Christmas

[Mucka]

"I'm here to chew bubblegum and kick ass and I'm all out of bubblegum.  (Not aimed at you or MetO Fergie)

 

RE weather warnings. Likely a directive from government?

All part of the dumbing down of society and to reinforce the idea that we are helpless without "officialdom" 

The ones directed to health workers etc are absolutely fine and in context but the ones directed at the public these days are typical nanny state ramblings.

Of course being a member of the public I get to have an opinion on that regardless of how officialdom tell me how I should feel. 

 

 

What I find odd is that any potential cold snowy weather being modelled seems to be very much downplayed until it is actually certain it will arrive at which point we seem to go to the other extreme. There doesn't seem to be any middle ground. Well that's my opinion and you know what they say about opinions...

 

London ECM ensembles very much behind a warm up but where did the control run go?

I assume that found some undercut or perhaps it maintained high pressure over the UK? Anyone know?

 

 

 

Edit

 

Correction. Blue line is GFS Operational. 

Edited December 26, 2014 by Mucka

[10 Days Away]

"I'm here to chew bubblegum and kick ass and I'm all out of bubblegum.  (Not aimed at you or MetO Fergie)

 

RE weather warnings. Likely a directive from government?

All part of the dumbing down of society and to reinforce the idea that we are helpless without "officialdom" 

The ones directed to health workers etc are absolutely fine and in context but the ones directed at the public these days are typical nanny state ramblings.

Of course being a member of the public I get to have an opinion on that regardless of how officialdom tell me how I should feel. 

 

 

I agree, if I can see my breath it's getting cold..... put heating on & check on my elderly relative.

 

Job done ! Don't need a health advisory me thinks.  Flame away all you want everyone.

Edited December 26, 2014 by TN26

[nick sussex]

Looking further ahead, the encroaching Atlantic bumping into cold air will surely produce some snow?? I would say, after that most models are going for atlantic dominated weather. Id also imagine, the northwest would be first to feel the milder air.

It depends on the angle of attack, if the block sinks with fronts coming in from the nw then the cold will mix out before the precip arrives. If the attack is from the west/sw then yes a chance, currently most models go for the sinking route.

[swilliam]

"I'm here to chew bubblegum and kick ass and I'm all out of bubblegum.  (Not aimed at you or MetO Fergie)

 

RE weather warnings. Likely a directive from government?

All part of the dumbing down of society and to reinforce the idea that we are helpless without "officialdom" 

The ones directed to health workers etc are absolutely fine and in context but the ones directed at the public these days are typical nanny state ramblings.

Of course being a member of the public I get to have an opinion on that regardless of how officialdom tell me how I should feel. 

 

 

What I find odd is that any potential cold snowy weather being modelled seems to be very much downplayed until it is actually certain it will arrive at which point we seem to go to the other extreme. There doesn't seem to be any middle ground. Well that's my opinion and you know what they say about opinions...

 

London ECM ensembles very much behind a warm up but where did the control run go?

I assume that found some undercut or perhaps it maintained high pressure over the UK? Anyone know?

 

 

That is not the control run it is the GFS 00Z Op.

[IDO]

Sorry, but that's very ill-informed. What has been issued is a health alert for cold weather (these are done in conjunction with health professionals) - NOT a 'severe weather warning' within the scope of what comes from NSWWS.  Statistics show very starkly how mortality rates of certain elderly/vulnerable people rise sharply when certain temperature thresholds are reached - be these for cold or indeed hot weather. The alert is to focus attention amongst carers and others, who then operate a pre-determined mode to ensure greater viligance for vulnerable groups. The alert is only issued when the forecast shows certain threshold temperatures will be attained/sustained for a certain period (like heat alerts in summer) and in this case, it's exemplified by the fact that the period from Sat through to Tues is expected to be the coldest of 2014 on the basis of overnight minima.

 

 

Understand that but perspective was what I suggested 

 

The thresholds are:

 

• Mean temperatures below 2 degrees Celsius for 48 hours or longer
• Heavy snow and/or widespread ice

 

Severe Weather Action is issued if one of the above conditions is met. So if we get max temps of 3c and min of -2c for a couple of days a Severe weather action is issued. You get headlines like this: http://news.sky.com/story/1397761/boxing-day-snow-as-uk-slides-towards-15c 

 

I suspect that some weather forecasters in other countries will be surprised by this alert. I only mentioned it as family members saw the news covered in snowmaggedon stories and were worried about travelling. It sometimes causes more confusion than help. If they were just issued to the NHS instead of TV and papers, who hype them up, then no problem. Anyway only in my opinion.

Edited December 26, 2014 by i'm dreaming of...

[MR EXTREMES]

It depends on the angle of attack, if the block sinks with fronts coming in from the nw then the cold will mix out before the precip arrives. If the attack is from the west/sw then yes a chance, currently most models go for the sinking route.

Something that I've recently noticed is the more South East route of low pressure and the alantic has not been dominant!.

It's also worth noting that recently the models have been struggling in fact last year and the year before every year I've been on here winter model watching is very volatile as of coarse spring and summer even autumn seem to have more consistent outputs.

[Mucka]

That is not the control run it is the GFS 00Z Op.

 

Doh!

Of course it is, blame the holiday sauce. Thanks for the correction. Will edit.

Edited December 26, 2014 by Mucka

[A.J]

please post met-office & 'weather in the media' posts in the relevant threads as they really are nothing to do with the model discussion.......thanks

[fergieweather]

Back to the here and now - signs now well underway of changes in leading edge of PPN, all going largely as modelled with cold pool taking shape. Snow falling readily at the moment at the Hawthorns (West Brom) and sticking on the pitch in last few mins.... a taste of what may now follow into this evening and tonight. Latest analysis suggests we can't rule out some snow even well south of M4 later into the eve/night. Wintry showers tomorrow for many districts (incl. in south), giving some accumulations over higher ground.

[pyrotech]

Subtle differences fairly early on from the last GFS to this run ( i know we should compare similar runs really)

By new years day they become significant.

One question is will the high over Western Europe be kept up.

The low over the med seems to help keep it in place

a new low to West of UK

Is this the start of a migration over the next few days towards the high being propped up and undercut scenario early in New year.

 

Its not what the models show, but tentative changes towards that possibility .

 

 

With that, its just more progressive and if anything the High slips further South. However Low in Med seems to be further West. There is a lot to play for with this scenario.

Active Atlantic with stormy conditions , or undercutting low scenario?

As this is model discussion i will say Atlantic looks like winning out, but there are inconsistencies 

Edited December 26, 2014 by pyrotech

[Bonjangle]

Back to the here and now - signs now well underway of changes in leading edge of PPN, all going largely as modelled with cold pool taking shape. Snow falling readily at the moment at the Hawthorns (West Brom) and sticking on the pitch in last few mins.... a taste of what may now follow into this evening and tonight. Latest analysis suggests we can't rule out some snow even well south of M4 later into the eve/night. Wintry showers tomorrow for many districts (incl. in south), giving some accumulations over higher ground.

As in South East Wales 'Fergie  

[gottolovethisweather]

A favourable NH Jet position for the near-term if there ever was one, relatively strong too.

 

 

This may well assist in pushing in some colder 850s ever Southwards along with a few snow showers overnight into Sunday morning.  :smiliz19:

 

 

Best grab these opportunities while we can as the HP signal is a strong one and once any snow settles it will take some shifting under cold to very cold surface conditions in prone regions.

 

 

Looking back, remember this chart form nine days ago, this was where things were forecast to be at 1200hrs today.

 

 

The actual reality at the start of today's runs is as illustrated below.

 

 

A fair few differences in the eventual modelling there and indicates precisely why we should read to much into general specifics at such a range. With the added complication of transient snow conditions in the mix, this is why wintry synoptic forecasting is a nightmare for professionals and amateurs alike.

 

As to the longer-term, I'm not looking into the New Year yet but I have a gut feeling (perhaps due to too much over-indulgence) this post might end up reasonably near the mark.     Having said all of that, showery outbreaks in the flow and especially the timing of passage will most probably allow for further opportunities of wintriness as we head into the first week of January if not before, with HP the main player however. 

Edited December 26, 2014 by gottolovethisweather

[dragan]

Atlantic weather looks likely to establish itself once the high sinks itself away. This has been modeled many times and looks likely to kick in about 31st or 1st. I cant see an undercut happening as these seem like rare events, plus none have been modeled.

Edited December 26, 2014 by dragan

[Neilsouth]

 Wintry showers tomorrow for many districts (incl. in south), giving some accumulations over higher ground.

 

Hi Fergie.... I notice some have been looking at models re: possible snow accumulations Saturday night/Sunday into EA/SE. Is this regarding back edge showers or streamers in from the North Sea? Thanks

[gottolovethisweather]

Hi Fergie.... I notice some have been looking at models re: possible snow accumulations Saturday night/Sunday into EA/SE. Is this regarding back edge showers or streamers in from the North Sea? Thanks

 

I know fergie can probably add more detail, but please do have a look at my post above. There is a relatively strong Jet stream overhead tomorrow so this in itself, aids in pushing showers further inland. Timing is crucial too.

Edited December 26, 2014 by gottolovethisweather

[Neilsouth]

Nice one thanks

[Eugene]

Looks like a very disturbed pattern setting up for the first half of January, cold at times with some wintriness in the showers but mainly a cold and very wet pattern with the risk of localised flooding.

[Winter Cold]

It doesnt look all doom and gloom to me. Tonights UKMO actualy shows the uppers getting colder again as the Atlantic moves in, and GFS and P also show what looks like a cold zonal pattern with 850s often below 0 for the majority of the runs.

 

There could be further days like today where we see some wintryness. Lets see what the ECM makes of things tonight shortly

Edited December 26, 2014 by Winter Cold

[Froze were the Days]

Atlantic weather looks likely to establish itself once the high sinks itself away. This has been modeled many times and looks likely to kick in about 31st or 1st. I cant see an undercut happening as these seem like rare events, plus none have been modeled.

Totally agree - models have been forecasting this for the last day or so, no undercut in any shape or form. In my view a long way back to anything substantially cold, perhaps again a return to some Pm intrusions and the jet perhaps being forced somewhat further south but unfortunately all that will result in is heavier nationwide rainfall.

 

just seen Eugene's post and agree to a degree and the feeling the LRF models again might unfortunately not be too far off the money.

Edited December 26, 2014 by Froze were the Days

[johnholmes]

I know fergie can probably add more detail, but please do have a look at my post above. There is a relatively strong Jet stream overhead tomorrow so this in itself, aids in pushing showers further inland. Timing is crucial too.

I am not sure I understand the comment about the jet stream. Shower cloud will certainly not be to that level. Perhaps you mean the jet being well south suggests colder air?

The 850mb air is pushed south by a combination of the surface isobars and the 850 mb winds.

Edited December 26, 2014 by johnholmes

[gottolovethisweather]

I am not sure I understand the comment about the jet stream. Shower cloud will certainly not be to that level. Perhaps you mean the jet being well south suggests colder air?

 

No, I'm referring to the strength of the Jet John, admittedly not at the surface, fits in with official media forecasts anyhow. It is also stronger than currently indicated as the low passes through. The focus being primarily on Western areas of the UK where the Jet is shown to be at its strongest. This region including Wales and NW England could get hit several times by streamer type showers, all IMHO.

Edited December 26, 2014 by gottolovethisweather

[igloo]

its bad news for us when the usa and eastern canada go in to a deep freeze which is forecasted to do over the new year its a winter eater and like last season non starter enjoy the next 2-3 days for the people who get lucky with a  thin covering as january looks set to be be be fairly stormy and wet start with flooding also possible i'm  afraid  with a chart like this the PV looks like its glued to NE canada and greenland  

 

[MR EXTREMES]

its bad news for us when the usa and eastern canada go in to a deep freeze which is forecasted to do over the new year its a winter eater and like last season non starter enjoy the next 2-3 days for the people who get lucky with a  thin covering as january looks set to be be be fairly stormy and wet start with flooding also possible i'm  afraid  with a chart like this the PV looks like its glued to NE canada and greenland  

 

Very stretched vortex and might as well say it's split vortex.

Still lots and lots of cold polar air waiting to rush the uk.

Ok might not be any good for us on the south coast but still better than last year.

[Snowman.]

Very stretched vortex and might as well say it's split vortex.

Still lots and lots of cold polar air waiting to rush the uk.

Ok might not be any good for us on the south coast but still better than last year.

 

 

Anything is better than last year.

 

Some people over the next day or so are seeing there first snow in probably 2 years.

[Joe Levy]

I wonder if someone could answer this for me - now that we know the front is slightly further north than forecasted, will this have any implications for model output with regards to the next week or so? Or even further... If anyone has any suggestions/explanations/ideas I'd appreciate it!