Winter Model Discussion 12Z 22/1/13 onwards.

[Great Plum]

Interesting ensembles... Look at the gradual cool down...

http://www.netweather.tv/index.cgi?action=charts;type=ens;sess=

[TEITS]

Some crazy NH patterns now evident post T300. like i said earlier, i doubt the boredom will last too long on here. let the manic depressives wear themsilves out and then the fun can start again !

Pretty sure in around 7-10 days time I shall be posting with excitement again.

Just want to clarify something though with some members that im not rubbishing the effects of the Stratosphere. Inactual fact is some respects its the SSW that is giving us the poor charts at the moment. For example if you look below you can clearly see the effects how the Stratosphere has impacted the PV.

Look what happens though as the Canadian lobe moves E.

This is why a SSW isn't guaranteed to bring cold weather to the UK. You also need luck on your side and unfortunately for us we have some bad luck coming our way with that lobe moving E.

[Mark Bayley]

I remain far from convinced that as we approach the middle of February, the upper pattern will look as the GFS FI portrays. Stratospheric temperatures and mean zonal winds have yet to return to normal. The warming and reduced mean zonal winds should continue to impact for most of February, lending support to a disrupted PV, although with uncertainties as to where this will locate. Unfortunately it has recently displaced towards Greenland (+NAO).

The models are bullish with progressing the MJO through phase 7 and into 8, which teleconnects to higher pressure in the mid-atlantic/Greenland region, although perhaps a hint of a western based -NAO about it (higher heights also centred in the Canadian Arctic)

The GWO has also progressed quite rapidly towards phase 5, which the composites show is normally associated with below average UK temperatures.

This, combined with a recent warming event near the Greenland region, would lead me to favour a colder than average first half of February over a milder one (similar to the meto long range forecast).

Interesting to note that the ensembles are starting to trend slightly colder again (long term). Its a trend i would look out for over the coming days.

Edited January 22, 2013 by Mark Bayley

[shaky]

Very very interesting ecmwf!!breakdown delayed by a day!!and we actually see an undercutter on friday!!oohhh boiii!!things are gettin really tense now!!

[Snowmad79]

I remain far from convinced that as we approach the middle of February, the upper pattern will look as the GFS FI portrays. Stratospheric temperatures and mean zonal winds have yet to return to normal. The warming and reduced mean zonal winds should continue to impact for most of February, lending support to a disrupted PV, although with uncertainties as to where this will locate. Unfortunately it has recently displaced towards Greenland (+NAO).

The models are bullish with progressing the MJO through phase 7 and into 8, which teleconnects to higher pressure in the mid-atlantic/Greenland region, although perhaps a hint of a western based -NAO about it (higher heights also centred in the Canadian Arctic)

The GWO has also progressed quite rapidly towards phase 5, which the composites show is normally associated with below average UK temperatures.

This, combined with a recent warming event near the Greenland region, would lead me to favour a colder than average first half of February over a milder one (similar to the meto long range forecast).

Interesting to note that the ensembles are starting to trend slightly colder again (long term). Its a trend i would look out for over the coming days.

Re: the GWO temp composites... 4 show Mild, 3 show Cold and 1 Shows average. Odds are in favor of Average or above average 2m temps on those composites unless I'm reading them wrong.

[Mark Bayley]

Re: the GWO temp composites... 4 show Mild, 3 show Cold and 1 Shows average. Odds are in favor of Average or above average 2m temps on those composites unless I'm reading them wrong.

Note the numbers on the GWO plot, then associate the composite numbers with them.

[Snowmad79]

Note the numbers on the GWO plot, then associate the composite numbers with them.

Ah yes, much better. Cold it is ha-ha. Thanks!

[Cheshire Freeze]

Once again the latter frame of the ECM shows the PV splitting after temporarily intensifying, as was hinted on the 12z yesterday. Some nice looking NH profiles in the GEFS suite in FI too. I think the return of the eye candy may be to be expected within the NWP in a few days time.

[BLAST FROM THE PAST]

Once again the latter frame of the ECM shows the PV splitting after temporarily intensifying, as was hinted on the 12z yesterday. Some nice looking NH profiles in the GEFS suite in FI too. I think the return of the eye candy may be to be expected within the NWP in a few days time.

Indeed lets see what models show Thurs at earliest, then we can see wherfe we are going possibly. Nothing is 'nailed' certainly not on longterm basis anyway

BFTP

[fourseasons]

Very very interesting ecmwf!!breakdown delayed by a day!!and we actually see an undercutter on friday!!oohhh boiii!!things are gettin really tense now!!

Didn't a similar situation happen a year or two again (don't exactly remember when) when until 48 hours before, the constant prediction was that the Atlantic would slam through the cold block but against the odds the block ended up winning.

I know that this block has actually not been very strong but you never know. The fact that the breakdown has been delayed by a day shows how the models may be underestimating how stubborn a cold block can be and perhaps overestimating the power of the Atlantic.

[Mac_SE]

Desperately disappointing to see a lot of posters caught by the (inevitable) post-snow depression that occurs after a good old dumping and before a return to zonality. I share your pain, but think we all need to lose whichever attachment we have to whatever set-up lights our meteorological candle and try and focus as dispassionately on the models in front of us as hard as that is.

The see-sawing that will surely take place with the models over the next two weeks or so should be hugely interesting - the jigsaw pieces each shifting around run by run - and especially when the pros hint that real winter still lies ahead. Let's try and enjoy the ride even if it ultimately doesn't give us all what we'd like to see.

[MattH]

Top post Mark (post #28) highlights and discusses the charts as they exactly are. Sometimes the weather surprises us all, but as ever in meteorology it is a case of putting together the 'jigsaw pieces' and once you have done that the end result is a 'forecast' and clearly combining the information you have discussed clearly doesn't point towards a zonal/mild/Greenland PV dominanted month.

I wonder if anyone out there could do me a favor, those statisticians who like that NOAA Physics Science reanalysis website. Not for publication but I am after an example of the overall expected synoptic pattern for each of the different MJO phases. Perhaps someone has already done this and has the images sat on their PC...

Thanks in advance to anyone who can rustle these up.

Matt.

[Stuie]

Very very interesting ecmwf!!breakdown delayed by a day!!and we actually see an undercutter on friday!!oohhh boiii!!things are gettin really tense now!!

That was exactly my reaction, interesting. Look forward to tomorrows runs already, this may not be a straight forward Atlantic period after all.

Edit: image

Edited January 22, 2013 by StuieW

[Cheshire Freeze]

Interestingly CFS remains rock solid in running with anomalous + heights stretching from Greenland to Scandi in February with -ve heights across mainland Europe. Consistent with EC32 and good inter run consistency for the moment.

EDIT: The image has just updated.....Still showing potential heights but not quite as good as previous updates

Edited January 22, 2013 by CreweCold

[fourseasons]

That was exactly my reaction, interesting. Look forward to tomorrows runs already, this may not be a straight forward Atlantic period after all.

I just can't see it being that straightforward that the Atlantic will just ram through without much of a battle. I still think that the Atlantic is favourite to win in the weekend (as the models have been consistently indciating) and we might be in a zonal period for at least a couple of weeks but we'll just have to see.

[cooling climate]

I know its FI sort of but the ECM t240 chart screams east/northeasterly by t300+ if we had such

charts.This is definitely the direction we should be looking at again for freeze two and quite

possibly much more severe in nature.

I am thinking Feb 91 cold here with much of the country under -14 to -16c 850's although the

ECM might be a little premature in building heights to the north again(hopefully not).

Apologies if to some (or most) if this seems a wishful ramp but looking at the strat profiles over

the last two and a half weeks this is the way I have always seen the pattern and synoptics heading

hopefully.

[Cloud 10]

Top post Mark (post #28) highlights and discusses the charts as they exactly are. Sometimes the weather surprises us all, but as ever in meteorology it is a case of putting together the 'jigsaw pieces' and once you have done that the end result is a 'forecast' and clearly combining the information you have discussed clearly doesn't point towards a zonal/mild/Greenland PV dominanted month.

I wonder if anyone out there could do me a favor, those statisticians who like that NOAA Physics Science reanalysis website. Not for publication but I am after an example of the overall expected synoptic pattern for each of the different MJO phases. Perhaps someone has already done this and has the images sat on their PC...

Thanks in advance to anyone who can rustle these up.

Matt.

I think these are what you are after Matt?

MJO.html

[Stuie]

I remain far from convinced that as we approach the middle of February, the upper pattern will look as the GFS FI portrays. Stratospheric temperatures and mean zonal winds have yet to return to normal. The warming and reduced mean zonal winds should continue to impact for most of February, lending support to a disrupted PV, although with uncertainties as to where this will locate. Unfortunately it has recently displaced towards Greenland (+NAO).

The models are bullish with progressing the MJO through phase 7 and into 8, which teleconnects to higher pressure in the mid-atlantic/Greenland region, although perhaps a hint of a western based -NAO about it (higher heights also centred in the Canadian Arctic)

The GWO has also progressed quite rapidly towards phase 5, which the composites show is normally associated with below average UK temperatures.

This, combined with a recent warming event near the Greenland region, would lead me to favour a colder than average first half of February over a milder one (similar to the meto long range forecast).

Interesting to note that the ensembles are starting to trend slightly colder again (long term). Its a trend i would look out for over the coming days.

Even if you haven`t a clue, this is worth digesting. Really interesting and informative.

[Boro Snow]

mmmmmm the breakdown has been delayed on the ecm by another 24 hrs, are the models underestimating the cold block, we have had a few lows from the atlantic try and it hasnt happened and on thurs we have -8 uppers some very cold air above so why do we expect this low on friday just to fly through and easily push the cold air aside, im still learning so i might be talking absolute rubbish, apologies if i am

[fourseasons]

mmmmmm the breakdown has been delayed on the ecm by another 24 hrs, are the models underestimating the cold block, we have had a few lows from the atlantic try and it hasnt happened and on thurs we have -8 uppers some very cold air above so why do we expect this low on friday just to fly through and easily push the cold air aside, im still learning so i might be talking absolute rubbish, apologies if i am

I don't think what you are saying is rubbish, it's a valid point. Let's just see what happens ...

[Gibby]

Good evening. Here is the evening report on the 12z output from GFS, UKMO and ECM for tonight Tuesday January 22nd 2013.

All models show a continuation of the very cold conditions for a few more days. Tonight's snowy low pressure in the English Channel will continue to spin an area of snow over Southern England over the next 12 hours or so while areas further North stay largely dry but cloudy with just a few snow flurries in the NE. Tomorrow will see the Low to the South slip slowly away SE taking the worst of the snow with it. Further North a dry day seems likely but still cloudy and cold. Over Thursday all areas become dry and cold under a brief ridge of High pressure before a Southerly wind springs up and brings a band of cloud and rain into the UK from the West during the later end of Friday and Saturday. A spell of snow is expected to precede the rain over the North and East. It will become less cold over the weekend .

GFS shows that once the milder weather gets across the UK the weather enters a phase strong winds and spells of rain especially in the North and West as the basic of Low pressure to the North and Northwest is balanced by High pressure to the South and SE and later the SW as winds turn from a mild long fetch South-westerly to a slightly fresher Westerly flow for a while.

The GFS Ensembles show uppers rising in a few days time as winds turn into the West. they become briefly quite mild before a return to more average conditions develop thereafter through to the end of the run. All areas are shown to see rain at times.

The Jet Stream shows the flow lifting from its Southern Europe latitude to be near the UK in a weeks time as Low pressure in the Atlantic lifts it over the UK in association with sinking High pressure over Europe in the coming days.

UKMO for midday on Monday shows Low pressure North of Scotland with a broad and chilly West or SW wind bringing showers and sunny intervals in a blustery wind following the rain and the rapid thaw of the previous day.

ECM tonight shows quite a limited warm up with potential for a snowy breakdown for some early in the weekend ( locations to be confirmed). With the first band of rain and snow clearing a second band of heavy rain crosses on Saturday night followed by a cold and windy day on Sunday for many with heavy and squally showers in the West, wintry on hills. Early next week sees the much milder weather arrive with a long fetch SW flow in association with High pressure to the Southeast with rain and strong winds copious in the North and Western high ground. Later in the run things could turn very mild in the South as High pressure over Spain feed very mild Atlantic winds up over the UK from latitudes well South in the Atlantic.

In Summary the weather stays cold for a few more days before an abrupt change to wet and wild weather at the weekend and possibly very mild and drier conditions in the South later next week. GFS Ensembles don't show an overly mild agenda though apart from a few days early next week, and the breakdown at the weekend though guaranteed may be somewhat less straightforward than has been shown in models of late. Whatever the outcome of the weather over the period there are still some interesting synoptics around tonight albeit for 'mildies' rather than 'coldies'.

[David 'Minty' Hill]

I don't think what you are saying is rubbish, it's a valid point. Let's just see what happens ...

I think its how its going to do it. Its not the low thats going to break it its the winds it pulls from the SW as it starts to move close. it wont be a totall smash as the forecast is possibly heavy snow first before rain.

[lorenzo]

At 120 hrs models all in strong agreement about the Atlantic winding up into a frenzy, not just GFS having a dartboard masterclass, well advertised cranking up of LP, unsurprising considering what is above, The wandering vortex not wishing to entertain any form of substantive Greenland Block.

Then enter the 10hpa level warming forecast and things start to mix up a bit again in terms of how this impacts this side of the NH, the very fragile vortex not having re-established itself going to be interesting to see what this wave of warming does.

On top of this factor in the MJO movement and the update from GP on the GWO phases and there are a few decent signals for this elusive Greenland Block, which appears to be a complete rank outsider in the face of the current NWP output.

This is the constructed analog which was favoured for use by the CPC guys last time I read the update, Phase 8 plot has been posted already and previously.

Looking through some dates on SSWs today and a couple of re-analysis charts 1985 caught my eye, the warming slightly ahead of this years in terms of central date but thought this may be of interest in terms of lagged responses, considerable anomaly change in these two time frames and the first period below reminds me of the Canadian Vortex draining out.

Table used is here.

Finally, the much maligned CFS also looks like it might favour something in this area as February progresses. ( well today it does).

In the face of it you cannot ignore the models in front of you and the ghastly immediate outlook for cold, however considering the above you could ask would you be confident in a mild pattern locking in ?

The best question I have seen out of today is what is the influence of the NAO / AO position leading into an SSW event, this is worthy of investigation I think by minds better than mine..

Greenland High or no Greenland high, anyone got a crystal ball....?

[Methuselah]

Any chance of sticking to model-related talk? There are numerous threads far more suited to individuals' voicing their weather-predictions...

[David 'Minty' Hill]

Any chance of sticking to model-related talk? There are numerous threads far more suited to individuals' voicing their weather-predictions...

IM sorry was just replying if that was aimed at me. I cannot comment to much on models as I am still learning sorry again