Model Output Discussion 17th Dec.2013-12z onwards.

[Gaz1985]

Maybe a white Christmas for parts of the SE? 

 

[bluearmy]

Maybe a white Christmas for parts of the SE? 

 

 

 

i assume its an error anyway. gfs has dp's above zero when the precip runs through on the 18z tomorrow night.

[Biensie]

i assume its an error anyway. gfs has dp's above zero when the precip runs through on the 18z tomorrow night.

[SMU]

ENS 18z are pretty good at 192- lots for tilted ridging towards Greenland in the runs-

 

As for the NAE- looks like an error with 850 thickness @ 1300 DAM- which is past the borderline really- but could change.,....

 

 

S

[bluearmy]

ENS 18z are pretty good at 192- lots for tilted ridging towards Greenland in the runs-

 

As for the NAE- looks like an error with 850 thickness @ 1300 DAM- which is past the borderline really- but could change.,....

 

 

S

 

the snow map was from the gfs 18z run steve. as for the nae and euro 4, both have sub zero dp's just nw of the possible rainband. if it does rain, i wouldnt' rule out a surprise in the chilterns where the rain meets the colder air.

[Captain Shortwave]

i assume its an error anyway. gfs has dp's above zero when the precip runs through on the 18z tomorrow night.

Nah, it misses out north east Suffolk and most of Norfolk. *Pretty spot on to me* 

 

* note for newbies - search for triangle of doom

[Mucka]

GFS ensembles totally scrambled in FI, it is having trouble nailing what the pattern change is likely to be through the first week of Jan

[bluearmy]

GFS ensembles totally scrambled in FI, it is having trouble nailing what the pattern change is likely to be through the first week of Jan

 

beginning to trend towards the ecm solution mucka.  

[draztik]

Just been looking at the updated EC32 on weatherbell, and the anomaly charts maintains a somewhat zonal flow throughout January, with troughing constant to our NW. This does not seem favourable to deep cold conditions, and the 5000ft temps reflect that. Tho it should stay slightly below average through Jan.

[Jason M]

just looked through the ensembles myself. Must admit that I'm a bit disappointed factoring in the other runs today and the GEM ensembles. Still a signal for HLB but more muted now IMHO and this set look close to the GEM ensemble suite.  

 

As per Mucka there is a scatter but being objective the odds maybe tilted back towards ongoing zonality. Still, tomorrows another day assuming the roof doesn't blow off tonight

[Mucka]

beginning to trend towards the ecm solution mucka.  

 

I'm not convinced ECM has a handle on things post 144/168 either. Quite a complex situation I think with the Arctic high and Southerly jet in the mix, a powerful PV on the move and some forcing from the Strat. I wouldn't want to forecast January as a month though it will likely start cool and unsettled.

Edited December 24, 2013 by Mucka

[bluearmy]

I'm not convinced ECM has a handle on things post 144/168 either. Quite a complex situation I think with the Arctic high and Southerly jet in the mix, a powerful PV on the move and some forcing from the Strat. I wouldn't want to forecast January as a month though it will likely start cool and unsettled.

 

i meant the extended ecm ens solution - sorry wasnt clear.  off to view the ec32

[Mucka]

i meant the extended ecm ens solution - sorry wasnt clear.  off to view the ec32

 

That looks to be trending toward cool/cold zonal to me but  I only have the graphs so can't be sure.

Can you post the EC32?

You have to pay for that don't you?

Edited December 24, 2013 by Mucka

[draztik]

That looks to be trending toward cool/cold zonal to me but  I only have the graphs so can't be sure.

Can you post the EC32?

You have to pay for that don't you?

 

Mucka, you can sign up for a free trial, lasts for about 7 days. Then you can decide whether you want to keep the subscription

[bluearmy]

That looks to be trending toward cool/cold zonal to me but  I only have the graphs so can't be sure.

Can you post the EC32?

 

looks like a continuation of the 15 day ens. mid atlantic high occasionally pushing east. troughing in our vicinity, extending to our s and se. highish anomolys over the pole.  i read what draztik posted above and see it as a potentially colder scenario depending on what track the secondary features take. if they go to our east, will be alternating warm sectors and pm incursions behind cold fronts. possible lee easterlies before the ah ridges across the top (temporarily). if they manage to pass to our sw, we will be more wintry with se flows off the continent ahead of the systems.   i doubt exeter will make too much of any wintry potential and just go with 'remaining unsettled with temps generally just below average with the chance of some snow in the north and over hills".

[Mucka]

looks like a continuation of the 15 day ens. mid atlantic high occasionally pushing east. troughing in our vicinity, extending to our s and se. highish anomolys over the pole.  i read what draztik posted above and see it as a potentially colder scenario depending on what track the secondary features take. if they go to our east, will be alternating warm sectors and pm incursions behind cold fronts. possible lee easterlies before the ah ridges across the top (temporarily). if they manage to pass to our sw, we will be more wintry with se flows off the continent ahead of the systems.   i doubt exeter will make too much of any wintry potential and just go with 'remaining unsettled with temps generally just below average with the chance of some snow in the north and over hills".

 

Excellent analysis thanks.

I think you are spot on about the MetO as well, they would need a strong cold signal to call anything, it would be silly to try and predict what may well be transient snowfall.

If it does go that way I will be quite pleased with my efforts to call it, my thoughts have always been that we would see some transient ridges and weak MLB/HLB rather than a strong block first half of Jan with perhaps something more sustained cold wise in the second half. That's why I was hinting that there may be some good snowfall but of course  it depend how much cold air we can get in the mix and we could just get cold and wet. 

Hopefully not though and we can get some good snowfall on the northern and Eastern flank of disrupting lows, and if I really look into the crytal ball there could even be a channel low surprise for the South in the second week. 

Ah well who knows really but at least the output has some potentially wintry interest again at last.

Edited December 24, 2013 by Mucka

[Brassmonkeylily]

My God .. we are having the the most dramatic weather in years and some of you experts are still looking for a bit of cold … get real and join the real world… actually you might enjoy it ..

[Machu Picchu]

My God .. we are having the the most dramatic weather in years and some of you experts are still looking for a bit of cold … get real and join the real world… actually you might enjoy it ..

This is the model output discussion thread, the current set-up has already been discussed if you want to go back and have a read.

I'm sure many of the members posting in here are also posting in the regionals etc regarding the current storms.

[That ECM]

http://images.meteociel.fr/im/1911/ECH1-144_gru7.GIF

http://images.meteociel.fr/im/4578/gfsnh-0-144_cie7.png

http://images.meteociel.fr/im/2391/UN144-21_yhq4.GIF

Much to be decided. IMO GFS shows the most promise.

At T 216

http://images.meteociel.fr/im/8529/gfsnh-0-216_xjy6.png

http://images.meteociel.fr/im/5619/ECH1-216_iho6.GIF

ECM shows the most promise.

What none of them show is a low going se into Europe.

Edited December 24, 2013 by That ECM

[Captain Shortwave]

Well the ECM yet again is not really going for anything which suggests a prolonged cold spell to be honest. On the other hand that might not be a bad thing considering it's the model that cries cold 

GFS and GEM look to have more promise

Low resolution looks a little unbelievable to me here so I stopped at this point.

GEM

Lets see how things go. To be honest I'm going to probably just focus concerns on Fridays "bomb" before looking at any cold potential in the new year.

[Summer Sun]

UKMO have Friday's low at 950mb

 

 

ECM has it at 955mb

 

 

GFS 945mb

 

 

GFS wind speeds

 

 

Wind gusts will be much stronger with 60 to 80mph gusts in some parts

[Snowman.]

It's a waitin game runs are going to start varying rapidly soon so don't feel surprised if you see some mega lows in the mix from the GFS. The warming will create some stress for the outputs in low res. another thing beginning to trend is a warming starting to edge into Canada and Greenland if this was to happen it would shift the Pv over eastward as it's the only place left it can go leaving us free for heights to build ne.

[Gibby]

Good morning folks. Here is todays report taken from the 12 midnight outputs of NWP for today Christmas Eve 24th December 2013.

 

All models show an intense depression close to the far NW of Scotland with a showery WSW flow over the UK following the stormy fronts clearance over the SE later this morning. The showers will be heavy but scattered with some snow over the hills at times. The strong winds will gradually subside away from the far NW by tonight. Christmas Day and Boxing Day are shown with our deep depression filling to the North and moving away with both days being dry and bright days for many though coastal areas of the South and West may see scattered showers, still wintry over the hills. It will feel rather cold. Late on Boxing Day another rapidly deepening Low is shown to drift past Western Ireland and Scotland with yet more heavy rain and severe gales over Boxing Night clearing to sunshine and showers, wintry on hills again over Friday and Saturday.

 

GFS then shows a cool and showery end to the weekend as winds blow down from the NW though much lighter than previously. Then as next week begins it's back to square 1 as a new deepening Low swings NE over the North with strong winds and rain for all followed by showers, turning wintry from the North on New Years Eve. Then through the extended parts of it's output the run keeps very changeable conditions going over the UK with showers or longer spells of rain in near average temperatures but it looks less stormy than recently.

 

UKMO closes it's run with Low pressure up to the NW of Britain with another set of fronts carrying strong winds and rain across the UK to start next week.

 

GEM today also keeps Low pressure belts to the North and NW with strong WSW flows over the UK with spells of rain and showers for all in average temperatures.

 

NAVGEM is similar with deep Low pressure ending up just to the West of the UK a week from now with wet and windy weather still the most dominant weather events for the UK in temperatures near average.

 

ECM this morning also shows very changeable conditions persisting into the New Year with fast moving depressions crossing the Atlantic to the NW or indeed over the UK maintaining the very frequent areas of rain followed by showers type weather going. The depressions are shown to be less deep though and as a result the winds should not be as fierce later.

 

The GFS Ensembles trend very slightly downward in the 850 values late in the run but there is little overall evidence of a major shift towards anything generally cold. Instead there is less heavy rain shown later in the run with the emphasis shifting more towards the NW later.

 

The Jet Stream profile remains wrong for cold over the UK in the coming two weeks. The flow remains strong and while it remains just South of the UK currently it moves back North over the UK later and tracks in a NE direction across or to the NW of Britain late in the run.

 

In Summary the weather remains very unsettled for the foreseeable future. There is still room for more severe weather in the pre New Year period as more storm systems develop very deeply to the NW. However, as time goes the depressions look less intense as we move into the New Year and while they will still each bring their own version of wind and rain to many areas they look less inclined to bring severe gales. However, the further rain they bring will only exasipate the already saturated ground to maintain a flood risk in places. For those looking for colder weather I have nothing to report this morning as if anything the amount of wintriness in the showers on the passing of each storm system looks likely to become more and more restricted to the ususal locations over the mountains of the North with temperatures holding up well towards average in the basic West or SW flow.

[IDO]

UKMO & ECM both have a flat pattern and they both model weak heights over Greenland (T96):

 

UKMO:   ECM: 

 

GEM in total contrast has strong heights in Greenland: 

 

This, combined with a cross flow, strong heights in America, stalls the Canadian vortex, and the whole run is static with a low pressure system dying in situ over the UK for about 7 days, very slowly edging east. Not good.

 

The GFS has the GH but the trigger low gets caught up with another LP system leaving Canada and gets dragged east preventing any troughing:

 

 

Looking through the mean at that time, there is support for that scenario:  

 

To be honest even at T240 there are no defining clusters within the ensembles, no trend or pattern and the spread sort of highlights this:

 

 

Just for fun, at T384 a UK trough or MLB are closely matched ahead of the pack, followed by HLB then zonal. Again no real help:

 

http://www.meteociel.fr/cartes_obs/gens_panel.php?modele=0&mode=6&ech=384

 

Even NOAA 8-14 day anomaly 500 chart is not that helpful: 

 

Weak signal for a UK trough.

 

We are in a transitional phase for the models with seemingly a pattern change on the horizon. Not a good time to draw conclusions but at least there is some interest in the outlook. 

Edited December 24, 2013 by i'm dreaming of...

[Cecil Hogmanay Melchett]

0Z runs are not good if its cold you are after.

Low heights remain to the north west.

ECM in particular looks flat as a witches ....

Just back from the strat thread still signs of an attack on that deep angry vortex so maybe things can and will change as we move through January.

Edited December 24, 2013 by Cecil Hogmanay Melchett