Model Output Discussion 19th January 2014-18z onwards.

[Jason M]

I know I sound like a stuck record but it does this every time in these setups and I frankly don't believe it. The 06z is usually the worst of the lot at it, I know Steve M always dismisses it.

Just my opinion of course

Steve's views are well known on this. I respect them but don't agree with him (at least not completely). I do agree the 06Z and 18Z runs are less reliable but I wouldn't ever dismiss them. This situation is particularly interesting as the issues are in the first few days. At 72 hours I'd even be loath to ignore the North Korean model :-)

If GFS was showing a cold easterly at day 5 (as opposed to a not cold one!)it wouldn't be ignored in here.

I'm not fussed about the low res today as that's just a classic GFS 'zonal until spring' run.

Edit: To be clear I'm not saying I think GFS is right! The brain says METO but this being winter 2013 / 2014 its a brave man that backs the colder solution!

Edited January 25, 2014 by Jason M

[Frosty.]

@ swfc....have you seen the ecm 00z ensemble mean charts I posted? they scream snow potential with a cold pool becoming entrenched and persisting across at least the northern half of the uk beyond T+240 hours.

[karlos1983]

+120 from the 00z on the 20th Jan, are pretty impressive across the board really, below GFS, UKMO, ECM

 

Reality 00z 25th Jan

UKMO probably just nudges it again on verification. so the signs are good perhaps.

[shedhead]

A plausible evolution from the 6z gfs, given the gefs mean post 180! Reinforces the favourable route back to zonality post nxt wk! This winter is incessant, if nothing else!

Unfortunately it does look plausible and represents a real horror show, especially for this part of the world.  Not giving up on the cold spell quite yet, but to be honest I'd trade anything now for some dry weather; the idea of more heavy rain bands frequently smashing in off the Atlantic does not bear thinking about right now...

Edited January 25, 2014 by shedhead

[gottolovethisweather]

For those confused by the differing viewpoints in here, I would advise those not so au fait with model discussion, I would advise you to attempt to separate postings into two types, FI and non-FI. FI (fantasy island) will also differ according to individual viewpoints but for me, FI is where scatter starts to show across all NWP outputs and can be witnessed very easily by using the various ensemble spreads. I imagine FI is very near-term right now, all things considered. My Fax Charts post from last night backs this uncertainty up IMHO. Anyway, to stop rambling, I will attempt to focus on the near-term so here goes.

 

Today sees milder than average Temperatures for nearly all of the UK, a band of rather vicious showers/storms accompanied with strong winds and T&L trundling SE'wards across all parts eventually.

 

Tomorrow (SUNDAY) is suggested to be MILD during the main rainband event, however, once this clears through, expect to see increasing wintriness from the WEST spreading EASTwards at times and perhaps a period of wet SNOW into the overnight period for a few lucky folk, largely at elevation but not exclusively, although hardly likely to settle I imagine. A similar day to today in fact with a trend to increasing showers by nightfall. *see the netweather warning even for Southern UK.

 

http://www.netweather.tv/index.cgi?action=weather-alerts;reg=7;sess=517fb8cbecb6adb71e5c314ab713623f

 

 

MONDAY through FRIDAY is hard to pin down but there will be some further wintriness for many, initial suggestions are for this to be a right wintry mix and more exclusively for parts of the North and East as time goes on and largely the North and West coastal localities beforehand. There is expected to be bands of rain at times too, so don't expect any lasting snowfall just yet, however this is liable to change.

 

Winter is coming as I've stated many times recently. My opinions have not changed regarding this spell and that's because I urge myself to not isolate every GFS run and I stick to the discussions and conclusions of others regarding the afternoon and evening NWP suites only.

Edited January 25, 2014 by gottolovethisweather

[J10]

NAE shows showers turning wintry tommorow night http://www.weatheronline.co.uk/cgi-bin/expertcharts?LANG=en&MENU=0000000000&CONT=ukuk&MODELL=euro4&MODELLTYP=1&BASE=-&VAR=prty&HH=48&ZOOM=1&ARCHIV=0&RES=0&WMO=&PERIOD=

 

That's EURO4, NAE successor. But the last few days have suggested similar.

[tinybill]

well looking  at the models  its not good  news could be a lot of flooding soon,even looking into fantasy world their looks  like a  lot of rain heading  the  uk way at the moment

Edited January 25, 2014 by tinybill

[bluearmy]

ECM suite picks up a signal for the Azores to ridge a little further ne day 6 which prevents the next trough from digging as far west as previous runs. Clearly gem and ukmo are backed further west so this isn't relevant. it's only one run but it needs a lot of respect at such close range. the op amplifies more than the mean as per usual and the trough is east of the UK thereafter. Again, the op at days 6/7 needs respect but there is as much chance of the mean verifying at that range.

Dave's idea of a middle ground would be fine as it means the UK is solidly in the battleground.

[The Eagle]

Two more negatives to add to the growing list. NAVGEM, as much as I like to ignore it, has moved to less favourable all be it different type of breakdown at 120 hrs. And the GFS ensembles against expectations based on the UKMO and GEM are awful at 120 hrs. There is not one ensemble member in the entire suite supports the UKMO or GEM evolution. The vast majority are with the GFS op run/ECM - brief coldish incursion quickly flattened from the west followed by coldish northwesterlies is the overwhelming theme.

 

 

Let's see if we can get any clues from the UKMO further outlook.

Edited January 25, 2014 by The Eagle

[karlos1983]

GEFS P4,8,12 & 19 are my picks at +108 for cold next week and further down the line, with potential battleground scenarios galore. None of the P1-20 are what I would call mild from it's 06z.

[weather eater]

For those confused by the differing viewpoints in here, I would advise those not so au fait with model discussion, I would advise you to attempt to separate postings into two types, FI and non-FI. FI (fantasy island) will also differ according to individual viewpoints but for me, FI is where scatter starts to show across all NWP outputs and can be witnessed very easily by using the various ensemble spreads. I imagine FI is very near-term right now, all things considered. 

Interesting points, I would go along with the idea that FI at any time is where we start to see a scatter in the ensembles or op runs. However the UK is really a very tiny island, so FI for us is rarely much more than 3 days, simply because what appear to be very small differences in placements of pressure systems, temperatures, wind speeds, precipitation are for us hugely important, its why forecasting in the UK is such a nightmare so much of the time. 

Edited January 25, 2014 by weather eater

[Polar Maritime]

MONDAY through FRIDAY is hard to pin down but there will be some further wintriness for many, initial suggestions are for this to be a right wintry mix and more exclusively for parts of the North and East as time goes on and largely the North and West coastal localities beforehand. There is expected to be bands of rain at times too, so don't expect any lasting snowfall just yet, however this is liable to change.

 

Winter is coming as I've stated many times recently. My opinions have not changed regarding this spell and that's because I urge myself to not isolate every GFS run and I stick to the discussions and conclusions of others regarding the afternoon and evening NWP suites only.

 

Yes Winter is coming as you say GLTW.

 

Monday Peak District.

Cold with the likelihood of heavy rain or showers through the day, falling as snow at altitude. Some significant snowfall likely above 200-300m with some temporary falls to lower levels possible too. This risk is mainly during the early morning, with a chance that freezing levels will rise during the day for a time, but with rain or sleet continuing.

http://www.metoffice.gov.uk/public/weather/mountain-forecasts/peak-district#?tab=mountainWeather

Edited January 25, 2014 by Polar Maritime

[SMU]

Morning-

 

No more posts from me today-  ive a busy day.

 

 

Following the GFS06z & building your opinions on that are akin to building a house out of a deck of playing cards & using a bowling ball for a chimney.

 

The GFS will be progressive, 100% it will be. not 99% or 98%-  100%. We will get an attack from the atlantic, because thats howe our weather works, however it anyone thinks that is going to bulldoze through like the GFS says they can think again.

 

UKMO is NOT the favoured solution today- ( deep cold ) nor is the progressive GFS.

 

The PF straddling the UK is the favoured solution, with rain in the SW & snow further East.

 

post that there is as much chance of cold coming from the N/ NE ( a la GEM / ECM ) as there is from the pony & trap GFS....

 

have a good day people-

 

S

Edited January 25, 2014 by Osbourne One-Nil

[Jayces]

Interesting points, I would go along with the idea that FI at any time is where we start to see a scatter in the ensembles or op runs. However the UK is really a very tiny island, so FI for us is rarely much more than 3 days, simply because what appear to be very small differences in placements of pressure systems, temperatures, wind speeds, precipitation are for us hugely important, its why forecasting in the UK is such a nightmare so much of the time. 

 

This should be highlighted and pinned somewhere and more people should take heed of it. People often post varying thoughts on FI but the above really applies to all our weather all year round especially when marginality creeps into it.

[IDO]

The 06z is an outlier temp wise from T156: 

 

That spike has a little support with different timing and relates to the warm sector running through: 

 

Not much support for that. The mean at that time confirms this:  op: 

 

So ignore the op (need i have said that!). The mean is, as you would expect, very similar to the 0z, maintaining the uncertainty, with many possible outcomes. That include (by T216):

 

ECM like:   zonal:  in-between: 

 

AH bit player:   Scandi/GH: 

 

Undercutter:  complicated: 

 

Interesting:   PV on move: 

 

GH:  Rubbish: 

 

GFS maintains Shannon Entropy pre second slider!!!

Edited January 25, 2014 by i'm dreaming of...

[The Eagle]

I think the focus should be more on potential frontal snow events rather than a direct easterly blast myself. Could be wrong, certainly hope i'm wrong. I don't disagree with Steve re one run, one model. However it's not only the GFS, it's the ECM at 96 hrs and the orientation of the LP that we hope will be a trigger by 120 as on the UKMO that's the crucial phase here. 

 

But I don't think anything should be ignored. The 6z GFS is comparatively poor (although given the winter so far...!) as is the ECM. But they are only "poor" against the expectations being raised on two models post 96 hrs that ordinarily wouldn't get a look in if the roles were reversed here and it was the GFS/ECM most bullish.

 

It will end up middle ground as usual - let's just hope we end up on the right side. 

[SnowObsessor90]

Bar the odd run here and there has the ECM really shown that much interest? it would just be typical if it turned out to be right on this particular occasion.

[Long haul to mild]

Interesting to note that the ECM and UKMO at 120 are not a million miles apart in their synoptics for the UK. Yes, the UKMO has a stronger Easterly flow but they're not chalk and cheese.

However, the differences at T144 are quite stark; therefore anyone trying to confidently call anything more than 5 days ahead is very brave!

Also, only the GFS 06z could come up with a situation in deep FI where we get a Greenland High, but still manage to end up with mild SW'lys thanks to a Euro High!

[Polar Maritime]

Turning a good deal colder next week across the british isles according to bbc news 24 weather..this is hot off the press folks.

 

Yes just heard that myself Karl.. 

 

NMM Chart here to show Snow potential Sunday morning.

 

Edited January 25, 2014 by Polar Maritime

[kumquat]

Some transient cold in the offing. Good for the MO not to get too caught up in the easterly hype which looks like it might deliver some snow to the north and east only. The rest of us will need to keep our wellies in the porch.

[Ali1977]

Sounds like the cold spell may prove to be a damp squib for many reading today's posts....hopefully those at the METO says the UKMO model is still the favorited solution

[Basil_Fawlty_Walks_On_Water]

I think the focus should be more on potential frontal snow events rather than a direct easterly blast myself. Could be wrong, certainly hope i'm wrong. I don't disagree with Steve re one run, one model. However it's not only the GFS, it's the ECM at 96 hrs and the orientation of the LP that we hope will be a trigger by 120 as on the UKMO that's the crucial phase here. 

 

But I don't think anything should be ignored. The 6z GFS is comparatively poor (although given the winter so far...!) as is the ECM. But they are only "poor" against the expectations being raised on two models post 96 hrs that ordinarily wouldn't get a look in if the roles were reversed here and it was the GFS/ECM most bullish.

 

It will end up middle ground as usual - let's just hope we end up on the right side. 

 

Totally agree with this, at least for the next week or so. Considering the winter we've had so far, there is no way anyone should be writing off a more progressive, Atlantic-influenced solution, so can't rule out the GFS yet. However, there are certainly some indications that a much colder period is imminent, and a middle ground solution could end up with a run of undercutting lows which could provide some snow even without a truly cold easterly. Interesting times ahead!

 

Also, interesting to finally discover the meaning of "FI". Have been lurking for years and always assumed this was "forecast interval", i.e. the period until which the forecast had a fair degree of certainty to it.

[Snow Grain]

Sounds like the cold spell may prove to be a damp squib for many reading today's posts....hopefully those at the METO says the UKMO model is still the favorited solution

I think with each output through the weekend you will see a watering down of the cold spell. It will probably feel chilly compared to recent weeks, perhaps a bit sleety apart from high ground in the north and heavier showers in the east away from the coast where it may fall as snow. By time we get to next weekend it's back to wind and rain.

[chionomaniac]

Model thread!

[seabreeze86]

This is amazing model watching at the moment. I cant remember the huge differences between the UKMO and ECM in the semi reliable timeframe. The GFS on the other hand has been wrong at short range when modeling high pressure to the east.

 

When it has been the other way around with the ECM showing big easterlies in the past ive always looked to see if the UKMO supports is evolution before i get excited. So using that way of thinking, the consistency and the met office forecast im going to say the the UKMO is leading the way this time.

 

( could just be wishful thinking)

 

 

http://www.meteociel.fr/ukmo/runs/2014012500/UW120-21.GIF?25-06

 

Just thought id post this chart s its worth looking at and its at 120hrs