Model Output Discussion - 05/01/2016 18z onwards

[KTtom]

Its one of those knife edge situations and one where your location really will be key for what is a 'good run'. I'm sure, like myself, those in the south west will not want any further westward corection in future runs, although it extends the cold spell we miss out on the potential for frontal snow, even if its tempoary. There is always the risk that we reamin cold and dry for a couple of additional days before as GFS shows we end up with a tame warm up as oposed to something a little more exciting. UKMO obviously the pick of the bunch which what looks like a continuation of undercutting if it went out further.

[MR EXTREMES]

Absolutely full of joy this morning the fresh clean polar air with sunshine and models showing what Steve Murr was talking about yesterday good call Steve hope the pattern holds ukmo model shown its worth.

some nice blocking let's see if we can get a nice north east or east flow certainly possible

[Weather-history]

GFS op runs for 1pm Friday from last Sunday's 0z run to current

Edited January 13, 2016 by Weather-history
wrong day

[Frosty.]

What a wonderful start to Wednesday, especially the ukmo and ecm 00z! Cold becoming entrenched in the days ahead...winter at last!!

[Nick F]

Despite the most powerful computers in the world at the disposal of weather centres in Europe and N America, blocking patterns over N Atlantic and Europe and the transfer of upper flow energy around them can still bring low confidence past as early as 5-6 days. Why it's often good to use the ens mean and anomalies, plus any clustering trends in individual ENS members, rather than move on a roller coaster of  the high res.

Hats off to the much maligned UKMO global model at first picking up on the stronger ridge building north into with the Atlantic and troughing going under to our SW early next week, while the main players, particularly GFS, were keen to bring in milder SWlys by early next week.

Not only do we have the complication of trough disruption over the Atlantic, which GFS seems to be particularly bad at handling at times, not just in winter blocking spells, but we have a cold vortex dropping painfully slowly down across Scandinavia, which could introduce a cold northerly again if the ridge holds strong to the west and  northwest. If only we could get that Scandi cold vortex to drop south into central and Eastern Europe then we could potentially see the cold extended even further, as winds turn NEly then Ely. Not out out the realms of possibility given the direction EC goes to a point. 

However there is an increasing trend, particularly from ECM EPS for the AO to turn neutral then positive later this month, certainly can see on the ops and ens mean from EC and GFS lower heights/pressure returning to the Arctic, so it may seem inevitable that we see blocking fade to a more Atlantic mobile signal. But it may not last for the rest of the winter, given positive signs that the PV maybe torpedoed by warming later in the month.

Edited January 13, 2016 by Nick F

[nick sussex]

I'm not sure I'm feeling quite the same love for the UKMO today!

It does go onto develop a more snowier outlook but I'd rather it was a bit sharper with the troughing at T96hrs. That's just me perhaps being overly cautious!

Indeed one could say its moved a bit towards the GFS whilst the ECM has moved towards last nights UKMO.

In terms of the ECM that shows signs of re-amplifying the upstream flow over the eastern USA by day ten which could help dig the troughing to the west further south pushing the high further ne again.

This mornings GFS has continued to edge the pattern further west and those shortwaves could bring some snow.

Overall bar my slight irritation with the UKMO a good start to the day in terms of cold prospects and the UKMO could be quite snowy.

 

[Frosty.]

4 minutes ago, nick sussex said:

I'm not sure I'm feeling quite the same love for the UKMO today!

 

 

Oh Nick you are hard to please, as far as I'm concerned this is heavenly compared to the blow torch hell back in December!

[mb018538]

Looks good to me! Granted this cold spell probably won't go down in the pantheon of truly memorable winter weather, it's a decent attack of cold air after the warmest December and biggest CET departure on record. Much welcomed!

[nick sussex]

1 minute ago, Frosty. said:

Oh Nick you are hard to please, as far as I'm concerned this is heavenly compared to the blow torch hell back in December!

Never assume that things will go right with this type of set up! lol Margin for error always needs to be factored in especially when you're dealing with shortwaves and undercutting. For that reason the ECM gets a Green light from me, the UKMO Orange.

The undercut isn't just down to the high to the north but the interaction upstream of low pressure which digs the cold into the eastern USA this helps to draw energy away from the main low to the west of the UK.

Anyway I'm not here to deflate the mood, I'm happy that the ECM has picked up the UKMO baton which the UKMO has fumbled with this morning. Not quite the GB relay team disasters, as everyone knows whose been here for years I tend to get picky and look for what can go wrong, once I'm happy that theres sufficient margin for error I will ramp away!

[carinthian]

Good Morning, still a good chart this morning from UKMO regarding cold prospects. So doubt remains regarding the quicker route to milder conditions. The UKMO still think by middle of next week a likely return to milder flow after a transitional snow event in places. However, looking at this chart and some of the other Euro models, I am not too sure. As you can see the high pressure still holds out over Iceland with a cold block now established over the British Isles. The trough disruption evident to the SW could easily transfer into mainland Europe as indicated on last nights chart. This would help the main player as I see It to produce the goods for a continued cold spell, possibly snowy weather is the continued strengthening depth of cold air over Scandinavia that could easily spawn out troughs SW wards,  as one to watch.

C

[Frosty.]

5 minutes ago, mb018538 said:

Looks good to me! Granted this cold spell probably won't go down in the pantheon of truly memorable winter weather, it's a decent attack of cold air after the warmest December and biggest CET departure on record. Much welcomed!

And it's still evolving, it could yet become truly memorable!

[TEITS]

The most notable feature is this morning output is the frost we could well see this weekend into next week. Considering the dreadful winter so far I would be happy with a frost that lingers all day.

Still looking at the output beyond +144 and there is still plenty of room for improvement. Ideally I would like to see a more E/NE,ly flow with the block remaining to our NW and not sinking S. Whilst we have seen an improvement this morning, we are a very long way away from a decent cold spell synoptically speaking.

 

 

 

 

 

Edited January 13, 2016 by TEITS

[nick sussex]

Just now, TEITS said:

The most notable feature is this morning output is the frost we could well see this weekend into next week. Considering the dreadful winter so far I would be happy with a frost that lingers all day.

Still looking at the output beyond +144 and there is still plenty of room for improvement. Ideally I would like to see a more E/NE,ly flow with the block remaining to our NW and not sinking S. Whilst we have seen an improvement this morning, we are a very long way away from a decent cold spell synoptically speaking.

 

 

 

 

 

I agree there still needs to be changes in the outputs. Can I say Dave its very good to see you posting again. You're one of the old timers like myself! lol

[Gibby]

HERE IS MY LATEST ANALYSIS USING DATA SUPPLIED BY THE NWP OUTPUT COVERING 5 OF THE WORLDS MOST POWERFUL WEATHER COMPUTERS ISSUED AT 09:00 ON WEDNESDAY JAN 13TH 2016

THE CURRENT GENERAL SITUATION   A weak ridge of High pressure will move away east today followed by an Atlantic depression and fronts moving erratically ESE across the UK tonight and tomorrow

http://www.wetterzentrale.de/pics/Rtavn001.gif

 CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the British Isles will lie around 1000m or 4000ft today and falling further towards 500m or 2000ft in Northern and Central parts later tonight and tomorrow.

http://www.snow-forecast.com/maps/dynamic/uk

http://www.natice.noaa.gov/pub/ims/ims_gif/DATA/cursnow.gif

MODELS-2 WEEK HEADLINE  Cold and frosty with the chance of snow in the South for time early next week then becoming milder.

THE GFS JET STREAM FORECAST  The main theme of the Jet Stream today shows the Jet Stream continuing streaming East across France at the moment before it changes to flow South across the UK by the weekend and start to next week. It then breaks up for a time before realigning on a much more Northerly latitude in the second week.

http://www.netweather.tv/index.cgi?action=jetstream

GFS OPERATIONAL The GFS Operational Run today shows cold conditions lasting across the UK for the next week as the cold North or NW flow with wintry showers is replaced by High pressure crossing east over the UK with fine and frosty conditions likely. Then for a time next week a battleground between milder Atlantic air and cold air across the UK is played out across the SW with rain and snow likely for a time before a more general switch to milder Atlantic SW winds take hold from the middle of next week with some rain at times in the NW. It could become quite mild for a time especially over the South and East before things cool down again by the end of the period with the return of frost and fog patches nigh and morning as High pressure re-establishes near the UK.

GFS CONTROL RUN The theme of the Control Run shows a very similar pattern to the Operational with a messy transition away from the cold pattern towards the middle of next week to much milder SW winds with rain at times thereafter though changes to somewhat colder conditions on a NW breeze looks likely at times too with High pressure never far away to the South and SW later keeping things largely dry and benign there.

http://www.wetterzentrale.de/pics/Rtavn1441.gif

http://www.wetterzentrale.de/pics/Rtavn3841.gif

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=144&mode=0&carte=0

http://www.meteociel.fr/modeles/gefs_cartes.php?code=0&ech=384&mode=0&carte=0

UKMO The UKMO model today is again wanting to prevent milder Atlantic air into the UK next week with a push of mild air into cold air across the South of the UK likely early next week with potential for significant snow in the South and SW early in the week and cold and frosty conditions maintained elsewhere as Low pressure to the SW disrupts and slides ESE into France.

http://www.wetterzentrale.de/pics/Rukm1441.gif

THE FAX CHARTS The Fax Charts show a cold North to NW flow with wintry showers near coasts giving way to fine and cold conditions as frosty High pressure moves slowly East across the UK at the weekend.

http://www.weathercharts.org/ukmomslp.htm#t120

GEM GEM this morning shows cold and anticyclonic conditions from the weekend as High pressure is maintained close to the UK for the early days of next week. On this run there is no push of Atlantic air into the SW so no snow risk shown before milder air moves across the UK from a more NW'ly direction in a much less eventful fashion with the run ending in relatively Atlantic based winds for all of the UK in 10 days time.

http://www.wetterzentrale.de/pics/Rgem2401.gif

NAVGEM NAVGEM looks fine and settled this morning but cold. Once the next few days of wintry showers have cleared away East over the weekend the beginning of next week looks generally cold and fine with frosty nights with the run ending with a large High pressure area close to or over Western Britain in he middle of next week.

http://www.wetterzentrale.de/pics/Rnvg1681.gif

ECM ECM today has changed markedly since yesterday morning and now has followed the lad from UKMO in maintaining cold across the UK until the latter stages of next week at least. High pressure moving into the UK at the weekend will replace the wintry showers near eastern coasts giving most places a very frosty, bright and cold weekend. then early next week low pressure fronts to the SW move into the cold air before shearing away to the SE. Snow is likely from these across the South before fine and cold weather returns midweek. Then towards the end of the run High pressure is shown to collapse SE allowing mild SW winds to make inroads across the UK from the NW.

http://www.wetterzentrale.de/pics/Recm2401.gif

ECM 10 DAY MEAN The 10 day mean chart shows High pressure likely to lie to the South or SE of Southern Britain in 10 days time with milder conditions having spread to all areas by that time. Pressure is unlikely to be very low so the South and East could be largely dry and benign but stronger SW winds across the North and West will more than likely lead to some rain at times here.

http://www.wetterzentrale.de/pics/Reem2401.gif

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The models continue to show different options towards how the extension of the cold weather across the UK takes place. However, the end theme remains for milder weather for all by the end of next week.

31 DAY HISTORICAL VERIFICATION STATS FOR GFS, UKMO & ECM The verification Statistics of GFS, UKMO and ECM show at 24 hours ECM ahead at 99.6 pts with UKMO  and GFS at 99.4 pts respectively.  At 3 days ECM is leading with 97.5 pts to UKMO's 96.6 pts while GFS lags behind at 96.1 pts. At 5 days ECM leads with 89.4 pts to UKMO at 87.6 pts then GFS at 86.9 pts. Then at 8 Days ECM still leads at 66.1 pts over GFS's 63.1 pts. Finally at Day 10 ECM is ahead of GFS at 49.2 pts to 46.8 pts respectively. 

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day1_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day3_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day5_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day8_PMSL_MSL_G2NHX.png

http://www.emc.ncep.noaa.gov/gmb/STATS_vsdb/allmodel/daily/cor/cor_day10_PMSL_MSL_G2NHX.png

MY THOUGHTS   In the last few days there has been a marked stand-off between most of the output and what UKMO has shown in the evolutions of milder air reaching the UK next week. In the last 24 hours this seems to have been resolved with most of the output returning output today more akin to that of UKMO so hats off to that model for sticking to it's guns. The result of this is that I can now more confidently say that the UK is going to stay cold rather longer than previously thought and it looks like the end of next week at least before many areas see a return to Atlantic winds. More importantly for many is that there looks to be a real risk that a period of snow may affect the South and SW early next week as mild Atlantic air pushes against the cold air established across the UK before shearing it away SE into France. As is usual with these situations details of where, if any and how much snow will fall will not be realised until later in the weekend and for many it is likely to just stay cold and frosty with sparkling sunny days. Then as we look longer term all output that stretches out beyond the middle of next week still show the Atlantic winning back with all areas becoming milder with some rain at times particularly in the North. However, as has been proven in the last few days that is a million miles away in weather terms and there is plenty of time to suspend any milder air into the UK even further. It is a welcome relief I'm sure for those afflicted by recent floods to see a week or so at least of much drier and cold conditions to alleviate and expedite a slow return to normal life and if you live in the South going on this morning's output there is a real risk of seeing some snow early next week. For many this will be the first time a snow event from the SW such as shown has appeared in the charts in a reasonably short time frame for some years. It will be fascinating to see how this unfolds within the models over the coming days and the longer term prospects too. See you tomorrow for the next instalment. 

Next Update Thursday January 14th 2016 from 09:00

[Timmytour]

Delighted with the outcomes this morning's models are showing. And though I certainly can't say it's anything I predicted, I always am optimistic that where a slowly evolving block to the east has developed and is far west enough, the models will always rush too much to push the Atlantic through and the block will prevail.  My happiest experience of this is from 1979 I believe when I went to bed just after seeing the BBC weather after the news say milder air was pushing in overnight and lookign outside to see the falling snow already turning to rain.  I woke up to Narnia!

However with a potential breakdown to come from the Azores, i think this may be more potent. So, although I know it's some way ahead, I think this will be the way it goes and we could end up with some pleasant days in 9-10 days times albeit with chilly nights. And potential for further cold spells in Feb

[mushymanrob]

note the noaa 500mb charts never supported the gfs mild southwesterlies, for a week now they suggested a ridge just to our west slowly drifting in towards us, with the uk being under a northwesterly upper flow.

yet again they trump the ops...

[mushymanrob]

1 hour ago, Nick F said:

 

Hats off to the much maligned UKMO global model at first picking up on the stronger ridge building north into with the Atlantic and troughing going under to our SW early next week, while the main players, particularly GFS, were keen to bring in milder SWlys by early next week.

 

......... but the noaa 500mb charts predicted that for over a week now, so im not sure why the ukmo are getting the praise!  see the attached charts for jan 6th, and 12th, they have consistently suggested this pattern which is why some of us refused to believe the gfs mild solution. (ok the latest suggests a weakening of the ridge and the atlantic systems returning later next week? ).

 

[marksiwnc]

Just now, mushymanrob said:

......... but the noaa 500mb charts predicted that for over a week now, so im not sure why the ukmo are getting the praise!  see the attached charts for jan 6th, and 12th, they have consistently suggested this pattern which is why some of us refused to believe the gfs mild solution. (ok the latest suggests a weakening of the ridge and the atlantic systems returning later next week? ).

 

Indeed and they seem to think that the high pressure should last up until 26/1 according to the latest one 

[Nick F]

23 minutes ago, mushymanrob said:

......... but the noaa 500mb charts predicted that for over a week now, so im not sure why the ukmo are getting the praise!  see the attached charts for jan 6th, and 12th, they have consistently suggested this pattern which is why some of us refused to believe the gfs mild solution. (ok the latest suggests a weakening of the ridge and the atlantic systems returning later next week? ).

 

Yes they have, but in my post I was referring to the high res / operational outputs rather than the means or the prognostic NOAA analysis to which you refer. Of the high res runs, UKMO has done well compared to GFS in particular with EC close behind with regards to maintaining the blocking longer and put back any return of SWlys.

But agree with your last post re: the NOAA 8-14 day anomaly charts being the best source for likely pattern in that timeframe, John Holmes often bangs on about how well they verify, so good to take note of his anomaly updates when he's around.

I also find the NOAA CPC analog charts fairly good at picking up patterns too, these are based on official CPC forecasts for out to day 11 but using analogs of days in the past that matched the official forecast pattern within a 35 day time frame of the forecast period.

more about how to interpret them here:

http://www.cpc.ncep.noaa.gov/products/predictions/erf_tools_info.php?outlook=814&var=500&tool=an

Edited January 13, 2016 by Nick F

[johnholmes]

7 minutes ago, Nick F said:

 

more about how to interpret them here:

http://www.cpc.ncep.noaa.gov/products/predictions/erf_tools_info.php?outlook=814&var=500&tool=an

thanks for that Nick will bookmark the info, another source of data for checking the mid term forecasts.

Can you give me the actual link for the charts please Nick?

Edited January 13, 2016 by johnholmes

[chionomaniac]

1958 is in there again @Nick F! ( @lorenzo take note!) 

Ensembles keen on UK ridge with Atlantic held back and by day 15 GEFS this:

 

Close to day 13 EPS

medium term has a fairly good outlook.

[Nick F]

5 minutes ago, johnholmes said:

thanks for that Nick will bookmark the info, another source of data for checking the mid term forecasts.

Can you give me the actual link for the charts please Nick?

There you go John: http://www.cpc.ncep.noaa.gov/products/predictions/814day/analog.php

06z looks quite progressive again, with lifting jet energy NE of the U.K.

[carinthian]

20 minutes ago, Nick F said:

There you go John: http://www.cpc.ncep.noaa.gov/products/predictions/814day/analog.php

06z looks quite progressive again, with lifting jet energy NE of the U.K.

 Looks like GFS now in a rush to bring in super mild Tm overnight next Wednesday into Thursday.Any transient snow would melt away before the sleep is rubbed away from your eyes. We will see.

[Glacier Point]

CPC analogues rolled forward days 10-12 confirm the idea that we are heading towards an Atlantic ridge / Scandinavian trough solution in the last week Jan into early part of Feb... which might be useful as the models seem to be losing all coherence as we approach the business end of the winter.

Relative angular momentum has peaked in the last few days and, as tendency in relative angular momentum (the rate of acceleration or deceleration) cannot be maintained forever, some negative tendency is expected in the next 10 days. Total and relative angular momentum will however remain high as a large surplus of westerly inertia remains in the atmospheric system, demonstrative of a fully coupled atmospheric - ocean circulation.

That places the GWO in a quasi stationary phase 6-7 orbit for the next 10 days. Composites are a bit messy but broadly align to Scandinavia trough a deep low in the Western Atlantic. This is complicated as we are approaching a monthly change, and February's composites hold some value.

But generally Atlantic attack from the south-west and re-asserted Scandinavian trough as the theme.

The GFS and EC monthly and EPS MJO signals suggest the MJO to become coherent in the Indian Ocean and towards the Maritime Continent during weeks 2-3. It should be remembered that there will remain a low frequency signal for convective anomalies in the Central and Eastern Pacific as well, so the MJO projection onto the system will be altered and angular momentum will remain high. MJO composites alone of limited value and it should be stressed again that the MJO signal needs to be transposed onto the GWO.

 

The main point to draw from this signal is that angular momentum will begin to rise again during week 3 (early Feb). This gives a stable GWO phase 7-6-5-6 type look to the pattern for the next 2-4 week period, with phase 6 being a strong attractor within the base state. Composite is very consistent and now familiar as we turn towards the back end of Jan into Feb...Scandinavian trough, anomalous ridge centred just south of Greenland. Those looking for early spring warmth in the first part of Feb may be disappointed.

As wind vectors, I would be thinking NW, N and NE, allowing for a bit of westerly flow days 7-10.

Edited January 13, 2016 by Glacier Point

[Chris101]

Hi all, I don't write much on here, but still read everyones thoughts and obviously learn a lot from the very knowledgable.

Am i right in thinking that you can have the worlds most expensive computer to model but at the end of the day accuracy comes from the data that you put into it. Now i was always under the belief that the areas we want to get the cold from are very data sparse areas compared to the amount of data that is available from the more zonal areas, am i right in thinking if you put a ton of data in from zonal areas and considerably less from our North that this is why models can be way too progressive for a return to normality.

Cheers Chris