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

[Su Campu]

There is a plethora of ECMWF (and other model) data available from the Icelandic met here, and other data here

ECM 0.5°: T850 anomalies, here are the last 10 days versus the next 10 days (MSLP solid lines, T850 dashed lines)

 

Similarly 500 hPa height and thickness anomalies (solid and dashed lines, respectively)

  

ECM Ensemble: Out to 15 days. Thickness (coloured), 500 hPa mean heights (solid lines), spread (dashed lines)

[No Balls Like Snow Balls]

1 minute ago, Weather Boy said:

Great charts, thanks, but what are the dates?

Point of interest is gradual migration (and strengthening) of anomalous HP from central/western Canada towards Greenland.  The last one has it centred over Hudson Bay.  You would expect it to continue slowly east towards Greenland.

It does say initialized 08/12/2015 (bearing in mind Americans have date wrong way around), although it was posted only 11 hours ago. Info could have changed by now, who know's lol, but interesting none the less.

[Cloud 10]

3 hours ago, radiohead said:

There has been an awakening...can you feel it?

 

 

Great screensaver.

 

Cracking control run from the GEFS amongst all the other gravy this morning.

 

[No Balls Like Snow Balls]

7 minutes ago, nick sussex said:

Interesting thanks for posting that. I had to laugh though this is the same Ventrice who derided the MJO as being a false signal, said basically winter was over because changes to the strat would come too late. He went to great lengths to belittle a fellow twitter user who disagreed with his " MJO false signal" and is now eating humble pie! lol

Ah yes I remember that tweet. I think I even posted it in here lol

[nick sussex]

Looking at the ECM De Bilt ensembles there is a decent cluster taking the wind direction round to the east/ne for several days.

http://www.weerplaza.nl/15daagseverwachting/?r=midden&type=eps_pluim

[Weather Boy]

3 minutes ago, No Balls Like Snow Balls said:

It does say initialized 08/12/2015 (bearing in mind Americans have date wrong way around), although it was posted only 11 hours ago. Info could have changed by now, who know's lol, but interesting none the less.

Ah, yes, of course, silly me, I spotted that date but didn't twig about it being American.  Thanks.

[bobbydog]

3 hours ago, Steve Murr said:

Cracking overnight runs & at day 8/9 - A possible surge of heights North into greenland aided by 'push' from pressure out of the azores into the already well established atlantic high ( GFS control at 204-228 et 'al )

UKMO sticking to its guns - but out of its fails lets hope this is the one that verifies as its on a par with last nights JMA 

- very similar to the above control run & also feeding into the arctic high

all at just 5-6 days away !!!!

S

you up for a truce steve? i'm all for a good debate but we should all keep it friendly. at the end of the day, we're here for the same reason and when you step back and look at at it, there's no point falling out over something we have absolutely no control of!

or we could sort it out with a snowball fight in a few days time....?

[johnholmes]

I still think that 'cold' will be around for 8-10 days. As always beyond 14 days from now I do not go, starting over this weekend and out to at least 15-16 January probably beyond. Becoming high pressure dominated after 3-4 days from the start.

[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 6TH 2016

THE CURRENT GENERAL SITUATION   A new depression will swing a set of troughs NE across the UK again later today, these becoming slow moving again across the far NE and followed by a somewhat showery Westerly flow across Southern and western areas tomorrow.

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

CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the British Isles ranges from between 1500ft just to the NE of Scotland to nearer 4000ft over Southern England rising somewhat for a time tonight before falling again to around 5000ft again 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  Becoming colder and still rather unsettled with some rain, sleet or snow at times and frost at night.

THE GFS JET STREAM FORECAST  The main theme of the Jet Stream today shows the Jet Stream continuing to stream East across France over the next week before a shift of orientation to more of a NW to SE flow across the UK through the second week as a deep trough lies across Scandinavia.

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

GFS OPERATIONAL The theme of the GFS operational run today shows two sections this morning with the next week seeing Low pressure sinking down across the UK through the period maintaining cloudy and sometimes wet and windy weather with sunshine and showers too giving some snowfall at times on the hills with time. Then through next week Low pressure drifts off slowly East and allows cold air to sink South overall areas. On this run the air is unstable too with snow and sleet at times, almost anywhere for a time before a short drier interlude under High pressure moving across briefly gives rise to some frosty night and bright days before a return to cold and unsettled weather develops again later with more rain and snow as winds switch to the East.

GFS CONTROL RUN The theme of the Control Run is very similar to the Operational run this morning with the second week showing all the interest for cold lovers. In the meantime there remains a lot of complex Low pressure over the UK with rain and showers at times and some snow on the hills before all areas become cold and unsettled from early next week with some snow at times, even in the South as low pressure to the East throws cold North or NE winds across the UK until the end of the run.

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 today shows Low pressure still in control of the weather but with subtle changes in positioning meaning a stark change for the UK next week. With rain and showers the main message between today and the start of next week is rain or showers with snow on the hills before all areas become cold next week with NW winds and snow showers extending down across the UK to all areas by midweek.

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

THE FAX CHARTS The Fax Charts show a continuation of the unsettled spell with strong winds and rain at times on troughs repeatedly driven across the UK in a SW flow decelerating and becoming slow moving across the UK with rain and showers at times for all and snow at times on the hills of the North.

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

GEM GEM this morning is somewhat different longer term as it shows the current wet and windy weather of the next 4-5 days slowly giving way to dry and bright weather with frosty nights as High pressure builds across the UK later next week. The transition period does show a spell of cold North based winds with some wintry precipitation across parts of the UK for a time before the better weather arrives 

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

NAVGEM NAVGEM shows a slow transition from the current wet and Low pressure based theme towards a colder and unstable NW slow  as Low pressure moves off towards the East and pressure builds across the Atlantic. This would mean the cold air would turn precipitation to snow at times even in the South next week.

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

ECM ECM today shows a somewhat lesser wintry theme longer term although in the mid term i.e. early next week it also shows a spell of cold NW winds bringing wintry weather SE to many areas as the UK based Low pressure of the weekend goes off to the East and pressure builds over the Atlantic. By day 10 the coldness has modified across the UK but it does look like a Northerly could be renewed soon after the term of the run.

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

ECM 10 DAY MEAN The 10 day mean chart shows Low pressure likely to be to the East and High to the West in 10 days time. A generally Northerly flow is likely across the UK with temperatures well down on recent times with frost at night and wintry showers in all exposed locations but a lot of dry and bright weather inland.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The theme of the output continues to strengthen towards drier and colder conditions developing across the UK 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 96.5 pts respectively.  At 3 days ECM is leading with 97.6 pts to UKMO's 96.9 pts while GFS lags behind at 96.4 pts. At 5 days ECM leads with 89.8 pts to UKMO at 88.0 pts then GFS at 87.6 pts. Then at 8 Days ECM still leads at 66.1 pts over GFS's 61.6 pts. Finally at Day 10 ECM is ahead of GFS at 47.9 pts to 46.1 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   For those seeking cold this morning the models have delivered a set of output that I feel many of them will be happy with this morning. There is almost a 100% guarantee now that at long last we are soon to lose the continuous conveyor belt of Atlantic Low pressure and attendant rain and showers and swap it with a colder flow coming down from the North as Low pressure transfers to a point to the East of the UK while High pressure builds North across the Atlantic. In the short term we still have 4-5 days of familiar Low pressure often parked over the UK and continuing to bring spells of rain and showers and snow over the hills of the North. It's then in the early days of next week when this Low pressure is pulled East to Europe and cold North or NW winds are pushed down across the UK aided by rising pressure over the Atlantic and a marked slow down in the Jet flow. All areas look at risk of some snowfall next week but the favoured coastal locations pointing North will see more than sheltered inland locations which look most likely to see the change in the form of sharp frosts by night and cold crisp days rather than snowfall. Then the question is how long will it last? Well in terms of GFS quite a while this morning as there appears to be a second surge possible later when GFS shows the chance of an easterly developing. ECM on the other hand shows a more measured response to that question and it poses a question at day 10 in as much as there appears a strong chance that the evolution from then also shows a second cold surge likely soon after mid month. The one thing that I can confidently say and have been saying since the hints of cold from the North were shown some days ago is that it is going to happen but for how long this pattern remains once here is open for debate. The pressure pattern look much more favourable for cold next week that at any stage this Winter so far with a Jet stream well South over Europe and High over the Atlantic. Persistent Low pressure to the East should encourage runaway Low pressure from the NW to feed SE over the UK at times each time reinforcing a cold North feed behind them and if High pressure can eventually ridge all the way into Greenland who knows what may develop longer term. Interesting model watching indeed in the days ahead. 

Next Update on Thursday January 7th 2016 at 09:00 approx 

[Singularity]

29 minutes ago, Yarmy said:

 

I quite like Mr Laminate Floor's chutzpah (when he's talking about weather anyway), but why are the North Atlantic SSTs key now, but not during the record mild of December? We had a persistent large Atlantic high during late summer, and a persistent Atlantic trough during December, yet the SST anomaly has been more or less the same throughout. On that evidence they make little difference, or at least are easily overridden by larger atmospheric patterns. 

According to this analysis, we didn't have a persistent large Atlantic high, more a Greenland high:

Indeed there was an unusually deep/persistent 500 mb trough closely matched with the negative SST anomalies.

The second pair of charts shows how both the anomaly and trough weakened in August. So I believe it has played a considerable role in our weather in the past year.

[No Balls Like Snow Balls]

From Twitter

 

 

[The Northern Ramper]

48 minutes ago, nick sussex said:

Regarding the ECM being too flat this is quite ironic because the operational run is often accused of being overly amplified!

Only when it suits the mild rampers Nick

[Paul]

For those wanting to embed tweets, please have a read of this guide:

 

 

[Yarmy]

5 minutes ago, Singularity said:

According to this analysis, we didn't have a persistent large Atlantic high, more a Greenland high:

Indeed there was an unusually deep/persistent 500 mb trough closely matched with the negative SST anomalies.

The second pair of charts shows how both the anomaly and trough weakened in August. So I believe it has played a considerable role in our weather in the past year.

Ok, data wins over dodgy memory as I recall a long-lasting fat mid-Atlantic high. However, according to the oceanographers there is a correlation between cooler summers (in the UK) and a negative AMO. The link between the AMO state and winter (in the UK) is less clear and likely statistically insignificant.

[Glacier Point]

13 minutes ago, Singularity said:

According to this analysis, we didn't have a persistent large Atlantic high, more a Greenland high:

Indeed there was an unusually deep/persistent 500 mb trough closely matched with the negative SST anomalies.

The second pair of charts shows how both the anomaly and trough weakened in August. So I believe it has played a considerable role in our weather in the past year.

Wholly agree with this assessment. With a +AO regime, this becomes horribly warm as per November and December. With a -AO, suddenly things begin to look a lot different. What was your foe now becomes your friend.

Very good agreement between EC EPS, GEM Ensembles and GEFS around day 10 for increased rate of sub-tropical flow into the Atlantic. Further upstream amplifications already likely, which will all work to cold pattern's advantage. Definite signal for persistence of the cold. Whilst a west based -NAO is a risk at times (guidance suggests more long term trend eastwards - or centrally based to be more accurate), this does open the door for moisture to come into the SW approaches. The upstream amplification coming will help to correct any trend for too much west based NAO stuff I think.

Meantime, total angular momentum off the scale.

 

Edited January 6, 2016 by Glacier Point

[Barry12]

As I said last night, I expect a more prolonged and significant cold spell than most people see. The models this morning are starting to reflect that. Expect further upgrades in the coming days.

 

Get set...it's coming.

[LeeSnowFan]

8 minutes ago, Barry95 said:

As I said last night, I expect a more prolonged and significant cold spell than most people see. The models this morning are starting to reflect that. Expect further upgrades in the coming days.

 

Get set...it's coming.

Great Charts this morning! A Cold spell is certainly on the way how cold and for how long! who knows but lets just enjoy it! Us coldies have been waiting a long time for it

 

Where is FROSTY at a time like this!!!

[beng]

20 minutes ago, Glacier Point said:

Whilst a west based -NAO is a risk at times (guidance suggests more long term trend eastwards - or centrally based to be more accurate), this does open the door for moisture to come into the SW approaches. The upstream amplification coming will help to correct any trend for too much west based NAO stuff I think.

West based but cold due to Scandi troughing and a decent STJ - gradually becoming more Central/East based - if that plays out,  it's actually hard to think of a better pattern for a sustained cold spell.

 

Edited January 6, 2016 by beng

[bluearmy]

Re any trend to west based -NAO

I did note this looking at the the anomolys this morning

however, with low heights over Europe, we should be ok to stay cold whether the moisture come from the n or s 

 

 

[Singularity]

14 minutes ago, Glacier Point said:

Wholly agree with this assessment. With a +AO regime, this becomes horribly warm as per November and December. With a -AO, suddenly things begin to look a lot different. What was your foe now becomes your friend.

Very good agreement between EC EPS, GEM Ensembles and GEFS around day 10 for increased rate of sub-tropical flow into the Atlantic. Further upstream amplifications already likely, which will all work to cold pattern's advantage. Definite signal for persistence of the cold. Whilst a west based -NAO is a risk at times (guidance suggests more long term trend eastwards - or centrally based to be more accurate), this does open the door for moisture to come into the SW approaches. The upstream amplification coming will help to correct any trend for too much west based NAO stuff I think.

Meantime, total angular momentum off the scale.

 

Your highlighted statement calls to mind a persistent mid-Atlantic trough propping up the blocking to our NW as it did during July's (extremely) -ve AO period, as a consequence of the jet being pushed so much further south. I like what I'm seeing there 

The idea that we may see lows coming up from under the block and bringing some nervous times with rain/snow boundaries was something I mused over about a week ago, again with respect to the possible effect of the 'Cold Pool'. Very glad to see that you are thinking along similar lines GP 

...and just look at the AAM go! I noticed GEFS still managed to slightly underestimate it even at just 1 day's range yesterday, and the longer-term guidance is reducing the drop-off slowly but surely. What a time to be following the model output!

 

[winterof79]

11 minutes ago, Barry95 said:

As I said last night, I expect a more prolonged and significant cold spell than most people see. The models this morning are starting to reflect that. Expect further upgrades in the coming days.

 

Get set...it's coming.

Interested to know What you base your forecast on Barry?

[Tim Brawn]

Any thoughts on the impact of very cold temps on saturated ground ,  assume it will freeze like blocks of ice a thaw would be slow and when it does warm and rain again flooding will be even worse as any water will just run off .

 

[BLAST FROM THE PAST]

06z at t132, LP more SE over UK than 00z.  The LP way to our SW, how will that interact with it?  Very favourably on 00z as in ..it didn't...let's see.

 

06 z continues on very favourbale theme.....astounding really.....its got me if it comes off, didn't expect to see this for a 2-3 weeks yet. 

 

is this 'maddenesque'

 

BFTP

Edited January 6, 2016 by BLAST FROM THE PAST

[No Balls Like Snow Balls]

Latest Daytime max temp forecast for London from Norwegian Met (they use ECMWF for their forecasts) www.yr.no 

Thurs 7th, 9c

Friday 8th, 9c

Sat 9th, 9c

Sun 10th, 7c

Mon 11th, 5c

Tues 12th, 1c

Weds 13th, 0c

Thurs 14th, 0c

Fri 15th,  1c

Cold enough for snow from early next week, if there is any precip about.

Proceed with caution though as I believe ECM temp forecast are not entirely accurate, but defo looking like turning much much colder.

 

 

Edited January 6, 2016 by No Balls Like Snow Balls

[icedust]

Well what an interesting set of charts is developing.  The duration of the upcoming cold spell seems to hinge on developments over the Tropic of Cancer! Watch how models develop a very low latitude low over the Bahamas in the next 24-48h and move this northeast over the next week. Where this ends up is crucial to where the Atlantic High develops. If this Low gets to the Azores this will allow a decent ridge to anchor north to Greenland and not slip south.   On the other hand the T+240 ECM keeps the low far west possibly resulting in some decent northwards warm advection over the Atlantic and causing a good ridge north to Iceland/Greenland and block eastward flow south of those islands. On yet the other hand the whole development of this low latitude low may fizzle and we get back to a boring westerly breaking through again. Incidentally, I for one am 100% convinced our record breaking December was caused by 'global warming' with that very persistent warm block out of Africa and across Europe for the whole month. Is this forecast Tropical low also due to 'global warming' or an El Nino feature?