Model output discussion pm 13/01/2016

[Weather-history]

8 minutes ago, northwestsnow said:

Still uncertainty on the extent of the atlantic early next week, looks cold until wed/thur to my eyes looking across the board this morning.

Highres/FAX charts will lead the way now

Talking about FAX charts look at the difference between old 96hrs and the new 84hrs. 

More high blocking on the new 84hrs, fronts in retreat on that FAX chart compared to the old 96hrs for the same time.

84hrs

. 

Edited January 16, 2016 by Weather-history
Charts

[Polar Maritime]

A few posts containing BBC/Meto forecast have been hidden. Please use the appropriate threads, And continue with discussion only on what the models are showing in here, Many Thanks.  

[northwestsnow]

5 minutes ago, Weather-history said:

Talking about FAX charts look at the difference between old 96hrs and the new 84hrs. 

More high blocking on the new 84hrs, fronts in retreat on that FAX chart compared to the old 96hrs for the same time.

84hrs

. 

Great spot kevin.FAX says cold persists until thur/fri imho.

[stratty]

Off the scale snow for tomorrow!!!

GFS still going for warmer uppers over the coming days than some models still?

 

Edited January 16, 2016 by stratty

[IDO]

It looks like the models are pushing the milder air into the South/SW from Monday-Wednesday with those areas returning to above average temps. The boundary of cold should keep the North/NE/E in the colder air, so the risk of snow on that front. We then get a couple of days as the HP fights back before the fronts in the west push the high east and most of the UK returns to average to above temps.

All subject to adjustment in the next 24 hours but no sign IMO that this spell will develop into a cold block, though that doesn't rule out further attempts down the line, especially as GP, Tamara and the other experts are confident of further waves by the end of the month.

The ex Hurricane Alex has probably not aided the longevity of cold, as I would assume that it has re-invigorated the trough to our west.

All models are flattening the pattern upstream so there is little to halt the jet pushing through the lower heights across the Atlantic and this will aid the reformation of the trop PV, so a holding pattern preventing cold looks very likely after D7:

D10 three main models:

Very little potential there for a cold block for our sector for D8-12 based on that output and we will see what happens after that in due course but probably at least week 3 till another change. 

Some potential for snow almost anywhere but the SW in the next five days and remaining cold in the North till Friday at least.

 

[carinthian]

Well done UKMO for sticking to its guns. Looking at the charts below for mid week, clearly the fax chart update keeps a cold block at the surface to the east and attempts for Atlantic frontal attack weakening against this block. Probably will get a renewed attempt at a push again later in the week. The 850 mb wind flow chart from GFS also shows a cold flow out of the block with possible disruption to the far SW  of England. Progress of the first front looks like being slow and could even retreat. Overall it looks like much of the coming week will keep will keep much of the UK and Europe on the colder side of the higher upper jet flow with a warmer displacement trying hard to shift it.  Snow forecasting movements and amounts will always be difficult it this developing set up. Good for chart watching though.

 C

Edited January 16, 2016 by carinthian

[Polar Maritime]

NetWx-SR take on snowfall later today.

Edited January 16, 2016 by Polar Maritime

[carinthian]

1 minute ago, Polar Maritime said:

NetWx-SR take on snowfall later today.

 

Looks like heading for you PM.

[Darlo snow]

My first post here after lurking for a few years. Looks like we will finally get some snow these next few days after a few years of little snow.

Edited January 16, 2016 by Darlo snow

[nick sussex]

So the UKMO ditches last nights 12hrs output! Finally we actually have cross model agreement from the big 3 for the overall pattern upto T144hrs.

Good grief I might have to go and lie down!

The ECM postage stamps generally not really interested in better undercuts, there are some stragglers that would keep the cold even longer.

http://old.ecmwf.int/samples/d/inspect/teasers/samplers/banner/mean_sea_level_pressure_and_temperature_at_850hpa!120!pop!od!enfo!enplot!2016011600!!/

You often find this with ensembles in these types of set ups, the lower resolution often causing problems in terms of modelling the distribution of energy ne/se.

[Man With Beard]

1 hour ago, mushymanrob said:

feature moving se wards from western scotland later today is expected to deliver some snow for..... me! ... and i dont want it!

bbc has pretty mild temps ahead of mondays frontal system, up to 9c in the southwest..

meanwhile the ever reliable noaa 500mb charts dont support pressure building to our east or northeast (other then as a transitory feature) , but do suggest a bartlett type high to our  near south/southwest .

 

I see another possibility on the NOAA charts (and increasingly on others) - a high pressure centred quite close to the UK (e.g. Belgium), meaning mild SWlies for the north west, but much of the UK under a slight continental influence. We haven't seen a high like this in winter for years. It would bring a lot of dry weather but it would be cold away from the NW, with sharp frosts. I'm coming round to thinking this would be the next stage after the undercutting business is finished. A decisive undercut sealing heights to our north is still an option for me too, though perhaps 10%.

[Polar Maritime]

17 minutes ago, Darlo snow said:

My first post here after lurking for a few years. Looks like we will finally get some snow these next few days after a few years of little snow.

Welcome Darlo, Please use the winter discussion thread or your regional area thread for general chat away from the models. Thanks 

Edited January 16, 2016 by Polar Maritime

[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 SATURDAY JAN 16TH 2016

THE CURRENT GENERAL SITUATION   A cold ridge of High pressure across the UK will give way to a frontal wave depression sliding SE from the NW of Scotland down across NW England the Midlands and SE England tomorrow.

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

 CURRENT SNOW FORECAST AND FREEZING LEVEL OVER THE UK The freezing level across the British Isles is uncertain for the next few days ranging from 2000ft or 500mtrs in the East rising to as much as 4000ft or 1000mtrs over the West and SW at times from 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  Very Cold and frosty with the chance of snow for a time next week then probably becoming less cold for all with some rain in the North by the end of the week.

THE GFS JET STREAM FORECAST  The movement of the Jet Stream longer term is very uncertain this morning though currently the message is that the flow moving South across the UK in the coming days will become weak and ill defined later next week as far as the U is concerned before it blows more West to East across the UK for a time thereafter though details are very uncertain.

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

GFS OPERATIONAL The GFS Operational Run today shows a very mixed pattern with the general message out of a very much more complex pattern being that Low pressure disrupting near the UK could bring rain and some snow in raw cold conditions early next week before some resurgence of cold High pressure from midweek brings fog and frost before milder air moves NE across most parts and continues off and on thereafter with fronts crossing at times though with colder High pressure never that far away to the East and South.

GFS CONTROL RUN The theme of the Control Run longer term message is for very much milder and windy weather longer term as the Atlantic bandwagon of wind and rain resets to the North and West of the UK. in the short term details still look quite elusive but the cold air looks to be proved stubborn to move for much of next week with troughs running into cold air delivering a mix of rain, sleet and some snow before the milder air pummels through by the end of next week.

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 this morning shows a period of trough disruption across the UK as fronts edge NE across the UK early next the week before High pressure rebuilds midweek and then slides away SE late on in the run. Rain, sleet and snow would move across the UK early in the week before cold and frosty and perhaps foggy weather develops for a time finishing the week with milder SW winds affecting the North and West unlikely to reach the SE until next weekend. 

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

THE FAX CHARTS The Fax Charts today show the difficult battle between cold air across the UK and warmer Atlantic winds with a messy mixture of troughs delivering some rain and snow to Western and Central areas early in the week with the cold air winning back any territory lost as High pressure rebuilds close to the NE of the UK midweek.

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

GEM GEM this morning shows the same messy mix of weather next week as repeated attempts by milder air to the SW of the UK interacts with the colder air over the UK and NW Europe. Eventually the North and West sees the mild air win out later next week and elsewhere over next weekend. Through the week though the raw weather is shown to deliver some rain, sleet or snow in places.

NAVGEM NAVGEM follows the theme of much of the output this morning with the battle between milder winds from the Atlantic hitting the cold air across the UK with some rain and snow for some before High pressure builds into the UK for a time later next week before milder Atlantic winds make a more concerted push across the North and west by the end of next week and elsewhere eventually though High pressure remains close by just to the SE at the end of the period.

ECM ECM today shows very slow progress in dispersing the cold air across the UK next week with a couple of attempts shown on this morning's run each failing with rain and snow for some for a time. The power of the Atlantic does overwhelm the High pressure block formed to the NE midweek later as the High is pushed to the SE and SW winds along with the Jet stream realigns across the North with rain at times to the North and West at least in milder air for all.

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

ECM 10 DAY MEAN The 10 day mean chart has Low pressure in it's natural habitat near Iceland with High pressure to the South and SE with the Jet flow across Northern Britain meaning we are likely to see less cold and wetter conditions with rain at times in the North and West especially with the driest weather in the East and South.

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

NOTABLE TRENDS & CHANGES FROM PREVIOUS RUNS The models all show mild air eventually with an agreed delay of the onset of this now until later 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 97.6 pts to UKMO's 96.7 pts while GFS lags behind at 96.3 pts. At 5 days ECM leads with 89.6 pts to UKMO at 87.9 pts then GFS at 87.0 pts. Then at 8 Days ECM still leads at 66.0 pts over GFS's 63.4 pts. Finally at Day 10 ECM is ahead of GFS at 49.6 pts to 45.6 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   Finally today we do appear to have gained some common ground between the output today as the general message is for the current cold snap to hang around for a while longer with messy attempts of milder air to come into the UK from the SW next week largely failing away from the SW itself. In fact there is also common ground today to develop High pressure close to the NE of the UK by the middle of the week pushing back any push from the Atlantic then and returning frost and freezing fog patches for many for a time. Equally we have good support that this High will more easily slip away SE across Europe late in the week opening the door to a resurgence of the Jet stream on a much more Northerly track and SW winds, first for the North and West and eventually for all. The change to milder weather looks quickest in the North and West where some rain at times becomes likely while the South and East stay drier and still a little cool at times as on most output High pressure stays quite close to the South and East. While the above sentiments do express the most likely outcome painted by the models this morning day to day differences especially early in the period are still likely as the remnants of ex hurricane Alex in the Western Atlantic muddies the waters with the progress East of any mild weather still very uncertain. This of course is crucial in determining who has snow and who has rain as each push of milder air attempts to cross Britain but if I had to pin anywhere to have a god chance of snow from Sunday to Wednesday I would say the Midlands and the SE could be the sweet spot but of course that is open to change. So finally while snowy armageddon is unlikely from this morning's output some areas are going to see some meaningful snow soon and while the end result looks like returning the milder Atlantic winds late next week there is still a lot of water to cross under the bridge before we arrive at next weekends solutions we can only hope that the models remain to progressive in the dispersal of the cold block.  

Next Update Sunday January 17th 2016 from 09:00

[ANYWEATHER]

27 minutes ago, Darlo snow said:

My first post here after lurking for a few years. Looks like we will finally get some snow these next few days after a few years of little snow.

Hello and welcome to the wonderful world of Netweather!   Can you please put your location in your avatar please,  Enjoy your time here

[Weather-history]

This is last Saturday's GFS 0z run for this Saturday morning

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=174&mode=0&heure=0&jour=9&mois=1&annee=2016&archive=1

 

And ECM 0z

http://www.meteociel.fr/modeles/ecmwf.php?jour=9&mois=1&annee=2016&heure=0&archive=1&mode=1&ech=168&map=0&type=0

 

 

GFS has had a shocker.

 

[nick sussex]

Early next week is looking very tricky forecast wise.

Shortwaves moving in hitting colder air and where that boundary between rain/snow is. The good thing about todays trends is the high holding on upto T120hrs so chances that favoured areas could get snow with no rain following and then some lovely dry sunny and frosty conditions to enjoy it.

I think overall theres a strong signal to sink the high, timings could of course change slightly but trying to keep the high further north will be difficult because of the energy spilling east towards Greenland, theres also a lack of sharpness to the upstream troughing, too flat so this counts against keeping that high.

Given the timeframes I suppose we could see some adjustments but we'd need things to change upstream. I suppose it depends on your view re glass half full/empty. In the context of the winter so far getting cold conditions to last as long as suggested by the operationals is good going.

[nick sussex]

16 minutes ago, Weather-history said:

This is last Saturday's GFS 0z run for this Saturday morning

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=174&mode=0&heure=0&jour=9&mois=1&annee=2016&archive=1

 

And ECM 0z

http://www.meteociel.fr/modeles/ecmwf.php?jour=9&mois=1&annee=2016&heure=0&archive=1&mode=1&ech=168&map=0&type=0

 

 

GFS has had a shocker.

 

Yes all of its failings have been summed up this week. Too progressive and as soon as theres a possible undercut it spills all the energy ne'wards. A very poor show from it. The UKMO had done very well until last nights rogue run.

GFS 06hrs run T48hrs update, already changes stronger high to the north, pattern edged west.

These small changes early are likely to lead to an improved picture later in terms of where the lobe of high pressure sets up.

Edited January 16, 2016 by nick sussex

[Chris1986]

Nice stall shown on 06z 

Edited January 16, 2016 by Chris1986

[IDO]

2 minutes ago, Weather-history said:

This is last Saturday's GFS 0z run for this Saturday morning

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=174&mode=0&heure=0&jour=9&mois=1&annee=2016&archive=1

 

And ECM 0z

http://www.meteociel.fr/modeles/ecmwf.php?jour=9&mois=1&annee=2016&heure=0&archive=1&mode=1&ech=168&map=0&type=0

 

 

GFS has had a shocker.

 

In fact if you look at the height verification for D6 for the most recent days (where entropy has been high) the GFS has performed amongst the top (including the GFS Parallel) where as expected the UKMO has performed abysmally, down to 0.71 (GFS 8.8 same time) on the most recent run:

Of course this is for the whole NH, but even from a layman's POV the UKMO over did heights and then had a dog's dinner of a run last night. Consistent output from the GFS with relation to breakdown from the SW around 17th-18th for about a week now, though they didn't see the rebuilding of heights from the NE early next week. The UKMO was building Greenland Heights, Omega blocks, locked in cold and clearly was wrong. The reality was not a strong block just the old war between Atlantic -v- HP to the east, and GFS was on the ball with that signal, just over did the Atlantic strength, which is it's bias, so we can forgive it not getting the undercut correct. Because it had the right synoptics it clearly will verify much better than the UKMO as the latter was building big blocks a week ago.

[stodge]

Morning all

Another day, another delay in the arrival of Team Mild. The main forecast models hold the East and South-East in cold conditions until Thursday or in the case of ECM, Friday.

I'm more interested in looking beyond that. 

Tamara (I believe), both last winter and this, posited the scenario that an attempt to destabilise the PV would have an initial impact then there would be a recovery and re-formation of said:

This is where we are now in terms of PV degradation under the current attack.

By this time next week, the response has happened - the PV has reformed, apparently stronger and colder than ever but the assertion made by the experts last winter was that said re-formation was part chimera - we would be looking at a 7-10 day window of a renewed PV driving the northern hemisphere before further amplification would cause a second weakening.

One stretched vortex. I suspect once we lose the cold we will have to endure a week or so of something milder before the next onslaught and that takes us into the early February window mentioned by so many LRFs. Those arguing for an anticyclonic evolution do, I think, have a strong argument and while that won't please fans of snow, I think fans of cold have plenty to look forward to in February/March. We are only just halfway in winter so there's a lot of time for things to happen.

[Weather-history]

11 minutes ago, IDO said:

Consistent output from the GFS with relation to breakdown from the SW around 17th-18th for about a week now, though they didn't see the rebuilding of heights from the NE early next week.

The wag in me, says from your summation is that GFS was consistently wrong then. Consistently showing a breakdown at that timeframe but not seeing the other  means it was wrong all the time. 

Edited January 16, 2016 by Weather-history
,

[Stuie]

Bit of a delay with this front coming in but Monday night/Tuesday morning has some interest. Used the Arpege as the example but GFS similar.

but will it be cold enough? Doesn`t quite look like it but something to watch.

[nick sussex]

3 minutes ago, Weather-history said:

The wag in me, says that by your summation was that it was consistently wrong then. Consistently showing a breakdown at that timeframe but not seeing the other  means it was wrong all the time. 

I think IDO has got a secret job working for the GFS Public Relations Dept! lol The GFS has been an abysmal failure when the chips were down on the most important aspects of the output re the undercut.

[Froze were the Days]

UKMO has done well in regards to keeping the cold block over us but at times it has shown (a few days or so back) some under cutting which doesn't look like materialising and more of a sustained block to the north. ecm meanwhile has been a bit in between, anyway certainly has been a marathon episode for the models which hasn't largely bore fruit although a frosty dry spell is welcomed by all.

What are people's thought about the end of January and into February?

[Hammer]

9 minutes ago, SaffW said:

Bit of a delay with this front coming in but Monday night/Tuesday morning has some interest. Used the Arpege as the example but GFS similar.

but will it be cold enough? Doesn`t quite look like it but something to watch.

Yes Monday evening / Tuesday morning look very interesting as currently modelled. GFS looks similar to French model in regards PPN.