comet
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Posts posted by comet
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18 minutes ago, feb1991blizzard said:
I think it was Dec 2012 - THAT ECM, but the one thing I remember about that, is the misconception that the Met Office were on board, they were on board for a much more watered down version and their update never ever reflected some of the extreme model output that was being emitted.
Cheers for the reply yourself and Bluearmy but it was not that long ago and I am sure it was in January. I think I will trawl the archive charts to see they jog my memory.
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1 hour ago, booferking said:
Metoffice update going with it's on model very cold later next week & snow.
It will be very interesting to see which way this goes. The UKMO says yes while the ecm and gfs ops say no. I wonder if anyone can remember what year it was when the metoffice along with the ecm and gfs were calling for an easterly but the ukmo model stubbornly refused to climb aboard. After several days the met and the other two models bowed to the ukmo model. This time things are reversed with the ukmo model and again the met more gun-ho for a colder more wintry east/north easterly and the ecm, gfs against. Whats the betting this time the UKMO model will be wrong this time that is the sort of luck us coldies in the UK have.
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15 minutes ago, DIS1970 said:
Thanks for that, i don't think i'll post anything again, as finding the correct words is difficult, so i think i will just watch from a distance. Been trying to recover for 10 years, and 3 from the op, so it's unlikely. Forget about that, this is a weather forum, so i won't interfere again.
There was nothing at all wrong with your post. I knew exactly what you were referring to as I suspect many other posters did. Some on here just like to be pedantic.
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11 minutes ago, tight isobar said:
Continental europe has a tendancy to quickly go 'cold/deep cold.(this time of year)
Thats exactly why chewing on modeled upper air temps, and cold pooling at this range is all very much speculative.
The overall signal remains very possitive in terms of potential cold..
And dont be suprised at-all to begin the note of deeper 850s showing up as things progress!!!
Yes I am very well aware of that, just commenting on the op runs and what they are showing not what they may or may not show in a few days time.
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42 minutes ago, DIS1970 said:
Nothing to get excited about as this goes pear shaped yet again i'm afraid.
Yes I think most people reading this thread know exactly what you mean. It is very frustrating looking at the abundance of deep cold across the pond while in our locale the models try to eek out some very diluted cold uppers from a shallow surface high to the north/north east. The only saving grace this morning is the ukmo and although its accuracy at the end of its range is suspect it leaves some hope of a east/ north easterly with a bit more bite to it.
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12 minutes ago, feb1991blizzard said:
I will have a number 8 please.
Ring any bells almost 30 years ago to the day????
Nothing like the depth of cold but a very tasty run. Probably 10% likely of verifying if that. Very nice to look at though.
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Only looked at the control run from the ens but it is a peach of a run for a short but potent cold snap with some snow to boot. still no reason to get overly optimistic. Could very well turn out to be a close but no cigar such as we have seen a few times in the last several years.
Scotland may well see a wintry weather from the shallow high that forms to the north/ northeast though.
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1 minute ago, feb1991blizzard said:
To be fair BA has not ever said a bitter Easterly is likely to develop if you read his posts, nor has he sad that the GEM 0z hours run is likely to verify.
To be equally fair I never said or intended to imply that he said anything about a bitter easterly maybe I should have worded it better. The fact that he said the Gem is also a high res model implied to me that he puts more faith in its output than myself that is all.
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16 minutes ago, bluearmy said:
In which case, why object to a high res decent model like GEM being highlighted?
Fwiw, the eps run at 14km out to T240. The gfs op is at 13km. The ec at 9km and the other ops between 15 and 18km
so if we are going on resolution alone, the 50 eps members are as useful as the gfs op??
The icelandic view eps clusters are available here : http://brunnur.vedur.is/kort/ec-ens/2017/12/30/00/
It was not an objection just a view point, posters can do as they please obviously. Eps runs together with ens etc are skewered from the start of the run so to speak, but hey I know how you love your stats so you stick with them. I am just following numerous past failings of ensemble runs even when things looked like a lock (not that they do this time ) and instead using experience and intuition which tell me no its not going to happen. You obviously have more faith in the Gem model and ensembles fair play another 36 to 48 hours will probably be enough to sort this puzzle out and I very much doubt the gem or 06z will prove correct. Again I really hope I am wrong and we get the snowy bitter easterly we grave.
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Fail to see why models like the gem are trawled out to muddy the waters of an already uncertain outlook. I know some look to find a model run that supports what they want to see perhaps, but so far it is only the gem and the 06z gfs op run that show anywhere near the amplification to support the slider south/ south east trajectory and leave us in a east/ north easterly airflow for more than a day or so (ECM op run). Quite frankly this does not fill me with any confidence in the pattern going forward. With the higher resolution op runs struggling I doubt whether the ens. eps etc will over much useful guidance either.
Fingers crossed I am wrong and the 06z is the new trend setter but I doubt that very much.
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Surprised the ecm 216 chart was as good as that ( which is not saying much). Quite underwhelmed this afternoon and evening by the model runs from a coldies point of view. Yes they are a lot better than last year but that does not make them great. Of course there will be changes to come that's for sure.
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32 minutes ago, TEITS said:
Nothing to do with one upmanship. I just disagree with how Teleconnections are used on here.
Personally I feel Teleconnections are useful for seasonal forecasting. They are useless when I see posts trying to predict an E,ly for the UK via a Scandi HP. You simply cannot put that amount of detail for such a tiny Island like the UK. The same rule applies if you're trying to predict a N,ly or SW,ly.
Let me put it another way. Why is it at +384 the GFS runs can vary so wildly? The simple answer is despite these supercomputers working out a massive amount of equations, the runs end up different due to slight changes much earlier which only increase as the run progresses. The chaos theory will always be troublesome for long range forecasting. So if a supercomputer struggles with these slight changes then how on earth can teleconnections compensate for the chaos theory. The simple answer it can't!
So sorry but I would rather use seaweed than rely on teleconnections for the next few weeks. if someone made a post in the Autumn about the possible trends for the winter then I would take more note. So nothing to do with one upmanship. I am more interested in accuracy than who can make the most technical post by using as many abbreviations as possible!
Finally didn't you say in a recent post that "winter might be over"?
Good post. A cold forecast was made only to be replaced by a much milder zonal pattern but just like the NWP models, forecasts are changing all the time. Trying to put to much detail into a long range forecast will probably lead to failure. Rather than trying to pin point where highs and low pressure areas for our little Island will be surely it would be better to give a broader brush idea of what to expect ie colder, milder, wetter, dryer, etc.
Their is amplification to be had in the northern hemisphere weather pattern over the next few weeks which may be conducive for us but as always the models are struggling with the amount and location of such.
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1 hour ago, TEITS said:
Classic example of what I mean.
Based on some of the comments over recent days with regards to the Strat the GFS should not be showing these charts!
Also look at the difference between the 06 & 0Z. If a supercomputer can churn out such a massive difference then what hope do us humans have in making an accurate LRF!
I wrote a post yesterday hoping to show that there is still residual downwelling from wave breaking, warming at the 10mb level around 9th of December. This can be traced using the ESRL mean and anomaly composite charts. I think some have perhaps forgotten that there is normally a lag time with these warmings as they propagate down through the layers.
I to very much doubt we will see a Scandi high at least not in the time frame that the 0z gfs was showing. In fact the 06z run proves how uncertain the models are with regard to modelling this downwelling with a completely different pattern to its previous run. There will I think be some amplification in the pattern ahead but how much and exactly where it will manifest itself is still very much up for grabs.
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Would not want to put any confidence into any forecast 3 weeks out whether it is showing deepfreeze or torch no matter where its source came from. The downwelling and warming I spoke of in a earlier post today is again probably the reason for seeing the synoptics that are showing in the 18z run but being the 18z run without good support from the ECM tomorrow and consistency from further gfs runs then will consign to the bin. We shall see.
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Just thinking aloud the warming that Catacol has shown to have taken place at 30mb and possible subsequent geo heights could very well still be showing its hand as it continues to downwell as we go into January. Normally there is a lag period and we have seen the affects this week of wave breaking and downwelling that occurred around the 9th of the month. The models are still toying with weaker heights to the north and north east which may be traced back to this downwelling . Again the ESRL mean and more especially the anomaly composite charts give perhaps a better idea of what I am referring to
The mean composite chart for the 25th at 70mb where you can see the weakness between the low heights
The anomaly chart for the same time shows the weakness better
The anomaly chart for 23rd Dec at 2OOmb
Now for the 25th of Dec and you can see there is an anomaly for stronger heights over the pole.
The anomaly map of GEO heights are not that strong as can been seen on the mean chart below but are the very reason the states are seeing the brutal cold wave that is engulfing them.
These slightly higher heights moving across the pole are what the models are trying to portray in the H500 charts over the coming 10 days or so. That is perhaps why we are not seeing the normal west to east zonal or very mild south westerlies that we would normally see under a very strong vortex.
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4 hours ago, Blessed Weather said:
No disagreement amongst the GEFS members in the overnight output (0z 28th Dec), with all 21 members now forecasting a stronger-than-average Vortex (10hPa 60N) by 12th Jan. The zonal mean zonal wind is currently 43.8 m/s and the forecast for 12th Jan is 59 m/s.
Today:
12th Jan:
Wave 2 activity forecast for around the 8th Jan, but on this occasion this doesn't seem enough to disturb the upper strat at 10hPa? (Any comments/views on this last point would be welcomed please).
Charts http://weatheriscool.com/
Perhaps the theory that a negative or easterly QBO = weaker vortex, needs to be re-examined along with the idea that a stronger vortex would lead to greater significance or impact when split etc. The trouble with this theory is that a much stronger vortex is of course that much harder to disturb.
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GFS strat forecasts lend some support to the synoptics seen on the H500 charts with warming and geopotential heights from pacific and European side stretching the vortex. Of course could be gone in a couple of runs time we will see. Certainly height rises our side of the pole could be very beneficial so long as they are strong enough otherwise a euro slug may be all that's on offer.
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1 hour ago, Tim Bland said:
Strange how weather.us and Windy etc seem to be showing the 00z ECM output?
Ps 8-10cm so far here in Hertfordshire @ 100m ASL so ECM was much closer to the mark than most others. Euro4 was way out
Looks closer to 5cm to me which is still probably double what we had roughly 11 miles south of you, although you do have that extra bit of elevation in Stevenage.
Back to the models and on the face of it they do look a lot, lot better this morning than they have done. Just a word of caution though the nw/se PM airflows quite often flatten out when enter the reliable timeframe. Not saying it will be the case this time but something to keep in mind. However a lot more to be optimistic about this morning that's for sure.
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17 minutes ago, northwestsnow said:
Looks bleak..icelandic low/ euro high.
All courtesy of strat forcing, AAM, GWO etc, etc following suite.
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1 hour ago, johnholmes said:
It's ironic really this constant search for cold and snow, almost always in the furthest reaches of synoptic models, even further a lot of the time.
I ;'real' time we have a probable snow set up and almost no one is talking about it. I wonder why?
Answers please folks, come on is it not interesting to you all?
Anyway a quick look shows it off SW Eire and predicted (By UK Fax charts) to track SW Wales across to just north of London. How far will the ppn belt extend north? will it be snow? How much might fall?
A nice weather set up to keep us all away from the left over turkey today, is it not?
A couple of reasons I would imagine...
Probably because its been talked to death already and lol by the same posters that say its not worth talking about as the track will change nearer the time etc, etc.
Once it gets to within 24 hours the conversation transfers into the regional threads.
and last but not least as Feb1991blizzard has said, most are looking for a deepfreeze with laying powder snow and severe frosts etc although personally seeing snow fall for several hours and the chance for children to get out during the Christmas holidays and if they are lucky build a snowman and have some fun is worth it for me.
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1 hour ago, Steve Murr said:
Morning All
The recent updates in the zonal wind plots @10MB continue to temper any proposed significant deceleration post peak on New Year’s Day-
The mean now peaks @ 52M/S which ironically is all but identical to last year-
Its worth watching over the next 5-7 days as the deceleration- originally progged to develop from 1st to about the 8th along a sharp gradient is now just forecast to dip to average to about the 10th-
This is obviously ensemble driven data & not entirely reliable at day 10-16 however the ‘trend’ isn’t going the right way-
For that reason the forecast would be
less than 5% chance of Greenland high developing before the 7th
less than 25% chance of a Scandi high developing before the 7th
* The 7th being that the chosen date because that’s the current projection to be around average in terms of the zonal wind.
The strat once coupled will nearly always trump the troposphere in terms of driving the blocking until there is a significant warming event to impact it-
No SSW forecast out to at least the 7th...
Generally the Nina base state with the -EPO ridge driving cold into the NE states looks to be the only MLB - with short interludes of cool/ chilly polar North westerlies being our only chances for snow.
The update may change however confidence is fairly high for the next 10-12 days..
S
Yep quite agree. Coupled strat/trop, strat dictates everything else falls in line.
Interesting the zonal wind plots identical to last year when of course the QBO was polar opposite to this year. Some people put way to much emphasis on the QBO state, although I must admit I would rather see a negative QBO than positive one.
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9 minutes ago, ukpaul said:
I can understand the hopecasting but it isn’t, it is pretty much the same, a little north to start, slightly south as it turns across the country. In any case, this time before the previous event the met office were onboard with forecasts and warnings, this time they are having none of it. Even looking at the Welsh mountains they are showing sleet.
The 28th/29th though may turn out to be more interesting, with lower temperatures, lower 850s.
No model will have the exact path laid down yet and won't do until maybe 12 hours before hand, therefore I would suggest everyone enjoy the rest of Christmas eve, have a lovely Christmas day tomorrow with family, friends and loved ones and then see where we are Boxing day.
Merry Christmas to all on Netweather.
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37 minutes ago, s4lancia said:Top post again Catacol. Many thanks for going to the time, as indeed did (still does I sincerely hope) Tamara and GP.
At least going to the effort to explain why that in all likelihood we are going into a less blocked phase. As opposed to just basing everything on a static seasonal LRF, which in all likelihood was only (or at least primarily) based on the ENSO state.
Now, that doesn't make that LRF ultimately any less accurate and, at the moment at least, it looks a pretty good call, as Nina seems to be returning to the forefront..
For me though, the real skill is in the ONGOING interpretation of the dynamics of the ever changing atmosphere and its drivers.
Phrases like Knife edge and tipping point certainly seem to reflect this winter and just because we end up going default doesn't mean (necessarily) that we didn't miss out going the other way by a whisker. It's a bit like a striker with an open goal in front of him and scoring off the underside of the crossbar. That is exactly the same result, a goal, as smacking it clean between the posts. But if the ball instead hit the crossbar half an inch higher, the end result would of course have been completely different, a miss. The goal being a standard mild winter. A miss being something of a colder nature. Not sure if what I am trying to get at makes sense, sort of does in my head anyway :-)
Keep up the good work. Maybe we will get lucky for once, against the odds!
Will it still be a top post if say in a couple of weeks it proves to be totally incorrect like the ones of GP and Tamara plus if things in the tropics can change as quick as that then they can do so again. Its as if these teleconnects and AAM budgets, GWO etc are the holy grail of weather forecasting lol. I am sure they play a part but I have yet to see any reliable long range forecasts on here or anywhere else. Sure on the face of it the outlook beyond some interest next week does not look great but that can soon change. Also there is never much mention of the strat forecasts in any these musings and yet when the strat and trop are coupled the strat plays a very important part on the tropospheric weather patterns regardless of the above teleconnets etc.
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47 minutes ago, January Snowstorm said:
Interesting that many of the experts are predicting a mild fest ahead whilst the models continue to upgrade the short term. Many parts could see at least falling snow over next 5 days yet I struggle to remember anyone predicting it.....
Obviously you have not been reading my posts over the last several days then, but as you say some interest over the coming Christmas holidays.
Model output discussion - into 2018
in Forecast Model Discussion
Posted · Edited by comet
That looks like a bit of an understatement to say the least. I wonder if the met office have started the new year celebrations early for there is nothing in the models so far this afternoon to suggest the outlook they have made for a weeks plus time.