JamesL
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Posts posted by JamesL
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Cwmbach, Nr Aberdare this morning. Around 7" now and still snowing
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Aproaching 6" here in Cwmbach and snowing steadily. Very powdery and quite remarkable for mid/late March
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Jeeeeeez still goin on about Derek? Really?
What used to be a decent forum has become a total farce.
Get a grip people, you must all lead incredibly boring lives to still be talking about Derek after 2.5 weeks.
He would be flattered to know that you're still talking about him.
Im done here.
Over and out
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Quite fascinating. The Met Office's amber warning zone is the zone with no precip ???
I'm guessing there is more precip looking to move in later?
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All this talk of Derek is getting boring. I think everyone has made their point clear.
Be better concentrating on the weather conditions in Wales.
Currently dry here in Cwmbach after earlier snow
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Light snow now falling in Cwmbach north of Andy at the top of the Cynon Valley
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Wishing all the SE contingent all the very best of luck for a good fall of snow over the next 48 hours. Having lived in N. Kent for 23 years I always keep abreast of what is happening weatherwise especially when it snows. I remember 1987, 1991, 2005 to name just a few of the great falls we've had around Sittingbourne on the Downs.
Im now living in SE wales just below the Heads of the Valley and we've had a fantastic winter for snowfall. Now with another amber warning for Sunday here I await our 3rd foot of snow this winter.
Quite remarkabke!
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Indeed and it's almost a carbon copy of the area that the Red warning was issued for 2 weeks ago
potentually up to 25cms I would guess for Heads of the Valleys again!!!
We have had a great winter for snow
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1 minute ago, Mike Poole said:
And right on cue, one has just been issued exactly there, looks the Met Office going with the HIRLAM - almost to precision.
Haha notification just came through. Almost exactly the same warning area as the red one issued for us just over 2 weeks ago.
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18 minutes ago, Mike Poole said:
HIRLAM 12z out now, takes us to Sunday lunchtime, and showing the risk of snow for wider part of the south:
Just adding the 6z (to 6am Sunday) for comparison:
12z brings Wales and SW into the game later on Sunday.
I'm intrigued to see how this plays out across southern central and SW England as well as Wales and whether we may see further amber warning appear further west.
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2 minutes ago, Mike Poole said:
Hi JamesL, the first three are just from when the precipitation is just snow, the Finnish one is all precipitation from the start of the run (12pm today), doesn't differentiate snow.
Many thanks Mike ??looks like SE Wales could do pretty well again.
30cms in December 2017
40cms+ Feb/march 2018
?? March
not a bad winter here snow wise it must be said
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5 minutes ago, Mike Poole said:
After looking at the 12s, it seems clear that the major global models don't have much more to tell us about how this weekend will pan out. The spreads on the ensembles give a good indication of the uncertainty that remains, here the GEFS spread at just T66, it's all around the south of the UK and I guess it is all to do with the instability or otherwise, which of course will affect snowfall bigly:
Prior to the Beast #1 we've not seen convective snow for a long time, certainly the last time was before I starting model watching. So we have several new higher resolution, short timescale models available to view that we haven't had in previous events, so this a really good time to evaluate them. I think it's accepted that HIRLAM did well a couple of weeks ago, what do these models say now?
Here's some cumulative snow charts, recognising that this is total precipitation as snow based on an assumption of a 10:1 ratio of snow to water, not snow depth. ARPEGE first, out to Monday 6am:
HIRLAM next, out to Saturday lunchtime:
ICON-EU (not to be confused with the ICON global model) to Monday 6am:
Finally the Finnish HIRLAM, this is just pure precipitation in mm, but given the T850s we can assume it's mostly snow at a 10:1 ratio, here up until 6pm Saturday:
Pick the bones out of that lot!
Lot's of uncertainty, everyone in with a chance.
Hi,
When do these charts start from? Would they include any precip prior to the snow? Or is it purely snowfall?
To be clearer, they start from when all the parameters for snow are met?
Thank you
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9 minutes ago, SizzlingHeat said:
I was only posting what the ECM is showing for Sunday. -4 or -5 in the last third or march isn't exceptional and therefore its unlikely to be snow for all under those uppers. Irrespective of whether the -10 air crosses the country, the ECM progs it to flash through pretty quickly. Not long enough in my opinion for the cold to be entrenched at ground level unlike the last cold spell a few weeks ago. Therefore, during Sunday, if the ecm was correct (*if*) as it doesnt have much support at the moment then I would imagine temps in the south would be more likely between 3-6 degrees and dew points between 0-2 degrees which would be pretty marginal for low level snow and/if there were any snow it would unlikely settle particularly well.
However, thankfully for most, this isnt likely to happen based on the blend of 12zs this evening. Likely to be all snow if the low crosses east to west in a favourable manner.
However, I wouldn't discount the ecm at 72 hours showing the increase in marginality if the thrust of cold air is too far north. The latest BBC forecast at 6.28 showed temps indeed of 4c for London and Birmingham and 6 degrees in Plymouth whereas before they were only showing 2-3 c nationwide. Also the metoffice video published online does show rain mixed with snow with a 30% chance of this happening. The other 70% was for the Easterly to maintain snow showers across the east in particular.
I'm not trolling. I would like more snow like the rest of us but only posting to discuss the charts as they emerge.
I am chuckling at this. "You would imagine...." you're probably better off not imagining and going on what the models are showing. 3-6 degrees is not being shown neither are 0-2 degree DP (normal exceptions of course) so going by the models (which is what the thread is about) 99% will see snow. If your boat is moored in Cornwall you may not see settling snow on the deck ?
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Trust me there will be no marginality on Sunday wrt snow. Check out the DP's before making any conclusions. With a continental feed, 850's below 0 and DP's below 0 it will be snow
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So it seems now there has been a shift north of the upper cold pool and subsequent instability. I did say it would need to move around 100 miles north to bring more of us into the game here in Wales.
That now seems to be the case with some people experiencing snow depths of over 20cms in the SE of England in particular.
Where does this leave us?
Well my feelings are now that anywhere south of mid wales could well have falling snow that could accumulate. The further south and east the better the opportunity. I see that even Cardiff is again covered by the warning zone.
So in the past 24 hours things have certainly got more interesting with a fragmenting cold front coming westwards on sat that could produce a little snow particularly with elevation, then over night and into Sunday the latest fax chart show a Channel low with associated trough across SE Wales which could produce more extensive and disruptive snow.
So those areas that were hit two weeks ago look likely to get more of the white stuff over the weekend, albeit not with the intensity or severity that we had then.
However it's a fluid situation and I expect there to be a few surprises (and disappointments) for us in Wales and I expect a few amber warnings issued especially in the east and south east of England for sat night into Sunday.
Lets see how it plays out but there are very interesting times ahead
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27 minutes ago, Steve Murr said:
Nice post & just to add to this - Ive often thought of how to forecast snow without the aid of models due to there inability to quantify PPN totals from Streamers -
you can do the same for anywhere but The following parameters are important:
This is a very crude way -
A) Timeline of optimal instability - 24 hours
B)Max PPN rates from showers - ~2cm per hour
C)% of time You can optimise from the optimal instability time - max 75% (0.75) because the streamer locale usually changes.
This means the equation to the 'top out' values at sea level is A X B X C
so my forecast sweet spot at sea level would be 36cms within the window available.
In terms of elevation ( again crude ) based on reports I have seen from scotland then corresponding reports from Glencoe - that when sea level got a fall of 15cm, the Glencoe car park would be 2X (600M) ~ 30cm
So I would go with a 0.33 increase in depth per 100M
Tops of the downs are @ 200M Mostly - So 'top out' for the downs would be 59CM.
This is on a par with 2009 where low ground of NW kent got to 30-35cm in a 30 hour window & the high downs were in the 50's.
Taking the beast from the last week the GFS ppn rates/ snow depths look to be about 5-8X to low under convection where as the high res models like Hirlam / Aperge feel about 1.5X to short
Best
S
Remember that top out forecast. 36cm which is in the streamer sweet spot location TBC?
Thanks Steve and thanks for explaining your reasoning.
I find this absolutely fascinating and while I read your post in my home here in SE Wales (where we had 40cms plus 2 weeks ago) I have my parents (who still live in our family home in Kent) sitting here next to me panicking.
Esp as my father is travelling from Newnham over the Downs to Lenham and along to Gatwick very early Sunday morning to go......yep you've guessed it....skiing lol ?
Could be Slightly ironic haha
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I'm thinking along the same lines as Steve M.
Having lived in Kent for over 23 years (on the N Downs) I have seen some tremendous LOCALISED totals where shower trains just dump snow for hours on end.
The last Beast my parents had 8.5" of level snow between Faversham and Sittingbourne on the N Downs, whilst people down the road barely got a covering.
You hit the jackpot here you could be looking at 25cms easily, even with precipitation limited to around 48 hours (maybe a little longer in Kent)
Don't be surprised to see MO warnings turn orange in localised areas. The winds this time seem a little more NE so expect mid Kent to get hit hard rather than west Kent IMO
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12 minutes ago, bluearmy said:
The envelope remains extraordinarily wide on the 00z suites thanks to gfs whose model suite (op and ens mean) takes the cold pool through e France, close to strasbourg! Meanwhile, ec and icon flying the flag with the former the furthest north across s England. Gem, ukmo in the middle ground over the Low Countries. With ec and gfs at both ends of that envelope, experience tells us that ukmo looks a good call. (And that would be a pretty good showing from the model (if I verifies like that)
eps shouldn’t vary too much from the mean at day 4 but they showed a considerable spread on the last run (six clusters) so still to be pinned down I expect from the model. it’s only Wednesday - expecting to know what Saturday will bring apart from cold remains elusive.
I must admit that the UKMO has been pretty much rock solid sending the upper cold pool just south of the UK. Will be fascinating where it ends up.
My thoughts are still unchanged this morning. Parts of the SE (Kent in particular) could have 10-15cms and other parts from the Humber south a covering. The Channel Islands could also do well this time as they were a little too far south with the last beast.
Time will tell but considering the Scandi high hasn't even formed yet I think we will have to wait intil the 12z tomorrow to firm up
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So to the weekend and it looks unseasonably bitter this weekend BUT here in Wales I can't see a whole lot of snow ❄️ especially on the 0z charts this morning as the main upper trough flirts with the SE and S Coast, Normandy and the Channel Islands.
IMO if you're going to have -12 to -14 upper air in MARCH!! (Which is almost unprecedented) you have at least got to make it interesting with some snow.
Our only saving grace would be if the upper trough is going to move north by 100 miles (which is possible as the Scandi high hasn't even formed yet), OR we get some decent solar heating and create our own inland showers (again which is very possible given the strength of the March sun)
So although quite incredible depth of cold is shown for at least 2 days, the synopsis is fairly underwhelming if like me you want some snow.
I do hope I'm proved wrong. I think by the 12z tomorrow we will have firmed up on the details of the upper cold pool and where it will and will not hit.
Right now it looks like Kent could get hit with 10-15cms of snow overnight sat into Sunday and maybe some other southern most counties could scrape a covering.
For Wales I just see a lot of blue skies and sunshine which out of the wind, should feel pleasant on your face despite the temps being only a degree or so above freezing.
Id like to know others thoughts too.
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28 minutes ago, andymusic said:
now you are talking silly - the papers talk up the blizzards when there are absolutely no chance of it happening just to sell papers and get people to click on their pages on the net to earn ad revenue - but Derek WAS NOT COMMITED TO THE COLD AND SNOW THE FRIDAY BEFORE THE LAST EVENT - HE DID NOT WARN UNTIL THE ACTUAL WEEK OF THE EVENT (so only a few days notice - not enough for the elderly/infirm to prepare for something like that) - BUT THEY KNEW BEFORE THAT, THAT SIBERIA WAS COMING AND HOW COLD AND NASTY THIS COULD/WOULD BE - AND FROM THE LOOKS OF THE GFS AGAIN IT'S GONNA DO IT AGAIN A WEEK TOMORROW! - I wonder if Derek will wake up this time for this one - I think he might because I have my inclings and I haven't been on his twitter acc, that he was abused by some people in Wales and his boss give him a dressing down - because he seems to be different somehow on his forecasts the last few days, in fact he and the meto went overboard with the snow the other night, like a spring back reaction - making sure as many as possible knew - but in fact this time I only had rain - and again I knew that was gonna happen to cause it just didn't feel cold enough - HE's maybe a little more concerned he does his job better now - it could be on the line if he just can't keep up - after all he only does one job - I work in music do numerous jobs within music - and still am able to forecast ahead of him and warn when we are gonna get bad weather - and my serious warning that went out was shared on facebbook I think about 400 times - amazing - that was the one I wanted all of you to copy and paste into your own facebooks - at least it might help one or two from seriously hurting themselves! - and i'll do it again if it means saving someone's life
We will agree to disagree andy. ?? And the Express comment was very tongue in cheek.
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8 hours ago, andymusic said:
I'm not on about any red warning - I'm on about a general warning one to one and a half weeks in advance - a proper heads up that things could very well take a turn for the worst and the very very cold air is gonna be crippling for the elderly/homeless and vulnerable - and life will become a lot harder with the frozen pipes potential power cuts - and snow disruption - by giving out a general warning way in advance people start to prepare and get ready - yes red warnings asap on the day or the night before is right thing to do - but at least give the general public a chance to get supplies in and work out all their back up plans to stay safe then! surely that's a good idea not a bad one - and refer to my post above if the weather veers off in another direction - get the beeb or met office to explain properly to try and make people understand why it didn't quite materialise the way it should have - BUT IT WAS ABSOLUTELY OBVIOUS THAT THIS TIME WAS GONNA BE BAD AT LEAST 2 weeks OUT
I think hindsight is a great thing. We can all look back at the models and see what they were showing BUT how often have they come to fruition? The Met were talking about a cold spell in the monthly outlook a couple of weeks prior but until they are fairly sure what the broad Synoptics are they can't just panic people Andy and go mainstream. That's just how it is.
In an a ideal world we would all know (with certainty) when a high impact event will hit but in the chaotic world of weather it's just not possible.
We will agree to disagree. Imo people were given a heads up a week or more before the events last week through forecasts and the media.
Sometimes the responsibility has to lie with the public. There will always be those idiots that go out no matter what. That's life. 99% of people took the warnings seriously.
And I will say again. The Met, BBC and other media outlets did a great job throughout. Hey even the Express got it right lol!
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3 hours ago, Peter A said:
I think Wales was adequately warned about this event, it was flagged up very early in the week by Derek, all the talk was of 'the beast from the east' etc, possible snow depths were widely publicised in advance, so job well done. The fact that that practically all the schools were closed in advance, places of work shut early , and hundreds of motorists weren't trapped overnight in their cars suggests the message did in fact get out.
Totally agree ?? You only had to have seen the live updates from the A470 at 6pm Thursday night before the real heavy stuff started. One car every 30 seconds. Normally it would be a traffic jam. I think the message was taken on board.
Remember that a red warning CANNOT be issued 12-24 or more hours before a severe event is "highly likely"
To issue one would again be foolhardy and panic people unnecessarily. The Met and BBC IMHO did a very good professional job regarding the severe weather.
Infact handled better than any other event in the last 10 years where there has been plenty of egg on faces
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11 minutes ago, Bafan said:
Snowing here at the moment. Massive flakes, not like the powdery stuff from a few days ago.
We have sleet here down in the valley in Aberdare. My guess is Tredegar across to Brynmawr will have another couple of inches of wet snow later on tonight/early tomorrow morning
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1 hour ago, Seasonal weather required said:
I think what Andy is saying though, is that Derek is only concerned by his own appearance in front of the nation as opposed to the information he is to deliver.
Will be interesting to watch Derek from now on as the pressure is most certainly on .
Knowing that he is being heavily scrutinised akin to a premier league football manager could make or break him .
He is already nervously flapping a bit so we shall see .
Im not happy with the way he laughed about Hendy having no snow .
Thats a crime against us weather enthusiasts and one for which is a sacking offence on its own .
Then to call / mock Swansea for being tropical at 5 degrees - well , not only is that factually incorrect it’s also a sacking offence - in my opinion of course - which could be right or it could be ridiculous wrong of course .
I've got to admit I've always liked Derek and his enthusiasm for cold snowy weather. I'm normally so engrossed in the charts that I don't really look at the presenter, although BBC Wales does have some pretty awful ones. Always thought Derek was decent.
Model output discussion - after the beast, what next?
in Forecast Model Discussion
Posted
Quite remarkable Synoptics showing up this March. Especially given the fact that many have decent cold to tap into.
How often in the past have we seen great charts but lacking in cold to tap into. It seems the cold over the pole keeps draining south and west.
Is this still all to do with the second wave of SSW?