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Model Output Discussion - The Run In To Christmas


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Unfortunately, there needs to be a recognition that if we share at *this tentative juncture* the exact nature of what we have as Ops Centre guidance, certain individuals will inevitably extrapolate/wa

If the UK can't get cold from an upstream pattern with a negatively tilted troughing setting up over the ne USA , indeed the best set up since two winters ago then I will seriously consider throwing m

The good news just keeps on coming!   Upstream pattern is falling into place to deliver what many people in this thread want to see, NCEP give us the best update since winter 2012/2013,  indeed I'm

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Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Third set and if anything, the spread is increasing in area, especially approaching to our west

    Most recent first

    attachicon.gifimage.jpg

    attachicon.gifimage.jpg

    attachicon.gifimage.jpg

    That's unbelievable given we're only talking of T144hrs. That also ties in with NCEP thoughts:

     

    A GREAT DEAL OF HIGH-LATITUDE NORTH AMERICA 'RESHUFFLING' TAKES

    PLACE THIS MEDIUM RANGE PERIOD---WITH THE DEEP CYCLONE IN ONTARIO

    WRAPPING AND FILLING THROUGH TIME. ENSEMBLE SPREAD BEGINS TO

    INCREASE DRAMATICALLY---AT THE SURFACE AND ALOFT--- OVER

    LABRADOR/THE DAVIS STRAIT AND IN THE NORTHERN ROCKIES...IN

    RESPONSE TO THE DEGREE OF AMPLIFICATION AND TRAJECTORY OF THE

    DAY3-4 CYCLONE MIGRATING INTO NORTHEAST CANADA. IN THE WAKE OF THE

    DEPARTING SYSTEM...THE FLOW ACROSS THE LOWER 48 AND SPREADS OVER

    THE ROCKIES PERTAINS TO THE MID-LEVEL TROUGH AND HEIGHT FALLS

    DIGGING AND MIGRATING THROUGH THE GREAT BASIN

    Edited by nick sussex
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    Posted
  • Location: sheffield
  • Weather Preferences: cold ,snow
  • Location: sheffield

    That's unbelievable given we're only talking of T144hrs. That also ties in with NCEP thoughts:

    A GREAT DEAL OF HIGH-LATITUDE NORTH AMERICA 'RESHUFFLING' TAKES

    PLACE THIS MEDIUM RANGE PERIOD---WITH THE DEEP CYCLONE IN ONTARIO

    WRAPPING AND FILLING THROUGH TIME. ENSEMBLE SPREAD BEGINS TO

    INCREASE DRAMATICALLY---AT THE SURFACE AND ALOFT--- OVER

    LABRADOR/THE DAVIS STRAIT AND IN THE NORTHERN ROCKIES...IN

    RESPONSE TO THE DEGREE OF AMPLIFICATION AND TRAJECTORY OF THE

    DAY3-4 CYCLONE MIGRATING INTO NORTHEAST CANADA. IN THE WAKE OF THE

    DEPARTING SYSTEM...THE FLOW ACROSS THE LOWER 48 AND SPREADS OVER

    THE ROCKIES PERTAINS TO THE MID-LEVEL TROUGH AND HEIGHT FALLS

    DIGGING AND MIGRATING THROUGH THE GREAT BASIN

    where or what effect does this have on the mo nick??
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    Posted
  • Location: Remote North Yorkshire 474ft ASL
  • Weather Preferences: All seasons veteran of the 1981 winter
  • Location: Remote North Yorkshire 474ft ASL

    I noted we were going quite negative AO and slight NAO negative post Xmas into the New year before turning neutral positive so am surprised we are not seeing charts with more northern blocking than the flatter patterns shown....maybe still a twist yet or can few seasoned posters can shed light on this?......

    I like your username Greenland 1080mb I wish there was one within T+144 hrs. It's to early to show a northern block just yet I would say there's a lot of low pressure activity north/ East and west of Greenland for this to happen just yet . fellow members maybe able to help you further as I have limited availability on my smartphone to copy and paste what I want to explain and show you . regards Steve. I'm new on here just hope I'm been useful to members and not been to self opinionated I'd hate to think that. Weather is just my passion .and model discussion.
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    Posted
  • Location: Essex Riviera aka Burnham
  • Weather Preferences: 30 Degrees of pure British Celsius
  • Location: Essex Riviera aka Burnham

    204z to 216z on the GFS op looks all over the place, HP developing over Greenland at around 1028mb then completely collapses after looking promising in just 12 hours! and you can see what the model wants to do after that.

     

    As said should be interesting watching what happens in the medium term.

    Edited by Froze were the Days
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    Posted
  • Location: st albans
  • Location: st albans

    Amongst all your weather charts I see you have your football team there BA...priorities footy and weather!

    Woh! That could have been embarrassing! Only just closed the sylvanian families page !!!!

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    Posted
  • Location: Morecambe
  • Location: Morecambe

    Dunno, beats me too John. Just the latest fad if you ask me.

     

    Strange thing this. I come home, look at the models and am gobsmacked at the cold setups and great festive fun we're about to have.

     

    Then I read half the posts on here and it's like you are living in a parallel universe. I think a lot of it is reverse psychology: NW model addicts love cold weather and tell everyone else, and try and convince even themselves, that everything is just so awful it's hardly worth breathing before January. Then everything that actually occurs is a pleasant surprise.

     

    Meanwhile in the real world: great cold setups ahead. It's going to be a lot of fun.

     

    For a cold perspective, I'm not sure UKMO is much to shout about, when I first saw this run, I was quite deflated to be honest, it looks like it will follow what other GFS runs have been showing and that is returning back to Atlantic based weather before you know it. 

     

    The GFS is not an awful lot better either, it just looks like we may head into what we had for most of December and that is a cool PM shot but just not cold enough to deliver much in the way of lower level snowfall... All half hearted really. 

     

    The deep low does need to be watched though, could potentially be quite a deep one. 

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    Posted
  • Location: Batley, West Yorkshire
  • Weather Preferences: Heat and Snow
  • Location: Batley, West Yorkshire

    Dunno, beats me too John. Just the latest fad if you ask me.

     

    Strange thing this. I come home, look at the models and am gobsmacked at the cold setups and great festive fun we're about to have.

     

    I can't see these 'cold setups' anywhere, what 'festive fun' are we about to have? One day on the GFS looks interesting as we get cold uppers moving in, but they don't exactly last long. And anything interesting is 8+ days away...

     

    If you live in the south, any chance of low level snow is very unlikely!

    Edited by Barry95
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    Posted
  • Location: Manchester
  • Location: Manchester

    All eyes than remain on the strat for a colder spell after mid January.

    Sadly the 12z gfs has dowwngraded the warming in FI considerably and does not offer a vortex split. Let's hope the split returns in future runs.

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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    where or what effect does this have on the mo nick??

    As you can see from BA's post the largest spread of solutions is over the east/ne USA and ne Canada and that's very important because that reflects the uncertainty which will effect the block and any cold into the UK. It's quite unusual to see such a large spread at T144hrs.

     

    I know people want to see a resolution to this but we're going to have to wait till the major models agree on the pattern upto T144hrs.

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    Posted
  • Location: just south of Doncaster, Sth Yorks
  • Location: just south of Doncaster, Sth Yorks

    It's the shortwave which runs east across the USA between T96hrs and T120hrs, it then phases with the deep low over ne Canada which holds this back from pushing east so quickly.

     

    You'll see by comparing the UKMO and GFS's the different handling of events upstream which has a big impact on the pattern downstream.

     

    thanks Nick

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    Posted
  • Location: London Waterloo 0m/ Leeds Bradford Airport 200m
  • Location: London Waterloo 0m/ Leeds Bradford Airport 200m

    Christmas eve looking increasingly interesting for the northern half of the UK with a deepening LP diving across Northern Scotland with some pretty cold air wrapped up with it,and quite a change on the latest fax chart when compared to the one issued this morning.

     

    latest..attachicon.gifPPVK89.gif  earlier..attachicon.gifPPVL89.gif

     

     

    Might give some folk a "default" white Christmas.

    Interesting, I would imagine a fair few streamers would set up from that scenario.

    Might be a white Christmas for parts of Northern England if this comes of.

    A slack flow with -5

    post-8968-0-58254800-1419184847_thumb.pn

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    Posted
  • Location: st albans
  • Location: st albans

    As you can see from BA's post the largest spread of solutions is over the east/ne USA and ne Canada and that's very important because that reflects the uncertainty which will effect the block and any cold into the UK. It's quite unusual to see such a large spread at T144hrs.

     

    I know people want to see a resolution to this but we're going to have to wait till the major models agree on the pattern upto T144hrs.

    Actually, it was 144 hours this morning nick - the top chart is 132 hours now!

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    Posted
  • Location: South Essex
  • Location: South Essex

    GEFS are largely zonal again. A few half hearted attempts to build heights to our NE. Some ptrbs have ramped the PV up so much that Greenland has vanished under a giant black hole!

    Whilst there are some large differences to iron out in the short term as alluded to by Nick, I am starting to think that in the medium to long term it won't matter that much as its one of those situations where a long period of zonality is almost inevitable whatever changes occur in the short term.

    It seems there are some uncertainties to iron out up until new year and then we are probably looking at a minimum of 10 days of zonality. There still seems to be some optimism in the strat thread so maybe the models are wrong. It wouldn't be the first time.

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    Posted
  • Location: Sowerby Bridge, West Yorkshire
  • Weather Preferences: Click on my name - sorry, it was too long to fit here......
  • Location: Sowerby Bridge, West Yorkshire

    I was hoping to work out from the GEFS ensembles the changes needed for those that show Greenland height rises after day 8 but, and I find this unfathomable, there are none, nada, zilch, right the way out to 384h. A couple which cling on by the fingertips to day 10 but for the next week none at all.

     

    Now this isn't usually the case, you will get some variation and it's been showing as such for weeks then suddenly it's as though a switch has been turned off. Maybe Nick Sussex has some clue from the NOAA, any clues as to what just happened?

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    Posted
  • Location: NR LOURDES SW FRANCE
  • Location: NR LOURDES SW FRANCE

    Actually, it was 144 hours this morning nick - the top chart is 132 hours now!

    Lol! that's even worse then! I do hope the ECM says a big No to the UKMO output. Later on I'll see what the NCEP State forecasts have to say, the New York one is normally in a lot of detail and gets updated around 9pm UK time.

     

    What a relief the ECM doesn't back the UKMO at T96hrs.

    Edited by nick sussex
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    Posted
  • Location: South Essex
  • Location: South Essex

    I was hoping to work out from the GEFS ensembles the changes needed for those that show Greenland height rises after day 8 but, and I find this unfathomable, there are none, nada, zilch, right the way out to 384h. A couple which cling on by the fingertips to day 10 but for the next week none at all.

     

    Now this isn't usually the case, you will get some variation and it's been showing as such for weeks then suddenly it's as though a switch has been turned off. Maybe Nick Sussex has some clue from the NOAA, any clues as to what just happened?

    In truth, there has never really been any great blocking shown even in recent days. Usually just transient height rises caused by the Azores high ridging. I think Greenland heights are firmly off the table now and if any HLB does appear it will likely be to our NE. With persistent heights to our South, the northern arm of the jet will make it difficult to get a proper easterly (not impossible, but difficult).

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    Posted
  • Location: Buxton, Peak District
  • Weather Preferences: Snow
  • Location: Buxton, Peak District

    GEFS are zonal again this evening. I am now expecting a typical stormy start to January with no signs of any lowland snow for southern England.

     

    The stormy weather will keep us interest though. Just a shame that we have missed out on a potential cold spell over the Christmas period.

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    Posted
  • Location: Banbury
  • Location: Banbury

    I think half of the angst on this forum is caused by quite a number of people defining a cold spell as being something of 1963 proportions!

     

    To be honest, fleeting snowfalls that melt within a day or two are very common memories for me growing up, and it is really quite exceptional for large parts of the UK to get anything else.

     

    So for me the models still hold some hope of something of interest, but my expectations are not of such a level that I am expecting to be skating to work for the next two months :)

     

    I am also a firm believer of the chaotic nature of weather so I won't be writing off large periods of time as being destined to be set to one weather pattern (although I must add that I respect LRFs and model output/analysis despite my reservations).

     

    The GFS tonight would certainly keep the interest levels up!

    I don't , people on here are quite sensible , not sure I see the snow locations that some do but certainly haven't seen what you are suggesting

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