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Model Output Discussion - 23rd Jan - 12z onwards


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Short answer   The short answer to your question is yes, the presence of low pressure (at higher altitudes, being coincident with very cold upper air), makes the air more unstable, as the gradient i

Welcome to "Celebrity Model Discussion". Let's go out to our reporter, who has managed to corner the miracle man himself, Jesus Christ, for his thoughts: Reporter : Thanks for joining us Jesus, first

If people will insist on analysing the 850mb temperatures every single run here's something to bear in mind when viewing the output for the upcoming period - -6c is a baseline figure to put snow/rain

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The trend of the last 36 hours seems to be a gradual toning down of the low heights to our NW. Okay, the opp don't show screaming sub zero easterly winds, but we are now in the game. The GFS opp was one of the worst options at 192. Most GEFS had an easterly drag across the South. Gem ens also show this.

I'll take this mornings 00hrs suite over yesterday's.

The cold is probably a given for 8 days, it's now whether we can get a decent snow event. That one will be a harder question to answer.

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This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

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Met office hinting at breakdown next weekend.

http://images.meteociel.fr/im/7859/ECH1-240_bki1.GIF

Output suggesting this possibility, yet when someone suggests it they often get shouted down...

If this were the other way round, not many would have a problem with people hunting for cold....

A little respect to others opinions and each other would be a good discussion I feel.

 

That's a 10 day ECM chart, not the MetO. If it comes to pass that way then you are right. However GFS for the same slot has a much more marked low pressure signal to the south

gfsnh-0-240.png?0

So all in all I'd say outlook uncertain. Hints of a breakdown are neither consistent nor clear.The only thing that IS clear is that energy is riding over the top of the atlantic and that makes this "longest lived toppler ever" [Chio] scenario a fascinating one. I dont recall ever seeing a situation quite like this - and with other signals (MJO and strat) suggesting that the medium may favour more blocking then I'm genuinely clueless as to what the patterns will look like by Feb 9.

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At the moment I would say we do have good consensus from the models and that being.

1. Colder conditions will persist for another 7 days, give or take

2. The high will topple and end up over or just to our west

3. getting  blocking in the right place for the type of easterly we want to see seems highly unlikely no matter how often the ensembles might point that way, This is not to say that during the week ahead there will not be an easterly component to our weather but nothing that involves HLB where we want it

However we should also keep it in mind that a week is an awful long time in synoptic evolution and things can swing very rapidly.

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This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

Well that sounds grim to be honest . Mid February and the jet running North of uk with high pressure to South , that's put an end to my fanthom easterly then . If that's really the case and winter whistles away again then considering all the potential since autumn this will be another rubbish winter with no high lat blocking for a second year on the trot
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This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

Well not what many people would want to hear I'm afraid but sadly for many a very plausible outlook. Seeing that it is coming from a senior professional then i place a lot of credence in it!! 

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Well that sounds grim to be honest . Mid February and the jet running North of uk with high pressure to South , that's put an end to my fanthom easterly then . If that's really the case and winter whistles away again then considering all the potential since autumn this will be another rubbish winter with no high lat blocking for a second year on the trot

 

Im shocked too at that signal. we dont know how strong it is though, as 'signs' doesnt sound very convincing. Hope it fades.

 

When we have fantastic posts on here from Tamara for example, giving a very convincing argument for a 'good' February through providing a very detailed report on background signals then this signal seems to go against everything. It sounded like everything was in our favour reading her brilliant posts.

 

Cold looks locked in until Friday anyway, plenty of -8 850s around from Sunday onwards and models do show features and kinks in the isobars so is not all doom and gloom :)

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easterly? what easterly?... placing too much hope on one unsupported run is a mugs game imho... :nonono:
so yes, its cold, yes theres some snow around, but its going to be far from a decent dumping or big freeze for most of us. and after tuesday whilst it remains cold with hard overnight frosts (and fog i suspect where the breeze dies down) its a pretty normal cold spell.

for those of us (me! lol) who dont like february cold, the outlook this morning is good with strengthening agreement that the cold will fizzle out slowly over days 7 - 10 .

post-2797-0-62687700-1422611291_thumb.gi post-2797-0-51165000-1422611303_thumb.gi :clap:

 

post-2797-0-25835300-1422611369_thumb.gi

yep its currently fi.... and could of course change though i suspect its the timing thatll change more then the outcome. no easterly here. 8)
 

Edited by Paul
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This is from ian f in the south west regional thread

Yes. However, despite currently strong EC and MOGREPS signals for cold to relent by end of next week, this still has to be accepted with due caution, with further trough disruption(s) to E still possible to complicate matters and prolong cold weather. That said, it must be noted that - above caveat aside - 00z EC plumes do point with greater consensus towards a clear departure from cold conditions past Friday. Rising GPH remains strongly indicated as high pressure moves in from W; but prior to that, a messy and probably snowy transition (for some). Cold nights still very likely once ridge established, despite moderation in daytime chill.

Signs thereafter, including in UKMO long range model output, broadly suggest that into mid-Feb we will see a phase when a stronger jet will become displaced to a more northerly position, with stronger zonality (and lower GPH) to N of UK and better chance of stronger ridging and thus more benign weather to the south.

Underpinning it all through medium range remains weak teleconnective drivers: MJO not expected to be influential; no signs of any SSW in near future; weak or very indecisive El Nino.

Playing devils advocate, you could also go the way of my highlighted text.

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This would be really warm and springlike weather, am I right? compared to this coming week.....I am joking really, but am not sure if this is what is meant by the breakdown, surely it is just another version of cold and wintery? and is this too far in the future for it to be likely?

post-22381-0-69043500-1422611685_thumb.p

Edited by Woollymummy
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Hang on a minute !! Wasn't GS5 and Mogreps showing a strong signal for a blocked pattern 10 days ago ? Very strong signal I seem to remember for mid feb. Goes to show that it's not always right.

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A breakdown in 7/8 days time is a bit of brave man FI scenario to call isn`t it?

 

Looking at the mean 0z ECM 850`s for Norwich they actually want to trend even lower until the 6th. That will do as a benchmark for now. 

 

03492_3000.gif

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easterly? what easterly?... placing too much hope on one unsupported run is a mugs game imho... :nonono:

so yes, its cold, yes theres some snow around, but its going to be far from a decent dumping or big freeze for most of us. and after tuesday whilst it remains cold with hard overnight frosts (and fog i suspect where the breeze dies down) its a pretty normal cold spell.

for those of us (me! lol) who dont like february cold, the outlook this morning is good with strengthening agreement that the cold will fizzle out slowly over days 7 - 10 .

attachicon.gifRtavn2402.gif attachicon.gifRecm2402.gif :clap:

 

attachicon.gif814day.03.gif

yep its currently fi.... and could of course change though i suspect its the timing thatll change more then the outcome. no easterly here. 8)

 

Have to agree I see no Easterly, I see maybe more Disruption to the Atlantic for a short while longer but I think the writting is on the walls that in 7-10 days time the Atlantic will roll in with High Pressure to the south as per the charts you have posted..... not the end of winter by any means but it will give those who want a bit of warmth something to cheer.

As for who called this spell correct..... Firstly lets wait until after its over Its easy to claim someone is right before the event, especially when the same cliam is made every day...... Like Shooting Fish in a barrel unfortunately no one has made a hit yet.

Edited by Paul
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A breakdown in 7/8 days time is a bit of brave man FI scenario to call isn`t it?

 

Looking at the mean 0z ECM 850`s for Norwich they actually want to trend even lower until the 6th. That will do as a benchmark for now. 

 

03492_3000.gif

Indeed, still time for things to change in the week 2 range.

Speaking of complications from the east. The 06z GFS does offer a relatively brief east to north easterly during the later half of next week

gfs-0-144.png?6

The -8C isotherm gets across the whole of England and Wales with snow showers for eastern coasts. Even if the Azores high simply rebuilds into the UK after this, there is potential to eek something decent from this. It wouldn't take much to get some very cold air over the UK from the East and with low pressure over Europe, there is always the chance of something moving up from the continent.

So in all turning a little less cold and more westerly from next weekend looks most likely at the moment, but I still feel that even by Friday some places may still see some of the white stuff falling from the sky.

Edited by Captain shortwave
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Hang on a minute !! Wasn't GS5 and Mogreps showing a strong signal for a blocked pattern 10 days ago ? Very strong signal I seem to remember for mid feb. Goes to show that it's not always right.

Yes but the blocking position was not mentioned, because it was unknown. 

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Could be a bit of a repeat pattern being attempted here i think http://www.wetterzentrale.de/pics/Rtavn1681.gif!!! It wont make it though as heights too low to our north!!

 

At 192 there is nowhere for the high to go im afraid it certainly cant go north http://www.wetterzentrale.de/pics/Rtavn1921.gif

 

We just cannot get rid of the limpet polar vortex to our north!! Despite all the good background signals it has been stuck there all season 

Edited by Continental Climate
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Yes but the blocking position was not mentioned, because it was unknown.

Yes but I wouldn't call the Azures high ridging in a blocked pattern. Ian also mentioned strong zonality.

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Indeed, still time for things to change in the week 2 range.

Speaking of complications from the east. The 06z GFS does offer a relatively brief east to north easterly during the later half of next week

gfs-0-144.png?6

The -8C isotherm gets across the whole of England and Wales with snow showers for eastern coasts. Even if the Azores high simply rebuilds into the UK after this, there is potential to eek something decent from this. It wouldn't take much to get some very cold air over the UK from the East and with low pressure over Europe, there is always the chance of something moving up from the continent.

So in all turning a little less cold and more westerly from next weekend looks most likely at the moment, but I still feel that even by Friday some places may still see some of the white stuff falling from the sky.

On that chart it seems that the whole Atlantic is high pressure with 2 big cells.

Also you could say the Azores high is replaced with a low pressure of 1010.

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There seems to be a pattern here. The 0z runs seem to try to flatten, whereas all other runs for the day seem to re-amplify the pattern.

I agree.. Why is this.. But even so if we compare today's 00z with yesterday's for the end of the week the cold spell has been extended.

Edited by TSNWK
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