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Model Output Discussion 29th December - Into mid-Winter.


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Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire

Only a few days ago models were predicting the atlantics return with SW wind and rain for my location (W Wales) by next Tuesday 24th - this has now been delayed until at least next Friday 27th and even then it is a slow and painful process - look at atlantic Jet almost vertical north to south !! 

Edited by Jonathan Evans
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Posted
  • Location: East Ham, London
  • Location: East Ham, London

Morning all :)

Well, I got a bit of stick yesterday morning for apparently saying we were in for 14 days of zonal conditions from the middle of next week.

I never actually used the word "zonal" but Atlantic-dominated but there you go.

The 00Z GFS Ensembles are solid at T+162 for a SW'ly or S'ly flow. P18 is the best option for those hoping for what Steve Murr calls "the continental solution" and I happily concede it may take until Thursday next week for the milder air to reach the SE but I don't see much hope of undercuts and the like at the moment.

As others have said, GEFS in FI is starting to sniff around some alternative solutions but even at T+336, at this time, I would argue the majority show the Atlantic in charge in one form or another - the minority blocking solutions are varied but are a minority at this time.

UKMO is interesting at T+144 and it's a model on recent performance you have to take seriously - the orientation of the HP is more akin to where we are now than the triangular orientation on ECM which collapses ESE more quickly.

I still think we're looking at 7-10 days minimum of milder Atlantic-based conditions from the middle of next week and perhaps up to 14 days.

 

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL
Just now, Jonathan Evans said:

Only a few days ago models were predicting the atlantics return with SW wind and rain for my location (W Wales) by next Tuesday 24th - this has now been delayed until at least next Friday 27th and even then the atlantic it is a slow and painful process - look at atlantic Jet almost vertical north to south !! 

As Teits mentioned, it's not helping us get anything more wintery and the days are ticking on, maybe it'll hold on long enough for some SSW assistance early Feb which may help it into a more benificial location for some proper cold

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Posted
  • Location: Bournemouth
  • Weather Preferences: Dry mild or snow winter. Hot and humid summer.
  • Location: Bournemouth

Is this the first sign of the Pv coming under pressure?

IMG_8269.PNG

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Posted
  • Location: bingley,west yorks. 100 asl
  • Location: bingley,west yorks. 100 asl
1 minute ago, That ECM said:

Is this the first sign of the Pv coming under pressure?

IMG_8269.PNG

Although not the best orientation for us in think we are going to see some cracking eye candy popping up in 3-5 days imo.

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Posted
  • Location: East Ham, London
  • Location: East Ham, London
3 minutes ago, That ECM said:

Is this the first sign of the Pv coming under pressure?

IMG_8269.PNG

There were some hints of cross polar ridging and a split vortex yesterday and it's something to keep a close eye on.

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Posted
  • Location: Drayton, Portsmouth
  • Location: Drayton, Portsmouth
28 minutes ago, That ECM said:

Is this the first sign of the Pv coming under pressure?

IMG_8269.PNG

Judging by previous SSWs, I'd have thought at least a week from this date before anything too dramatic, maybe more? (bit of a novice in this area)

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Posted
  • Location: North East Cotswolds, 232m, 761feet ASL
  • Location: North East Cotswolds, 232m, 761feet ASL

I like P11!! Defo PV destruction in the ENS in FI

IMG_4038.PNG

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Posted
  • Location: Bude
  • Weather Preferences: Extreme weather...heavy snow and heat waves
  • Location: Bude
1 hour ago, stodge said:

Morning all :)

Well, I got a bit of stick yesterday morning for apparently saying we were in for 14 days of zonal conditions from the middle of next week.

I never actually used the word "zonal" but Atlantic-dominated but there you go.

The 00Z GFS Ensembles are solid at T+162 for a SW'ly or S'ly flow. P18 is the best option for those hoping for what Steve Murr calls "the continental solution" and I happily concede it may take until Thursday next week for the milder air to reach the SE but I don't see much hope of undercuts and the like at the moment.

As others have said, GEFS in FI is starting to sniff around some alternative solutions but even at T+336, at this time, I would argue the majority show the Atlantic in charge in one form or another - the minority blocking solutions are varied but are a minority at this time.

UKMO is interesting at T+144 and it's a model on recent performance you have to take seriously - the orientation of the HP is more akin to where we are now than the triangular orientation on ECM which collapses ESE more quickly.

I still think we're looking at 7-10 days minimum of milder Atlantic-based conditions from the middle of next week and perhaps up to 14 days.

 

Yes,I like what you've done there,Reverse psychology...

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Posted
  • Location: East Ham, London
  • Location: East Ham, London
1 hour ago, Seasonality said:

Again. Brave call considering the models don't go out that far. Even at 192h on the 06z it isn't Atlantic dominated. But I guess if you keep pitching an Atlantic fortnight you'll eventually be right. 

It's not a question of "bravery" - it's a question of you and I having a different sense of what "Atlantic dominated" means. Here at T+150 would you call this an Atlantic dominated chart ?

gfs-0-150.png?6

I think I would - our air is sourced from the Atlantic not the Continent. It's hardly zonal - battleground at a stretch.

At T+192, I agree the continental solution is making inroads especially in the south east corner:

gfs-0-192.png?6

On to T+240:

gfs-0-240.png?6

I'd call that Atlantic dominated wouldn't you ?

What 06Z OP offers is an initial inroad of Atlantic air, a brief fight back by the block and then the Atlantic crashing through.

In the light of that (IF it verifies), it would be churlish of me not to concede a brief potential interruption in the Atlantic flow but from then on it's Atlantic all the way - NOT zonal. 

Glancing at the 06Z OP Ensembles at T+240, the main area of dispute seems to be between those favouring a strong northern arm to the NE and those seeing blocking. Either way, the British Isles ends up in S or SW'ly winds so nothing desperately cold.

 

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Posted
  • Location: New Forest (Western)
  • Weather Preferences: Fascinated by extreme weather. Despise drizzle.
  • Location: New Forest (Western)

gfs-8-150.png?6

Technically that Thursday chart has Atlantic sourced air for all but the SE but granted, it's close to Atlantic dominated in that sense.

Unlike ECM, GFS doesn't quite achieve enough of a slide SE of the disrupted trough to pull the genuine continental air back in; Fri-Sat sees us under gradually mixing out TM Atlantic air while a wedge of PM approaches from the west.

gfs-8-204.png?6

The massive surge across the mid-Atlantic from the west with a very strong section of jet stream remains at a week's range so I hesitate to expect it to power through just yet. Let's see if any complications arise in the flow first :)

Edited by Singularity
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Posted
  • Location: st albans
  • Location: st albans

What seemed significant to me on the eps this morning was the mean jet in the extended period continuing to drift ever south so that little of it is left across the south of the uk. we could be drifting towards a mean undercut or a very unsettled and potentially windy spell. 

the key will be how much of a jet streak we get in the 8/12 day period - any relaxation on the prediction.and the block should be able to force it to undercut convincingly

 

 

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Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire

Listen folks - the models were suggesting a return to atlantic w/sw weather early next week - with some runs having deep lows centred over the UK - it ain't gonna happen  - what the chance that they haven't got a firm handle on later next week - must be a fair probability. The downside is we are eating up precious wintertime with benign weather - although on the positive side at least it's dry !

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Posted
  • Location: Scouthead Oldham 295mASL
  • Location: Scouthead Oldham 295mASL
26 minutes ago, bluearmy said:

What seemed significant to me on the eps this morning was the mean jet in the extended period continuing to drift ever south so that little of it is left across the south of the uk. we could be drifting towards a mean undercut or a very unsettled and potentially windy spell. 

the key will be how much of a jet streak we get in the 8/12 day period - any relaxation on the prediction.and the block should be able to force it to undercut convincingly

 

 

Well the clock is ticking now blue, i was hoping to see some ambiguity in the meto update today but there seems to be little doubt in Exeters mind that a period of Atlantic weather is forthcoming.

All my eggs in the strat warming and a fairly quick trop response.

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Posted
  • Location: Pembrokeshire
  • Weather Preferences: Snow
  • Location: Pembrokeshire
1 hour ago, seaside 60 said:

Yes and the UKMO and Exeter were forecasting drizzle cloudy and warmer for down here on mon and tues, for thursday and friday, so why hold out on their forecast.

Spot on pal - the met do give the caveat of low probability cold and snow in their extended so as always there is a 'get out clause'

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Posted
  • Location: Wythall, Worcestershire, 150m asl
  • Weather Preferences: Continental climate, snow winter, sunny summers
  • Location: Wythall, Worcestershire, 150m asl

GFS very progressive on the 12z run, south westerlies across whole country by t96! UKMO disagrees and keeps the euro block closer.

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Posted
  • Location: Leeds
  • Weather Preferences: snow, heat, thunderstorms
  • Location: Leeds
5 hours ago, Seasonality said:

Again. Brave call considering the models don't go out that far. Even at 192h on the 06z it isn't Atlantic dominated. But I guess if you keep pitching an Atlantic fortnight you'll eventually be right. 

It's reminiscent of certain people who thought zonality in December would last until February - only for it to be cut short after 2 or 3 days. 

But as you say, bang on about it enough and eventually it will happen.

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Posted
  • Location: Norwich
  • Weather Preferences: Cold winters, hot summers, misty autumns
  • Location: Norwich

12z GFS is what you call 'battleground'! Block refusing to give way, but we aRe fractionally in a SWerly feed by next weekend, ridiculous inaction!

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Posted
  • Location: Penwortham nr Preston, Lancashire
  • Weather Preferences: Severe frosts, warm sunny summers,
  • Location: Penwortham nr Preston, Lancashire
3 hours ago, bluearmy said:

What seemed significant to me on the eps this morning was the mean jet in the extended period continuing to drift ever south so that little of it is left across the south of the uk. we could be drifting towards a mean undercut or a very unsettled and potentially windy spell. 

the key will be how much of a jet streak we get in the 8/12 day period - any relaxation on the prediction.and the block should be able to force it to undercut convincingly

 

 

Yeah, picked that up yesterday too on a chart that someone put up, if we can keep the block in situ and get a few small lows heading into the Biscay area we could be game on. One of many outcomes of course, typical UK north west southeast split is one too... One which i dread the thought of! 

It's all a bit of a stand off at the moment with neither side really wanting to take the initiative

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Posted
  • Location: G.Manchester
  • Location: G.Manchester
29 minutes ago, cheese said:

It's reminiscent of certain people who thought zonality in December would last until February - only for it to be cut short after 2 or 3 days. 

But as you say, bang on about it enough and eventually it will happen.

A bit unfair comment when you consider the majority of the UK has been very mild so far this winter with winds from the south or west. Here in the south east we've had a more continental influence with hard frosts thus temperatures for Dec/Jan were much less mild, almost near normal. Complete reverse to last winter of course where northern areas were colder.

The likeliest outcome is for atlantic winds to win out later this month but perhaps continental air to return later on in February possibly giving southern areas their first below average winter season since 2012/2013. Especially by night.

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Posted
  • Location: Reigate Hill
  • Weather Preferences: Anything
  • Location: Reigate Hill

The suggestion that we can get some retrogression from the stubborn euro high despite none of the GEFS indicating that, has always been the call. Of course we have the situation where the high has held on giving the SE some lovely sunny days but cold mornings and we are now looking into the second week of Feb for any chance of a better cold/snowy pattern developing. By D8 the GFS and GEM have similar flat Atlantic sectors:

gfs-0-192 (7).pnggem-0-192 (1).png

Just the usual challenges of PV -v- Azores high, so differences as to where the jet pushes through the UK? From there the MO has been for the PV to shift slowly from the Siberian to Canadian area so not a lot of opportunity for anything interesting for FI for our region re amplitude, though EPO going negative as per previous runs (around D9):

D9gfsnh-0-234 (2).png  D14 gfsnh-0-336 (1).png

Which is one factor in the PV moving to its way to Canada/Greenland. So a pretty awful delayed wet period upcoming once the non-easterly high drifts east. I don't expect the wet weather to last long based on the winter pattern, though with that delayed euro high any sympathetic ridge from the Pacific ridge is likely to come from our east. That is not good for the UK IMO. So likely a very poor setup for cold in early Feb. Of course the high could keep delaying it and we waste more time waiting for a non-easterly but we really need to get the trop profile changed as time is running down.

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