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Model output discussion 13th Feb onwards


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GFS 6z smelling the change in trend, into FI the cold air is replaced with cooler incursions from the NW, with bog standard conditions - also looking fairly zonal into this time frame, which I wouldn't discount based on the cold air mass now showing on GFS for eastern Canada. Jet looks like being fired up yet again!

 

Comparing yesterdays 12z GFS with this mornings 6z at similar time intervals, we see the change *albeit into FI, but its the trend and signal fading for cold, which is all too apparent now* 

 

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12z @t204 6z @ 192

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Big shift in the output today with the pattern being shunted much further East which would essentially keep any Northerly plunges away to the East as well.

There would still be a notable cool down from where we are, more especially in the North, and more cloud around but hopefully little rain to contend with.

At the moment the SW looks best placed for any continuation of warmish settled weather.

I did expect some more lateral movement of the pattern but I am surprised it has been shifted quite so far overnight.

 

If that is maintained in this evenings output then the cold snap/spell looks to have melted away from the output once more which is no great loss for most I suspect.

 

Will the second half of March still be cooler than the first as I have insisted?

It looks much less certain than it did yesterday, more especially in the South but let's see what this evenings output brings.

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12z UKMO shows the high starting to move south by Monday

 

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GFS still drags some colder air down mid next week but it only lasts one day

 

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We then have a weak ridge of high pressure

 

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Before it turns unsettled again

 

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Pressure then rises again over Spain and western France which drifts over parts of the UK initially before slipping south again later

 

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So next weeks cold snap is still showing albeit more watered down this afternoon all over to GEM and ECM now

Edited by Summer Sun
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Not that I want to wee on any coldie's chips, as I'm a cold weather fan too, but, from the perspective of my part of the region I cannot see any snow producing conditions developing over probably the next 10 to 14 days. The threat remains for parts due North and East but even that is dependent of where the PV decides to set up shop. To be fair, the current UKMO thoughts suggest this as being a decent probability from six days on. Further South, the Azores High continues to be modelled nearby to our South and Southwest after it tends to lose its grip over the UK this coming weekend. With this in mind, the drier towards the South and wetter and windy, often cooler conditions for the North continues to be the overriding forecast, as has been the case for some time. Solely looking at today's GFS 12z, it tries as it might to bring a zonal flow but you can see where the effects of this won't be felt and that is places which are nearer the HP's influence. IMHO, when the GFS models some sort of HP influence lurking out into low-res output, we should at least take note, given its passion for default zonal conditions. As for Temps, it is unlikely to be a mild fest with frosts by night for some and some cool days when cloudy.

Edited by gottolovethisweather
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GFS 12z rainfall chart keeps most of England, Wales and southern Ireland rain free till at least the 18th again this afternoon where we do have rain in northern England its only a few mm so very little compared to previous weeks

 

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Temperatures remain above average for all of us till at least the 19th

 

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Edited by Summer Sun
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A blow to the hoped for cold blast from the 12z Op run at least

 

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A glancing blow if that with a posible bit of frost here and there but nowt else.

 

The ENS show a lot of scatter however so it could go either way

 

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Yesterdays GFS 18z ensembles were typical of what we had been seeing for a few days, a firming up of a cold snap. Today has been a massive swing away from that in under 24 hours.

 

Check today's 12z and compare it with yesterdays 18z, that is a huge change for a mean in under 24 hours given there was very good cross model support for a cold snap while today there is good cross model support for no such development.

 

 

Yesterday

 

http://www.meteociel.fr/cartes_obs/gens_display.php?x=288&y=125&run=18&runpara=0&type=0&ext=1

 

Today

 

http://www.meteociel.fr/cartes_obs/gens_display.php?ext=1&x=288&y=125

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Not that I want to wee on any coldie's chips, as I'm a cold weather fan too, but, from the perspective of my part of the region I cannot see any snow producing conditions developing over probably the next 10 to 14 days. The threat remains for parts due North and East but even that is dependent of where the PV decides to set up shop. To be fair, the current UKMO thoughts suggest this as being a decent probability from six days on. Further South, the Azores High continues to be modelled nearby to our South and Southwest after it tends to lose its grip over the UK this coming weekend. With this in mind, the drier towards the South and wetter and windy, often cooler conditions for the North continues to be the overriding forecast, as has been the case for some time. Solely looking at today's GFS 12z, it tries as it might to bring a zonal flow but you can see where the effects of this won't be felt and that is places which are nearer the HP's influence. IMHO, when the GFS models some sort of HP influence lurking out into low-res output, we should at least take note, given its passion for default zonal conditions. As for Temps, it is unlikely to be a mild fest with frosts by night for some and some cool days when cloudy.

 

As a matter of interest are you saying the PV is driving the troposphere circulation in the NH at the moment?

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Well after this week we see some changeable conditions from the weekend onwards at first with the southwest of the uk, seeing the best of the weather, then if we go to T+240 the theme is for colder and more unsettled weather to develop as we go through deep into March. Ok , T+240 is way out in the unreliable time frame , but if you look at the charts nothing in the output screams mild! To be honest ,I expect the second half of March to be much colder than the first half. A lot of twists and turns, but some of you snow starved folks may well see some snow ,before Winter does indeed give up the Ghost.Posted Image Posted Image Posted Image The charts below are from Ecm and Gfs. And the Scottish Ski Industry will also be delighted with these charts.....Posted Image

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Edited by ANYWEATHER
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Looking increasingly likely the further south you are the high the pressure will stay over the next few weeks with pressure on the London ensemble going no lower than 1012mb on the 22nd after which a steady rise starts

 

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Further north the Manchester ensemble shows pressure dropping to around 1010mb maybe a touch lower on the 22nd after which a steady rise starts

 

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On the Aberdeen ensemble pressure is lower peaking at a low of around 1003mb on the 22nd after which a steady rise starts

 

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As a matter of interest are you saying the PV is driving the troposphere circulation in the NH at the moment?

 

I'm not in a position to answer that as my handle on those aspects isn't as good as some others on this forum. However my understanding is with the PV on the move, it will certainly have ramifications as to what happens at the surface, perhaps over the UK but more likely over the nearby continent. More appropriately its association with the NH Jetstream and how that reacts to it will be key for future developments. I see it moving to Greenland at least initially and should it remain there, the effects over the UK will be consistent from that point forward I reckon. Here's where, purely my gut feeling takes over and my view is that we see the Azore High continuing to often ridge in over the UK, especially the South through a large part of Spring. 

 

What I'm hoping any newer members or those lurking will take from my rambling is that we need to look at Northern Hemisphere pattern and factor that in, before chasing any relevant details further down the line. Posted Image

 

From media forecasts I have seen, there is high confidence that this spell will continue right through to the end of this weekend at least.

Edited by gottolovethisweather
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http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=6

 

http://www.meteociel.fr/modeles/gfse_cartes.php?mode=2&ech=204

 

as  much as  some  people on here have  got blinkers  on thinking summer is here already  it  looks  like  the  break down  been put  back till at least the 19th  then after that its  looking a  bit  more unsettled  for  a while

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There IS going to be a breakdown.There WILL be some colder/cooler weather.It is NOT going to be dry and fine until October. Anyone who believes it will is delusional just as I would be if I believed there will be no warm sunny dry weather this summer.

Completely agree. That would be as unlikely as going through October until march without a single cold snap. Oh, wait a minute.....
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have a look at which model at the 10 day range, look at the 500mb pattern, seems most like the 3 anomaly charts I use. That will be the one most likely to verify as they have consistently gone for the change from upper ridge over uk area/mostly Europe with a flow at 500mb mainly s of west north of uk where main unsettled weather is. To the idea of a more trough type weather pattern with temporary ridges and brief Pm air into much of UK but chiefly NW with spells of rain again chiefly for NW but not exlusively for the 6-10 day period, say from about the weekend to see this change. No sign of any deep cold or any prolonged cold but less mild/warm than many southern areas are currently enjoying. Some rain but not to any great extent for the S/SW areas.

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Ext ecm brings unsettled and briefly cooler air into days 8-12, before high pressure is seen to return to the UK at the latter stages of its output tonight.

yes, this chart is for day 15, but ecm temp anomaly now has much of Europe going positive. Don't need to guess where the cold is...

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Yes John, the models show a good deal of dry weather over next week or so, hopefully we'll get a few weeks of this weather so the water table can drop a fair bit more now.

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Models continue to support a return to unsettled conditions from the NW as we move into next week as the current high retreats to the SW and we pull down a trough to our NE, so very slowly trending more unsettled and generally cooler for all especially the north.

 

Still a week of dry weather is nothing to be sniffed at and just the tonic given the horrendous wet period we have been locked in since early December, but it will take more than a week of dry weather to dry things out.. we need a good few months of such conditions..

 

The high has arrived just at the right time for decent temperatures given the strength of the sun, a similiarly positioned high even a month ago would no doubt be delivering temps struggling into the low single digit figures and one between late Nov and late Jan no doubt sub freezing conditions to many. What a difference the sun can make by March. Indeed if this was May then temps in mid 20's would easily be achieved in sheltered western parts, with western coasts bathed in the best conditions many can hope to see in such locations.

 

The current high is perfectly positioned for these parts - can't ask for a better placed high.. fingers crossed this isn't the only time we see such a high this side of September!

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I'm happy to see the Ecm 12z showing colder incursions on a nw / se aligned jet next week, there could be some wintry ppn and frosty nights. Hope this trend continues. :-)

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The picture doesn't seem to have changed a great deal. Slight discrepancy between GFS and ECMWf but looking like a brief sojourn into a stronger easterly flow beginning next week that the the GFS returns to by the weekend but ECMWF builds the Azores high more. Okay again in this part of the world.

 

Continued warm temp anomaly in the arctic and NH in general apart from eastern US. Surprise.

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Edited by knocker
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Can people not except others opinions.. It was 9c here yesterday which is mild for my location in March, but it felt very chilly in the N/E wind ! 

 

Another run from GFS still showing it's wild swings out 7 days in FI, hopefully over the next 2/3 days we will have a better picture on the upcoming cool and unsettled spell as it creeps into the reliable time-frame.

 

Yes Knock, a big drop in temps for the US next week again, a 30 degree difference in temps by Thursday !

Edited by Polar Maritime
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Ecm 00z op is almost a carbon copy of 12z yesterday with a nw / se jet profile for next week enabling brief cold incursions, especially further north and a generally more unsettled pattern compared to this week.

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