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Model output discussion - into Christmas

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GEM and GFS remain bullish about the weekend being cold with a decent ridge , the UKMO doesn’t. The GEM and GFS also continue to show a breakdown of the HP mid next week of sorts!! Over to the ECM !!

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984BD10E-0C51-4676-86F9-DEF58DCE33E1.gif
 

ECM not budging, so who’s correct 

23B43657-07D7-4E76-9E6A-F96B0DD15EF4.png

Edited by Ali1977

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Actually, role on a day and the ECM has shifted slightly to the GFS 

F648EE92-387C-4006-B4A7-543935A558C4.png

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^^^ Tricky for the models to get the D5 mini-ridge correct as timing and phasing will make all the difference. It is a brief feature as the tPV chunk(s) circle to our north.

All agree on the subsequent flattening of the pattern. The GFS op has a N/S divide with the ridge favouring the south before deja vu, back to the relative NW to SE flow into a ScEuro trough:

anim_nej2.gif

We have seen that modelled and fail before so not hanging my hat on that verifying just yet! GEFS are a mixed bunch with no real underlying theme. Also the GFS op less keen on the Pacific Ridge this run so another scenario we cannot bank ATM (maybe seeing an omnipresent oscillating Pacific High instead, as per last winter?).

Up till D10 no real change, afterwards the GFS suite is struggling. Of course, it has done this in the past and it was a bit of a do about nothing, so not necessarily too hopeful of something more seasonal, but the chances are better than they were a few days ago which is a positive. Though still wary of that Russian high as to date it has been a spoiler rather than helpful.

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GEFS pretty confident of the cold weekend, I am going to stick my neck out and say this is an ECM fail!! A toppler, but it’s atleast a day that’ll feel like winter!! 
 

Ref next week , only 4/5 ens follow the Op with possible fronts from the W/NW

83B44688-4DF2-4547-885F-A33A5C1175D9.png

B75AE60A-3883-4B71-8EAF-A6B69BBDE489.png

Edited by Ali1977

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10 hours ago, northwestsnow said:

Yes that is very true ...

The 360 ext eps did not look appealing i must say...

Continuity even worse today, as early as the 8/12 day period which is even more unusual for the eps 

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5 minutes ago, bluearmy said:

Continuity even worse today, as early as the 8/12 day period which is even more unusual for the eps 

Can we take this as a positive?

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1 minute ago, shaky said:

Can we take this as a positive?

I suspect not, we are about as far away from a cold spell as possible.

 

 

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1 hour ago, Ali1977 said:

GEFS pretty confident of the cold weekend, I am going to stick my neck out and say this is an ECM fail!! A toppler, but it’s atleast a day that’ll feel like winter!! 
 

Ref next week , only 4/5 ens follow the Op with possible fronts from the W/NW

Interesting the divergence between models for the degree of amplification in the upper flow this weekend.

GFS and GEM ops going for a brief coldish N/NWly, EC and UKMO not amplifying the ridges and troughs so much so cold plunge not reaching the UK.

Yesterday morning's 00z output consensus of building a ridge over the UK in the medium range seems to have evaporated in the EPS means, with quite a flat, zonal / cyclonic picture now. GEFS seems to want more ridging though, but not far enough north to stem a mild maritime flow.

Models chopping and changing more than usual, but you kind of get that niggling feeling any hints of colder incursions, albeit brief, will be watered down or gone as we draw nearer when they are originally shown.

Edited by Nick F

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On 28/12/2019 at 17:12, carinthian said:

Following from the above observation , it would appear that the UKMO run in the short /medium term at 144t brings a much colder air mass into the British Isles with coldest uppers into NE Scotland as shown in the chart below. In all honesty the latest 500mb flow chart would indicate this cold to be only transient. However, the UKMO run continues to dig a sharper trough to the east that again differs from the very flat GFS runs at this time..  I think during the next few days we will soon develop curve ball lows which develop and move at a pace around the high pressure . Eventually, I think a flow from NW to SE could eventually predominate by day 10. Just my thoughts.

untitled.png

In relation to the above post sent last Saturday , I have tried to find a chart that resembles some sort of curved ball low around the high to try and break the strangle hold of the Euro/Azores high pressure belt. Below the latest GEM run at 240 t trys to retrogress the high as the curve ball low approaches the British Isles from a more attacking angle. Whether it breaks through and veers the flow to a longer colder regime has to be seen. Just looking for a ray of hope after what looks like a relentless run of doom and gloom charts . Nothing will change until we can get the Scandinavian trough to dig much further south and erode the high on its Eastern flank, unless the chart below starts to verify. Of course by then the Russian high may have other ideas, good or bad.Cold lover have to keep the faith.

C

GEMOPEU00_240_1.png

Edited by carinthian

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14 minutes ago, Nick F said:

Interesting the divergence between models for the degree of amplification in the upper flow this weekend.

GFS and GEM ops going for a brief coldish N/NWly, EC and UKMO not amplifying the ridges and troughs so much so cold plunge not reaching the UK.

Yesterday morning's 00z output consensus of building a ridge over the UK in the medium range seems to have evaporated in the EPS means, with quite a flat, zonal / cyclonic picture now. GEFS seems to want more ridging though, but not far enough north to stem a mild maritime flow.

Models chopping and changing more than usual, but you kind of get that niggling feeling any hints of colder incursions, albeit brief, will be watered down or gone as we draw nearer when they are originally shown.

Until that horrid PV relents we are knackered for cold chances.

I see zero appetite on the 00z suite for that happening anytime soon.

 

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New Year's Eve looks to be mostly benign but with a chance of fog...Or, in Daily Express parlance, a 'horror storm' is nigh!:oldgrin:

h500slp.png    h850t850eu.png

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Always problems getting the correct positioning of high pressure,850 hpa temperatures do not tell the 

true story of 2 meter temperatures.England mostly single figure while parts of Scotland barmy temps.

Frost and fog on the agenda for England,and hints of colder weather mid month

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46 minutes ago, shaky said:

Can we take this as a positive?

 

42 minutes ago, northwestsnow said:

I suspect not, we are about as far away from a cold spell as possible

well it means that a lot more options are on the table but very few look to be of the wintry variety most on here are seeking .....

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5 minutes ago, bluearmy said:

 

well it means that a lot more options are on the table but very few look to be of the wintry variety most on here are seeking .....

I would plum for increasingly unsettled as we move through Jan.

Clearly the 00z EC det from yesterday was pie in the sky.

For all the talk of AAM spikes, wave 2, descending QBO the uber PV just spins away to the NW eating away the clock.

 

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6 minutes ago, northwestsnow said:

I would plum for increasingly unsettled as we move through Jan.

Clearly the 00z EC det from yesterday was pie in the sky.

For all the talk of AAM spikes, wave 2, descending QBO the uber PV just spins away to the NW eating away the clock.

 

Was gona say the exact same thing!!we have had wave 2 and wave 1s forever now lol and nothing happening!!was gona say forget the 18z from last night cos you just knew come this morning it will flatten out!!at 168 hours and 192 hours on the 00z run it looks more like ecm now!!!my thinking is if we are gona get a cold spell its going to be one of those legendary out the blue moments or we can just forget bout it mate!!and also im just waiting for the moment someone posts that the gfs now looks flatter at 120 hours in regards that mini northerly lol!!not that ive seen the 06z but knowing our luck it will slowly flatten out!

Edited by shaky

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2 minutes ago, shaky said:

Was gona say the exact same thing!!we have had wave 2 and wave 1s forever now lol and nothing happening!!was gona say forget the 18z from last night cos you just knew come this morning it will flatten out!!at 168 hours and 192 hours on the 00z run it looks more like ecm now!!!my thinking is if we are gona get a cold spell its going to be one of those legendary out the blue moments or we can just forget bout it mate!!

Maybe it's time we all learned to put individual 'phenomena' into a new perspective? Are we 'not seeing the wood for the trees', so to speak?:shok:

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^^

Shaky you have been here as long as me and we both know GFS will, 80% of the time back down in a standoff situation.

As depressing as it sounds, first half of jan minimum is a write off.

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1 minute ago, northwestsnow said:

^^

Shaky you have been here as long as me and we both know GFS will, 80% of the time back down in a standoff situation.

As depressing as it sounds, first half of jan minimum is a write off.

Too damn right mate!!The only positive is the roads actually look dry around here after nearly 2 or 3 months lol!!!they have looked damp forever and looking at the ensembles there is no meaningful rainfall for another 10 days at least but its getting to that stage now where we really want to start seeing wintry charts otherwise we be in February and main part of winter would have past by!!

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53 minutes ago, northwestsnow said:

Until that horrid PV relents we are knackered for cold chances.

I see zero appetite on the 00z suite for that happening anytime soon.

 

Yes, no signs of the coupled strat-trop strong polar vortex weakening anytime soon, certainly not in the stratosphere anyway.

u_65N_10hpa.thumb.png.d4e7cb75d16d94f05cbc86c5cba8a488.pngu_65N_10hpa_gefs.thumb.png.a5e343dadd353eeec2afbdf257cd1241.png

Was reading on another forum that SSWs don't normally happen when the Indian Ocean Dipole (IOD) is positive so a SSW is probably unlikely over next month at least. With regards to the strong IOD recently, this has been hindering the MJO orbit and even when it starts to move it tends to go through the colder phases of the MJO quickly / low amplitude and spends longer in the warmer phases. eQBO descending may put stress on the sPV eventually, but it seems not anytime soon. It's going to be a struggle to shake off the influence of a raging PV over coming weeks, but too early in the winter to give up hope that it won't dominate all winter.

Edited by Nick F

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Yes, the 6z GFS has downgraded the amplification for the end of the week/weekend and by Sunday the southwesterly flow is back.

If we can't have a proper frosty high I'd rather we get a full blown stormy Atlantic weather, something to attract a bit of interest.

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The zonal winds plot posted Nick is utterly awful..

If anything it is showing the PV getting stronger as we move through Jan,

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11 minutes ago, karyo said:

Yes, the 6z GFS has downgraded the amplification for the end of the week/weekend and by Sunday the southwesterly flow is back.

If we can't have a proper frosty high I'd rather we get a full blown stormy Atlantic weather, something to attract a bit of interest.

With all the rain many parts of the uk have had since early autumn & with the ground absolutely saturated I doubt many want what you do, I certainly don't, this dry weather can keep on going, we seriously need to dry out! Not to mention I'm seriously sick & tired of constant rain lol. 

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1 minute ago, Smartie said:

With all the rain many parts of the uk have had since early autumn & with the ground absolutely saturated I doubt many want what you do, I certainly don't, this dry weather can keep on going, we seriously need to dry out! Not to mention I'm seriously sick & tired of constant rain lol. 

That's fine, different tastes. For me this weather is like moving from autumn to spring which is awful as it has been happening for several years now. Storms can bring excitement at least and when a deep low passes through you can get a brief cold spell too.

Anyway, back to the 6z and it wants to bring more active weather after the high sinks. 

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1 hour ago, Nick F said:

Interesting the divergence between models for the degree of amplification in the upper flow this weekend.

GFS and GEM ops going for a brief coldish N/NWly, EC and UKMO not amplifying the ridges and troughs so much so cold plunge not reaching the UK.

Yesterday morning's 00z output consensus of building a ridge over the UK in the medium range seems to have evaporated in the EPS means, with quite a flat, zonal / cyclonic picture now. GEFS seems to want more ridging though, but not far enough north to stem a mild maritime flow.

Models chopping and changing more than usual, but you kind of get that niggling feeling any hints of colder incursions, albeit brief, will be watered down or gone as we draw nearer when they are originally shown.

Ay Nick that might be true, but the NOAA Anomaly charts are consistent, and "iron out" those pesky inter run/ inter model variations to produce a much clearer picture albeit bereft of much detail. To my eyes the expected mean upper flow will be too strong to allow much of a northward ridging amplification for long, despite higher pressure to our near south.



 

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