Model Output Discussions 18z 31/01/2016

[phil nw.]

A new thread ready for the new month then.

It looks like the first week of February continues as January is finishing with an active Atlantic jet heading across the UK with more wind and rain at times.

The 36hrs fax and GFS windflow/speed charts shows the next low named Henry heading this way tomorrow and bringing some more stormy conditions into Tuesday.

and after a somewhat quieter spell mid-week another active low is modeled to approach the UK late on Thursday

 so we carry on with this changeable setup with temperatures varying day on day as the warm and cold sectors pass through.

Ok then usual rules- please post on topic and in a friendly manner.

 

 

[Mucka]

Okay new thread, new attitude from me.

It has been a long disappointing Winter and coldies are feeling pretty jaded, myself included, and we are faced with more wet and windy weather rather than blocked and cold but there are some pluses on the horizon if we can summon up the positivity to explore them.

There will be some cold PM air over us from time to time over the coming week or two and looking at the ensembles and reading between the lines the signal for the zonal onslaught begins to fall away from around Feb 10 to 12. That indicates a slowing of systems crossing the country which itself indicates increased blocking.

There isn't a strong signal for HLB and a prolonged cold spell but there is a growing signal for MLB (likely Atlantic based) and increased chances of a cold snap and if we can get blocking in place then there is always the chance of prolonging any cold.

Thus far it is just outside the range of ECM and GFS Op output has been disappointingly stubborn in wanting to maintain the storm fest right out to mid month and beyond but the ensembles are sniffing that a potential pattern change exists in the run up to mid month. As stated previously any pattern change will likely be triggered by low pressure running SE into Europe so this is what we want to look for first and foremost from around Feb 9/10 (give or take) as this will enhance any upstream amplification and give us a greater chance of staying on the cold side of the trough.

So putting my optimist hat back on (actually it is a replacement for the last one I burned during the last failed cold spell) I will be hoping to see GFS Op output come up with much better charts in future runs and the ensembles to firm up on the derailing of the zonal train (at least temporarily and long enough for some cold)

Perhaps in a couple of days we will have model support on some form of cold snap forming in the run up to mid month?

 

 

[Frosty.]

As day 10 Ecm 12z ensemble mean charts go, I have seen a lot worse this winter...so no, I won't throw the damn towel!

[Rocheydub]

11 minutes ago, Frosty. said:

As day 10 Ecm 12z ensemble mean charts go, I have seen a lot worse this winter...so no, I won't throw the damn towel!

Indeed Frosty, the 12z GFS op hinted at heights rising around that timeframe in that area too. Certainly worth watching at least.

[Allseasons-si]

Nice post Mucka

looking at the latest ensembles,the 12z is curtainly colder than the 00z

00z12z

looking at the 500hpa height anomoly's @240hrs

ECM,GEM and GFS

ECM and GEM quiet similar there with a ridge,trough,ridge from eastern seaboard to the west of the BI where as the GFS doesn't have that ridge west of the BI so doesn't allow a northerly of some sorts and a sort of west baised there,so i hope that ECM and GEM are something on those lines come t0

oh!,by the way,these are my white towels and untouched

 

 

 

 

[Lewisian Lass]

I learnt a long time ago not to write off winter for any snow until end of April. I am thinking back to March 2006, when we had the most snow I have seen for many years.

A change is afoot. In the meantime, Storm Henry will feel more like a hurricane over the western Isles tomorrow, high tides and strong winds will make some treacherous conditions. I think all models have underplayed this one. It has a nasty sting in its tail.

 

[Blizzardof82]

Looking very stormy next weekend on 18z GFS, the UK is there somewhere.

[Allseasons-si]

That's a little zipper at 174 hrs,so maybe the south could be in the firing line

Looking @ 192 hrs,the low off the eastern seaboard is a lot shallower compared to the 12z and has a neg tilt to it,this should be a better run further down the line

12z18z

[SMU]

Evening-

I think I mentioned yesterday - the extremes of weather are getting more distinct & the US certainly looks like being on the recieving end of a mega -EPO ridge & huge negative departures away from the norm - circa 10-15c

This chart with snow all the way down to texas is a rare beast indeed -

a pretty good day 10 ECM means as well as 18z out to 240....

 

S

[Timmytour]

30 minutes ago, Lewisian Lass said:

A change is afoot.

Have seen this so many times this winter.....and we are like the disappointed women who find out, despite the promises, it turned out not to be a foot but a couple of inches at best!

Nonetheless my hope shall not diminish....I don't think the 18z really offers any change except I shall grab on the the "tentative signs" shown in All Seasons post above....

[Allseasons-si]

This is much better from the 18z gfs

pv pulled more west than the 12z

12z @ 25218z @ 240

and the 18z gfs 500hpa height anomaly's @ 240 hrs,a clean ridge in the atlantic with now lp there,baby steps

 

 

[Timmytour]

3 minutes ago, Steve Murr said:

Evening-

I think I mentioned yesterday - the extremes of weather are getting more distinct & the US certainly looks like being on the recieving end of a mega -EPO ridge & huge negative departures away from the norm - circa 10-15c

This chart with snow all the way down to texas is a rare beast indeed -

a pretty good day 10 ECM means as well as 18z out to 240....

 

S

My daughter is off to New York in a couple of weeks time with her school...i have been warning her all weekend to make sure she takes some thermals with her!!!

[Mucka]

2 minutes ago, Timmytour said:

My daughter is off to New York in a couple of weeks time with her school...i have been warning her all weekend to make sure she takes some thermals with her!!!

If GFS is to be believed she may as well be going to the North pole.

[Ali1977]

5 minutes ago, Allseasons-si said:

This is much better from the 18z gfs

pv pulled more west than the 12z

12z @ 25218z @ 240

and the 18z gfs 500hpa height anomaly's @ 240 hrs,a clean ridge in the atlantic with now lp there,baby steps

 

 

Good at day 11 then bowled over a few days later, can't seem to get the Synoptics right for any decent sustained cold spell - just transient ones...If a transient one could produce the goods for the south I'd be happy though!! Hopefully next year the beast can show up.

[nick sussex]

Looks like there might be an opportunity around day ten to develop a bit more interest as that ridge builds in to Alaska and that chunk of the PV heads over to Hudson Bay.

This would normally correlate with a mid Atlantic ridge ahead of that deep USA troughing and troughing to the east of the UK.

A northerly flow possible but I suppose the issue is whether that chunk of the PV can hang around over Hudson Bay or whether this pushes east flattening any ridge quickly.

 

[Frosty.]

These are the type of charts I hope to see verify from the Gfs 18z but to also to build on this with a more sustained cold blast...let's hope that better times are to come for all the coldies on here! 

[TomDav]

12 minutes ago, Allseasons-si said:

This is much better from the 18z gfs

pv pulled more west than the 12z

12z @ 25218z @ 240

and the 18z gfs 500hpa height anomaly's @ 240 hrs,a clean ridge in the atlantic with now lp there,baby steps

 

 

I find standard deviation more representative

[Singularity]

Well the pub run makes it all seem so simple doesn't it? A stronger ridge through Canada by +168 which pulls the cold further south and so encourages the main lowering of heights to develop further that way too as there isn't the seepage of cold air into the Atlantic that fueled the deep LP development SW of Greenland on the ECM and GFS 12z runs.

ECM took until day 10 to get that ridge in order while GFS never did.

For that reason, ECM looked more promising going forward (trough in mid-Atlantic liable to sink with ridge over the top) but now GFS has taken that title as it offers a quicker route to something appreciably cold and snowy. It's the first run in an absolute age to show more than a few flakes of snow in my neck of the woods.

Hopefully, as the MJO is resolved and the consequential additional kick to the 'mega -EPO ridge', this trend from GFS can continue tomorrow. Though even if it does we'll probably have to deal with some bumps along the way!

[Iceni]

39 minutes ago, Timmytour said:

My daughter is off to New York in a couple of weeks time with her school...i have been warning her all weekend to make sure she takes some thermals with her!!!

Better to give her some extra $$$ and buy them there. They know all about cold weather clothes in NYC.

[Daniel*]

I sense today provides a reason to be more upbeat.

Approaching mid month a cold snap/spell of arctic origin holds some weight - with it being cyclonic I'm sure there would be scope for widespread snow events, as illustrated by charts below:

[Pembroke Dangler]

It's like the u.s is draining all the cold out the arctic down into the mid west and as far south as northern Florida. But the problem is if we get cold Synoptics they won't be that cold because the states has drained the core of the cold and leaves us with a few dregs. It's so frustrating but hey we are a little island in the north east Atlantic about 1500 miles from the arctic circle. Go figure lol

[Mucka]

29 minutes ago, Iceni said:

Better to give her some extra $$$ and buy them there. They know all about cold weather clothes in NYC.

And they don't rip their citizens off with every tax under the sun.

Slowly but surely more cold runs appearing among the ensemble suites and the mean creeping down.

[wishingforsnow]

There is definitely a lot of model confusion right now. Uncertainty still as to the  mid February outcome: we could see anything from a prolonged cold spell possibly helped by a SSW to a mere short toppler sandwiched between southwesterlies, zonality and the raging Atlantic. Hopefully the positive trend towards colder conditions building continues and the solution to this currently murky picture is a blocked sustained cold pattern to end a mostly terrible Winter. 

[Timmytour]

3 minutes ago, Mucka said:

And they don't rip their citizens off with every tax under the sun.

Slowly but surely more cold runs appearing among the ensemble suites and the mean creeping down.

Haha....but it might be worth talking the posts from the previous thread into a shop over her to persuade them that winter's over now and they might as well flog off the thermals they've got left in stock off cheap before it's spring already!!

 

[Chris1986]

8 hours ago, Mucka said:

 As stated previously any pattern change will likely be triggered by low pressure running SE into Europe so this is what we want to look for first and foremost from around Feb 9/10 (give or take) as this will enhance any upstream amplification and give us a greater chance of staying on the cold side of the trough.

So putting my optimist hat back on (actually it is a replacement for the last one I burned during the last failed cold spell) I will be hoping to see GFS Op output come up with much better charts in future runs and the ensembles to firm up on the derailing of the zonal train (at least temporarily and long enough for some cold)

Mucka,

The 00z seems to had heard you as a nice low fired into Europe drags a good dose of cold air across the UK not quite as south East as we would want but there is always room for improvement