Model output discussion - proper cold spell inbound?

[East_England_Stormchaser91]

17 minutes ago, daz_4 said:

I find this upcoming cold spell quite underwhelming. The cold pool over Europe will not be as strong as previously advertised by models and the slack flow won't really do much - grey, dull weather. Hopefully few days without above freezing temps are on the cards but snow will be scarce (I guess you guys in UK will see much more of it). Still a nice change since February was mostly a spring month these past few years.

As Ive said earlier. Watch how that Ukrainian low develops, as the models have had that all over the place. They currently have that low removing the cold away from Poland and Baltic states. It hasn't even formed yet. So we could see that cold pool remain in place depending on where that low ends up. 

[Frosty.]

Just been looking for signs of the talked about very cold second half of Feb on the GEFS 6z and I found some!!..fingers crossed we get the easterly or north easterly blast that most of us are dreaming of to deliver a great big sting in the tail to winter 2017 / 18!!

[Singularity]

1 hour ago, Catacol said:

Off to watch rugby - but a sneaky copy of a Ventrice tweet to sooth the pains of those worrying about the situation next weekend before I go:

GLAAM set to rise to +2SD by mid month. Layer this on top of strat impacts (Tony - what % chance do you give a reversal on top of the split?) and the long term picture is good. For those suggesting this in "normal" February I suggest your definition of normal is not the same as mine. This is not a 1 in 100 year setup - agreed... but it has a feel of 1 year in 10.

Thanks for your highly informative round-ups over the past few days in particular. If only the models would be so giving!

Adding to the pot, here's the freshly updated ECMF for the MJO, which now has many more members keeping it amplified into P8, with the mean notably higher. As much as the propagation rate is a bit sluggish, the sustained amplitude in P7 is in itself a great eventuality, as you have put across via those JMA-sourced composites recently .

[shaky]

Any updates on the icon!!any positive changes?

[Singularity]

13 minutes ago, shaky said:

Any updates on the icon!!any positive changes?

 

As it happens, yes might well be; for Tue afternoon LP to the S is a little deeper and a fair bit closer to our shores.

This may help the cold air to 'pool' more ahead of the next Atlantic attempt Thu-Fri and improve the chances of that front occluding to snow across the UK.

We'll soon know.

Edit: A day further on and it's somehow a little faster with the Atlantic push than the 06z was. The models just keep on giving the tight thermal gradient the dominant say in matters but I'm still not convinced. It is admittedly getting a bit late in the game for the Thu-Fri chances but I'm not yet ruling out a shorter-term correction of some note.  The weekend is still very much up for grabs though I should think. Fight night: Momentum Budget Theory versus Computer Modelling! 

Edited February 3, 2018 by Singularity

[That ECM]

7 minutes ago, Singularity said:

 

As it happens, yes might well be; for Tue afternoon LP to the S is a little deeper and a fair bit closer to our shores.

This may help the cold air to 'pool' more ahead of the next Atlantic attempt Thu-Fri and improve the chances of that front occluding to snow across the UK.

We'll soon know.

Jersey in the sweat spot

[Singularity]

Okay well let's try with GFS now shall we? Lower heights and colder air further west from the continent on the 12z (right).

Increased snow streamer chances on Monday as a result:

[Rocheydub]

7 minutes ago, That ECM said:

Jersey in the sweat spot

It won't be that warm!

The NWP are struggling with the precipitation too, and at this range (72) it always will. I'd suggest we look at HIRLAM and their ilk 24 hours before hand and then a bit of lamp post watching for the best accuracy!

[Singularity]

 

Well, these are nice adjustments so far at least; 12z (right) has colder uppers in from the NW and also to the east.

[winterof79]

Glad I'm no off to Spain for a break

[SteveB]

1 minute ago, winterof79 said:

Glad I'm no off to Spain for a break

Why is it showing all snow for Spain in what looks like no more than -4 850's.

[Ice Day]

5 minutes ago, Singularity said:

 

Well, these are nice adjustments so far at least; 12z (right) has colder uppers in from the NW and also to the east.

Yes indeed, no major changes but incrementally the Atlantic is being kept a bit further west on this run

[winterof79]

Thursdays front already delayed.The colder dense air further west

12z

06z

12z

06z

Edited February 3, 2018 by winterof79

[Daniel*]

5 minutes ago, Singularity said:

 

Well, these are nice adjustments so far at least; 12z (right) has colder uppers in from the NW and also to the east.

Those incremental slight changes good for wintry weather are very common I find. Much less of a mild sector more squeezed out on that, it is hardly a mild sector but relative to the E and NW.

[winterof79]

2 minutes ago, SteveB said:

Why is it showing all snow for Spain in what looks like no more than -4 850's.

It is quite feasible for snow as has been discussed in here before and it is a large land mass with no temp modification upward. Unlike us surrounded by the sea

Edited February 3, 2018 by winterof79

[Daniel*]

Less progressive again it’s a trend today.

v

 

[Radiating Dendrite]

10 minutes ago, SteveB said:

Why is it showing all snow for Spain in what looks like no more than -4 850's.

On the continent it is normal for snow to fall with 0c 850s. The lack of an ocean influence and colder dps allow for this. Additionally, interior Spain is quite mountainous, Madrid is about 600m asl.

Edited February 3, 2018 by Radiating Dendrite

[ICE COLD]

Anyone got 12z UKMO ? 

[shaky]

Arpege continues from the 06z run!!further west and a colder easterly flow across england!

[Singularity]

 

Yes this is good to see; the 12z on the right is not only quite a bit slower with the front, but has signs of a secondary low trying to develop in the warm sector which reduces the ability of the front to push through. Clearly seen in the wind plot at +120:

 

From swooping in to being tugged back a bit.

[That ECM]

1 minute ago, ICE COLD said:

Anyone got 12z UKMO ? 

Similar to gfs.

[Daniel*]

GFS makes very little of that mild sector in SE England gets squeezed out more SE it goes bodes well for potentially all snow in the SE quadrant whereas elsewhere rain is likely at least for a time.

[Singularity]

Well it didn't get there with the secondary feature but the trend is encouraging. Perhaps linked to the AH ridging being toned town?

Next in line is how sharp the Atlantic ridge can become. It's a little more so on this run and with enough adjustment it could allow the disrupting trough across the UK to develop further circulations across Europe that could then support more ridging N of it.

 

Signs of that here. Little by little...?

[bobbydog]

12z generally better all round so far, including a rain to snow event on friday, instead of just rain-

the cold seems to be digging in....

[ICE COLD]

The fire is well and truly burning up top ? again ?