Model output discussion - Post SSW - Will it turn cold?

[Stuie]

4 minutes ago, Steve Murr said:

& another boom to end the run... look at the proportion of the block- alligned perfect  to the strat-

 

Steve, where are you sat today, 5% or are you going to nudge higher? This 10 days away thing is starting to grate me unfortunately.

[Optimus Prime]

Temperature deviation for the 26th:

Obviously analysed outside of the reliable timeframe but it shows what will very likely be heading our way. Between 12°c-15°c below average at 4000 feet. Down at sea level that will transpire to maximum temperatures at or several degrees below freezing. Probably slightly colder than at the start of March 1986. 

[Deep Snow please]

1 minute ago, MattStoke said:

Previous run still had the cold air to our east at 240 hours. This run has the cold air spreading in at 216 hours. A step in the right direction for cold. The GFS too has moved things closer. Not long ago it had the cold not arriving until the start of March instead of the end of next weekend.

It's certainly a step in the right direction, no disputing that. However most of us in here spend far too long drooling over fantasy island charts.

That's said the easterly is now well within the reliable time frame, so the key is keeping it long enough to get the real deep freeze weather in and having snowfall including in the package.

[Ali1977]

I just wish it was only 48 hours away, if the ECM sticks with that theme and then veryifys - between now and then would feel as long as 10 x Xmas eves as a child. 

[bobbydog]

GFS at 192hrs

ECM at 240hrs

the beast is (apparently) coming... its just a matter of when...

[Rayth]

When did the NAO last do this ? The control disappeares 

Edited February 17, 2018 by Raythan
Would have helped if I attached the chart

[Froze were the Days]

Once the modelling gets to 120hrs and down then I'll be a believer, watching the GFS for any possible 'bad' trends...sometimes it picks them before the ECM.

Lets just hope this isn't going going to be known as 'that SSW' in years to come.

[daz_4]

Looking at ECM today brought up memories of February 2012.

2018

It will be interesting to see what max temps will be if this verifies.

[Optimus Prime]

2 minutes ago, daz_4 said:

Looking at ECM today brought up memories of February 2012

2018

It will be interesting to see what max temps will be if this verifies.

I believe that was the last time in which the river in Amsterdam froze over. Will probably happen this year judging by the surface cold. 

[Froze were the Days]

Keep an eye out for troughs developing into something bigger in the easterly flow before it gets here...this can hamper the deep cold getting to our shores. A few GFS perbs have shown this sort of thing and on the 12z op run.

[SMU]

9 minutes ago, Stuie W said:

Steve, where are you sat today, 5% or are you going to nudge higher? This 10 days away thing is starting to grate me unfortunately.

I think 75-80% to day 6 around GFS / UKMO / ECM all being similar

60% now for -10c air to hit UK

20-30% for deep cold sub -11c.

Evolution has now edged to 168-192 ...

JMA 192 is to the party as well now 

 

Edited February 17, 2018 by Steve Murr

[nick sussex]

If this cold does hit the UK I’m sure some in here are going to be unable to sleep with excitement !

The actual cold pool is quite wide , but of course getting the perfect track this far out is difficult given the timeframes.

I would love to see at least sub -15 850s together with those lower heights getting into the UK.

At least no worries about slush or marginal dew points and the North Sea would become a convection machine !

[Southender]

Anyone concerned the coldest uppers could drift south of us as has happened so many times in the past? Or am I worrying too much? ?

[bluearmy]

This ec op very much on the same page as the gefs mean and 50/50 cluster from the 00z eps at day 8/9. Perhaps still a tad suppressed to the south 

[LRD]

22 minutes ago, bobbydog said:

GFS at 192hrs

ECM at 240hrs

the beast is (apparently) coming... its just a matter of when...

I agree and this isn't based on any scientific analysis at all but I think not only will this happen but with the added bonus that it will be brought forward by 24-48 hours

The models will start to accelerate the Easterly over the next couple of days

Edited February 17, 2018 by LRD

[pureasthedriven]

3 minutes ago, Southender said:

Anyone concerned the coldest uppers could drift south of us as has happened so many times in the past? Or am I worrying too much? ?

Book the holiday to Greece now..? 

[Frosty.]

A super ending to the Ecm 12z which would be even more amazing beyond day 10..I'm hoping the current trend continues..actually hope it speeds up a bit and that by next weekend the anticipation / excitement levels will be very high for a major very cold outbreak from the east!.. 

[tinybill]

19 minutes ago, nick sussex said:

If this cold does hit the UK I’m sure some in here are going to be unable to sleep with excitement !

The actual cold pool is quite wide , but of course getting the perfect track this far out is difficult given the timeframes.

I would love to see at least sub -15 850s together with those lower heights getting into the UK.

At least no worries about slush or marginal dew points and the North Sea would become a convection machine !

hope the net weather servers are well oiled this place will melt down as the charts are so good,this takes me back 6 years in march when i started my new job as a temp!! with temp off _12 in the daylight  must have  got through  i tas im  full time still there

Edited February 17, 2018 by tinybill

[Summer Sun]

UKMO extended picking up an SE'ly flow

[Met4Cast]

12 minutes ago, tinybill said:

hope the net weather servers are well oiled this place will melt down as the charts are so good,this takes me back 6 years in march when i started my new job as a temp!! with temp off _12 in the daylight  must have  got through  i tas imf ull time still there

Nice to see the ECM come on board with an Easterly flow as early as 72hrs. There is a risk that the high will be too far South to allow deep cold into the UK, that's always a risk in these setups but generally all models eventually shift the high Northwards and bring the real cold air into the UK.

We're sitting in a good place at the moment, we can relax a little now and watch the cold creep Westwards through Europe.

Edited February 17, 2018 by Paul

[Chesil View]

Perfect ECM completely in line with meto outlook

[Stu_London]

6 minutes ago, Southender said:

Anyone concerned the coldest uppers could drift south of us as has happened so many times in the past? Or am I worrying too much? ?

I don’t think you are worrying too much. I suspect the milder ensembles would be showing central Southern Europe in the freezer with milder uppers spilling over the top of them. That said, the nearer these sort of charts get into the reliable, the more likely they will verify. 

[Froze were the Days]

5 minutes ago, Summer Sun said:

UKMO extended picking up an SE'ly flow

Difficult to tell how similar this is compared to the ecm and GFS at 168 but both have a south easterly (particularly the ecm) - without the chart moving to the east it's a bit tricky to see - but certainly looks like some continuity there. 

Edited February 17, 2018 by Froze were the Days

[Tamara]

Posted February 10

Irrespective of what the ECM goes on to show shortly and irrespective of what my head keeps telling me of how the effects of this SSW could be mitigated,  I am not sure I have seen anything programmed quite like this thing.

Polar easterly reversals are often enough mitigated at least to some degree by other tropospheric drivers, but I am beginning to come to round to thinking this may not be one of them where that happens so easily and its going to take over a lot of the NH for some time.

 it could be the case that it would start to be more prudent not to underplay the SSW, than place caveats as to what might mitigate it. On that basis maybe its me who should have a bit of a ramp, and not others who should restrain themselves

However it plays out in terms of what comes out of the sky in the coming weeks - and despite the fact that the actual phenomena of SSW's is not new, this is quite a significant specimen indeed we are watching unfold

............................................................................

A week on, and a crazy amount of pages later, what has changed?

Well I haven't had another ramp, and the deepest cold is still 9/10 days away

But what has become clear in the course of a week is that the first stratospheric break-down salvo is set to verify for certain this week - and that day 9/10 day period marks Phase 2 and the time when the Canadian vortex to the NW should finally back off and the down-welling process of -ve zonal wind anomalies really start to make themselves felt in out part of the Northern Hemisphere

On that basis we can give credence to the shape of the mid and higher latitude pattern and emerging block alignment with the deep cold backed up like a dam waiting to be unleashed

I am amongst the most sceptical of day 10 UK deep cold in NWP and very often based on the realistic signals, barely take a second glance, if even much of a first glance at all

But this SSW is a significant specimen indeed, and no further deep analysis is needed. On that basis I will be taking this particular day 10 deeper cold rathe more seriously as a contender

The fact that Phase 2 marks the time when the strongest sibling vortex lobe starts to finally cave in after its winter rule, increases the chances of deeper cold air advection at that time-period not just because the block to the NE can start to orientate in ideal position as polar jet energy is finally being squeezed out, but because the chances of retrogression are also much higher so that at some stage re-loading deep cold has a heightened chance of finding out even this little Island.

Probably the most simplified basic principle post you will get from me - but less is more sometimes and nothing else needs to be added

 

 

[BLAST FROM THE PAST]

32 minutes ago, nick sussex said:

If this cold does hit the UK I’m sure some in here are going to be unable to sleep with excitement !

The actual cold pool is quite wide , but of course getting the perfect track this far out is difficult given the timeframes.

I would love to see at least sub -15 850s together with those lower heights getting into the UK.

At least no worries about slush or marginal dew points and the North Sea would become a convection machine !

It will miss Redhill....? ?

BFTP

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