Model Output Discussion 1st January 2014-06z onwards.

[LomondSnowstorm]

It's an utterly blockbuster run, with a killer Arctic shortwave, a stronger low than on any previous op. with less trough disruption early on and the weakened heights settling in over Greenland. However, we still have a negatively tilted trough, a wedge of HP and, eventually, the undercut:

The shortwave may end up bringing in a northerly but that's such a convoluted evolution it would almost certainly give Nick S a heart attack if we had to follow it all the way through

Edited January 8, 2014 by LomondSnowstorm

[Tamara]

The pendulum with this trough disruption is going to keep swinging to and fro with each output suite at this range - and for our small island then increments of amplification of the pattern, and energy within it, are going to make a large difference on the micro level.

 

I think that the updated EPS ensemble members illustrate this very well...no surprise that the official METO line is as tough to call as it is. Its maybe as well that the postage stamps only go as far as day 5..all bets are off at least at this time, if not before

 

 

Evidence does point towards the north at least provisionally having wintry potential early next week, but the degree of negative/positive trough disruption to assist cold air advection south across the whole UK is going to prove cricital to the wire (as always with the UK at the crossroads of things)

[Cheshire Freeze]

Dont want to be a party pooper CC but thats RAIN for the majority.By Tue night we're still above freezing..

 

Don't take at face value. I'd take the short term pain for the potential pay off.

[Geordiesnow]

I hope the pub run won't turn out to be late night horror ----  'Nightmare on Netweather Street' !

 

Nick Sussex must be a nervous wreck!

 

The chart on face value may not be what you want too see but on a general basis, that chart is certainly not a "Nightmare on net weather street". 

 

Personally happy with the 18Z run, again detail will vary a lot but the main message is still there. Unlike the ECM, there appears to be less amplification over in the US so that is another thing to look out for it seems. 

[Dancerwithwings]

DiagonalRedLine, It ain't just the GEM that deserves an Oscar.... Good post

[snowbob]

To be fair

Did anyone really expect the 18z to upgrade the 12z

It is renowned as the pub run every single night

Why should tonight be different

Let's all just stay happy and see what the 00z say

Hopefully another great day tomorrow.

Not saying the 18z is bad

Just saying

Edited January 8, 2014 by snowbob

[Continental Climate]

I am happy with the 18Z which gives us what the other models gave us and that is a pressure rise to the north and some southerly tracking lows, its all variations on a theme and at this range (+144) that's all we can hope for. Lol the next three days are gonna feel like an eternity getting all this to T72 with as little damage as possible to the overall pattern.

[Zenarcher]

The beast from the East versus the Atlantic Express...Game on!

 

Let the battled commence!

 

 

The good charts continue today with some positive surprises as well along with some fantastic well put together posts from some of the members on here.

[nick sussex]

I hope the pub run won't turn out to be late night horror ----  'Nightmare on Netweather Street' !

 

Nick Sussex must be a nervous wreck!

Lol! not yet! I was more worried about any sudden changes within T72hrs, the models still can't decide where the high is going to set up here we have a more Greenland/west Scandi combo.

 

It's an intriguing set up with those shallowish lows running se, overall its fine, to get a clean easterly though you'll need to see a clearance of the shortwave energy that's draped nw/se.

 

The issue is not really whether its going to turn colder or snow, its really the detail as to what happens with the trough disruption and where that takes place, overall the GFS 18hrs is just a variation on the same theme with an added twist of a chance of the colder pattern holding out for longer.

Edited January 8, 2014 by nick sussex

[LomondSnowstorm]

We now end up with an attempt at a Greenie high and Scandi trough after all that:

Still, as I said earlier today with the 6Z the slower evolution suits me fine given a model propensity to sink the pattern southwards once we hit mesoscale range. Actually, any of the operational runs look fine.

Edited January 8, 2014 by LomondSnowstorm

[Cheshire Freeze]

The NH pattern is infinitely better at 192 hours from a NH perspective....it maintains the PV split for a start!

[Panayiotis]

I think an Atlantic/Greenland ridge is coming up...

EDIT: Nope, low res GFS wants to be over progressive!

Edited January 8, 2014 by Panayiotis

[Snowman.]

We now end up with an attempt at a Greenie high and Scandi trough after all that:

Pressure rises in the mid Atlantic is likely, many models have suggested this which forms and MLB somewhere around the UK.

 

Keeping it cool but most importantly dry!

 

 

Just the bit between now and then is uncertain.

[Ice Day]

At 192 and the cold uppers are still way to our east.  It just doesn't want to get here on this run.  Still only one run though, and let's face it, the 18z has never decided anything!!!

 

[Wilxy]

Watch that high in FI sink like a sack of potatoes

[cooling climate]

It is entirely possible of course that the down welling wave 2 in the lower stratosphere

will amplify over the Greenland plateau as shown by the 18z. I am not saying it will happen

but it is definitely a possibility.

Hard to believe you could have a chart such as at t192 and yet most of the country is

only covered in -2to -3c 850's

[Jason M]

I like this run. The quicker the cold gets in the quicker it will be gone and vice versa.

 

No doubt in low res the Atlantic will take over but at the end of high res that's a good position to be in going forward.

 

Some cold days with frosty nights ahead of the onset of deep cold would also help lower the ground temps. Any snow falling otherwise won't be around for very long!

[damianslaw]

Possibly the busiest this thread has been all winter so far.. always a sign that something wintry may be stirring.

 

What a difference 48 hours makes when I last viewed the charts, however, over a good week now there were signs of trough disruption possibly occurring as we approach mid-month point with heights building to the north of scandi/Svalbard and this certainly looks like happening early next week.

 

The Jetstream forecasts shows a very meridional buckled flow developing next week with the UK locked on the cold side of the jet.

 

Interesting to note the models are suggesting heights building more NW towards Iceland as opposed to sticking in situ over scandi- sign of some form of retrogression and whilst such an evolution would make it much more difficult to tap into very cold uppers from the east, it is a better profile longer term for locked in cold, as energy will be forced SE more sharply and there is always the chance of a significant snowfall as low pressure comes up against the block.

 

In the short-term after 5 weeks of a raging atlantic, things finally look like settling down as we move into the weekend with the return of frosts - wow some frost at long last and temperatures around average in the south and a little below further north as we see quite chilly uppers descend across northern parts.

 

Wouldn't be surprised if the BBC show there first 'cold graph' this weekend - i.e. one showing a temperature dip, I bet the forecasters have been sick of saying the same old thing these past few weeks.

 

Perhaps next week will end up a slightly toned down version of the same week last year.

 

 

[phil nw.]

Understandable excitement created by some enticing runs today.

Great analysis by Steve,Nick and quite a few others helping especially the newer chart watchers.

My own view is still the same as earlier, underlined by Tamara's realism above.

Yes we pretty much know a blocking high is likely to our ne and the Atlantic jet will split around our local.

What modeling can't calculate at this range is where the boundary will lie between the 2 air masses and those ECM stamps highlight the uncertainty.

I wouldn't like to call this one as this pattern change is probably the most problematic for any forecasting tool to solve.

Let's enjoy the cold patterns in these current runs but know that until the crucial period is closer in modeling terms the Easterly is in the balance.

[pages]

We now end up with an attempt at a Greenie high and Scandi trough after all that:

Still, as I said earlier today with the 6Z the slower evolution suits me fine given a model propensity to sink the pattern southwards once we hit mesoscale range. Actually, any of the operational runs look fine.

Think we might end up with a proper greenie high in far reaches of fi, the vortex is on its last legs at 264.

[Purga]

Could be a nice solid cold 'Fergie' block forms to the NE - the difficult to shift variety.

 

Of course GFS gets the fat lady to clear her throat at this stage

 

[Duane S.]

 

Great 18z. Takes a bit longer but the wait is worth it. Look at the pressure over Europe. So much potential.

 

We would have to be pretty unlucky to miss out now IMO, stranger things have happened though of course.

[Cloud 10]

The 18z NAVGEM looks very "slider-ish" at 144 hrs.

 

[East_England_Stormchaser91]

18z sends most of the cold into the near continent, although Thames streamer setup looks possible along with snow showers along Kent and S Coast. Loving how stereotypical FI just shoves a block with -15 to -20 uppers out the way as if it is literally nothing !!

[Cheshire Freeze]

18z sends most of the cold into the near continent, although Thames streamer setup looks possible along with snow showers along Kent and S Coast. Loving how stereotypical FI just shoves a block with -15 to -20 uppers out the way as if it is literally nothing !!

 

It sort of twigs on though and almost produces a second bite of the cherry