Model Output Discussion 01/09/17

[northwestsnow]

2 minutes ago, bluearmy said:

Whilst the London eps continue to look cold, from my perspective, the 00z suite moves the outlook away from cyclonic cold closer to anticyclonic cold. Still between the two and it remains within the swinging pendulum, back and forth. 

In the medium term, if the halfway house solution of the Atlantic cut off low escaping and running around the top of the amplifying ridge is correct then this could well run into the base of the developing trough as per the 06z gfs. The ec control did this - whilst it cuts off the northerly it does provide for a big potential snow event somewhere across the uk  

I'd much prefer cyclonic cold blue

But anticyclonic cold is fine by me.

GFS seems to have completely lost what muted signal it had for a warming in the strat- not sure what the Berlin site shows us regarding zonal winds...

[karlos1983]

Nice to see the control taking err control of the situation 

[northwestsnow]

8 minutes ago, Bring Back1962-63 said:

Hello, I never like to contradict anyone directly on this thread but I continue to feel that you (and many others) are doing the UKMO rather an injustice. Their 0z T +120 and T+144 are actually almost identical to the GEFS 0z (and now the GFS 6z) at these times! My posts on pages 250 and 253 explain this with the relevant charts. The UKMO has the major disadvantage in not going past T+144. Summer Sun's posts with the T+168 UKMO charts are a little misleading as we cannot see the eastern Atlantic and UK view - even more important with the current set up. We cannot assume that the UKMO will not find the path to another northerly reload - in fact I firmly believe that they will. The GEFS 0z took that small LP over the top of the Atlantic HP and the GFS 6z takes it underneath. Both models end up with the Arctic reloads. So, we all need to be patient and not make assumptions which are really not yet shown! Give the UKMO a chance and I feel that it will all be resolved during the next few runs. All paths lead to cold LOL!

I do hope that you take this in the right spirit as I have no intention of upsetting you and i respect everyone's opinions.

Well thats no problem

I again disagree tho, look at the low in the mid Atlantic on ukmo 144 and then gfs6z 144, theres a huge difference in plaement of that low, 

ukmo

gfs

That will have huge ramification , just my honest opinion..

edit and we can see by 168 the difference is huge- all brought about by the 144 chrts above..

 

Edited November 27, 2017 by northwestsnow

[Met4Cast]

No closer to a solution this morning than we were last night. What we do know is that this week will be cold with chances of snow that probably aren't yet being modelled.

Beyond that, temporarily "milder" next weekend before it turns cold again. How cold/how long is unknown at this point, UKMO really isn't budging and given todays ECM I'm slightly worried now, there's less wiggle room. 

Good 06z GFS though, but things are less clear moving forward.

[sundog]

3 minutes ago, stodge said:

 

To depress some, and it may simply be GFS struggling and reverting to type, I do wonder if come mid December we'll be looking at a more normal pattern. The Aleutian HP moves up over the Pole and it may be that will serve to lower heights over Greenland but that's a very long way off.  

I know I'm getting way ahead of myself here but just hope we aren't sacrificing the second half of Dec with Xmas,the more business end of Dec for a chilly first half. Can't have it all I know but just a thought. Or if the middle part of the month became somewhat milder perhaps much colder again by the end........... Overthinking it I know.

[Had Worse]

As usual, it will end up a blend of the modelling. Could be 60/40, 30/70 etc but in all fairness, we wont be getting the deckchairs & BBQ's out. 

[weirpig]

Opp Run very close to the mean on quite a bit of the run  certainly no outlier  the control on the other hand. does dip slightly  but still    decent ensembles from the 6z

Edited November 27, 2017 by weirpig

[Northwest NI]

This is my second  winter on the forum. I get the feeling if I ever get to see a proper winter snow scenario evolve I’ll be too knackered to enjoy it! I’ll wake up and it’ll be like nothing ever happened.

 

[Man With Beard]

Yes a bit of shift in the ECM ensembles this morning but on the same token it is noteworthy how consistent the op run is being for the D7-D10 period. If we take the past 4 sets of clusters, we see that by 5th December it has almost the same shape of block in the Atlantic, and troughing in the same vicinity near the UK:

       

Latest GFS 06Z is a fair match for the op run cluster, maybe a little further east on the trough - control run is similar a day further on:

  

However, it is clear that the ensembles have jumped ship a little over the past few days, particularly with reference to the extent of ridging to the north and the gradual erosion of options with lower heights towards Europe. So it's a bit of the op vs the ensembles right now. Not a good position from which to call the eventual outcome.

The D10-D15 pattern eventually drifts away from a focus on Atlantic blocking, but not in a hurry: even by D12, that ridge is still the main feature and plenty of potential for another episode of a dropping trough from the Arctic towards the North Sea:

The latest GEFS has this scenario the slight favourite by D11 although closer inspection of ensembles reveals several flatter options too (this alternative cluster having strong Euro heights which is why the mean looks raised over Europe:

All in all, considering that cold spells over the UK are always subject to D4/D5/D6 alterations let alone D11/D12, I don't see any reason for anyone confidently predicting a permanent breakdown of the cold pattern just yet. What instead we are seeing is the potential for short bursts of Arctic weather, rather than sustained cold - entirely normal for a UK cold snap. If the pattern gets through a couple more times, I'd surprised if we weren't hearing about snowfalls in parts even away from high ground.

 

 

 

 

 

[West is Best]

All looking very interesting at the moment. The 6z is a bit of a lesser cold run than the 0z but ups and downs are to be expected and nothing for cold lovers to be alarmed about. The main trend is of cold start to winter. That's something that seems to have eluded us all too frequently in the last 30 years.

What I'm looking for are rising heights over Greenland and in that sense I'm encouraged to see the 500hPa beginning to show some greens, and even yellow, heights - the kind of true GH for which we search elusively. I remember a winter or two back that we all got terribly excited over rising heights to our east. But these rarely produce the goods without a proper upstream block and Greenland High displacing the PV.

[Frosty.]

It's going to be turning progressively more wintry from the north through this week with arctic air sweeping south across the uk bringing increasingly wintry showers, especially to exposed northern, eastern and for a time, western areas..some of us will see snow..Frosts becoming more widespread with icy patches..thurs / fri look even colder and the cold air lasting longest further south-east, even into the weekend. The conditions moderate for a time with less cold uppers but then next week, if the Gfs 6z / Ecm 00z are right, a more severe wintry spell will be on the way!..could it be boom time next week?..hope so????

Edited November 27, 2017 by Frosty.

[Geordiesnow]

15 minutes ago, Daniel Smith said:

No closer to a solution this morning than we were last night. What we do know is that this week will be cold with chances of snow that probably aren't yet being modelled.

Beyond that, temporarily "milder" next weekend before it turns cold again. How cold/how long is unknown at this point, UKMO really isn't budging and given todays ECM I'm slightly worried now, there's less wiggle room. 

Good 06z GFS though, but things are less clear moving forward.

Think thats a decent summery of where we are at the moment, the models have done well forecasting this upcoming Northerly. The only worry I have as you have alluded too is that there does seem to be less wiggle room this time, for the Northerly the models did briefly suggested we could see a Greenland high occuring, that did not quite happen but its still enough to give us a decent Northerly flow for this week.

It will be interesting too see how this plays out but the trend does seem to be high pressure will remain to the west of the UK for the foreseeable so the prospects of fog and frost after the Northerly flow has all but gone but hopefully we get the proper retrogression into Greenland instead which will make up for it for sure.

[Gavin Hannah]

6 minutes ago, Frosty. said:

It's going to be turning progressively more wintry from north through this week with arctic air sweeping south across the uk bringing increasingly wintry showers, especially to exposed northern, eastern and for a time, western areas. Frosts becoming more widespread with icy patches..thurs / fri look even colder and the cold air lasting longest further south-east, even into the weekend. The conditions moderate for a time with less cold uppers but then next week, if the Gfs 6z / Ecm 00z are right, a more severe wintry spell will be on the way!..could it be boom time next week?..hope so????

 

Week of the 5th will really come down to what happens to the Altantic low. If the HP holds out and sends the LP north west towards Greenland, then we could be game on for another cold shot with perhaps even snowier weather than this week.  Will enjoy the weather this week and not get to carried away for the next week just yet.

 

 

 

[Seasonality]

25 minutes ago, Bring Back1962-63 said:

Hello, I never like to contradict anyone directly on this thread but I continue to feel that you (and many others) are doing the UKMO rather an injustice. Their 0z T +120 and T+144 are actually almost identical to the GEFS 0z (and now the GFS 6z) at these times! My posts on pages 250 and 253 explain this with the relevant charts. The UKMO has the major disadvantage in not going past T+144. Summer Sun's posts with the T+168 UKMO charts are a little misleading as we cannot see the eastern Atlantic and full UK view - even more important with the current set up. We cannot assume that the UKMO will not find the path to another northerly reload - in fact I firmly believe that they will. The GEFS 0z took that small LP over the top of the Atlantic HP and the GFS 6z takes it underneath. Both models end up with the Arctic reloads. So, we all need to be patient and not make assumptions which are really not yet shown! Give the UKMO a chance and I feel that it will all be resolved during the next few runs. All paths lead to cold LOL!

I do hope that you take this in the right spirit as I have no intention of upsetting you and I respect everyone's opinions.

Well written post. I'd very much like to see your reports return this winter as they were very informative last time around. We should dismiss the UKMO at our peril, but that said, plenty to be positive about. Europe is also cooling down very nicely, so this will help with any easterly incursions that may occur later on. Latest ensembles for Warsaw show this well, looking like it will turn rather colder than it was this time last year in central Europe, and the UK is set cold for the reliable time frame too! Lovely seasonal weather, plenty to smile about.

 

 

[Met4Cast]

This mornings FAX charts have a Pembrokeshire dangler on them!

[Summer Sun]

10 minutes ago, Daniel Smith said:

This mornings FAX charts have a Pembrokeshire dangler on them!

 

Any new members who don't know what a Pembrokeshire dangler is it is explained here https://www.youtube.com/watch?v=YqE2RKr03j8

[Luke Best]

32 minutes ago, Northwest NI said:

This is my second  winter on the forum. I get the feeling if I ever get to see a proper winter snow scenario evolve I’ll be too knackered to enjoy it! I’ll wake up and it’ll be like nothing ever happened.

 

Even as it's snowing outside, we'll all be glued to this forum discussing when the breakdown is coming! 

[stewfox]

47 minutes ago, northwestsnow said:

Well thats no problem

I again disagree tho, look at the low in the mid Atlantic on ukmo 144 and then gfs6z 144, theres a huge difference in plaement of that low, 

ukmo

gfs

That will have huge ramification , just my honest opinion..

edit and we can see by 168 the difference is huge- all brought about by the 144 chrts above..

 

For the uninitiated can you show the huge difference in that low re mid Atlantic. I might need to go to Specsavers

[Summer Sun]

GFS mean shows temps remaining below average for the foreseeable future we might get a fraction closer to the average very briefly around D10 but the overall message from GFS this lunchtime is it is colder all the way until around mid-December at least

[gottolovethisweather]

2 minutes ago, Summer Sun said:

GFS mean shows temps remaining below average for the foreseeable future we might get a fraction closer to the average very briefly around D10 but the overall message from GFS this lunchtime is it is colder all the way until around mid-December at least

The period through D4 (Thursday) through to D7 (Sunday 3rd December) looking potentially cold enough for some wintry stuff to fall in London right there as well. 

[karlos1983]

14 minutes ago, stewfox said:

For the uninitiated can you show the huge difference in that low re mid Atlantic. I might need to go to Specsavers

look at the High in the Atlantic, ukmo can't get between it and Greenland, GFS has superman'd it and found a gap to fly through..

The result.... we get our Lois Lane 

Edited November 27, 2017 by karlos1983

[karlos1983]

This week, now we can start using the short range tools at our disposal, if you are located anywhere on the east cost from say the boarders all the way down to East Anglia, especially if you have altitude on your side, you *could* see some nice snowfall. Northern Scotland also will as usual do very well out of this setup. 

Bone dry for me, but cold nonetheless. 

[bluearmy]

1 hour ago, northwestsnow said:

I'd much prefer cyclonic cold blue

But anticyclonic cold is fine by me.

GFS seems to have completely lost what muted signal it had for a warming in the strat- not sure what the Berlin site shows us regarding zonal winds...

no issue from where i'm sitting. gefs (yes I know they are biased) still looking like big displacement to the Asian side week 2 with mid level split for a time. the op near enough evolution not to worry. the ecm op 00z close enough to gfs at day 10.  no ens ecm data available to me.  

[bluearmy]

Not sure anyone noted the snow event across s england day 9/10 on the ec op. Purely academic at that range though a disturbance from the troublesome Atlantic low is what brings it as it scoots across the base of the developing  sceuro trough

[Frosty.]

The good news is it looks increasingly like further Northerly outbreak (s), more potent than this weeks and similar to what the Gfs 6z / Ecm 00z currently show..no downgrade regarding the mid / longer term!..a bit milder at the weekend with less cold uppers but then turning colder in the north early next week and then much colder everywhere thereafter..Fingers crossed this continues to be the form horse!????..in the meantime, enjoy this weeks cold!

Edited November 27, 2017 by Frosty.