[Ireland Regional Weather Discussion]

21 minutes ago, ForeverPomeroysnow said:

Ack that's a shame but hey its only weather

It's far more serious than that(joking). That warm sector is really irritating,  when we are supposed to be in the colder  air and precipitation is about we'll get rain,  then when the colder  air does get back in it looks fairly dry overall. Perhaps some features will pop up, it would be a real  kick in the teeth  if we limp back to milder weather  at the weekend

[Model Output Discussion - Colder but how cold and for how long?]

10 minutes ago, warrenb said:

I think by the end of the weekend we shall start to see some interesting charts toward the back end of the models. I have always thought late January into February an to look east rather than north

Something else  will no doubt come along to weaken the signal for robust blocking. The lesson from this chase is that Greenland  heights  if they do occur more often than not tend  to wane quicker than anticipated. I don't  know if that's the models picking up a signal  and over doing it or what, no doubt someone  will have an explanation.  We had the UKMO up to a couple of days ago saying milder interludes only for the south  to milder conditions gradually taking over next weekend is a bit disappointing. There is no such thing as locked in cold, we are lucky if we get 4- 5 days of cold. I am just hopeful as many people as possible  can get some snow next week. It will be a gut punch if we go zonal  without  a decent snowfall  somewhere  

[Model Output Discussion - Colder but how cold and for how long?]

23 minutes ago, Downburst said:

Week after next surface pressure anomalies (for the entire weekly mean)

x

It's followed by a resurgence of high pressure, with the following week showing that possibly moving north west, I think dry and hopefully sunny for the time of year looking at precipitation anomaly.

However, next week is the one chance I'd suspect of proper cold this January, with it gradually warming up. I think we may well have a dry spell end Jan well into February.

 

To add a rare at this time of frantic posts I put in December 19, to show the usefulness of these charts as a guide for probabilities

It's disappointing  in one way that much of February would potentially be eaten up with predominantly  dry weather,  but at the same  time it's preferable  to the GFS horror show which would could  lead to at least 7 - 10 days of zonal  weather if not more. One further thing I will  say is even  with a grim nh profile things can change for the better in the space of a few days- you only have to  look at the charts prior  to some noteworthy cold spell as evidence of that  .

[Model Output Discussion - Colder but how cold and for how long?]

1 hour ago, blizzard81 said:

I of course want ukmo to be correct this morning but more importantly - I do actually think it will be. I haven't been impressed with the performance of the ecm ops these last few weeks. They have been erratic to say the least. I will be closely following the ukmo output over the next couple of days as we close in on the cold spell. 

The bullish tone of the UKMO text forecast would give you a bit of confidence that  the UKMO maybe right. I guess we will find out soon enough. I really hope  the GFS is being its default  self with the return  of raging zonality by the weekend. I have had more than enough for rain over the last three months. 

[Model Output Discussion - Colder but how cold and for how long?]

21 minutes ago, Mcconnor8 said:

Delayed on this run by a day, and I expect it will keep getting delayed further run by run for a while.

I pray it does. Was it back in 2013 this kept  happening on the models during a cold spell? I am nearly sure it was either 2013 or 2012.

[Model Output Discussion - Colder but how cold and for how long?]

3 minutes ago, nick sussex said:

The wheels come off later as the Canadian troughing is ejected but then sort of runs out of puff .

The ECM is a bit like the GFS later which is somewhat bizarre given the divergence in the ne Pacific .

And also bizarrely the ECM is a close match to the UKMO in that region but we can see two quite different outcomes downstream .

If we accept that the ECM GFS idea of ejecting that troughing is more likely we then now have to see whether we’ll see more of a split in energy and so could see some wedges of heights which can at least keep some parts still in the cold with continued snow chances .

The UKMO doesn’t have a great track record at day 7 but a combo of the Euros might be okay .

The GFS has that progressive bias .

If we are to see a bit of a reset then it can take a few runs to settle down.

Earlier there’s a lot going on , the brief but potent north to nw flow . Then the Atlantic low drama , a few other shortwaves thrown into the mix .

It’s hardly bridge night at the village hall ! So a lot to keep us interested .

 

So maybe nothing  will be resolved till Sunday  evening as regards next week?

[Model Output Discussion - Colder but how cold and for how long?]

2 minutes ago, Scott Ingham said:

Tbh it’s too premature to write off any snow it’s just too far out and too premature to predict mild when a lot of signals point to blocking wedges keeping the jet south. Sometimes it’s good to second guess the models if you don’t feel it fits in with the predicted atmosphere and never take them at face value until inside 96hours. We don’t need to be down beat it’s a watching scenario still for both length and level of snowcover

I agree about snow chances, features could  pop up even if  the synoptics don't seem great.  I remember getting ninja snow over the years  when model output suggested it would be dry- the warm seas could aid us  in this scenario next week.

[Model Output Discussion - Colder but how cold and for how long?]

13 minutes ago, Scott Ingham said:

If you read Tamara’s take there are wedges that won’t be picked up until 120s. I agree the end back mild winning at day 9 but I wouldn’t put my mortgage on it if wedges send low pressure into Europe and keep us on the right side of the jet. That’s something to keep an eye on and until I see it I have to go with the ensembles atm and say I agree mild “should” be coming in 9 days time. Just watch this space….

Well I hope she is right, but the form horse looks a return to milder weather.  What we don't want is a tepid return to milder  weather, either let's at least have a massive snow dump from a frontal  event or a good unstable northerly airflow,  but I am not confident  of either happening now. If this is the case then it's a big anticlimax after what seems  like one of the longest chases ever 

[Model Output Discussion - Colder but how cold and for how long?]

Just now, Scott Ingham said:

The issue with frontal clashes is it tends to be a day of snow then mild air coming in 48 hours later. I prefer to keep the cold in and get several troughs shortwaves in a flow for a week or two. But each. To their own I guess!

Well that is a big ask, despite the suggestion from some  that cold may hang on past next weekend it doesn't seem likely now whether we have a frontal event or not, but I agree it could lead to a big dump of snow more widely  for a lot of people who will likely  be dry otherwise.

[Model Output Discussion - Colder but how cold and for how long?]

14 minutes ago, feb1991blizzard said:

Yes - watch and hope - they mention mild returning next weekend though, but their 6-15 doesn't tie in with 16-30 as that ends with mild and wet and the 16-30 starts of drier than average, and colder than 

Is there in house model- Glosea-  not going for a blocked  February? If the GFS is right about the strat February could be interesting too. Unless  it flipped the whole pattern to something negative. Anyway too far out to really worry about. We hopefully will have a 4 - 5 day snowy spell  next week. 

[Model Output Discussion - Colder but how cold and for how long?]

The UKMO 168 chart could be the gift that keeps on giving. 

[Model Output Discussion - Colder but how cold and for how long?]

31 minutes ago, Duane S. said:

Yep, I really think that has played a huge part Mike, just as you’ve put it. The strat vortex hasn’t been able to strengthen unabated through November/ December as it normally would. I think the E-QBO has played (and still is playing) its part as well. 

Just to be clear, are you saying that if QBO was in a westerly phase the Troposphere  impacting  the strat  the way  it is would not be able to happen- that we would not see these splits propagating upwards?

[Model Output Discussion - Colder but how cold and for how long?]

33 minutes ago, MJB said:

And potentially through the week until it warms up next week, looking at the charts

Potentially  warms up or are you of the view  it's almost  a foregone  conclusion that it will warm up everywhere?

[Model Output Discussion - Colder but how cold and for how long?]

5 minutes ago, SussexSnow said:

Spot the outlier / trend setter*

 

* delete as applicable 

We will see what happens  for the final week of January. I hope it remains cold and we all get a dump of snow at some point.

[Model Output Discussion - Colder but how cold and for how long?]

3 minutes ago, joggs said:

Just hope the next low after mid next week disrupts and keeps us cold.

I hope so too. I would like some snow of course, but I would be happy  if we could hang on to the cold and dry weather at the very least. We just said goodbye to the puddles, so i don't   want to see them back for a good while.

[Model Output Discussion - Colder but how cold and for how long?]

Just now, mountain shadow said:

So, the straight Northerly is now in the bin.

Looks like we're coming to a solution now

1. Poor Northerly with snow confined to NE Scotland.

2. Then mostly dry for a day or so before somewhere gets impactful snow

3. Snow quickly gone as Atlantic returns.

Hardly worth the build 

 

 

1 minute ago, bluearmy said:

That’s the glass half empty end of the envelope - yes 

I am sure someone  will mention ensembles showing otherwise and that there is no trend, but that's two GFS runs, along with the ECM and EC46 showing a more westerly influence for the final week of January.  Also John Holmes indicated this might happen too. On a more positive note any westerly influence  will hopefully be brief. I don't think I could take another lengthy Zonal period.

[Model Output Discussion - Colder but how cold and for how long?]

20 minutes ago, nick sussex said:

Very funny but some might accuse you of being part of the band playing whilst the Titanic sunk ! 

Or indeed Theresa May during the infamous 2017 GE election campaign .

Anyhow I do think the ECM is a mess past day 7 and is bound to change again by the morning . We’re though getting to the timeframe tomorrow when operationals start to take precedence over the ensembles .

 

Also the GFS op has been against its ensembles previously and still turned out to be right. So the post is somewhat  wide of the mark, even if most of the time the ensembles  do lead the way.  The GFS op if it does turn out to be right about next week will have trumped the other models. I certainly  hope it's wrong,  but this episode has shown you write it off at your peril.

[Model Output Discussion - Colder but how cold and for how long?]

Just now, Met4Cast said:

The GFS that was very much in the mild camp and well above the ensemble mean? That GFS?

People here put far too much stock into deterministic runs instead of looking at the larger picture, i.e the ensembles. Det runs are no more likely to be right in the 7 day range than any random ensemble member you could pick out. 

As stated a few days ago, the polar boundary will shift north and south with each run until models resolve the undercutting & strength of the high. Nothing has changed.

But it isn't  just the GFS. The ECM run is poor too. Sometimes  the op can lead the way.   Believe me I really hope you are right by the way,  but if it can go wrong  for us it usually does despite how fantastic  background drivers  can be.  By the way I appreciate all the time you put in explaining these drivers to us.  

[Model Output Discussion - Colder but how cold and for how long?]

8 minutes ago, Met4Cast said:

I see the standard over reactions to a single deterministic run are in full force!

Meanwhile MOGREPS 12z continues to make little of the mild incursion next week.

With respect  it's not just one run, it's two models showing a less than desirable outcome with a return  of a westerly influence.  Granted  the GFS might lead to a dumping for some.  I now need to take this opportunity to apologise to this forum. I committed the cardinal sin by telling a neighbour to get ready for the snow. I have my running shoes on....

[Model Output Discussion - Colder but how cold and for how long?]

A worrying trend. The ECM has backed the GFS in sending the low a bit too far north and then we end up back to a westerly  pattern. What's  the betting they have  arrived  at a consensus  now. If this is the case you'll likely see a change in the UKMO text forecast 

[Model Output Discussion - Colder but how cold and for how long?]

Just now, Drifter said:

Nope not great imo. What the northern members need to realise, is the further north this goes, the worse everything becomes for longevity. 

Unless it pushes  all back south on later frames.

[Model Output Discussion - Colder but how cold and for how long?]

1 hour ago, SizzlingHeat said:

But it wasn't always forecast to collapse via a shortwave, not until the GFS didn't back down when everyone dismissed it run after run for being an outlier. When the other models finally backed down and went along with GFS. Just always seems to be getting within striking distance and then something else happens and scuppers the really nice charts that always pop up post day 7 and 8. The ECM and Ukmo only until this morning were still showing what the icon is currently showing for 8 days time commencing at 144 hours, this has now again been pushed back. 

Yes, and the danger is the GFS could be right again in the face of opposition from other models, but some places will do very well  in terms of snow fall if that happens, so people in these  regions might not care too much about longetivity if they have a significant  snowfall.

[Model Output Discussion - Colder but how cold and for how long?]

How can the GFS change so much from one run to the next. This morning it looked good for extending the cold but now it looks like it may not last at all. I appreciate some could  get a dumping before  all that happens 

[Model Output Discussion - Colder but how cold and for how long?]

6 minutes ago, Mcconnor8 said:

Short-Mid range ensembles are WAY better though which are far more important than what is going on in hours 300+, also subtle changes in the ECM 06z compared to the 0z towards the GFS 06z output, brings the Northerly in earlier on the 14th and weaker Azores low aiding amplification.

So it would seem the GFS has led the way on this as lrd said. You are right about the ensembles longer term,if the op runs remain consistent it could be the ensembles change. I know it's usually the other way around though.

[Model Output Discussion - Colder but how cold and for how long?]

13 minutes ago, Jason M said:

Many of the GEFS raise heights over Iberia towards the back end. That's a death sentence for cold weather.

Way to far out to worry about though!!!

 

It looks like a lot of ensembles are trending the wrong way in fi contrary to the op runs. It's a long way out anyway to worry about it. Also there is a chance they could change to extending the cold. As long as the UKMO update remains bullish about the long range I am happy enough.