Harsh Climate
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Posts posted by Harsh Climate
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1 minute ago, TSNWK said:
better lift of heights into Greenland at day 7
The low to the SW of Greenland is much deeper on the 12z compared to 6z, sucking in a lot more WAA which should really inflate our blocking high. Looks a big upgrade compared to the 6z this does.
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2 minutes ago, TSNWK said:
But others are not happy.. even I’m a little confused
Looks very good to me
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4 minutes ago, Mike Poole said:
I’ll answer by saying what I think is important, which is getting a decent run at WAA into Greenland (as far west as possible) from the second low, here T192 on the ECM 0z:
If there is too much of a push north in front of the first low, then the angle for this becomes awkward. I think get this right, and any mess between it and the UK will go away as the run progresses.
I’m not sure I can see the low you are referring to near Greenland on the ECM chart.
On Ecm it is here:
Thankfully the low goes up the left hand side of Greenland , rather than into our block giving us a peach of a run late on.
Thanks for the explanation, That confirms what I was thinking.
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6 minutes ago, Mike Poole said:
Me too, but it is clear that others are looking in different places, and different times, which is often the way - not saying which is ‘right’ in this instance at all, once you have watched an evolution a few times I think each of us tends to focus on the areas/features that we think are important and aren’t always right!
Do you reckon how this low near Greenland reacts with our blocking Atlantic high around 180h is of greatest importance, or am I placing too much emphasis on just a small part of the jigsaw?
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2 minutes ago, nick sussex said:
You don’t want further obstacles put in the way so the ICON is not good .
The cleaner the evolution the better . Assuming things are going to evolve without further drama once you get the shortwave blowing up to the nw is likely to end in tears .
It’s neither one thing or the other . I’ve seen enough coldie disasters so for that reason the ICON needs to do one !
The Icon looks quite different to the UKMO and ECM at 180h, like it or loath it probably won't happen anyway! 10 bags says GFS 12z will be quite different; )
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2 minutes ago, nick sussex said:
The ICON looks like a dogs dinner . It might develop some cold with the slack flow but the shortwave to the nw blows up and the main ridge is stuck to the nw .
It looks very messy and unconvincing . And it would take an age to force the shortwave frenzy se .
It looks like it would get chilly from the east if the ICON was to go further, with disturbances popping in from the south and west turning to snow once it hits the cold air. Not bad at all in my opinnion
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Before the GFS 12z trickles out this the key area of interest to me. After 180h Most models are now in agreement that we get a large Atlantic block developing with much colder air about to drop into Scandinavia/ Northern parts of Europe.
This low pressure is the deal breaker in my opinion, if it follows the black arrow and sucks up SSW western side of Greenland we should get a perfect Greeny high. Follows the red arrow and we get a high perhaps in the wrong position and with pressure against it, from the top left side which we don't really want (especially at such an early stage.) Could eventually cause high to topple or milder air to filter in from the northwest while deep cold passes around the southeastern corner of UK then west into Europe....
Obviously, it is too far out to be coming to conclusions at this early stage but I would rather get a good trend going to start with, than having to chase and rely on 2nd or 3rd attempts at the cherry while winter slowly passes us by.
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16 minutes ago, blizzard81 said:
Feeling more positive now. Tamara's post earlier is incredibly positive and increases confidence that we can inch towards a cold spell.
I prefer it to the previous 150hr chart.
To be fair it has been brazenly obvious we are heading towards a cold spell since christmas eve! I don't know how anyone failed to pick upon it.
The question is how cold/severe will it get and how much snow will we get?? For that question we do not know. Doesn't matter how much waffle or word smithery someone uses, we will not know until T144H or sooner when all models are in agreement.
Like Mike Pool was saying earlier, we have now lost the possibility of a full on SSW event (All levels of the atmosphere) with full zonal wind reversal , instead we are looking at a weakened PV and PV displacement. With the Canadian warming event and the fact this is a El Nino winter, a full SSW event may not be needed for a major/lengthy uk cold spell.
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14 minutes ago, cold snap said:
My take
Short winter blast with snow flurries in the east possibly widespread . Before the high takes over then back to mobility.
To much traffic to the north .
I hope your wrong mate but certainly a possibility, I would say 30/40% chance of this happening
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14 minutes ago, Ruzzi said:
That chart you're showing is the warming taking place higher up in the strat .... and when you look at the mean windspeed up top for today/tomorrow, they are at the peak.
The reduction in the zonal winds doesn't bottom out until the 6th of January, again bearing in mind this is up top. There's no way that the great reduction of zonal winds can imprint its effects on the trop on Sunday when it's still 1 week prior to the reduction in windsoeed taking place. Following on from that, even when the windowed reduction takes place up top, there is going to be a wondering response time, with even a QTR taking some time to filter down to the trop. You can't have an instantaneous response, it just isn't possible. There needs to be a degree of time for the effects to filter down to the trop.
Thanks. To be fair though doesn't a strat warming usually take 3/4 weeks to be fully felt downstream?? What I am saying it will happen a lot faster this time around due to the other factors I highlighted (Canadian warming etc.).
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11 minutes ago, Mike Poole said:
No it’s not. The pieces have moved differently to how they were modelled a few days ago, and that is why we are not getting a reversal!
Yeah we have gone from a split PV with a full reversal to just a weakened/disrupted PV.
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3 minutes ago, Met4Cast said:
The SSW was predicted to happen around the 6th, we’re looking at the cold spell/blocking starting around the 8th.
I’m sorry, but that would mean an almost immediate impact and that’s just not what would have triggered our blocking/cold.
It may have prolonged/amplified it further down the line but it absolutely was/is not the cause of this blocking period.
It's already happening and in full flow by Sunday!
We are seeing an almost immediate impact due to the Canadian Warming and a few various other factors this is why we may not need a full SSW for Cold/Snow Nirvana Mid January, we might just get away with it but we are relying on pieces of the jigsaw coming together in just the right places.
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3 minutes ago, TillyS said:
We definitely should not discount it. The interesting thing is that when the GFS operational goes milder in FI (it’s not an outlier) is not when the ECM has the Beast from the East setting up. At the key period of the ECM’s Icelandic High (D6), and easterly, there is not a lot of support from the GFS ensembles:
9/10 of the time cold model output scenarios don’t materialise in the UK, especially Beasts from the East, so it’s best to be circumspect imho, whilst keeping some hope that this may be the 1/10!
I'm not saying discount the possibility of a more milder Atlantic driven end to run being shown by GFS OP, I'm saying that the run has very little support and is of little value when in its own right has no support from its own assembles and has no support from the ECM. I would even include the UKMO as well as that only looks COLD/BLOCKED from 168h on.
The chances of the GFS OP verifying with all the various data and signals at our disposal mostly signalling cold and blocked mid January, is about 10%. If we are to miss out on Severe cold (eventually or get little snow in January it is most likely from our Atlantic block being situated in the wrong position, leaving us dry and reasonably cold. Something like this:
Where all deep cold misses us sending Europe into the freezer. At the moment I think we are 70-30 against this scenario and looking more favorable so need to worry!
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4 minutes ago, TSNWK said:
I would be surprised if the ECM isn't one of the colder members of its own assembles, hopefully have some support though.
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Just now, Kasim Awan said:
We can't really discount both options yet, getting the wave to amplify well will be challenging, so we're far from 100% yet imo though very encouraging signs this morning.
Ye definitely on a whole far from cut and dry. I mean though that GFS is nothing to worry about without support from it's own assembles. Looks rogue to me.
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1 minute ago, TillyS said:
I've tended to agree about that.
But, wow, this time it has gone full tonto. It really is West v East. GFS v ECM.
UKMO has some mid-Atlantic high blocking at T168 but it’s different from the ECM evolution of the Icelandic high and a powerful easterly flow already in place at T192.
Either ECM has played a blinder or it’s going to lose this embarrassingly. High noon.
Good news GFS Op is well on mild side from the 10th, maybe even outlierish from that stage (but not getting into that debate again lol
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West Yorkshire mean close to -4/-5 latter half of the run which is not far off where we need to be, would like a few more perps straddling the -10 line and a few below that in the London essembles (sign of deep cold continental air) but nevertheless a good start to proceedings! Steady as she goes Captain
35 minutes ago, Kasim Awan said:Great gfs mean. Negative tilt at South Greenland at day 8.
Yeah doesn't get much better than that, at 240h looks just like the last 2 ECM runs!
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Just now, Lukesluckybunch said:
What would day time temps be at that stage? 0+2c I would guess?
Yeah good shout, showers all of snow now starting to settle down to sea level in the east
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Chart of the winter goes to ECM 240h, absolute perfection!
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I would prefer WAA more up the western side of Greenland, than the angle this run and ECM showing but the block should still hopefully retrogress and get there in the end.
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Just now, January Snowstorm said:
If this is a good chart our standards have dropped a lot over the years
Looks similar to Ecm12z does gfs 18z so far
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1 hour ago, LRD said:
What we're being shown is absolutely in line with what the professionals are saying for January isn't it?
Some of the takes in here this evening are utterly bizarre. If I see mild or, at least, not-cold I'll call it. I'm not seeing that at all. What I am seeing in this thread is whining one-liners, massive over-expectation and deep micro-analysis of every single frame of every single run of every single model...
Sorry to be rude but some of you need to give your heads a wobble. I reckon this is one cold spell that's going to come in relatively seamlessly. We don't know yet if it will be severe or relatively standard cold but just enjoy it being reeled in
Yeah ya right I was guilty of micro-analysing it, is a great chart really!
The trend is certainly our friend at the moment!
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4 minutes ago, Ali1977 said:
It’s the transition, it really does look like it’ll only improve and bring a continental feed - the cold is just sat there waiting close by. It would be great moving forward.
I'm not saying it's a bad chart lol. I'm just saying that there are better options still on the table!
As much as that chart could progress into something good, it could easily go wrong.
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17 minutes ago, Met4Cast said:
WAA into Greenland pumping up the high which would lead to fairly substantial HLB is.. a poor result?
That chart screams potential just a few days later.
The chart screams potential? I would rather it showed something that produced snow not a dry northerly, which could eventually topple! With what is on offer we want more than potential at that stage.
The low to the southwest of Greenland has traveled too far east into our ridge, that will not pump the high up for long!
This is what WAA pumping up a Greenland high looks like, not that cold fart of an attempt you highlight!
Look at the position of the low.
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Model Output Discussion - Into Winter
in Forecast Model Discussion
Posted
I was a bit worried for a minute, the angle of attack from the Atlantic, but we get just enough WAA early doors to sufficiently inflate our blocking high. Also advantageous is the low to the SW Greenland pumping up the WAA clears just about far enough north (left of Greenland) and weakens enough not to put a spanner in the works and displace our high back south and east. Excellent run, much improved on 6z.