Cold hunt - models and chat

[Leon1]

A couple weeks back people said GFS was a cannon fodder model. Why are people suddenly filling up 5 pages in 45 minutes faffing about it? We should be looking at the GFSP more seeing as it's meant to be an improved version...

[swfc]

Gfs parra is ok up to 162 mark then the energy slips south of Greenland,"granted fi"but the high is on a dodgy wicket there after

[kold weather]

Ok so the ensembles are once again a big mess...

However we clearly have TWO clusters at play:

1: Follows the GFS op + UKMO and takes the Polar vortex lobe over Canada into the Atlantic, it merges with a low further east and the whole thing collapses.

2: 06z GFS op run - basically the PV lobe rotates around the main lobe and doesn't come away and remains over Canada/ far W.Greenland, thids allows pressure to rise and we get our northerly.

Much more binary set of runs than we have previously seen. Probably still just about more support for cold, but like the ECM its basically close to 50-50.

Edited January 23, 2019 by kold weather

[kold weather]

2 minutes ago, swfc said:

Gfs parra is ok up to 162 mark then the energy slips south of Greenland,"granted fi"but the high is on a dodgy wicket there after

It actually sticks out abit of a synoptic outlier, in that it doesn't send the energy across the Atlantic but equally it doesn't keep it far enough west to prevent the Azores high toppling down. Interesting run though for sure, and certainly different!

ICON still just about ok as well on its 12z run.

 

 

[Leon1]

Never before have I got snow from a North-westerly albeit it was only a dusting this morning but usually those Brecon Beacons steal all the snow away!

[Mike Poole]

FV3 interesting run, here T162, looks good for snow for many and it's less tha a week away.  Interesting also to see where this run goes longer term.

Mixed output tonight, still think UKMO has potential, particularly if the wedge at T144 is modelled more strongly on subsequent runs.

[feb1991blizzard]

Hello! Hello - what do we have here on the GEFS, is this the first signs of the Easterly arriving in the extended.

[Timmytour]

Unbelievable ECM coming up.  It's going to be setting a new trend and getting us all very excited once again....  tick tock

Edited January 23, 2019 by Timmytour

[bluearmy]

This year seems to be worse than previous ones with people taking operational runs too seriously beyond day 6/7. As far as I recall, we hardly ever used ops post day 8 for anything other than a bit of fun. Now we have people going nuts because of output at day 11 or 12. It’s just madness.

ecm’s flatter solution in the mid term looks reasonable based on current modelling - beyond that, there may be a more amplified picture but that’s way beyond reliability of ops and ens continuity looks poor to take too much from it 

fwiw, the gefs continue to hint at blocking once we get to around 5th feb as the Canadian vortex is pulled west by the developing n Pacific segment - this was the pattern that gave us the December scandi height rise which was scuppered by the ex TS that came into the Atlantic with too much energy for it to survive- with that not a possibility early feb and the lower strat now with very slack flow, you would expect HLB to establish somewhere to our north after that date 

[kold weather]

Just to give a quick illustration of the two broad camps:

Here is the GFS OP and Ensemble no.7 one fails at the northerly, the other comes off.

So here are both at 108hrs, I've circled the area to watch:

Both PV lobes are in a more or less similar location and strength.

Differences start to show at 132hrs:

The P7 run keeps it as one discrete lobe and moves its around the stronger vortex lobe to its NW, in a fujiwara method (spinning around a central point). GFS Op on the otherhand is literally slicing away the energy and it is escaping into the Atlantic, just like I highlighted on the UKMO 12z as well.

And VERY different 156hrs charts.

The Op has a flatter pattern and the NW flattening to a westerly, the P6 has a much more amplified pattern and a northerly.

So in future, if you want to have a good clue as to what way the runs are going to go, LOOK at the lobe over Canada an d its movement. IF it looks like P7 its game on, if not then there is trouble. EVERY single run that looked like the OP on the ensembles went on the flatten the flow and introduced milder air to the south. Every run that looked broadly like P7, was either cold, or very cold.

We should have good clue about the ECM between the 960-120hrs charts, and almost certainly know by 144hrs.

[Froze were the Days]

Slug going no where even on the GFSP - occasionally tapping into some brief cold air either from the north or east but it's transient in nature, the slug is king here. Just watch the Azores area in future runs and if there is lowering of heights in the vicinity then we're in business!

[Johnp]

5 minutes ago, feb1991blizzard said:

Hello! Hello - what do we have here on the GEFS, is this the first signs of the Easterly arriving in the extended.

I just checked them all at 300hrs.

Two out of twenty had an easterly, most were quite poor.  Which ones are you looking at, or were you being sarcastic?

[❄️❄️❄️❄️❄️❄️❄️❄️❄️]

39 minutes ago, Froze were the Days said:

But what do they have in common?...yes the Azores slug will stay there but just oriented differently, some chilly days ahead but certainly not the Freeze the majority of us want...the models will drive me to drink (ah Ladyboys).

 

 

You could be a bond villain. Dr No (vocal chords) 

Not as as snowy as shown by this chart which is just for fun (or not) 

[kold weather]

4 minutes ago, bluearmy said:

 

fwiw, the gefs continue to hint at blocking once we get to around 5th feb as the Canadian vortex is pulled west by the developing n Pacific segment - this was the pattern that gave us the December scandi height rise which was scuppered by the ex TS that came into the Atlantic with too much energy for it to survive- with that not a possibility early feb and the lower strat now with very slack flow, you would expect HLB to establish somewhere to our north after that date 

Definitely noticed that, mind you a lot of those are the poor variation of an easterly with little to no deep cold due to the evolution of the previous 10 days.

Regardless of everything else, I still think we will get some good blocking at some point, I'm still happy with the 5-10th Feb, but I think your right in that area to watch may well be Scandinavia. Just hope there is a decent cold pool around by that point otherwise might be one of those HLB that looks impressive but little to back it up at the surface!  

 

[fluid dynamic]

7 minutes ago, Timmytour said:

Unbelievable ECM coming up.  It's going to be setting a new trend and getting us all very excited once again....  tick tock

yes, i am bracing myself and so should everyone i think !

[feb1991blizzard]

5 minutes ago, Johnp said:

I just checked them all at 300hrs.

Two out of twenty had an easterly, most were quite poor.  Which ones are you looking at, or were you being sarcastic?

you should have checked them all at 360, seen as thats the point in the run that has a mean Easterly!!!!!

[Froze were the Days]

19 minutes ago, Timmytour said:

Unbelievable ECM coming up.  It's going to be setting a new trend and getting us all very excited once again....  tick tock

I'll think the potential at day 10 and thereafter will be unbelievable on the ECM tonight so much in fact that I won't be able to sleep until tomorrows 0z ECM which will leave me in even greater expectation until eventually April is here and that full on easterly arrives! Full on brace position currently...

Edited January 23, 2019 by Froze were the Days

[kold weather]

2 minutes ago, feb1991blizzard said:

you should have checked them all at 360, seen as thats the point in the run that has a mean Easterly!!!!!

Yeah, there is definitely a signal for a Scandi high deeper into the run. Though they are right, most of the easterly's are of the useless grain producing variety, with very little in the way of meaningful deep cold at all.

Still need to be in it to win it. Regardless of what happens to our next set-up, still needs to be watched...though to go again for a 3rd time will be hard for people if that is what happens...

[nick sussex]

I quite like the UKMO.

If we could just get the pattern a bit further se. The first upstream low is already disrupting at day 6.

The next low upstream over the Great Lakes will phase with the PV lobe pulling that nw and removing the energy to feed that first upstream low.

The issue is just whether the pattern will be too far west , a correction se would help .

[I remember Atlantic 252]

4 minutes ago, nick sussex said:

I quite like the UKMO.

If we could just get the pattern a bit further se. The first upstream low is already disrupting at day 6.

The next low upstream over the Great Lakes will phase with the PV lobe pulling that nw and removing the energy to feed that first upstream low.

The issue is just whether the pattern will be too far west , a correction se would help .

you will do, -8 uppers, or is it too far East? still could be corrected west

[kold weather]

Right well the 12z ECM is off. Remember folks, if the upper vortex over Canada dives SE towards Atlantic between 120-144hrs its not looking good, if it rotates around the upper low we will be in business in all likelihood.

Beyond that and there are still going to be chances, so don't get too downhearted IF the ECM does indeed continue on its merry way. Does NOT mean its the end of winter, or that we won't get any cold for the rest of the winter, etc...maybe just make it a little harder, that's all!

 

Edited January 23, 2019 by kold weather

[Johnp]

I think people have gone a little stir crazy due to this poxy winter so far.

I'm still trying to get my head around how certain people think this is a poor chart

I remember in the past, the above chart would have sent weather forums into meltdown!

[Timmytour]

2 minutes ago, kold weather said:

Right well the 12z ECM is off. Remember folks, if the upper vortex over Canada dives SE towards Atlantic between 120-144hrs its not looking good, if it rotates around the upper low we will be in business in all likelihood.

Beyond that and there are still going to be chances, so don't get too downhearted IF the ECM does indeed continue on its merry way. Does NOT mean its the end of winter, or that we won't get any cold for the rest of the winter, etc...maybe just make it a little harder, that's all!

 

This is is one where TEIT's easterly begins to show up, just T120 away!

Seriously though Kold....great stuff from you....much appreciated analysis

[Penicuikblizzard]

1 hour ago, kold weather said:

Well that wasn't the best GFS run I've ever seen, still got a few chances but we basically end up with a good, but short lived NW airflow and a really weak NE/ENE airflow and that is about it for the cold spell for most...

Not exactly what we are looking for is it?!

GFS 12z gets a 6/10 from me. Not a total disaster as some are saying, but its a pretty poor end given the potential that is out there.

 

Would you rather a mild wet SW flow

[WhiteFox]

4 minutes ago, Johnp said:

I think people have gone a little stir crazy due to this poxy winter so far.

I'm still trying to get my head around how certain people think this is a poor chart

I remember in the past, the above chart would have sent weather forums into meltdown!

Back in 2003 we'd have banked that chart in a heartbeat! I guess last year has raised expectations!