Model Output Discussions 06z 04/11/16

[Ravelin]

Interesting progression within the last 4 GFS runs with regards to how far south the trough gets at t144 (our 'magical' 17th). From oldest to newest below...

    

Got to be a good few hundred miles further south on the 18z compared to the 0z.

[gottolovethisweather]

54 minutes ago, Fozfoster said:

Can someone say the last time we had a cold winter from a Russian high, they promise much but seldom deliver. 

 

 

 

The next time is clearly that memorable winter of 2016/17. I can dream, can't I?

 

For anybody else, worrying over the specifics, I'd suggest you don't. Questions remain over the precise details of how cold the 850s are, will we get an Easterly flow, is the continent cold enough, will the Russian Block push far enough East. Don't concern yourselves, look the global NH picture which indicates trending scenarios of a mid-Atlantic block, an NW-SE tilting jet, increasing amplification, a lessening of any SW'rly wind flow predictions in mid-range. At this range the intra-run trends 12z to 12z and 0z to 0z of the NWP outputs at the timescales of D4 to D10 are those we need to concentrate on, in order to determine whether this spell might last more than just a couple to three days, I think it will. As I stated yesterday predicting the weather some ten days ahead in late November 2010 made a fool of us, so trying to second guess things this time around, will likely do the same. Patience, Grasshopper! A colder spell is on its way, will it bring snow and ice before autumn is even finished with, watch this space!

Edited November 11, 2016 by gottolovethisweather

[Frosty.]

it's always nice to see snow on the map and the Gfs 18z shows a risk of snow from next thursday across exposed parts of the northwest, we get a decent dig of Polar maritime later next week with some frosty nights, especially sharp over the upland parts of scotland which receive fresh snow.

Edited November 11, 2016 by Frosty.

[snowblind]

47 minutes ago, Fozfoster said:

Can someone say the last time we had a cold winter from a Russian high, they promise much but seldom deliver. 

Jan 1987?

[January Snowstorm]

I think we have seen enough evidence over the last 48hours to understand something v special could be imminent.

The models have a recurrent theme of blocking in or around day 10. GP and Ian murmuring in a very positive way. It's only a matter of time imo (probably tomorrow) when cold, blocked charts move into the reliable....

[Mucka]

Certainly a nice 10 day chart from GFS this evening

[Ravelin]

GFS at t192 shows pretty big differences between the last 4 runs.

   

I think we live in just about the worst place in the northern hemisphere for predictability of the weather. I've noticed this over the last week or two, everywhere else other than N.Europe seems to vary little between runs, us, we can vary significantly from one run to the next.

[Mark Neal.]

6 minutes ago, Mucka said:

Certainly a nice 10 day chart from GFS this evening

Heights to NW, Heights to NE. Oooh. Looks good around us, can we gain from it though. I'd take that 10 day chart, looks primed. 

[Mucka]

6 minutes ago, Mark N said:

Heights to NW, Heights to NE. Oooh. Looks good around us, can we gain from it though. I'd take that 10 day chart, looks primed. 

Definitely, mainly because it has such a prominent Atlantic ridge.

The way GFS models the trough from around 228 is almost laughable IMO but no point in over analyzing FI charts.

So long as we keep seeing increased amplification in the Atlantic sector in those time-frames I'm good.

 

PS

Extended JMA didn't quite manage the ECM undercut but it is quite a similar synoptic.

Edited November 11, 2016 by Mucka

[feb1991blizzard]

Just now, Mark N said:

Heights to NW, Heights to NE. Oooh. Looks good around us, can we gain from it though. I'd take that 10 day chart, looks primed. 

I was just about to say hello 8th Dec 1990 but even though the uppers weren't that cold on that occasion, there just aren't the uppers around on these current charts for any kind of snow event but yes we are primed for future.

[Frosty.]

 The Gfs 18z shows the snow risk extending south during low res, nice charts for coldies! it's all about the trend and the trend is for a cold outbreak later next week which could last into the following week..another positive day / night of model watching!

Edited November 11, 2016 by Frosty.

[karlos1983]

1 hour ago, Fozfoster said:

Can someone say the last time we had a cold winter from a Russian high, they promise much but seldom deliver. 

Rare would be putting it mildly. In my mind, it's not even something I want to consider. Extremely difficult to get to our shores, would much rather heights to our north east, because we stand mor chance of getting the cold in, and for longevity of cold, retrogression is also a big possibility. Big Siberian high, yes would bring possibly deep cold pools, but leaves us precariously close to wet mildness. I don't think it's on the cards anyway. 

Everything still looking good, I expect some chopping around of the models over the coming 5-7 days, deciding where the PV heads and any blocking sets up. Interesting viewing indeeed!

Edited November 11, 2016 by karlos1983

[Paul_1978]

1 hour ago, Fozfoster said:

Can someone say the last time we had a cold winter from a Russian high, they promise much but seldom deliver. 

Watch this classic Feb 1991 forecast and see where the massive HP is ;-)

 

[Eskimo]

1 minute ago, Paul_1978 said:

Watch this classic Feb 1991 forecast and see where the massive HP is ;-)

 

Scandinavia? 

[Trom]

49 minutes ago, gottolovethisweather said:

The next time is clearly that memorable winter of 2016/17. I can dream, can't I?

 

For anybody else, worrying over the specifics, I'd suggest you don't. Questions remain over the precise details of how cold the 850s are, will we get an Easterly flow, is the continent cold enough, will the Russian Block push far enough East. Don't concern yourselves, look the global NH picture which indicates trending scenarios of a mid-Atlantic block, an NW-SE tilting jet, increasing amplification, a lessening of any SW'rly wind flow predictions in mid-range. At this range the intra-run trends 12z to 12z and 0z to 0z of the NWP outputs at the timescales of D4 to D10 are those we need to concentrate on, in order to determine whether this spell might last more than just a couple to three days, I think it will. As I stated yesterday predicting the weather some ten days ahead in late November 2010 made a fool of us, so trying to second guess things this time around, will likely do the same. Patience, Grasshopper! A colder spell is on its way, will it bring snow and ice before autumn is even finished with, watch this space!

There is a slight irony in posting "predicting the weather 10 days ahead made a fool of us..." before predicting cold and ice by the end of autumn in the very next sentence.  Nonetheless synoptically we remain in a much better place than in previous years so I do see your point. The vortex continues it's fragmented movement and looks a long way from being cohesive.  Can't see any signals for cold and ice for the whole country as yet but the potential is certainly there.  Just nice to have a season that is thus far free from raging zonality.  Think back to the last two years with the compact vortex over Greenland and the high pressure constantly to the south and east of the UK and the difference is stark.  I do agree at this stage of autumn/winter to focus on the specifics of each run is a little pointless but to focus on the long run broad patterns is encouraging if colds what you want.

Given this is my house at present and my family is living in the garden in a caravan the law of the sod says it's bound to be cold.  

[karlos1983]

19 minutes ago, Paul_1978 said:

Watch this classic Feb 1991 forecast and see where the massive HP is ;-)

 

Minus 4 on the south coast with wind chill of -15c. That's weather porn at its best! A 1050mb scandi high is what I will go to sleep dreaming of tonight  

Sidney's grandad was made of tough stuff! 

Edited November 11, 2016 by karlos1983

[Man With Beard]

2 hours ago, Captain Shortwave said:

A lot of talk about this block to our east, it is not a given that this will precede a wintry spell for the UK, we only need to go back to 2014 at this point where we saw persistent blocking to our east with a lot of positive signals only for the pattern to break down come the end of the month and a pretty average winter followed. 

CS I've been thinking the very same thing ever since the Scandi High appeared at the start of October and I've kept my expectations low for a long time as a result. But for me something happened last week that changed my mind. Back in 2014, the first chance that the pattern had to break down, the PV pounced and formed like a monster. I sensed last week was that opportunity for the PV, with troughing taking control over Greenland/Iceland for the first time. But to my amazement, D7-D14 modelling seems to want to disintegrate the PV even further, and now its coming to pass as we're seeing not only blocking to the east but hints of heights back on the cards to the west, too, and the PV all over the place. For me, right now is where 2016 diverges from 2014. I just think if the PV was going to take charge, this was the obvious moment. The fact it hasn't tells me there's something deeper in the weather pattern this autumn that isn't going to let it happen. I'm now expecting blocking to continue for some time, perhaps even well into December - who knows, even longer?!

[Mucka]

GFS ensembles seem to be firming up on a chilly couple of days around the 18th

That mean was close to zero this morning.

[karlos1983]

Not a bad thing to say about the GEFS ensemble mean 

Given the time of year, that's incredible 

Edited November 11, 2016 by karlos1983

[Summer Sun]

The fall in temps later next week is shown quite clearly on this ECMWF chart

 

[lorenzo]

Some very cool charts kicking around...

 

[ArHu3]

4 hours ago, Fozfoster said:

Can someone say the last time we had a cold winter from a Russian high, they promise much but seldom deliver. 

Here in Holland late January early February 2012, very very very cold (I saw -26C in the morning), shattered quite a few coldest day records

Edited November 12, 2016 by ArHu3

[Mucka]

GFS 00z

Snow on leading edge of channel runner in November?

It could be possible if this came off.

And staying chilly under our cold trough. especially up North

 

All in FI and quite different to previous runs so not to be taken too seriously but interesting nonetheless. 

 

GFS ensembles an absolute dogs dinner by day 10 with everything on offer. Take your pick;

 

A couple of chilly days clearly defined on the graphs now though.

Edited November 12, 2016 by Mucka

[IDO]

Looking at the ECM it was predictable that its D7 chart from last night was again over hyping the pressure rises. This morning it has toned it down, and therefore moves closer to the GFS, with that spoiler low (mobile pattern) preventing as much WAA into the Greenland region.

Last night D7  This morning 

Just for newbies, as the older members probably know by now that ECM ops after D7 are unreliable with respect to pressure rises.Of course this fail has a knock on effect, the more mobile Atlantic stops the Russian high from blowing up and migrating west, so last nights ECM op regression (D10) of that high was just ECM on one again.

Looking at the D12 onwards GEFS, and Shannon Entropy remains. Though no sign of the PV getting its act together on any individual stamp so promise there, but no dominant cluster and its clear there is little WAA to the higher latitudes into any part of the NH, so no sustainable blocks, just MLB(s) with pockets of HP meandering withing a semi-mobile disorganised PV.We need a driver to kick start a different pattern, either a strong MJO signal or a TS, or forcing from the ENSO. Our brief cold spell was partly derived from the last TS disrupting a seemingly locked in pattern.

 

[Summer Sun]

ECM shows a mixed pattern this morning mild till Wednesday then we see some chiller air for a few days before some milder air returns at by D7 and turning cooler again from the north at D10

Edited November 12, 2016 by Summer Sun