Model output discussion - after the beast, what next?

[JeffC]

8 hours ago, EllyTech said:

March 19th 1987 saw a very heavy snow shower in Cheltenham - it was Gold Cup Day. There was an immediate covering and very large flakes. It quickly melted leaving no settled snow in the town. (from my own diary).

Interesting possibilities being thrown up for another chilly spell. I doubt it will be as potent as March 2013 which from my perspective remains the benchmark for late season cold in isolation, i.e. not a continuation of an epic winter like 1947 or 1963.

We ended up with 24", that's 60cm in "New speak" on 22nd/23rd....quite impressive for so late in the year....

[nick sussex]

Barring the GFS the others are looking less enthusiastic for a quicker return to colder conditions .

The problem is that low near the UK just sits there filling with little trough disruption and then just phases with energy upstream.

We’ve moved away from that more elongated troughing to the w sw and have this bloated one which isn’t as good moving forward .

 

 

[Bottled Snow]

5 minutes ago, nick sussex said:

Barring the GFS the others are looking less enthusiastic for a quicker return to colder conditions .

The problem is that low near the UK just sits there filling with little trough disruption and then just phases with energy upstream.

We’ve moved away from that more elongated troughing to the w sw and have this bloated one which isn’t as good moving forward .

 

 

That about sums it up Nick. Also ECM collapses the block in to central Europe between 144 and 168 whereas GFS and to lesser extent ICON intensify the block to northeast with trough disruption to southwest, drawing in the easterly. UKMO looks similar to ECM at 144 so will be intersting to see the 168 chart later to see if it follows suit....GEM is ...well I don't even want to talk about that...

[SLEETY]

18 minutes ago, Broadmayne blizzard said:

ECM this morning does its usual trick having teased us with some potentially cold runs by producing something completely meh. It always seems to do this at some point when a cold spell is approaching. Jumps between it cold and mild clusters before settling back into the general run towards a colder outlook.

Spot on.And to prove you are 100% correct here are the ensembles,one of the mildest out of all of them.Useless model sometimes.Best stick with the Met and the models they use in these situations,and they mention Snow showers in the N and E again

 

 

 

 

[Duane S.]

My first post or check of the charts for over a week, that last rollercoaster took it out of me I think!

The period around 19th March was always likely to be that next window of opportunity with a building block to the NE and I was pleased to see the GFS and a few GEFS members playing it out very nicely this morning. ECM op says no but looks like there should be some support for a cold spell from within the ECM ens.

Beast mk2? What I would say is to cast our minds back to 5 days or so before the last cold spell. Virtually unwavering support from all ops and ens (for a severe cold snap, not any of the finer details). It’s not a must, but there will much a much lower chance of this occurring if we don’t get this trending in our favour over the next couple of days.

[bluearmy]

such a lack of continuity from the ops over the past couple days. Even ukmo has been shifting its ideas days 5/6

gfs stays on the same page for two runs now but that’s  what it usually does and the evolution to second beast can be altered quite easily with some subtle changes earlier in the run. 

 really is poor guidance in the 6/10 day period but the extended mean remains solid on mid Atlantic ridging of sorts and broad sceuro trough. Staying cold but cold enough?????

in the medium term, the eps spreads and geps offer some support to the gfs op. We would have to see other ops adopt this evolution by the 12z suites (inc ukmo day 6) if it is to verify by the 20th

Edited March 11, 2018 by bluearmy

[Purga]

12 hours ago, Man With Beard said:

A mean easterly on the ECM ensembles

  

which is usually the best indicator of an incoming easterly

On balance though (sorry to be a party pooper), to me I think it's still 60/40 we won't see significant cold from this - because it's so late in the year - needs a push of minus 10C uppers first to get the cold to "set-in" IMO

A bit like this me ol' cock sparrow....

[Summer Sun]

18th to 23rd the best place for the GFS 00z Op would appear to be the bin given the lack of support

ECM mean continues to show nothing overly cold the Op is obviously on the warmer side towards the end

[Tim Bland]

I’d put the ECM in the bin as well then as it’s a mild outlier ? 

[Rocheydub]

3 minutes ago, Tim Bland said:

I’d put the ECM in the bin as well then as it’s a mild outlier ? 

If outlier is the criteria for binning a run, then certainly, both ECM and GFS need binning!

[pdiddy]

10 minutes ago, Summer Sun said:

18th to 23rd the best place for the GFS 00z Op would appear to be the bin given the lack of support

ECM mean continues to show nothing overly cold the Op is obviously on the warmer side towards the end

Re the GFS, there are 4 similar members, including the op.  Not certain to happen, but certainly an option not to be ruled out.

[ICE COLD]

12 minutes ago, Summer Sun said:

18th to 23rd the best place for the GFS 00z Op would appear to be the bin given the lack of support

ECM mean continues to show nothing overly cold the Op is obviously on the warmer side towards the end

It's not totally alone tho ss is it ? I would agree with you usually  but it's not out at day 14+ it starts at day 6/7 , so bit of an over reaction there by saying bin it ? But I bet if it showed 14 degrees with sw winds you wouldn't be saying bin it ? 

This is only a week from today -

[Wilxy]

Think the GFS Op came home late from the club last night!

[bluearmy]

GFS op drops the day 8/9 beasterly as expected though will be interesting to see what it decides to do on this run if it’s headed on an alternative route - small adjustment or ecm type jump?? 

[Frosty.]

23 minutes ago, bluearmy said:

GFS op drops the day 8/9 beasterly as expected though will be interesting to see what it decides to do on this run if it’s headed on an alternative route - small adjustment or ecm type jump?? 

Not only does it drop the beasterly, it drops any cold whatsoever..next saturday looks very mild..sunday a tad cooler but still mild further s / e!..the models giveth and the models taketh away!

Edited March 11, 2018 by Frosty.

[SLEETY]

Good luck if you think any of this gfs run is going to verify .Its synoptic garbage,

[Eastnorthwest]

10 hours ago, Eastnorthwest said:

Even better it's just off the east coast by T 165 which hopefully with the time frame won't change much  on next few GFS runs

00Z run more or less same as previous run showing same easterly being replaced by NE Easterly by T 240

Very encouraging for coldies ,next 2 days crucial to more or less nail it

[Eastnorthwest]

Just now, Eastnorthwest said:

00Z run more or less same as previous run showing same easterly being replaced by NE Easterly by T 240

Very encouraging for coldies ,next 2 days crucial to more or less nail it

Ok so the other models are garbage compared to GFS but that will change if the AO shows no signs of going positive in the next 2/3 days ,next 2 GFS runs also crucial for the other models to come on board don't ya think?

[Nick F]

Some inter-run variation between the model operationals and ensembles over where to build heights and sustain them, GFS more keen than EC to build heights over Scandi on both operationals and in the ensemble means.

00z GFS vs EC operational comparison

00z GEFS and EPS mean the difference in 500mb pattern fairly apparent too over Scandi at day 7

It appears to me that the models may be having some issues with handling the cold wedges moving around the arctic region on this side of the pole, braod agreement between GFS/EC/UKMO for a cold upper vortex/wedge to drop SE into NE Europe and NW Russia next week, with pressure then rising across Scandi, but then 00z EC pushes a cold wedge across Greenland towards Scandi  which merges with the cold pool over NW Russia/far NE Europe, sinking the Scandi high and allow low pressure over the Atlantic to gain more northerly latitude.

The handling of these wedges of cold air in the arctic prone to error given lack of data in this area, but also compounded by downwelling of a second burst of forecast zonal wind reversal in the stratosphere which will try to build high latitude heights, as suggested by Berlin strat update yesterday

I personally would place lower confidence than normal in modelling over N Atlantic / arctic / N Europe for next week, given the second warming / wind reversal in the strat perhaps starting to impact the trop pattern from next weekend.

Edited March 11, 2018 by Nick F

[johnholmes]

Yes the 500 mb charts you show have been changing over the past 2-3 days. Prior to this morning there was little indication of the ridging and +ve heights shown on those first two charts Nick F has posted. NOAA has some indication, fairly consistently over a similar time scale of slight ridging in the Greenland area along with small +ve heights. By the 8-14 then the trough it shows over the UK area has been pushed east. A couple more days and consistency for the 3, both with themselves and one another, IF they continue with what they currently show and some kind of ridging allowing fairly cold air to move south into the UK seems a high probability, note I said IF. To me the push would be more likely from west of not east of the meridian.

NOAA below

http://www.cpc.noaa.gov/products/predictions/610day/500mb.php

[Cloud 10]

Just to be clear what an outlier really is when viewing the ensembles,here is a decent example.

 

[Methuselah]

5 minutes ago, Cloud 10 said:

Just to be clear what an outlier really is when viewing the ensembles,here is a decent example.

 

But that's the wrong type of outlier, Cloud 10. The other kind is simply one that doesn't do as it's told!

[feb1991blizzard]

9 minutes ago, Cloud 10 said:

Just to be clear what an outlier really is when viewing the ensembles,here is a decent example.

 

But that's not a natural outlier, that's as a result of false starting data (ie - 2m temps about 3 or more degrees lower than what they actually were).

[phil nw.]

There are signs of weak blocking in places to the north but currently not strong enough i would say to promise notable cold for us within the next 10 days.

Day 10 ht anomalies

 

The ht anomalies on gefs and ecm certainly indicate small wedges of heights ne and nw at different points during the runs with a stalling trough near our sw which does  shows signs of some disruption into Europe but it all looks a bit underwhelming to get any chance of an easterly that will bite this late in the season.

The Scandi wedge/Euro trough disruption does start to look promising at day 7 on both

 

but that's about as good at gets on these runs before westerly momentum takes over, especially on the eps

We really need to get an almost perfect alignment in the pattern from the ne in order to draw say -10C or colder uppers from what will be a shrinking source of deep cold.

If we compare say March 2013 we can see the sort of pattern needed

where we had the flow initially from the coldest area-the Siberian sector of the pv dropping sw down through Scandinavia and into the UK.

 

[Daniel*]

Clear to see ECM has had a big wobble this morning. Day and night. Mean brings in the easterly.