Model output discussion - late November

[Tim Bland]

GEM not that great either unfortunately...gripping tightly to the straw that is the ECM...

[Ali1977]

All quiet in here, I think there is a lot of people hoping this ECM falls right for coldies!! It’s the first chance of the season for nationwide cold, which just so happens to be on and around the first day of winter. It would be a big bonus to get strike one so early in the season , the confidence of a good run isn’t quite that of what it was at 0900 this morning!! 

[legritter]

Good evening gang ,all very interesting posts today and of course a good day if you are a cold weather fan .I shall be glued waiting for tonights ecm to arrive .the photo of the squirrel attached was taken today in Exeter just outside of the met office ,it kept on chattering about it had seen their charts which were top secret ,and was heard to say as it straitened his woolly hat ,going to bribe posters on net weather  ,a few bags of walnuts for a peep .great forum gang ,catch you all later .

[Methuselah]

3 minutes ago, Ali1977 said:

All quiet in here, I think there is a lot of people hoping this ECM falls right for coldies!! It’s the first chance of the season for nationwide cold, which just so happens to be on and around the first day of winter. It would be a big bonus to get strike one so early in the season , the confidence of a good run isn’t quite that of what it was at 0900 this morning!! 

I'd much rather see the weather fall right, Ali! But, I guess it'll be yet another year of seeing peeps' cherry-picked predictions of Snowmageddon go sailing down the toilet?

[January Snowstorm]

Often  (in fact nearly every time) rather than one model being right or wrong we get a merging of both ideas and a halfway house. This looks to be the case this evening with the 06z gfs being incorrect overall but correct in spotting a trend of the Greenland high being weaker  (at least initially)

For me the UKMO is looking cold but what happens after that is where our interest lies...

Over to the ecm which will resolve nothing but at least gives us a trend for the evening!

[feb1991blizzard]

@Tim Bland - yes but it could upgrade again on the 18z.

Anyway BOOM!

 

[MR EXTREMES]

interesting looking at all the 10 hpa strat charts the gfs models are the only ones for strat warming navgem yesterday but nothing today.

but gfs gefs have continued forwards with strat developments.

but the most interesting part is how much wave activity is getting into the northern hemisphere.

i'm 80% at the moment the atlantic greenland combination with lows dropping down into scandinavia.

but more runs needed to be much more confident.

[MR EXTREMES]

anyone for winter and this is what i believe will happen.

80% confidence at the moment anyway.

09/10 winter was the year i watched this model alot and it performed well.

 

Edited November 22, 2019 by MR EXTREMES

[BLAST FROM THE PAST]

24 minutes ago, Ed Stone said:

I'd much rather see the weather fall right, Ali! But, I guess it'll be yet another year of seeing peeps' cherry-picked predictions of Snowmageddon go sailing down the toilet?

I don’t , I think cold December has a real chance here.

 

BFTP

Edited November 22, 2019 by BLAST FROM THE PAST

[MR EXTREMES]

been a longtime since seeing a disruptive chart like this from he ukmo.

all it takes to throw a disruptive block in the way.

ecm will be eye  candy.

vortex on holiday in siberia well most of it.

[Rayth]

Bold to be predicting the first half of December  

 

Edited November 22, 2019 by Raythan
Type

[BLAST FROM THE PAST]

37 minutes ago, Tim Bland said:

GEM not that great either unfortunately...gripping tightly to the straw that is the ECM...

Well if one looks on towards t240’GEM then a very cold reload is developing with another trigger low coming over top on NNW/SSE axis.  There’s lot’s to be resolved......a northerly quadrant flow does this......but my confidence, the way Nov has behaved and the model output is that I anticipate cold chances confidence for Dec to have increased.

BFTP

[northwestsnow]

4 minutes ago, Raythan said:

Bold to be predicting the first half of December  

 

It is a very bold call TBH..

EC awaited with a few nerves after Exeter upped the ante in their update..

One can only assume MOGREPS agrees with EC ..

Edited November 22, 2019 by northwestsnow

[MR EXTREMES]

this mornings ecm was very nice with a proper blocking heights into the atlantic.

[Ali1977]

4 minutes ago, northwestsnow said:

It is a very bold call TBH..

EC awaited with a few nerves after Exeter upped the ante in their update..

One can only assume MOGREPS agrees with EC ..

I didn’t realise they updated to this , it’s rare they do this so far out, so that fills me with more confidence for the upcoming ECM. Happy days. 

Edited November 22, 2019 by Ali1977

[SMU]

I will login to Mogreps & have a look now.

Its not on the menu any more

Edited November 22, 2019 by Steve Murr

[MR EXTREMES]

2 minutes ago, BLAST FROM THE PAST said:

Well if one looks on towards t240’GEM then a very cold reload is developing with another trigger low coming over top on NNW/SSE axis.  There’s lot’s to be resolved......a northerly quadrant flow does this......but my confidence, the way Nov has behaved and the model output is that I anticipate cold chances confidence for Dec to have increased.

BFTP

i agree that would develop into a cold spell not a cold snap.

the normally rampant east coast of the united states is a little more calmer.

most of the cold action is into asia siberia.

vortex definitely under the weather.

but of coarse lots could go different.

but it seem likely cold start to december likely.

[Ali1977]

Nice heights over Greeny at T96.

[Downburst]

3 hours ago, Paul said:

It's none of the above. It's simply differences between input data and the amount and type of data available. It's run on the same super computers regardless of run and every run uses the same physics.

There's some evidence to suggest the 00z and 12z runs are stronger, and based on the presentation linked below, there's also less data available to the 06z (the presentation suggests ~30%)  than all of the other runs. 

https://ams.confex.com/ams/27WAF23NWP/webprogram/Handout/Paper273676/GFS4cycle_2015_NWP_Chicago_15A.pdf

This is obviously based on the older version of the GFS, but the input data sources haven't really changed in that time, as far as I'm aware. 

Great, 30% less data available tells us a lot. Appreciate that, hopefully this sinks in.

[knocker]

The ext GEFS continues to evolve the new NH pattern which has the following salient points

Amplification of the subtropical highs in the eastern Pacific and Atlantic.

TPV around Franz Joseph Land with trough extension > northern Canada >eastern North America

Ergo a very amplified pattern with a strong westerly upper flow exiting the eastern seaboard and the around the ridge in the east

As usual the det runs need to sort the detail but indications of a drier and warmer spell but tending towards a N/S split

Comment: 'My cup runneth over'

 

Edited November 22, 2019 by knocker

[Ali1977]

144 looks good to me, similar to the UKMO 

Edited November 22, 2019 by Ali1977

[Rayth]

3 minutes ago, Ali1977 said:

144 looks good to me,

Isn’t that the 120?

[coldwinter]

ECM 144 close to GFS, certainly a closer run thing with the phasing issue as the earlier GFS flagged up 

[January Snowstorm]

The ECM at 144hrs has more in common with the gfs than ukmo. Let's see how the rest of the run plays out

[MR EXTREMES]

or not maybe a cold snap depends how much that shallow block around iceland seen shallow scandi ridges play havoc on model outputs before overestimating or unestermating.