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phil nw.

Model output discussion pm 13/01/2016

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Sorry mods !! But I have to show my appreciation for the guys on here posting their thoughts !!  Brilliant !!!

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The latest NAVGEM 18hrs run to T90hrs is a carbon copy of the ECM 12hrs run at T96hrs.

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2 minutes ago, ALL ABOARD said:

Just to lighten the mood and give us all some time to destress here are some eye candy charts to help us all sleep !

We can all dream eyyy! 

gensnh-2-1-348.png

 

gensnh-5-1-348.png

gensnh-18-1-348.png

gensnh-12-1-348.png

When this is the eye candy, I know were in trouble :diablo:. In fairness, they are pretty much the best on offer from the GEFS.

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1 minute ago, Jason M said:

When this is the eye candy, I know were in trouble :diablo:. In fairness, they are pretty much the best on offer from the GEFS.

To be fair t384 does give us this ...

gensnh-18-1-384.png

All for fun of course :girl_devil:

 

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3 minutes ago, Jason M said:

When this is the eye candy, I know were in trouble :diablo:. In fairness, they are pretty much the best on offer from the GEFS.

This one a bit more reliable not but 1 week before your Charts..:D

gensnh-16-1-174.png

gensnh-16-1-192.png

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22 minutes ago, Nick L said:

Euro4 now drags the precip for tomorrow night east. It's a good 200 miles east of what GFS shows. ECM and ARPEGE in the middle. The ridiculous uncertainty goes on.

You never know the unthinkable may just happen ,falling and settling snow in AYLESBURY. #shocking

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43 minutes ago, ukpaul said:

For some reason the dew points are way higher on this run, hence lack of Monday breakdown snow, 850s also warmer but not as great a difference.

 

It s because the overnight feature on Sat/Sun is further E introducing moister air.

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Does anyone know why the ARPEGE just stops at 60h, then continues churning out charts some 1-2 hours later?

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Just in case anyone needed another dose of model confusion for tomorrow night, Netweather's own 18z Hi-res model takes the ppn down into Wales only tomorrow evening from the Irish Sea and even here it is light so pretty much another option on the table. This table is so full of options now, there is no room to sit around it and enjoy it properly. Like a christmas dinner, I am now tired and exhausted from all of the different foods and have been overloaded!

Edited by Costa Del Fal
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Remarkable just how much the 18z GFS has backed things west with the precip on Mon following the Sat/Sun feature.

High-res models clearly faring no better, seems no model can get a good handle on how well the warmer air, containing some from ex-Alex, manages to progress against the colder air ahead of it.

Welcome to the weekend of 'where's it going?!'

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8 minutes ago, PerfectStorm said:

Does anyone know why the ARPEGE just stops at 60h, then continues churning out charts some 1-2 hours later?

The 18z update only goes out to 60h for some reason, has really strange updates. It's in French but you can probably decipher the update details...

102h pour le 00Z, 72h pour le 06Z, 114h pour le 12Z, 60h pour le 18Z

 

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As Nick pointed out with regards to the eastern shift of the snow band, the precipitation is also further east by quite a margin on the ARPEGE. The below charts show the accumulative precipitation (if it all fell as snow). 

12z

arpegeuk-45-66-0.png?15-17

18z

arpegeuk-45-60-0.png?16-00

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9 minutes ago, Costa Del Fal said:

Just in case anyone needed another dose of model confusion for tomorrow night, Netweather's own 18z Hi-res model takes the ppn down into Wales only tomorrow evening from the Irish Sea and even here it is light so pretty much another option on the table. This table is so full of options now, there is no room to sit around it and enjoy it properly. Like a christmas dinner, I am now tired and exhausted from all of the different foods and have been overloaded!

I know the exact feeling, its like you cant be bothered with the festivities anymore and you want normality to resume 

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23 minutes ago, TEITS said:

Looking at the 18Z GEFS mean at +144 and to be honest it is dreadful. I would be amazed if the UKMO is proved correct and a return to milder weather is looking very likely in my opinion.  Still im not too disappointed because I didn't expect very much from this current cold spell and said many days ago we are a very long way away from a decent cold spell synoptically speaking.

 

gens-21-1-144.png?18

 

These mean charts can be deceptive... the NH mean chart at 144 is a lot more useful:

 

gensnh-21-1-144.png

 

You can quite clearly see there remains a strong mean signal for height rises over the UK and to our N/NE. For as long as the mean chart is picking up a signal for a ridge like this then there is most definitely reason for interest and optimism. Note also the troughing signal from Norway down through Germany and as far south as Italy and the adriatic.... again - given that this is a mean chart there is considerable scope for low pressure to be in place to our SE.

I would agree, however, that we are looking for something of a more blocked nature to begin to arrive in the operationals out beyond 7 days.... We are 268 hours away now from the predicted peak impact from the spike in AAM noted in and around 6th Jan... so as from tomorrow I will begin to scour the runs at 10 days with real interest. If we are going to get our cold end of month and cold Feb then it will start to make itself felt in various perturbations soon...

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Unfortunately tomorrow nights projected snowfall is down to radar watching really, its quite an unusual situation of a front heading into high pressure and despite upper winds being more southerly/SE'ly it still heads down the UK and looks to have some strength in it so no wonder the models are finding it hard pin pointing the details. 

As for next week, it could be interesting regarding the cold and mild battle but again details are uncertain at this stage but the trend still seems to be eventually the mild will win out and it could turn significantly milder although admittedly, it is being pushed back a little bit which could be interesting. 

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I've been reading this thread continuously over the past two weeks intensely. It seems no one knows what's going to happen.... I'm going to read some tea leaves, left in my cuppa after dunking a few biscuits. I'll let you all know what they say... Ha

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11 minutes ago, nick sussex said:

I just worked out those BBC weather for the week ahead forecasts that appear in the late evening are done using the 00hrs UKMO output.

Tonights forecast had high pressure over Scandi next Friday with an east/se flow into the UK , theres no way synoptically that  tonights UKMO output could evolve to that 24hrs later.

http://www.bbc.com/weather/features/35330201

Look around 2.50 into the forecast.

If the UKMO had completely disregarded their outlier solution and they went with the 00hrs run in that video perhaps that would explain this however this leaves a question mark over why then you'd put out a fax chart tonight that could not in any way evolve to that Friday chart shown.

This is one of my irritations! In the so called modern age of media, update the forecast with the latest info not output that's already yesterdays news!

Hmmm but we dont know what there models are showing that we dont see ?

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1 minute ago, helen47 said:

Hmmm but we dont know what there models are showing that we dont see ?

Their T120hrs fax chart that they put out tonight cannot evolve to the Friday chart shown in that video. If they think their output is an outlier then they should have modified their raw data so that the charts match the BBC forecasts.

I can see by the set up Friday that that is the 00hrs output as the evolution from that T144hrs to 24hrs later  would look inline with the BBC broadcast.

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 i see lots of comments on the ARPEGE in all the current excitement.  We are told that the GFS is always to quick to come across the Atlantic with a progressive bias. Typical Americans....bulldozing through  when it's been the UK holding back the block for so long.

But, being French, is the ARPEGE got a built in bias for the Atlantic to retreat?

 

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22 minutes ago, nick sussex said:

I just worked out those BBC weather for the week ahead forecasts that appear in the late evening are done using the 00hrs UKMO output.

Tonights forecast had high pressure over Scandi next Friday with an east/se flow into the UK , theres no way synoptically that  tonights UKMO output could evolve to that 24hrs later.

http://www.bbc.com/weather/features/35330201

Look around 2.50 into the forecast.

If the UKMO had completely disregarded their outlier solution and they went with the 00hrs run in that video perhaps that would explain this however this leaves a question mark over why then you'd put out a fax chart tonight that could not in any way evolve to that Friday chart shown.

This is one of my irritations! In the so called modern age of media, update the forecast with the latest info not output that's already yesterdays news!

The BBC longer range forecasts are always based on the 00Z runs after 48 hours I believe whereas before that is using the current data, do find it quite odd as the longer range forecasts during the week are used by the evening presenter so surely enough time to use all the 12Z raw output? 

The forecast does demonstrate a lot of uncertainty in the short term regarding the details but still sticking by the theme that it will eventually turn a lot milder sometime next week. 

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12 minutes ago, helen47 said:

Hmmm but we dont know what there models are showing that we dont see ?

They don't really exist to be honest going by what ex-Met colleagues have said, certainly not for short term forecasting, other than perhaps the super high res UKV.

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