Model output discussion pm 13/01/2016

[johnholmes]

24 minutes ago, IDO said:

In fact if you look at the height verification for D6 for the most recent days (where entropy has been high) the GFS has performed amongst the top (including the GFS Parallel) where as expected the UKMO has performed abysmally, down to 0.71 (GFS 8.8 same time) on the most recent run:

I do so love when folk post and cannot even quote correctly, and use terms that are a mite OTT!

Gawd IDO get things correct and how you can say GFS has been consisently correct in predicting a breakdown for the dates you quote is pantomime stuff.

We all have biases one way or another but come on lad some accuracy in what you post please.

 

[Weather-history]

19 minutes ago, Musical Chillies said:

Bit of a delay with this front coming in but Monday night/Tuesday morning has some interest. Used the Arpege as the example but GFS similar.

but will it be cold enough? Doesn`t quite look like it but something to watch.

Hi

The FAX chart is an old one. The new one for the same time frame has the front retreating to the SW

[Stuie]

Thanks for that WH.

[Captain Shortwave]

It is fair to say that things could have panned out a bit better in terms of long term cold and snow prospects, still the set up looks cold for many until the end of the week.

The GFS temperature predictions for a first half of the coming week. Not to be taken too seriously.

             

Very cold across central and northern parts, especially away from the coasts.

Some very cold nights too, this suggests a lot of sunshine in areas which are not underneath the frontal systems pushing in from the south west. Those fronts could prove to be quite snowy for lucky areas but there is too much uncertainty on this front.

This run turns slowly milder from Friday, but that is 6 days away in a period with the most uncertainty in the short term range that I have ever seen.

Edited January 16, 2016 by Captain Shortwave

[TEITS]

Nightmare to work out the snowfall potential on Monday. In these situations it's impossible to say who will be in the sweet zone. Now what I mean by this is depending on your location, you want the front to travel far enough NE to reach you but you do not want this to travel too far NE otherwise you're into the milder air. A stalling front in this situation can bring large amounts of snow but the sweet zone can be relatively narrow.

My early punt is parts of N/E Wales, W Midlands. I don't think it will reach the E Midlands/N England and will fall as rain to the SW and S counties.

Edited January 16, 2016 by TEITS

[IDO]

28 minutes ago, johnholmes said:

I do so love when folk post and cannot even quote correctly, and use terms that are a mite OTT!

Gawd IDO get things correct and how you can say GFS has been consisently correct in predicting a breakdown for the dates you quote is pantomime stuff.

We all have biases one way or another but come on lad some accuracy in what you post please.

 

I did back it up with a verification chart so I am not sure what else I can do John. The last two D6 verification runs for UKMO are 0.79 and 0.71 compared to GFS 0.87 and 0.89. That looks pretty conclusive to me? They cover the periods when this amplification started showing up in the models. Some may say these stats. cover the whole NH so for the UK the UKMO may have performed better, but we can only comment on what the figures say. Looking at Temp verification and the UKMO has performed even worse:

GFS for 6 days ago for today 12z: UKMO:

Current forecast: 

None of the models have been great, but we appear to have short memories on here as to what the UKMO was forecasting for this period and that was what I was referring to. We will not get stats. for the undercut verification for 3-4 days so we will then gauge who performed best then. But for the current verification I don't know how you can say UKMO>GFS?

 

 

Edited January 16, 2016 by IDO

[TEITS]

11 minutes ago, Captain Shortwave said:

It is fair to say that things could have panned out a bit better in terms of long term cold and snow prospects, still the set up looks cold for many until the end of the week.

The GFS temperature predictions for a first half of the coming week. Not to be taken too seriously

 

This run turns slowly milder from Friday, but that is 6 days away in a period with the most uncertainty in the short term range that I have ever seen.

Unless we see further energy heading SE then the high will inevitably topple and bring milder SW,lys.

[Ben Sainsbury]

4 minutes ago, TEITS said:

Nightmare to work out the snowfall potential on Monday. In these situations it's impossible to say who will be in the sweet zone. Now what I mean by this is depending on your location, you want the front to travel far enough NE to reach you but you do not want this to travel too far NE otherwise you're into the milder air. A stalling front in this situation can bring large amounts of snow but the sweet zone can be relatively narrow.

My early punt is parts of N/E Wales, W Midlands. I don't think it will reach the E Midlands/N England and will fall as rain to the SW and S counties.

Oh brilliant, love missing out on the fun! But nevertheless that's what the majority of the models are suggesting and I expect this we will be the outcome. Monday night into Tuesday does indeed look interesting as we may see the front head back into the SW, with snowfall on the back edge after passing eastwards earlier Monday.

[Catacol]

Amplification in the pacific evident at 7 days in the 06z

HP drifting to our East. Output now is indeed coming together, and disappointingly the transient northerly is turning out to be exactly that - transient. Gloomy Imbyism this morning suggesting no snow for lowland Somerset this week... :-(

But goggles on, chocks away - and good luck to those in central parts who look favoured to see snow in the next few days alongside an already snowy Scotland.

Looking further ahead if 1983 is indeed the template to follow, then we will see a milder blast from the atlantic at the back end of the week and then we wait to see how the amplified signal from the pacific will impact the atlantic. GP's AAM torpedo (!!) set to land in just over a week's time as we look to see more blocking establish itself. Any sign on the runs this morning? Yes there is. Almost bang on schedule a renewed push in our locale:

Will it push N, NW or NE? Way too far out to tell yet, but to my eye GP and Tamara's suggestions look good. I'll close my eyes to the disappointment of snow lovers in the SW regions this week, and keep my eyes firmly fixed on the last week of January. A ridge that is a bit stronger and a bit further west may deliver to the lowland SW yet.....

[nick sussex]

12 minutes ago, Ben Sainsbury said:

Oh brilliant, love missing out on the fun! But nevertheless that's what the majority of the models are suggesting and I expect this we will be the outcome. Monday night into Tuesday does indeed look interesting as we may see the front head back into the SW, with snowfall on the back edge after passing eastwards earlier Monday.

I wouldn't give up hope yet. You can see already just on the GFS 06hrs run how the pattern has been shifted westwards within the T48hrs timeframe.

Once these types of corrections start showing up with this type of set up then generally they don't suddenly start shifting eastwards.

Whats quite interesting here is the suggestion of a shallow low pressure setting up in the Channel.

Edited January 16, 2016 by nick sussex

[london and south east kent]

hi all looking cold and wintery looks like some snow moving from the north west heading for south east England London will see some snow tonight and even  more snow Monday south east England and London could be the sweet spot

Edited January 16, 2016 by london and south east kent

[Ali1977]

2200 prediction and what is happening now, front looks to be on a different path and coming in quicker.

[bluearmy]

1 minute ago, london and south east kent said:

hi all looking cold and wintery looks like some snow moving from the north west heading for south east England London will see some snow tonight and even  more snow Monday south east England and London could be the sweet spot

I suspect it wont LSEK but we live in hope

 

[Zakos]

Last 5 runs of the GFS for Thursday at 6.00am

Significant backtrack, was far too quick to bring the Atlantic in.

Its clear the cold air is not going to be swept aside easily, and If we are to see a breakdown next week it will be a gradual one with the potential for significant snow accumulations.

 

Looking at the Northern Hemisphere profile currently, the medium range potential for cold and further snow looks good,especially as we already have the advantage of having cold air in place over us. Every reason to be optimistic IMO

 

Edited January 16, 2016 by Zakos

[Ben Sainsbury]

2 minutes ago, Ali1977 said:

2200 prediction and what is happening now, front looks to be on a different path and coming in quicker.

How is the path looking different? I'm not sure?

[Long haul to mild]

16 minutes ago, IDO said:

But for the current verification I don't know how you can say UKMO>GFS?

 

 

Because GFS had us in mild SW winds for this weekend only a few days ago, whereas UKMO was always going for cold?

[Chris1986]

3 minutes ago, Ben Sainsbury said:

How is the path looking different? I'm not sure?

The front should stall as it passes across the uk which will slow it down significantly. Just a guess but I'll definitely be watching the radar today and hopefully  later the window  

[nick sussex]

The more I look at the early part of the week the more it looks like a forecasting nightmare of epic proportions.

Don't envy the UKMO on this, the shallow low formation and wave developing could invigorate the precip, the low also has the effect of changing the surface flow into the UK especially for more southern areas.

This then effects what part of France the flow ahead will come from and effects the dew points.

 

 

Edited January 16, 2016 by nick sussex

[Cloud 10]

GFS 06z 72 hr snow accumulations.

 

Edited January 16, 2016 by Cloud 10

[IPredictASnowStorm]

           still showing snow for tonight

[nick sussex]

13 minutes ago, Sweatyman said:

Living in brum I don't know if I ll be swimming to work or skiing by Tuesday !

My advice if you're currently in the sweetspot don't celebrate, if you're not don't despair. Any forecast even 24hrs out could still go pearshaped because the margins are quite small in terms of rain versus snow and where that will be.

These set ups can be lots of fun to see unfold as long as you're not the UKMO and aren't effected by the outcome!

This can come down to nowcasting, the thing to keep an eye out is the weather conditions especially dew points in northern France, Belgium.

The surface flow ahead of the fronts is going to be coming from there and later start swinging round to more ese which brings Belgium into the equation as the shallow low develops.

Of course that Channel will modify things, so southern coastal areas is a bit of a problem unless the flow can get round more to the ene.

 

Edited January 16, 2016 by nick sussex

[Alexis]

26 minutes ago, Ali1977 said:

2200 prediction and what is happening now, front looks to be on a different path and coming in quicker.

Bear in mind the map at the bottom is more squashed!

[Nouska]

43 minutes ago, Ali1977 said:

2200 prediction and what is happening now, front looks to be on a different path and coming in quicker.

It has another 11 hours to go till ten o'clock tonight - during that time looks like the front is back tilting on approach - models still showing similar set up but volatile situation so who knows what will actually transpire.

[offerman]

The front does look further west at the

moment on the radar compared to models. 

Edited January 16, 2016 by offerman

[offerman]

Wales getting more snow. A few flurries in southern England ( not sure if those are reaching the ground though).