Model Output Discussion 13/11/13 >

[terrier]

Much better run from the 18z but can we really trust the pub run? 

Edited November 15, 2013 by terrier

[Panayiotis]

Looks like that shortwave could pay us a visit...! I have interest in it because it could provide some moisture for snow...

Edited November 15, 2013 by Panayiotis

[Paul]

In our Spanish forum it has always been said that 00Z and 12Z runs are more realible because they include more data (the data gathered by the radiosondes - weather ballons). For example, in all my year watching the GFS runs I have noticed that in 06z and 18z runs it moves everything a little bit to the west, whereas in 00z and 12z runs it moves everything a little bit to the east again.

 

Any thougths about this?

 

Some info on this here:

 

http://forum.netweather.tv/topic/35985-what-data-does-the-gfs-use/

[weatherguy]

Hmm mixed feelings so far, it's a huge upgrade short term, but long term there's no WAA really heading up to Greenland, and on the other hand the shortwave is certainly sliding south east by +105h...Not quite sure how this will end up, a short lived easterly of sorts I imagine.

[Captain Shortwave]

Hmm mixed feelings so far, it's a huge upgrade short term, but long term there's no WAA really heading up to Greenland, and on the other hand the shortwave is certainly sliding south east by +105h...Not quite sure how this will end up, a short lived easterly of sorts I imagine.

The short term upgrades mean we should see a deeper cut-off low over Europe, meaning the high will probably collapse close to Scotland (half way house between the 06z and the 12z)

Wednesday night as the isobars open up could provide a widespread hard frost for most of the UK.

Edited November 15, 2013 by Captain shortwave

[Jonan92]

Some info on this here:

 

http://forum.netweather.tv/topic/35985-what-data-does-the-gfs-use/

 

Well, wikipedia says the following:

 

"Weather balloons are launched around the world for observations used to diagnose current conditions as well as by human forecasters and computer models for weather forecasting. About 800^[4] locations around the globe do routine releases, twice daily, usually at 0000 UTC and 1200 UTC."

 

I think that there is a reason to give more credit to 00z and 12z runs because of that, just my opinion and what I have usually seen watching models.

[Panayiotis]

Shortwave decayed by the time it reached Wales but nice features like this could cause a snow event so something to look for! At 120hrs we have some very cold surface conditions in South UK (lack of isobars) but look at the cold to the NE we need the high to move over to Scandi to bring us those NE winds..

Edited November 15, 2013 by Panayiotis

[carboncowboy75]

Hi first time poster long time reader 18z gfs looks much better short term great site by the way

Edited November 15, 2013 by carboncowboy75

[Panayiotis]

Short term overall is much better and we should be focusing on this part of the run! I think after 144hrs+ is just for curiosity!

Edited November 15, 2013 by Panayiotis

[Tony27]

a high of 2c in london on Tuesday and Wednesday going by the 18z 

Edited November 15, 2013 by Tony27

[SMU]

Well im quite satisfied today-  4-6 days @ -6 HPA, very cold dry surface air & a 'chance' of a retrograde High from day 8-

 

Not quite Nov 2010 but its not out for the fire yet & the Nov 2010 was the highest expectation we could have given it- so

very happy-

 

ground all frozen up suits me

[nick sussex]

It might on the face of it be a short wintry snap but it certainly is packing in complications in that window of opportunity. It looks like there will be two main bands of precip heading south, the first introducing the colder air the second in the shape of a shortwave running south afterwards. The complication more especially for the second one is how much this develops and whether we see a warm sector, if this does develop then areas to the east of the triple point will most likely have some snow but if it just remains a shallow feature then this would take out some of the marginality.

 

Later on the GFS18hrs  looks similar to its earlier 12hrs, with that slack flow there could be problems with fog and frost as the high builds eastwards.

[SMU]

Dare I say it 7 days with a CET close to 0c......

 

Nice Cold pattern there on the pub run!

 

http://modeles.meteociel.fr/modeles/gfs/runs/2013111518/gfsnh-0-162.png?18

 

COLD dry air

http://modeles.meteociel.fr/modeles/gfs/runs/2013111518/gfs-6-162.png?18

more so for England...

 

S

Edited November 15, 2013 by Steve Murr

[Panayiotis]

Could we get the -8C's back, we had them first!!?

Edited November 15, 2013 by Panayiotis

[SMU]

http://modeles.meteociel.fr/modeles/gfs/runs/2013111518/gfs-1-168.png?18

 

a pocket of -10c 850 HPA heading for the SE corner can it make it lol.....

 

S

[Captain Shortwave]

Could we get the -8C's back, we had them first!!?

Hello there..... is that a possible shortwave developing there over Germany that could track west with those coldest uppers. Now that if it were to appear in future runs, then that would interest me immensely.

Edited November 15, 2013 by Captain shortwave

[chionomaniac]

http://modeles.meteociel.fr/modeles/gfs/runs/2013111518/gfs-1-168.png?18

 

a pocket of -10c 850 HPA heading for the SE corner can it make it lol.....

 

S

Dare I say it but we are getting close to slider undercutting territory there as well - It wouldn't take much.

Edited November 15, 2013 by chionomaniac

[Mark Neal.]

-32 hpa mid Greenland.......

Tis a vortex still over that way. Really need that to shift to Siberia if we want reload and longer cold spell! Interesting GFS, and other models this evening is that it never really stops being cold, crisp foggy and frosty mornings with temps a good few degrees below average even if high pressure falls upon us after the cold snap next week. No sign of the Atlantic train/zonal!

[Panayiotis]

In the words of Steve, come to papa! SS is quiet... ?

Edited November 15, 2013 by Panayiotis

[Snowman.]

cfs looks intresting I wonder how rated that model is anyone know?

Good at trends in FI, crap in the GFS range it really has no Hi-res so every run is loony.

[cold snap]

Deep breaths now

Could be cobra run this ,colder air trying inhabit westwards

[Frosty.]

For those of you who fancy a wintry reload or three, I found some charts you will like from the GEFS 12z perturbations, there are some excellent charts here which would bring widespread snow and sharp frosts with even some ice days, there is pretty good support from the mean I have chosen in FI range..hope you like them as much as I do  

[Met4Cast]

The 18z goes to show just how important a sharper jet and slightly more amplified high actually is. The changes at the beginning of the run were absolutely minute but they have a massive effect down the line.

 

18z is something we can be pleased about.. it's just a shame it's the 18z, and the GFS. 

[Joe Levy]

The 18z seems to be reflecting how uncertain the forecast really is at the moment. We can be pretty sure it will get colder, but how much? It would be marvellous if a chart like this became reality, but given how different it is to some of the charts we have seen today, it's anyone's guess! It's all good fun guessing though and if this sort of weather came easily to us regularly, we would not have nearly as much fun following these sorts of charts in my opinion!

[Captain Shortwave]

Great way to end high resolution

Wintry, perhaps full blown snow showers packing into the east

Atlantic pattern looks good for a split flow and energy undercutting into southern Europe. Solid pub run and very close surface wise to the ECM mean.