Model Output Discussion 1200 hrs 15/11/14

[ribster]

Indeed

knocker, is there any chance you could put a little more detail in your posts please, one/or a few words and a chart doesn't mean an awful lot to the less knowledgeable amongst us? Cheers

[blizzard81]

Differences as soon as T96 between the op and parallel tell us everything we need to know about the current output.

Isn't the parallel supposed to be superior to it's older sibling ? In this case, I hope not 

[johnholmes]

With Thanks to the MET office for the reverse Psychology today

 

This posted at 4pm

UK Outlook for Monday 1 Dec 2014 to Monday 15 Dec 2014:

At the start of the period the most likely scenario is for a continuation of unsettled weather to affect western parts of the UK. Spells of rain are likely further east at times too but the best of the dry weather is expected here. As we head through the first week of December there are signs that rainfall amounts should become nearer normal. There is currently no signal for temperatures to become lower than average but instead stay around normal for many, perhaps slightly above, especially across southern Britain. Of course, a few rather colder spells are likely during any quieter periods of weather, with a chance of overnight mist and fog in places, and patchy frost - this may be more likely across northern areas.

Issued at: 1600 on Sun 16 Nov 2014

 

just 6 hours later

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014111618/gfsnh-0-174.png?18

 

vertical advection over Greenland -

 

Cheers guys

 

ONE run

[blizzard81]

With Thanks to the MET office for the reverse Psychology today

 

This posted at 4pm

UK Outlook for Monday 1 Dec 2014 to Monday 15 Dec 2014:

At the start of the period the most likely scenario is for a continuation of unsettled weather to affect western parts of the UK. Spells of rain are likely further east at times too but the best of the dry weather is expected here. As we head through the first week of December there are signs that rainfall amounts should become nearer normal. There is currently no signal for temperatures to become lower than average but instead stay around normal for many, perhaps slightly above, especially across southern Britain. Of course, a few rather colder spells are likely during any quieter periods of weather, with a chance of overnight mist and fog in places, and patchy frost - this may be more likely across northern areas.

Issued at: 1600 on Sun 16 Nov 2014

 

just 6 hours later

 

http://modeles.meteociel.fr/modeles/gfs/runs/2014111618/gfsnh-0-174.png?18

 

vertical advection over Greenland -

 

Cheers guys

 

  Nice one Steve. The only thing that worries me is that this is not the parallel run  

Edited November 16, 2014 by blizzard81

[SMU]

The upgrade doesn't appear to be venturing cold air in the near time frame

Courtesy WxBell

 

What about the 228 chart ......................

[Ice Day]

Cold flooding into eastern europe, good run so far

 

[knocker]

ONE run

 

Indeed and showing my ignorance what is vertical advection?

[Nick L]

Indeed and showing my ignorance what is vertical advection?

 

Strictly speaking, vertical advection is the transfer of a property in the vertical (i.e. from the ground upwards).

[knocker]

What about the 228 chart ......................

 

But you mentioned T138 so thought it better to reply within the same time frame.

[Duane S.]

Indeed and showing my ignorance what is vertical advection?

WAA going S to N

[blizzard81]

  Nice one Steve. The only thing that worries me is that this is not the parallel run  

Just to add though, parallel run shaping up nicely for a great Scandi whoppa!!

[johnholmes]

Indeed and showing my ignorance what is vertical advection?

 

I suspect the flow up the eastern side of the low shown on the chart Steve linked to

[knocker]

Strictly speaking, vertical advection is the transfer of a property in the vertical (i.e. from the ground upwards).

 

But I was under the impression advection was the horizontal transfer of any property.

[nick sussex]

Isn't the parallel supposed to be superior to it's older sibling ? In this case, I hope not 

It all unravels because it blows up the shortwave and this phases with upstream energy. As soon as you get this phasing you lose the dig south of the trough which helps to build the ridge towards Greenland, the UKMO is pretty similar with a blown up shortwave.

 

Because the models don't want to send that shortwave se then its crucial that it remains shallow, both the ECM and GFS do that, the GFS love child  P and the UKMO don't, sum total not great.

 

I would still urge some caution regarding all the outputs good or bad for cold, there are some uncertainties with events in the eastern USA which do effect how the jet exits the eastern USA past T120hrs.

Edited November 16, 2014 by nick sussex

[SMU]

But I was under the impression advection was the horizontal transfer of any property.

 

Vertical as in south to North over western Greenland on the flat grid that we look at.

 

S

[Ice Day]

It's the GFS....and the Pub Run, however the NH profile is looking excellent for future prospects.  Patience is the watch-word here, slowly and surely the pieces are coming together.  At 228 the PV is looking a bit punch drunk!

 

[Yarmy]

Perhaps the bigger picture is important here

The upgrade doesn't appear to be venturing cold air in the near time frame

Courtesy WxBell

And the bigger picture just a few hours later...

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=1&runpara=1&carte=1

...and then...

http://www.meteociel.fr/modeles/gfse_cartes.php?ech=6&code=0&mode=1&runpara=1&carte=1

...and then...

http://www.meteociel.fr/modeles/gfse_cartes.php?&ech=228&mode=1&runpara=1&carte=1

Sweltering.

[blizzard81]

It all unravels because it blows up the shortwave and this phases with upstream energy. As soon as you get this phasing you lose the dig south of the trough which helps to build the ridge towards Greenland, the UKMO is pretty similar with a blown up shortwave.

 

Because the models don't want to send that shortwave se then its crucial that it remains shallow, both the ECM and GFS do that, the GFS love child  P and the UKMO don't, sum total not great.

 

I would still urge some caution regarding all the outputs good or bad for cold, there are some uncertainties with events in the eastern USA which do effect how the jet exits the eastern USA past T120hrs.

Exactly Nick, that's what worries me about todays output, especially the UKMO agreeing with tonight's GFS parallel. Tomorrows runs

should resolve the questions over the shortwave - nervous Monday coming up!

[knocker]

Vertical as in south to North over western Greenland on the flat grid that we look at.

 

S

 

 Ah right. Just so I know in future what word does the thread use for CAA travelling north to south?

Edited November 16, 2014 by knocker

[Jason M]

Seems to me that nothing much has changed today really. It really doesn't matter what the detail is at day 10 or more. All that matters at that range is that there seems a consensus that high pressure will probably be sat over Scandinavia. The detail can be filled in later.

Edited November 16, 2014 by Jason M

[Jason M]

Ah right. Just so I know in future what word does the thread use for CAA travelling north to south?

'rare' seems to cover it!

[blizzard81]

Seems to me that nothing much has changed today really. It really doesn't matter what the detail is at day 10 or more. All that matters at that range is that there seems a consensus that high pressure will probably be sat over Scandinavia. The detail can be filled in later.

Yes, today's output screams Scandi High at day 10. How cold ? That will certainly take a few more days to resolve.

[bluearmy]

Ah right. Just so I know in future what word does the thread use for CAA travelling north to south?

Been a couple of years since we've needed one - can't remember!

[SMU]

Ah right. Just so I know in future what word does the thread use for CAA travelling north to south?

CAA

The advection name tag has just been specifically assigned to 'that date' in november 2010 -

Exactly Nick, that's what worries me about todays output, especially the UKMO agreeing with tonight's GFS parallel. Tomorrows runs

should resolve the questions over the shortwave - nervous Monday coming up!

Yes its a concern - updates to come in 6 hours!

[blizzard81]

GFS 18z parallel shows at classic battle post 240 hrs between Scandi high and the atlantic, something we haven't seen for many years.

A classic 80's winter scenario and one I remember quite a lot as a child. BBC forecaster, be it McAskill, Giles, Fish saying a front moving

in from the west, making it to the east coast, only for it to be shunted back west by the massive block to the east - oh happy days