Model Output Discussion 13/11/13 >

[johnholmes]

Looking further ahead, 6-14 day time scale and all 3 anomaly centres today have similarities; that is building heights to the ne of the UK with low heights over the se and ese of the country. NOAA 6-10 and 8-14 for an idea of what they now seem to prefer after the intial cold from the NW-N.

http://www.cpc.ncep.noaa.gov/products/predictions/814day/500mb.php

 

the upper low shows as 546dm height, the lowest I've seen for quite a while for the UK.

[shaky]

Another beautiful 18z run from the gfs!!and on that note am goona leave you peeps to it and am of to bed on a happier note.

[Cheshire Freeze]

GFS suggesting ice day for some parts on day 7.....not bad going for 21st November

 

[Mark Neal.]

GFS getting there it seems. Steve Murr posting just yesterday about how it does have a bias with energy and split flows. It seems to be finally getting to where we want it to go..! Another epic pub run perhaps?

[radiohead]

The air is a little colder by T174 than it was on the 12Z.

 

[nick sussex]

The GFS so far is a good example of how you can still get cold conditions into the UK even with the PV over Greenland. Earlier the GFS develops a shortwave which could produce some snow but too early to say exactly where as this is liable to change before then.

[Mark Neal.]

The GFS so far is a good example of how you can still get cold conditions into the UK even with the PV over Greenland. Earlier the GFS develops a shortwave which could produce some snow but too early to say exactly where as this is liable to change before then.

Maybe a favourable shortwave for us Nick. Usually a spanner in the works! Plenty of interest though for now!

[Snowy L]

We have the classic elongated west Atlantic Low setting up, could be seeing a Greenland High in FI.

[Snowman.]

Step 1 is the boring step the real good stuff is later

[Man With Beard]

T186 ... now this could be fun, energy going over the top but at the same time pressure building back towards Greenland from the mid-Atlantic ... could the energy drop down from the north by T240? would be a cold bomb if it did

edit: ok not this time, High pressure simply gets stuck in situ, cold but fairly settled. Of course it'll be all change by 5am!

Edited November 14, 2013 by rjbw

[I remember Atlantic 252]

The air is a little colder by T174 than it was on the 12Z.

 

 

Easterly, advantage in Nov, should be good convection off the warm sea, where as in march and april, see was too cold for decent beefy snow showers

[Allseasons-Si]

I see a reload as we get to the lower res of the 18z gfs from sw greenland as someone sugested a break in the ridge earlier.

[SMU]

http://www2.wetter3.de/Animation_18_UTC/138_35.gif

 

6 inches for the NW & midlands etc

[PolarWarsaw]

Very long sausages earlier...now a dose of 6 inches! 

 

Christ, it's been a strange day..

 

 

[radiohead]

18Z GFS in FI looking something similar to the 12Z ECM :

 

[Met4Cast]

GFS doesn't seem to have a clue what it's doing in the low resolution part.. what a mess.

[Duane S.]

Been busy watching from afar for most of this building cold spell. I have to say, and i suspect i am not alone, i am amazed at some of the charts now being churned out by the models. I did postulate last week that the anomalous high over the other side of pole could well start bring a cold spell for us downstream but really i had a small Atlantic ridge in mind giving us a few day North Westerly. I couldn't see the amount of amplification and subsequent waa now being modeled. Hasn't happened yet though of course..

[DubWeatherAddict]

Who sees what i seees ? 

 

[Ian Brown]

Been busy watching from afar for most of this building cold spell. I have to say, and i suspect i am not alone, i am amazed at some of the charts now being churned out by the models. I did postulate last week that the anomalous high over the other side of pole could well start bring a cold spell for us downstream but really i had a small Atlantic ridge in mind giving us a few day North Westerly. I couldn't see the amount of amplification and subsequent waa now being modeled. Hasn't happened yet though of course..

 

Yes it was difficult to see this coming, particularly as the Strat thread indicated a return to zonality. Of course a long way to go yet and to newer members I would say that if zonality is shown at T168 it is a virtual given, if easterlies are shown then it is well beyond the reliable timeframe.

[Allseasons-Si]

Who sees what i seees ? 

 

lightning off the west coast of scotland

 

@126hrs snow to my area(imby) of cause,we shall see.

 

Westerlies aproaching in the relms of fl on the 18z,ughh!!!.

Edited November 14, 2013 by allseasons-si

[MR EXTREMES]

Very long sausages earlier...now a dose of 6 inches!

Christ, it's been a strange day..

That's because Steve needs to give it some Niagara. Today has been very exciting indeed.

And frosty the love affair with Darren bett is Top draw great posts always enjoy your post.

Remarkable day excellent outputs.

[nick sussex]

Maybe a favourable shortwave for us Nick. Usually a spanner in the works! Plenty of interest though for now!

 It looks like quite a shallow feature which is preferable, it all depends on whether the models develop this further, if we see a warm sector then areas to the east of the centre will likely get the snow, west of there rain/sleet with perhaps some backedge snow. Of more interest going forward is what the models do if we get to this type of set up:

 

 

The red arrow shows the positively tilted troughing, the black the high trying to retrogress. Will the models change the axis of that troughing to more neutral or negative nearer the time, if its the latter this will help the retrogression, another interesting thing is where the PV goes, even if lets say we don't get the full retrogression we might still see at least the PV dropping a little further south to the east/ne injecting some colder uppers into the flow which eventually work  back in on the southern flank of the high.

[Panayiotis]

So my thoughts a couple of days ago was to have a Scandi high develop after the initial northerly, confidence is lower but a retrogression after the easterly seems plausible to me...

To get the cold from the NE/E we need a chunk of the PV to drop down into Russia, this should also allow retrogression to occur and its something I will be looking for after the cold next week...

Edited November 14, 2013 by Panayiotis

[UV-RAY]

Yes it was difficult to see this coming, particularly as the Strat thread indicated a return to zonality. Of course a long way to go yet and to newer members I would say that if zonality is shown at T168 it is a virtual given, if easterlies are shown then it is well beyond the reliable timeframe.

Wise words indeed Ian, many of of us have been here many times with easterlies that have imploded in the reliable timeframe, lots of uncertainty from day 7 onwards still for me to get too excited with regards to the longer term prospects. Other than that it's been fascinating model watching as we've seen big upgrades in the short term over the last 24 hours. Edited November 14, 2013 by Sceptical Inquirer

[Isolated Frost]

I do believe that we are in for a rather more prolonged, cold spell, rather than snap- it may gradually take some time to get into; but the EC again, is very encouraging and the 216/240 profile leaves you begging for more.

168 is my favourite (IMBY) frame though. -6c to -8c uppers with such a large temp difference? Convection overload, plenty of snow for eastern areas. Plenty of good stuff from the N and NW beforehand for the West as well. All in all, it does look pretty promising.