Model Banter, Moans and Ramps Autumn/Winter 2014/15.

[TonyH]

Our northerlies ain't what they used to be

https://xmetman.wordpress.com/2015/01/26/thumping-the-528-line/

[Dunlop Dave]

http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2902

Perfect example of how things can change so quickly. In this case for the better !!

[Hammerofwinter]

Dear All,

 

Please can you help me. The BBC, Netweather and other are forecasting temperatures all through the upcoming cold spell in the region of 6 or 7 degrees, but all the talk is of snow. This doesn't seem consistent or likely. Why is this?

[knocker]

Just a minor quibble from the MOD thread, lower heights do not decrease the lapse rate i.e. the average change of temperature with height dT/dZ. It just means that this lapse rate is applied from a lower altitude to the surface so as dZ is lower the increase in temperature dT from 850mb to the surface is lower. In this context, for rough calculations the lapse rate is considered to be a constant.

Worth mentioning because the lapse rate is an important part of basic meteorology. In fact where the reduced heights are accompanied by cold air advection the tendency is for the lapse rate to increase because of warming by surface layers and vice versa increased height with warm air advection, cooling from the surface decreases the lapse rate.

 

I noticed that and was going to mention it but then forgot. When you say for rough calculations the lapse rate is considered to be a constant I assume that would be the ELR?

 

I'm no doubt being a  bit thick here but not sure I understand this.

 

 

In fact where the reduced heights are accompanied by cold air advection the tendency is for the lapse rate to increase because of warming by surface layers and vice versa increased height with warm air advection, cooling from the surface decreases the lapse rate.

 

I understand the lapse rate will increase if the surface and adjacent layers warm but I'm not sure why they should warm during CAA. It appears contrary to lowering heights.

 

In the case of the current storm in the US the CAA has made the lower layers cooler in relation to, say, the 850mb temps, thus indicating a decrease in lapse rate.

Edited January 26, 2015 by knocker

[mushymanrob]

Dear All,

 

Please can you help me. The BBC, Netweather and other are forecasting temperatures all through the upcoming cold spell in the region of 6 or 7 degrees, but all the talk is of snow. This doesn't seem consistent or likely. Why is this?

Those temps are surface maxs, most of the time itll be colder and the upper air will be much colder

[Hammerofwinter]

Thanks Mushyman. So it is likely to melt at the surface if/until colder conditions become established?

[Met4Cast]

Really struggling to see what all the fuss is about.

 

A 5 day Northerly before the high topples and cuts the cold feed off is all I can see. No evidence at all (bar the odd ensemble member) of HLB, high pressure sitting in the Mid Atlantic is not enough to send us into a deep, prolonged cold. We need blocking over Greenland/Svalbard and I'm seeing no evidence of this in the trends, anomaly charts or anywhere else.

 

Hell, even the NAO and AO are forecast to return back to positive after a brief dip later this week.

 

Perhaps a 5 day Northerly would have been something to get excited about at the end of the 90's early 2000's. But certainly not now. Snow for Northern, Eastern and Western coastal areas but for a majority who don't live on Northern exposed coasts, cold and dry. 

 

Sure, outputs might change, but a dry for most Northerly before the high topples is currently most likely.

 

Snowless winter year 2 for here and many other areas continues. Woo.

[Alexis]

Our northerlies ain't what they used to be

https://xmetman.wordpress.com/2015/01/26/thumping-the-528-line/

 

Sorry I don't agree. This -10 isotherm is almost in southern France here:

 

 

Just because the air is coming from the Arctic Circle, it doesn't automatically mean its at maximum coldness all year round. In the same vein, an easterly is completely dependant on how the cold the continent is. 

[frosty ground]

Really struggling to see what all the fuss is about.

 

 

 

A 5 day Northerly before the high topples 

 

So you do know what all the fuss is about........ 

[JoeShmoe]

Off topic but keep an eye on the #blizzardof2015 hashtag - if only ....

[Pembroke Dangler]

Can I say "it's going to snow" all over the country at some point in the next 7 days in this thread? Because that's what I see going by these charts! ITS COMING nuf said it may even snow in the Channel Islands and my uncle in the Scilly isles st marys to be precise they might get some of the white stuff there too so there we go it's a snowy picture all over the British isles starting early Wednesday and lasting through to this time next week at least

[knocker]

Ooooh. Eye candy.

Chart weatherbell

 

[alex12]

Any word from Ian regarding Wednesday/Thursday event?

Edited January 26, 2015 by alex12

[sorepaw1]

Any word from Ian regarding Wednesday/Thursday event?

I think Ian and other forecasters are really earning there money this week,I'm sure he'll find the time to post here and have a pint with us,

[Interitus]

I noticed that and was going to mention it but then forgot. When you say for rough calculations the lapse rate is considered to be a constant I assume that would be the ELR?

 

I'm no doubt being a  bit thick here but not sure I understand this.

 

 

I understand the lapse rate will increase if the surface and adjacent layers warm but I'm not sure why they should warm during CAA. It appears contrary to lowering heights.

 

In the case of the current storm in the US the CAA has made the lower layers cooler in relation to, say, the 850mb temps, thus indicating a decrease in lapse rate.

 

Yes the environmental lapse rate. Of course in reality the ELR is far from constant with 850mb air as often as not sourced from completely different locations to the surface air, with different modifications, even if in the same air mass.

With regards to the latter point, I was considering more the surface modification from the oceanic tracks of our typical air masses, so yes you are correct, I should've been clearer.

Here is a quick scatter plot of 850mb heights vs lapse rate from radiosonde recordings at Lerwick so far this January. The choice of Lerwick is to stress as much as possible a well mixed atmosphere with a minimum of land surface radiative cooling. The average ELR is a fairly typical 6.75°C/1000 metres, but the trend shows the tendency for slightly greater lapse rates the lower the 850mb geopotential height, with subtropical Atlantic air having lowest lapse rates cooled by the sea surface.

 

 

Your point also raises something else I was going to mention, that the extremely low 850mb temperatures don't represent cold 'uppers' as such - obviously the air is cold aloft - but it is more an indicator of low surface temperatures with inversions or isothermal layers which can extend up to 850mb and beyond.

Edited January 26, 2015 by Interitus

[mushymanrob]

Thanks Mushyman. So it is likely to melt at the surface if/until colder conditions become established?

Thats about it, but altitude and timing also play a part.

[West is Best]

 

 

As requested this was you completely ignoring the output 6 days ago about next week......

Like i said I wouldn't  be in such a rush to highlight missing every fish in the barrel until you shot one... 

 

 

Here are all the posts I have made about the northerly. 

 

https://forum.netweather.tv/gallery/image/20768-/

https://forum.netweather.tv/gallery/image/20769-/

https://forum.netweather.tv/gallery/image/20770-/

https://forum.netweather.tv/gallery/image/20771-/

https://forum.netweather.tv/gallery/image/20770-/

https://forum.netweather.tv/gallery/image/20772-/

https://forum.netweather.tv/gallery/image/20773-/

 

 

I'm not really sure why you are doing this but if you think your forecasting is better, go ahead and do it on the model thread. Otherwise, may I politely suggest the best way to go about getting both of us banned or restricted is to 1. to get personal and 2. to be rude. Have a good evening, and may you have much frost on your ground.

[frosty ground]

Here are all the posts I have made about the northerly. 

 

You know why I am doing this..... you asked me to.... you asked me to provide evidence to back up my post..... and I did.

Now you took great pleasure in telling the world how you were right and how the 0z runs backed you up.... which have now been dropped so your boastful post seem to have been premature and of course wrong. Of course that may change but it's the fact things may change should make you not be so boastful especially when your track record is so poor.....

 

 

I'm not really sure why you are doing this but if you think your forecasting is better, go ahead and do it on the model thread. Otherwise, may I politely suggest the best way to go about getting both of us banned or restricted is to 1. to get personal and 2. to be rude. Have a good evening, and may you have much frost on your ground.

[SE Blizzards]

Hope mod's will allow me this one...

 

Fergie just tweeted..

 

How long will cold conditions stay once here? Latest UKMO diagnostics hint at less cold, more W'ly-influenced weather by end of next week. This change - as is often the case - may prove rather 'messy' (perhaps yielding a risk of further snow in *some* parts of UK)...

Cont'd...but until then, we have high confidence on cold weather frm Weds PM thro rest of this week; & also possible for a few days nxt week

Edited January 27, 2015 by SE Blizzards

[SnowLover2010]

Hope mod's will allow me this one...

 

Fergie just tweeted..

 

How long will cold conditions stay once here? Latest UKMO diagnostics hint at less cold, more W'ly-influenced weather by end of next week. This change - as is often the case - may prove rather 'messy' (perhaps yielding a risk of further snow in *some* parts of UK)...

Cont'd...but until then, we have high confidence on cold weather frm Weds PM thro rest of this week; & also possible for a few days nxt week

 

Simple answer they just aren't sure. Still a good week of cold & potentially snowy weather for many for sure.

[meathead]

Got a feeling upcoming cold spell is just massively hyped up and will disappoint many. Can't believe they are already saying a return to westerlies next week! What a joke. Temps don't even look that cold for my neck of the woods and even further north. Met are saying highs of 5 degrees on Sunday, hardly arctic weather is it. 

Edited January 27, 2015 by meathead

[FENDER.]

Only just below average really.    looks dry for most of England away from the coasts.   3s and 4s for my neck of the woods

[knocker]

The EC32 update points towards a return to zonal. The anomaly at T240 has trop. vortex Greenland extending to Scandinavian trough that extends south into Europe and lies east of the UK. Ridge SW of UK orientated SW/NE. Thereafter the Scandinavian trough weakens leading essentially to a zonal scenario with LP to NW > NE with increasing influence from the HP to the south. Temps generally around average but tending slightly above.

Edited January 27, 2015 by knocker

[knocker]

Chart for Saturday

 

[cfbath]

Business as usual for all us down South then. Was really hoping for a decent covering. 2/3 years since we've seen anything meaningful down this way.