Tracking the potential Polar Low - Thursday into Friday

[Jo Farrow]

It is a polar low, they aren't that rare, it is like a trough line but gets its own circulation, caught in the flow south. Met OFfice have said it is a polar low for those who are waiting on Ian F's opinion. MO model moves it across NI and then Wales with heavy PPN

[Weather-history]

Well it's only the SW and Wales that the precip will affect really. All areas will become less cold overnight, although northeast England will cling on to the colder air.

Confusing because Matt Hugo tweeted this

"Curly-swirly...Polar low-type feature (not an official one) set to bring some snow to SW Scot and NW Eng later today. pic.twitter.com/Dtj6dGotTn

[Nick L]

Eh? On the Western side they usually track, throwing off a lot of convection in the Irish Sea and into the NW.

 

I have seen one of these deliver a Foot of snow in the NW.

 

Confusing because Matt Hugo tweeted this

"Curly-swirly...Polar low-type feature (not an official one) set to bring some snow to SW Scot and NW Eng later today. pic.twitter.com/Dtj6dGotTn

 

Only going by the ECM, doesn't show anything really for those areas, goes through Ireland and into Wales and the SW.

[shaky]

Is this the feature that gfs 12z shows as heavy snow across central england tonight and into the south east!!

[Snowstorm1]

Well it's only the SW and Wales that the precip will affect really. All areas will become less cold overnight, although northeast England will cling on to the colder air.

Problem is nick is us in northeast England will we get any precipitation for snowfall?

[Dr. Astro]

Only going by the ECM, doesn't show anything really for those areas, goes through Ireland and into Wales and the SW.

 

I'll eat my hat if the ECM predicts it's track 100% spot on.

[Nick F]

So if a polar low can't be modelled

 

What is GFS modelling SE top of Iceland?

Call it an embedded shortwave trough if you like but really isn't it the model trying to predict instability and would it not be potentially a polar low?

 

I'm not entirely convinced it is a polar low as the low was up near Iceland yesterday evening as an open wave and seems to have formed at a boundary between less cold air coming west from Scandi aloft wrapping around the parent low just NE of the UK sandwiched between cold air over the UK and coming down from Greenland, with the 'warmer' air occluded out aloft as can be seen in the T500 chart for noon today:

 

 

Normally would expect 500mb air temps to be around -40C or below, -35C at the warmest extreme perhaps, can't really see the airmass over the low that cold.

 

Polar lows tend to be barotropic (forming within a cold airmass) rather than baroclinic (along boundaries of airmasses).

 

12z UKMO (meso) takes the little low to the NW southeast down across N Ireland then Wales then out across English Channel  around Dorset/Hants - looks like sleet and snow from this feature this evening across N Ireland then overnight mostly to the west of London -especially across Wales and the West Country overnight.

Edited January 29, 2015 by Nick F

[Gray-Wolf]

Folk need to remember that it is tied to the mother low and so it's track will be around her and moving 'with' her?

 

I see it ( decaying or not) tracking into the country via lakes to N.Wales ish? That places it across NWest, West Yorks ,Derbyshire and on toward the coast. Its cargo is spread over its width so either side of its track will see that 'cargo' ( rain /sleet/snow). 

 

If you look at where it has been drawing air in from I'd take suggestions of 'milder' with a tad of sceptisism? Those thoughts were based on mother low and her dictates but her 'son' has skewed things a bit? 

 

Ingested air from Sweden and heavy draw down of air from above. What was marginal for some might well now be 'On'?

[Nick L]

I'll eat my hat if the ECM predicts it's track 100% spot on.

 

Well regardless, it won't be cold enough for the most part.

[Steve Rob]

Any chance of this hitting the Isle of Man?!

[Dr. Astro]

Well regardless, it won't be cold enough for the most part.

 

South of mid Wales, agreed.

[Steve C]

Don't polar lows also decay rapidly on reaching land too? Much like hurricanes? Not at all convinced this is the real mccoy.

[Paul]

Can see how the NetWx-SR has modelled it on the 6z data (will update later with 12z stuff)

 

 

Some tasty gusts in there too

 

And of course snow...

 

All low confidence even at this point though...

[Catacol]

Click it then click the save button bottom right

 I mean this video graphic... :-)

 

http://www.yr.no/satellitt/europa_animasjon.html

 

Can anyone help me save this? 

Edited January 29, 2015 by Catacol_Highlander

[SP1986]

It is a polar low, they aren't that rare, it is like a trough line but gets its own circulation, caught in the flow south. Met OFfice have said it is a polar low for those who are waiting on Ian F's opinion. MO model moves it across NI and then Wales with heavy PPN

 

Ive witnessed some cracking Polar Lows, they form, but unfortunately I've rarely seen them barrelling down the Irish Sea.. they tend to die off Northwest Scotland in my own experience, but I still recall an absolutely amazing thundersnow event from a Polar Low back in 1995 or thereabouts.

[Cheshire Freeze]

Folk need to remember that it is tied to the mother low and so it's track will be around her and moving 'with' her?

I see it ( decaying or not) tracking into the country via lakes to N.Wales ish? That places it across NWest, West Yorks ,Derbyshire and on toward the coast. Its cargo is spread over its width so either side of its track will see that 'cargo' ( rain /sleet/snow).

If you look at where it has been drawing air in from I'd take suggestions of 'milder' with a tad of sceptisism? Those thoughts were based on mother low and her dictates but her 'son' has skewed things a bit?

Ingested air from Sweden and heavy draw down of air from above. What was marginal for some might well now be 'On'?

I agree, I don't think this is looking as clear cut as some of the NWP is making it out to be. Some areas will most likely take a hammering from this. Even if it is a high ground only event, precipitation rates could potentially see a foot of snow fall.

Edited January 29, 2015 by CreweCold

[Dr. Astro]

Thanks for them Graphics Paul...

 

Can guarantee, someone, somewhere is going to get a dumping from this feature, almost blizzard like conditions.

 

If I was in N.Wales,and parts of the NW / Mids North, i'd be getting twitchy.

[Nick L]

Euro4 has it tracking a bit further east with slightly colder air entrained.

Edited January 29, 2015 by Nick L

[Bullseye]

Thanks for them Graphics Paul...

 

Can guarantee, someone, somewhere is going to get a dumping from this feature, almost blizzard like conditions.

 

If I was in N.Wales,and parts of the NW / Mids North, i'd be getting twitchy.

What about Scotland or does it depend on the track?

[andy989]

Thanks for them Graphics Paul...

 

Can guarantee, someone, somewhere is going to get a dumping from this feature, almost blizzard like conditions.

 

If I was in N.Wales,and parts of the NW / Mids North, i'd be getting twitchy.

N Wales you say, I like this

[Met4Cast]

I agree, I don't think this is looking as clear cut as some of the NWP is making it out to be. Some areas will most likely take a hammering from this. Even if it is a high ground only event, precipitation rates could potentially see a foot of snow fall.

 

I think a foot of snowfall is probably a tad over optimistic.. But I agree with you on the models probably not having the track nailed down.

[Dr. Astro]

What about Scotland or does it depend on the track?

 

Really depends on the track but I think Glasgow could be on the *edge* of the system, so you might be lucky.

 

It appears looking at data & sat it could track into the Irish Sea, picking up more moisture.

[Polar Maritime]

An interesting bonus feature this Polar Low   

[Cheshire Freeze]

I think a foot of snowfall is probably a tad over optimistic.. But I agree with you on the models probably not having the track nailed down.

Yes, that's top end stuff-somewhere like Buxton etc.

[Winter Cold]

If it does go slightly east then id say West and South Yorkshire are in with a good shout as wed be on the NE side of it, and colder air. Will be a night of radar watching anyway lol!