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Model output discussion - 20th Feb onwards

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Apart from some patchy rain in the SW and snow on the Welsh mountains on Friday cold (as in below average) and dry until Tuesday.

gfs_ptype_slp_eur2_28.thumb.png.ad832a7a

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While I don't envisage a snowfest, the likes of the GFS aren't a fine enough resolution to pick up north sea showers particularly well. 

As an example Sunday morning GFS:

gfs123.thumb.png.69e4322337a03ac7324c12b

And Sunday morning Netwx model (12km version at this range)

netwx123.thumb.png.ffcc5cafe0e6211d1bb28

So quite different! Obviously I'd not be getting hung up on the specifics of any shower development etc right now, but  higher resolution models are showing more in the way of activity. You can view the Netwx-MR output here (free and extra users can use this address, it'll check if you're logged in or not and take you to the right place)

http://www.netweather.tv/index.cgi?action=netwx-mr;sess=

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Is this another case where the models have moved on but the public forecasts have not? Here are GFS/ECM 36 hours ago for next Monday; a keen easterly wind:

gfs-0-186.png?12

ECM1-192.GIF?12

And here's the latest - Kent clipper maybe but not much further north (sorry!). The ops are pretty much in the middle of the ensembles, too.

gfs-0-144.png?6

ECM1-144.GIF?23-12

Saturday into Sunday looks like the best chance of getting anything off the North Sea further north:

gfs-0-108.png?6 

Edited by Man With Beard
Removed quoted post

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How unusual the low is ejected north what's the mechanism behind this? 

image.thumb.gif.0499a97af2de663cb58ccb12image.thumb.gif.a6050f1a2948a86a038c29d5

image.gif

image.gif

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With regards to Daniels question. 

If you are relating to the small feature in the Irish Sea. My understanding would be that orbital lows will circulate around the main body of the stationary low pressure system. 

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16 minutes ago, PerfectStorm said:

With regards to Daniels question. 

If you are relating to the small feature in the Irish Sea. My understanding would be that orbital lows will circulate around the main body of the stationary low pressure system. 

I do not think it is like the earth orbiting the sun lol after some investigating maybe it has something to do with a segment/cut off part of jet stream over British Isles  :cc_confused:

I have never seen something like this before...instead of sinking into France as what would usually happen the low is taken on a conveyor belt, in essence up western half of the country.

image.thumb.png.5df486638bc83bbfb69766ea

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9 minutes ago, Daniel* said:

I do not think it is like the earth orbiting the sun lol after some investigating maybe it has something to do with a segment/cut off part of jet stream over British Isles  :cc_confused:

I have never seen something like this before...instead of sinking into France as what would usually happen the low is taken on a conveyor belt, in essence up western half of the country.

The orbital term has been used here quite a lot over the years. For example, a section of the polar vortex with a deep trough will often have smaller-scale features orbiting the main low, as they get dragged around the flow. Except this week will obviously be of smaller significance. 

For example:

1st.thumb.png.78b06d83781a58b0347ccb04792nd.thumb.png.32dc9380fb8a452de7b381d7be3rd.thumb.png.745edef32193a3da10fe7d896e

Edited by PerfectStorm
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1 hour ago, bobbydog said:

paul was referring to snow not cold. (i thought it was reasonably obvious) i dont think anyone is disputing it will be cold. as it stands (for now) not much will be falling from the sky for most of us.

See below- How do you know that ??

On the face of it this looks like another "blink and you'll miss it" affair. All over by Monday/Tuesday next week

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52 minutes ago, Daniel* said:

I do not think it is like the earth orbiting the sun lol after some investigating maybe it has something to do with a segment/cut off part of jet stream over British Isles  :cc_confused:

I have never seen something like this before...instead of sinking into France as what would usually happen the low is taken on a conveyor belt, in essence up western half of the country.

image.thumb.png.5df486638bc83bbfb69766ea

I think you are possibly making too much of this. It's just a small perturbation within the circulation of the main low.

gfs_z850_uv_t_eur_14.thumb.png.c640cf8bb

 

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4 minutes ago, knocker said:

I think you are possibly making too much of this. It's just a small perturbation within the circulation of the main low.

gfs_z850_uv_t_eur_14.thumb.png.c640cf8bb

Thank you for clarifying Knocker, thought I was being too vague. 

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anyway, what i was just in the process of adding to it was- its snowing here ( though not much and has just stopped ) the snow risk charts show nothing here

uksnowrisk.thumb.png.09dc2ce4f9fdbc198d4

just shows that things can pop up from seemingly nowhere despite what the charts show

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9 minutes ago, PerfectStorm said:

Thank you for clarifying Knocker, thought I was being too vague. 

BBC Weather last night indicated a small arm of the jet heading due north over UK and taking that with it.

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17 minutes ago, Climate Man said:

BBC Weather last night indicated a small arm of the jet heading due north over UK and taking that with it.

You could be correct but it doesn't show on the 300mb chart, merely the circulation around the main low. And small arm of the jet would be rather grandifying it as we are only looking at 45kts.

gfs_jet_300_eur_14.thumb.png.186900f2325

Edited by knocker

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26 minutes ago, bobbydog said:

anyway, what i was just in the process of adding to it was- its snowing here ( though not much and has just stopped ) the snow risk charts show nothing here

uksnowrisk.thumb.png.09dc2ce4f9fdbc198d4

just shows that things can pop up from seemingly nowhere despite what the charts show

I'm all for talking about the models in the context of what's happening on the ground. But it's 8c in Horsham, Ian who works for Netweather is based 2 mins up the road (and up a hill) and reports rain with some hail mixed in,  and the nearest weather stations who have reported recently say the same. So yes, of course things can come up weather wise which aren't shown, particularly when it comes to showers, but in this instance I think it's you that's perhaps mistaken rather than the models!

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2 hours ago, Paul said:

While I don't envisage a snowfest, the likes of the GFS aren't a fine enough resolution to pick up north sea showers particularly well. 

As an example Sunday morning GFS:

gfs123.thumb.png.69e4322337a03ac7324c12b

And Sunday morning Netwx model (12km version at this range)

netwx123.thumb.png.ffcc5cafe0e6211d1bb28

So quite different! Obviously I'd not be getting hung up on the specifics of any shower development etc right now, but  higher resolution models are showing more in the way of activity. You can view the Netwx-MR output here (free and extra users can use this address, it'll check if you're logged in or not and take you to the right place)

http://www.netweather.tv/index.cgi?action=netwx-mr;sess=

Well just checked and where are the  heavy frosts people are talking about, barely below freezing according to your output for most of the southern uk.

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10 minutes ago, Paul said:

I'm all for talking about the models in the context of what's happening on the ground. But it's 8c in Horsham, Ian who works for Netweather is based there and reports rain with some hail mixed in,  and the nearest weather stations who have reported recently say the same. So yes, of course things can come up weather wise which aren't shown, particularly when it comes to showers, but in this instance I think it's you that's perhaps mistaken rather than the models!

I know we are dangerously swinging away from topic, but if it's anything to go by, my parents in North Herts just told me it was snowing. I asked if it was hail/graupel and they notified me it was flakes (before anyone asks), and a few on my Facebook mentioning the same with the inevitable excitement.  

Obviously very localised but as Bobbydog mentioned, it has popped out of nowhere (model-wise) and has given some the chance to see a flake. 

Edited by PerfectStorm
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Ok, well I'm still not convinced of it as it doesn't look likely at all, but if you're happy it was snow then who am I to argue as I wasn't there! Guess we ought to get back to the models. 

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9 minutes ago, seaside 60 said:

Well just checked and where are the  heavy frosts people are talking about, barely below freezing according to your output for most of the southern uk.

Heavy frosts tend to relate more to surface temperature than just the 2m ones you're perhaps looking at on that viewer. 

As an example these are the sfc temps tomorrow night. 

coldnight-2302.thumb.png.f503bfcbb3759ee

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3 minutes ago, bobbydog said:

with all due respect paul, yes it is 8c here now but i've seen enough snow in my 46 years to know what it looks and feels like. i can assure you it snowed for a few minutes, turned to hail briefly then back to snow before then turning to light rain. point being, somewhere in todays atmospheric mix, conditions were briefly condusive to snow.

Indeed, despite not being favoured synoptically, always a chance of brief snowfall with showers under current setup where the freezing level is lowered (very) locally within convective downdrafts, with cold pooling at the surface further aiding snow to reach ground level.  You can see quite a mix (rain, hail, graupel, snow) given temp. fluctuation within/in vicinity of showers.  Have witnessed it myself at only modest elevation.  Cold air at 500mb currently pushing SE has contributed to shower development this afternoon over S/SE.

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1 minute ago, Paul said:

Heavy frosts tend to relate more to surface temperature than just the 2m ones you're perhaps looking at on that viewer. 

As an example these are the sfc temps tomorrow night. 

coldnight-2302.thumb.png.f503bfcbb3759ee

Opps sorry, doesnt say 2m temps on there,

Just says UK Temp.

Is there a link to the ground temps.
Thanks

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I really hope Joes not been reading the express to come up with that statement :)

Models definately not showing a winters worth of snow at the moment .... 

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Wrong thread, however as it's very quiet....

Joe is notorious for ramping up cold and snow, with very little substance behind what he says. Although I'm not disputing his qualifications, he's pretty much the Nathan Rao of the US. 

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