South West England Cold Spell Discussion

[snowking]

Yes, and on Thursday the NAE has a fat 22mm over us. 22mm of what?

http://expert.weatheronline.co.uk/daten/proficharts/en/nae/2010/02/16/basis18/ukuk/rsum/10021818_1618.gif

Yep wondering that myself

Can only assume itll be the system moving up from the SW, we just need to see the DP's, because it looked favourable on its NWern flank on the 12z

SK

[MP-R]

-0.5C and clear at the moment with a nice frost settling. oh how I would give for any precipitation to come during the night!

Bristle Boy: although I appreciate your point, even in recent years we've had proper snow in February, most notably 2004. Remember 26th Feb when it had been sunny all morning allowing the temperature to rise then at the start of the afternoon it began snowing and within half an hour it was settling.

[Bristawl Si]

-0.5C and clear at the moment with a nice frost settling. oh how I would give for any precipitation to come during the night!

Bristle Boy: although I appreciate your point, even in recent years we've had proper snow in February, most notably 2004. Remember 26th Feb when it had been sunny all morning allowing the temperature to rise then at the start of the afternoon it began snowing and within half an hour it was settling.

I'm not saying we don't see snow in February - i mean 1947 was basically all of Feb here in the West and Feb 95 was a good snowy month for us. But generally for a sustained deep cold spell like we had a few weeks ago it's prob too late.

I suppose Michael, with me approaching 'old fart' years, the winters of 78 to 87 spoilt me with fierce blizzards and deep drifting snow, even in Bristol itself. Wet snow that won't last long doesn't float my boat - however with elevation, conditions can be better in these late (ish) set ups.

Edited February 16, 2010 by Bristle boy

[Ian Fergusson]

New modified NAE fields and DT15z high-res models offer growing confidence of a NW shift tonight/tomorrow for snow risk - e.g., consistent signal (75% of ECMWF members) going for +2mm PPN Hereford and then transferring most snow likelihood into areas >100m for East Wales / Marches into Staffs, Derbyshire, Mancs etc. Still an error margin of about 50miles or more but crucially the latest NAE is keen to keep the WBFL up at 400-600m in the frontal zone.... hence we'd expect snow at 100m+ and perhaps down to lower levels in heavier bursts of PPN. Still a very uncertain outcome all round.

Latest NAE run has taken the low on Thurs somewhat further north and paints it as predominantly a rain story across the SW/West (i.e., coming into line with the GM expectation).

Edited February 16, 2010 by Ian Fergusson

[MP-R]

I'm not saying we don't see snow in February - i mean 1947 was basically all of Feb here in the West and Feb 95 was a good snowy month for us. But generally for a sustained deep cold spell like we had a few weeks ago it's prob too late.

I suppose Michael, with me approaching 'old fart' years, the winters of 78 to 87 spoilt me with fierce blizzards and deep drifting snow, even in Bristol itself. Wet snow that won't last long doesn't float my boat - however with elevation, conditions can be better in these late (ish) set ups.

Oh well yes definitely, deep cold is out the window really at the end of February. Having not been around, I can only go by people's descriptions of snow and look at archived weather records for such as 78 and 87 lol. As with many members though, February is the time to be looking for snow in itself rather than deep cold.

Having just watched the National BBC Forecast, it would seem the snow stays about 50 miles to the east of us tomorrow then the front fizzles from the south upwards before it even gets back here whether it be snow or rain by that stage. I am going to Egham tomorrow so will see what the central counties are like on my way up tomorrow morning.

[snowking]

New modified NAE fields and DT15z high-res models offer growing confidence of a NW shift tonight/tomorrow for snow risk - e.g., consistent signal (75% of ECMWF members) going for +2mm PPN Hereford and then transferring most snow likelihood into areas >100m for East Wales / Marches into Staffs, Derbyshire, Mancs etc. Still an error margin of about 50miles or more but crucially the latest NAE is keen to keep the WBFL up at 400-600m in the frontal zone.... hence we'd expect snow at 100m+ and perhaps down to lower levels in heavier bursts of PPN. Still a very uncertain outcome all round.

Latest NAE run has taken the low on Thurs somewhat further north and paints it as predominantly a rain story across the SW/West (i.e., coming into line with the GM expectation).

Yep thursday looks to be all down to precip intensity on the 18z

http://expert.weatheronline.co.uk/daten/proficharts/en/nae/2010/02/16/basis18/ukuk/prty/10021818_1618.gif

Quite clearly there only the heaviest precip bringing snow

Im pretty sure the rollercoaster isnt over yet though, it could well still be rolling on by this run tomorrow

SK

[Dartmoor_Matt]

Oh well, rain it is then.

Roll on Spring! Any chance of a southerly plume next week?

[kold weather]

New modified NAE fields and DT15z high-res models offer growing confidence of a NW shift tonight/tomorrow for snow risk - e.g., consistent signal (75% of ECMWF members) going for +2mm PPN Hereford and then transferring most snow likelihood into areas >100m for East Wales / Marches into Staffs, Derbyshire, Mancs etc. Still an error margin of about 50miles or more but crucially the latest NAE is keen to keep the WBFL up at 400-600m in the frontal zone.... hence we'd expect snow at 100m+ and perhaps down to lower levels in heavier bursts of PPN. Still a very uncertain outcome all round.

Yep, it seems like the NAE develops a wave feature along the front briefly though it soon goes, this seems to be the reason why the front is edged more to the NW. Will be interesting to see how this verifies because past experience has shown me the models tend to err too far to the west at times, the same thing happened to the NAE before the 5-6th of Jan set-up when it swang well wes tonly to have to come east when it didn't happen...

However each evolution is going to be different and no reason to doubt the 18z data but I am curious as to what the 0z data will show...I wouldn't be surprised to see a slight shift bacjk eastwards, the ECM op run looks better with the strongest of the front a little to the east of the NAE output.

[Nights King]

Because M, even if we got snow tom morn it'll be so marginal, it will be wet stuff that will melt straight away at low levels. You or our firends in the Cotswolds may fare better.

I'm not one for 'late snow' because temps just feel raw rather than freezer-like, a la early jan. For us in the west snow in late Feb/March tends to be short lived and messy, unless one has elevation....like you, Dartmoor Matt or those in the Cotswolds. 'Late Feb 78' type blizzards are v.rare, even 'back in the day' for us.

I can see your point although i think you have been blinded a little by the exceptional january? feb marginal is what we norm look for here in west country and feb/march is often our best chance of snow.

Wet snow has its plus side also because at least you can build snowmen/snowballs ect. jan snow we couldnt.

[Schmac]

Wet snow has its plus side also because at least you can build snowmen/snowballs ect. jan snow we couldnt.

Probably good for "Snow Zoos" too, which will be music to Dancing Daisys ears!!

[Iceberg]

NAE is still keen on enhancing the precip and keeping it further NW. This allows for a significant cold undercut IMO as shown by the 00Z NAE.

DP's and temps very quickly come down once the mild section has gone through.

Still alot of uncertainties around where the precip is, how intense it will be, how cold and quickly the under cut comes in etc.

[SteveB]

Rain here at the mo,

Dewpoint 0.2c

Temp 1.6c

[Nights King]

Sleet with lumps of snow mixed in to it at the moment although looks like main ppn is going to nudge slightly north of me!? how i thought this was going to be more south east?

just turned to snow.

Edited February 17, 2010 by mullender83

[Nights King]

NAE is still keen on enhancing the precip and keeping it further NW. This allows for a significant cold undercut IMO as shown by the 00Z NAE.

DP's and temps very quickly come down once the mild section has gone through.

Still alot of uncertainties around where the precip is, how intense it will be, how cold and quickly the under cut comes in etc.

that is quite interesting however i have a gut feeling it will move abit further north again and leave us in the wet.

[Bristawl Si]

that is quite interesting however i have a gut feeling it will move abit further north again and leave us in the wet.

Raining here and it's bl##dy cold! Bleak, still quite dark.

Roll on Spring!

[Iceberg]

that is quite interesting however i have a gut feeling it will move abit further north again and leave us in the wet.

Looking at how the NAE performed with this mornings rainband (precip is not as intense and the rainband quicker moving). Then tomorrows might be a damp squid, the question is will NAE make the same mistake twice. ?

[SteveB]

Just got to work in Nailsea & while travelling here it was sleeting, but currently light drizzle and 2.2c

[Lynxus]

Metoffice say heavy snow, However i cant see it happening today.

It is odd however.

A week ago we had snow and it was 4c and today its just above 1c and just warm rain.

N-W radar also confirms just rain for round here at the moment.

[Ian Fergusson]

Looking at how the NAE performed with this mornings rainband (precip is not as intense and the rainband quicker moving). Then tomorrows might be a damp squid, the question is will NAE make the same mistake twice. ?

Actually - let me just offer a major change of NAE emphasis tomorrow - new run offers 10-20cm snow potential in a band from SE Wales across to Lincs (including Glos) and clearly has makings of a high profile event; however this major change from last NAE prog is noteworthy (it's because new run wants to depress the BL temp's further tonight).... next run awaited before UKMO decides whether to go with early warning over and above current advisory.

[03jtrickey]

I think I will be wise in postponing my cycling trip until the weather calms down a bit.

At least I will be able to enjoy a potentially interesting period of weather; thanks for the update Ian!

[Higher Ground]

Actually - let me just offer a major change of NAE emphasis tomorrow - new run offers 10-20cm snow potential in a band from SE Wales across to Lincs (including Glos) and clearly has makings of a high profile event; however this major change from last NAE prog is noteworthy (it's because new run wants to depress the BL temp's further tonight).... next run awaited before UKMO decides whether to go with early warning over and above current advisory.

What does BL stand for please?

[03jtrickey]

This feels a bit like Deja Vu after the previous time we had a sudden NAE upgrade back in January, when we ended up with 15cm of snow. Interesting to see how it verifies this time.

[monkeyuk]

Actually - let me just offer a major change of NAE emphasis tomorrow - new run offers 10-20cm snow potential in a band from SE Wales across to Lincs (including Glos) and clearly has makings of a high profile event; however this major change from last NAE prog is noteworthy (it's because new run wants to depress the BL temp's further tonight).... next run awaited before UKMO decides whether to go with early warning over and above current advisory.

Thanks Ian for the update. Was there any indication of when this would occur? EDIT: Sorry I meant what time of day?

Edited February 17, 2010 by monkeyuk

[kumquat]

Thanks Ian. I noticed this (tomorrow's event) showing on the BBC graphics this morning. Bristol right at the edge of the zone as usual. I suspect, if anything, an M4 north event, but who knows? Also I noted that Jemma mentioned possibility of snow for next week.

Edited February 17, 2010 by kumquat

[03jtrickey]

Latest NW radar showing ppt. changing to snow near Cheltenham. Currently raining here, but the rain looks a little icy.