The South West Of England Regional Discussion Thread

[Iceberg]

um.... been trying to do a bit of nowcasting and comparing the recent pressure values and rain extent with the NAE forecast for around this time.

Firstly it looks like the low pressure is further north than is being forecasted

Secondly the rain is moving further north and east than is being forecasted.

Thirdly temps and DP's are around what was being predicted, a little bit lower in places and a little higher in places, but certainly in the ball park.

[AWD]

So not the best start then Iceberg?

[Nights King]

um.... been trying to do a bit of nowcasting and comparing the recent pressure values and rain extent with the NAE forecast for around this time.

Firstly it looks like the low pressure is further north than is being forecasted

Secondly the rain is moving further north and east than is being forecasted.

Thirdly temps and DP's are around what was being predicted, a little bit lower in places and a little higher in places, but certainly in the ball park.

Probably get a clearer picture by 11 or 12 tonight if we are in for any surprises as cold air starts to show its self. current temperature is holding at 2.9 now with steady rain.

[Iceberg]

So not the best start then Iceberg?

I honestly don't know. Too many variables to calculate, at least for me.

[Bristawl Si]

It's worth reminding ourselves that this is no classic Winter channel low situ - and by that i mean that there's been no cold easterlies for a few days first before the Channel Low approaches -

that type of Winter situ would have resulted in a raging blizzard here probably.

What we have instead is the probability of colder air undercutting as the night draws on and the possibility of snow in some of our area by early morning.

Edited December 15, 2011 by Bristle boy

[Mark Parsons]

what happened to the 60-70 mph winds ? or is it just heavy rain now?

Just rain now because of the low moving further south, hence the risk of snow coming a bit further south, in these set ups snow to the north of the low strong winds to the south of the low basically we are in the middle across most of the SW.

[weathe20]

Think its time members invested in NW radar, its brilliant. This type of event is great for watching on that radar.............watch as the rain turns to snow...........or stays as rain!!

[stewfox]

Think its time members invested in NW radar, its brilliant. This type of event is great for watching on that radar.............watch as the rain turns to snow...........or stays as rain!!

Its coming in faster then I thought , only about 70 miles from where I am , any snow anywhere so far ?

Edited December 15, 2011 by stewfox

[Nights King]

Think its time members invested in NW radar, its brilliant. This type of event is great for watching on that radar.............watch as the rain turns to snow...........or stays as rain!!

It is very good however I have never been totaly sure if it predicts what ppn is rather than nowcasting it!? because I have noticed it does from time to time show rain when clearly it is snowing outside and vice versa.

rain is currently up to bristol channel east of region and south west wales.

Another good source of information is to check the wonderground website and see how general temperatures are reacting in your region, should be able to get an idea of when the undercut of colder air starts to feed in.

http://www.wunderground.com/cgi-bin/findweather/getForecast?query=51.229%2C-2.526&sp=ISOMERSE28&MR=1

Edited December 15, 2011 by mullender83

[Aceman]

It is very good however I have never been totaly sure if it predicts what ppn is rather than nowcasting it!? because I have noticed it does from time to time show rain when clearly it is snowing outside and vice versa.

rain is currently up to bristol channel east of region and south west wales.

Another good source of information is to check the wonderground website and see how general temperatures are reacting in your region, should be able to get an idea of when the undercut of colder air starts to feed in.

http://www.wundergro...ISOMERSE28&MR=1

nice home page on the weather station, think i need to tweek mine a little. Also, never thought Chilcompton was that high up but clearly is!

[littlemissy]

Just rain now because of the low moving further south, hence the risk of snow coming a bit further south, in these set ups snow to the north of the low strong winds to the south of the low basically we are in the middle across most of the SW.

Thank you for your reply.I have been away for 24 hours and I am just catching up with things.

[Cheese Rice]

It is very good however I have never been totaly sure if it predicts what ppn is rather than nowcasting it!?

Member 'Backtrack' was wondering the same thing yesterday, this was my response..

The PPN type radar uses the NMM to create the overlay your seeing. So it basically looks at each variable (850's, Dew point, Freezing level etc) and then generates what in essence is a prediction of what is currently happening based on the various factors projected by the models. Its why for alot the times the radar is very inaccurate, nothing is real time.

Your suspicions are indeed correct.

Edited December 15, 2011 by Cheese Rice

[kold weather]

I honestly don't know. Too many variables to calculate, at least for me.

I'm just guessing but if the low is further north it'll shift the threat northwards a little as well, but in the end there should still be an undercut which will help turn it, just makes things more marginal then they already are.

[Schmac]

Evening all!

Back for another Winter on NetWeather!...

I would love to join in with the "temperature watch", but we've recently moved house and in the process of doing so the removal men smashed my weather station!

I doubt I'll get another one up-and-running before the winter is over (if it ever gets going that is!)...

The car said it was 4.5ºc about 30 minutes ago here.

Oh, I'm in Bristol now (Emersons Green area)... Not sure what the "ASL" figure is but will try and find out!

Not sure what to believe tonight... Will I wake up to a white world or a washout!

[Aceman]

Evening all!

Back for another Winter on NetWeather!...

I would love to join in with the "temperature watch", but we've recently moved house and in the process of doing so the removal men smashed my weather station!

I doubt I'll get another one up-and-running before the winter is over (if it ever gets going that is!)...

The car said it was 4.5ºc about 30 minutes ago here.

Oh, I'm in Bristol now (Emersons Green area)... Not sure what the "ASL" figure is but will try and find out!

Not sure what to believe tonight... Will I wake up to a white world or a washout!

shame you moved from trowbridge mate, remember last winter well when it dumped snow when everyone said it wouldnt!

[bellanite]

Currently 4.4^oC with a dew point of 2.8 in Stroud. The NW extra looks awesome at the moment I’m sure the South West is there somewhere under all that blue! Hope it will start turning pink a bit later for all who are hoping for snow! not sure if it will settle though the ground seems far to warm and wet only time will tell! Another sleepless night then!

[Mark]

It is very good however I have never been totaly sure if it predicts what ppn is rather than nowcasting it!? because I have noticed it does from time to time show rain when clearly it is snowing outside and vice versa.

rain is currently up to bristol channel east of region and south west wales.

Another good source of information is to check the wonderground website and see how general temperatures are reacting in your region, should be able to get an idea of when the undercut of colder air starts to feed in.

http://www.wundergro...ISOMERSE28&MR=1

I'm lucky to have a good weather station 200m from my location:

http://www.yeovil-we.../Wdl/index.html

so I get his live data... bargain, actually http://www.yeovil-weather.me.uk/ has been around for over 10 years and has been invaluable especially in the winter, and supplies the wunderground link in my signature...

Edited December 15, 2011 by Mark

[Lynxus]

Another sleepless night then!

Same here!!! However I fear mine is due to the small amount of blood in my alcohol stream.

[AWD]

To my Amatuer eye, it looks like the rain has arrived a little earlier, and got further north a little earlier than forecast!

[Bristawl Si]

This is a quote from Roger Smith in the Atlantic Storms thread from an hour ago - this guy knows his stuff -

"Would say the chances for snow are better above 250m a.s.l. in the current set-up. Between 150 and 250 m the most likely outcome would be sleet and below 150m mostly rain ending as wet snow perhaps.

Problem is that air temperatures can only get slightly warmer now, once the air starts moving and mixing, there will also be inflow from nearby warmer bodies of water, even a northeast wind late in the storm will be coming off 7-9 C water.

If the temperature field had been say 2 deg lower at 18z for onset, then this could have turned into a significant snowstorm across southern England, but given the current conditions, I think it's going to be mostly rain with higher elevation snow. But that won't preclude a few reports of heavy snow, it would be helpful if people could give their elevations above sea level in any such reports.

Update on track -- continues to look mid-Channel to me, I wouldn't even worry about damaging wind gusts on IOW. the Channel buoys are showing a decreasing wind speed trend characteristic of a low that has all its energy south of the centre."

[Schmac]

shame you moved from trowbridge mate, remember last winter well when it dumped snow when everyone said it wouldnt!

Yes, very true... Hopefully I might be in a good spot for tonight though... Time will tell! Not holding out too much hope as it really is "knife-edge" stuff... I'm not really expecting anything other than rain... But who knows... Could be lucky!

You may be in a good spot too... I see Wiltshire has been mentioned quite a lot in relation to the potential snow disruption tomorrow!

[Iceberg]

Pressure now down to 987mb in west Cornwall, but ALL the models are massively underestimating the precip and the movement of the precip north.

NAE had be down for 1-2mm by 9pm, in true I've had over 8mm so far. Rainfall has reached Birmingham and London, when it should barely have reached Birmingham by Midnight

[Frosty_wsm]

Back end of the precipitation is already visible on the nw & met radar, looks to me like it'll of passed by our patch by midnight or not long after! All the forecasts I've seen show rain/snow still falling around here by rush hour tomorrow!

Either there's more precipitation coming in which is out of range of the radar or this system is rattling through alot quicker than predicted.

Edited December 15, 2011 by Smartie

[Paul T]

Current synoposis;

Slightly colder than I thought at 4.5oC

PPN spreading itself around a bit more further afield than thought is expected

The band that will create the chance of snow isn't the one around at the moment (it will build in the coming hours)

I still don't see a snow event for low areas in yhe SW at the moment, but I may change my tune of I see genuine info that I agree with

Edited December 15, 2011 by Paul T

[Aceman]

do we think this whole situation will fizzle out before it can get going, regarding the wintry precipitation?

edit: cheers Paul T, answered my question

Edited December 15, 2011 by Aceman