South West/Central Southern England Regional Discussion 21/01/13 6z Onwards

[Frosty_wsm]

If you're in Devizes the latest graphics I've done probably puts you in 40%, the first 60%. This suggests that the general trend has been for the shift of more significant snowfall to move away from the far East of the warning areas and everything to shift slightly South and West. I wouldn't put Devizes in 60% on latest guidance.

Yes I'm very much liking your updated map

[lfcdude]

If you're in Devizes the latest graphics I've done probably puts you in 40%, the first 60%. This suggests that the general trend has been for the shift of more significant snowfall to move away from the far East of the warning areas and everything to shift slightly South and West. I wouldn't put Devizes in 60% on latest guidance.

Yeah.. but i expect it to go back east a little.. morning run is always west lately.. but i did click on the wrong one.. and think 60 percent lol

Edited January 21, 2013 by lfcdude

[TwisterGirl81]

Here's a link to Metcheck who are saying there maybe a possible 'snowbomb' tonight/Tuesday for parts of Devon and Somerset etc May it blow up over Exeter lol!! The link is below and the article is middle of the page, below first article:-

http://www.metcheck.com/UK/

[Frosty_wsm]

Yeah.. but i expect it to go back east a little.. morning run is always west lately.. but i did click on the wrong one.. and think 60 percent lol

Not quite, the 06z often pushes things east with the 12z shifting back west again, just hope it doesn't shift too far west that we miss it!

[Nights King]

Not quite, the 06z often pushes things east with the 12z shifting back west again, just hope it doesn't shift too far west that we miss it!

bbc graphics show it only clipping west somerset and mainly hitting devon. That would be painful to see it so close and miss us

[DanDorsetUK]

Think poole needs a bit more snow must of turned to rain here earlier than my area near ferndown all i can see is half built snow men all over the place. Amazing difference at such a short distance! Melting quite quick in poole. Would love to see poole get a decent dumping again!

[fergieweather]

bbc graphics show it only clipping west somerset and mainly hitting devon. That would be painful to see it so close and miss us

Cannot stress enough not to take such detail literally. I can't post here the snow areal probs from Chief Forecaster but can reiterate to blur the boundaries of what you are currently seeing in tv forecasts, which are driven by modified 6z NAE currently.

[kernowman]

Just started lightly snowing in Truro at work at the moment, very fine powdery snow. Checked the radar and it's shown as rain.

[GazzzaV6]

Think poole needs a bit more snow must of turned to rain here earlier than my area near ferndown all i can see is half built snow men all over the place. Amazing difference at such a short distance! Melting quite quick in poole. Would love to see poole get a decent dumping again!

Any chance do you think?

[otleygas]

Taking into account a blend of the latest NAE, UKMO and ECM guidance the strongest PPN signal for potentially disruptive snowfall is across North/South Somerset, North Dorset, South East Wales, potentially the Forest of Dean, all these regions now fall within my 60% probability catchment areas. There still remains a considerable amount of uncertainty over PPN totals and snowfall amounts due to a wide disparity in data, however ECM00Z projects a strengthening PPN signal, along with NAE with weaker signals from GFS. All guidance concludes that the greatest PPN spread, -4/-5oC T850 frontal deviation sits within the counties of Somerset and North Dorset and South Wales.

Those areas that have greatest potential to be upgraded are surrounding counties, the remainder of much of Dorset away from the coast initially, the remainder of Somerset and down into parts of Northern, Western and Eastern Devon, especially to higher ground. Other counties included in the 40% probability are South East Wales, Herefordshire and much of Gloucestershire. There remains some uncertainty on the Eastern extent across West Wilts and currently we have removed the 40% and have issued a 20% here, subject to change should a slight deviation exist in the model output today.

Areas in the 20% are less certain, either due to the extent of the PPN North and Eastwards across North Wales, Central Wales, Wilts, East Glos and Hampshire or due to the rain/snow line undulating across parts of West Devon and Eastern Cornwall. There remains potential in a slight Easterly focus to include West Wilts and East Glos and perhaps parts of Hampshire. As does the snowline to the South across Devon and Cornwall, this could be extended, but on current guidance a mix of rain, sleet and perhaps patchy snow would seem the most probable outcome.

• Slight downgrade from 40% to 20% for parts of Wilts
  
• Slight upgrade from 40% to 60% for parts of N/S Somerset
  
• Slight upgrade from 20% to 40% for parts of East and South Devon away from the coast initially
  
• W extremities of Glos remain in 60% although very marginal between 60% and 40%
  

Included is the original risk map issued yesterday:

The latest risk map issued today:

Conclusion

Confidence remains low to partially moderate for snowfall distribution and intensity of PPN ie. snowfall amounts. The risk of significant snowfall is still probable. The biggest disparity in guidance is with the GM GFS with wild fluctuations and a significantly weaker PPN signal, especially for the Northern most extent of the warning area. We will be looking for some consistencies and growing confidence from the GFS12Z in particular, and a stronger comparative ECM12Z to the ECM00Z which showed a strengthening PPN signal. Should ECM12Z and NAE continue to project stronger signals, an amber could be issued, especially if UKMO displays greater willing. A strong uniform set of runs, with broader and more comprehensive agreement is needed before a higher confidence than 60% is issued for any part of the region.

Can I check what the timing is for this potential event please? This evening into Tuesday morning, or later on Tuesday?

[lettice]

We are having very very light snowfall in gosport.

Almost like it is blowing in the wind, but looking up it is coming from the sky, was not expecting anything here today

1.2c, humidity 82%, wind chill 0.7c, 994.7hpa and slowly rising, dewpoint -1.2c

Edited January 21, 2013 by lettice

[snowmadchrisuk]

Ahh yes, the EC does show something more widespread over the West Country;

Yeah but if you look at that the main heavy ppn is off shore as per GFS , even GFS has light ppn over the area ...

[Blizzardof82]

So much to play for tomorrow I am struggling to get things done, need to get ready for work. Current temp 2.6c dew point 0.4c after rising to 1.5c an hour ago humidity 85% wind light easterly.

[Argyle1980]

Heavy and thick snow in Truro for the last hour .....looking Good

[Jason74]

Heavy and thick snow in Truro for the last hour .....looking Good

Hope it continues for you

[fUnKy]

Heavy and thick snow in Truro for the last hour .....looking Good

chuffed for you.

update on plymouth. 2.1 degrees.

yesterday was a record breaker. -1.1 min, highest all day 1.7

[kernowman]

Looking at the radar around Truro, unfortunetly it isn't going to last long, but very nice proper snow flakes now. I can almost believe it is Winter now.

[Mapantz]

Met Office warnings out.

[Wilxy]

Yellow Warning out for 2-5cm of snow, but mainly for the western side of warning with the risk of it extending into wiltshire and hampshire.

[warmintim]

Yellow Warning out for 2-5cm of snow, but mainly for the western side of warning with the risk of it extending into wiltshire and hampshire.

Subject to change as we get closer to the event...

No comments from anyone about Metcheck's 'snow bomb'? I'll be checking the radar a lot tonight!

[Nights King]

Yellow Warning out for 2-5cm of snow, but mainly for the western side of warning with the risk of it extending into wiltshire and hampshire.

Yes west of the warning area... I'm east Lets hope for an upgrade tonight maybe.

Who takes any notice of metcheck?

Edited January 21, 2013 by mullender83

[chris55]

This whole thing is far to uncertain for my liking, will really be a case of watching the Radar, from later today and into tomorrow.

[SNOW CRYSTAL]

Looking at the radar around Truro, unfortunetly it isn't going to last long, but very nice proper snow flakes now. I can almost believe it is Winter now.

Glad you have seen at least a few flakes this winter. Plenty of time for more!

[Ali1977]

Any chance of this warning being extending into the east if our region ? When are the next precip forecast out?

[SteveB]

So when is this snow actually supposed to fall? Is it tonight/ tomorrow morning, or is it tomorrow afternoon/tomorrow evening!

Edited January 21, 2013 by SteveB