Sunday's Low

[fear sneachta]

On Sunday, it seems the strongest winds will be in northern and western France, with Brittany taking the biggest hit.

The south of England will certainly have a very windy day too but won't be damaging.

Edited February 25, 2010 by fear sneachta

[bluearmy]

Is there any chance that the storm might track further west or is this a case of me desperately hopecasting? In terms of wind speeds do you have an idea as to what to expect down here? Given last year please tell me this won't be as bad!

i think you may be in panic mode nick. looking at the runs at the moment, i'd say any damaging winds are well to your nw. i'd be surprised to see a correction se on this now unless the feature doesnt deepen as much in which case its not so dangerous for you anyway.

[Duane S.]

I have to say that it is looking likely that wherever it ends up it will be a very dangerous storm. I can see a swathye of destruction occuring from Southern Brittany through Northern France to Holland, North Germany and Denmark. We look odds on to have a lucky escape but these features are notoriously volatile in terms of their behaviour.

I've read a few posts over the past 48 hours saying it is quite different to the October 1987 windstorm. Is it that much? I agree that the Rapid cyclogenesis is highly likely to occur at a lower latitude and track more NE but wasn't that pretty much what was supposed to happen to the 1987 one?

The charts continue to tease us with Northerly blocking and a potential last hurrah of the winter. Devil in the detail amd all that but a block above/over us in some form now looks increasing likely.

Edited February 25, 2010 by s4lancia

[Guest North Sea Snow Convection]

I think (and hope) too that Nick S will miss the worst of the winds from this storm, being far enough east as the low tracks to the NW towards North West France but i am even more concerned than before about our own neck of the woods - at least the most southern and south eastern parts of the UK.

The 'general' track (taking NW Europe as a whole) has probably been agreed. But taking into account the fact that the models are converging back tonight towards an intensification of the low I think reflects the fact that they are if anything underestimating the fuel that is available for a low pressure cell that has come from a much warmer far south tropical environment and is likely to just explode more and more the nearer it gets to the relatively polar air further north. And we are further north obviously than the countries upstream from Madeira, Portugal, Span and France etc. You only have to look at the UK atm and where the heavy snow to the north over Scotland is and where the real boundary to properly cold air is. The low is going to seek further towards that boundary. On that basis i really fear that this nasty low is going to be pushed further north than currently modelled into the south of the UK and the gradient will be even tighter . Bear in mind that will still be within the acceptable model range of general track on a global model scale.

I hope I am wrong, but I am especially worried tonight about the models tomorrow. It is no wonder that the BBC (and the very nervous and grim looking local forecaster for my region who closed shop very quickly after giving just tomorrows forecast) are not saying much. They may have too much to say tomorrow I fear - but as I say, I sincerely hope I am wrong.

Edited February 26, 2010 by North Sea Snow Convection

[AderynCoch]

I've read a few posts over the past 48 hours saying it is quite different to the October 1987 windstorm. Is it that much?

I would say the main difference is that of SSTs - they're getting very close to their annual minimum right now in the northern hemisphere, whereas in October they're relatively warm (having peaked in September). If there's one saving grace, it's that this system's potential for convection is lower than it would be if it occured during October.

How do the models deal with varying SSTs?

Edited February 26, 2010 by AderynCoch

[Guest North Sea Snow Convection]

I would say the main difference is that of SSTs - they're getting very close to their annual minimum right now in the northern hemisphere, whereas in October they're relatively warm (having peaked in September). If there's one saving grace, it's that this system's potential for convection is lower than it would be if it occured during October.

How do the models deal with varying SSTs?

I think the Oct 87 storm was fuelled BOTH by gradient differentials in terms of cold air pouring south from Canada down the western atlantic towards the far south west but also the relatively warmer seas in accordance with the season. All i know is for some reason the rapid explosive cyclogenesis happened on our doorstep with the cold front rapidly catching up with the warm front which is a characteristic of this type of low. There was a temp difference I read somewhere of 8C at Heathrow and 17c at Gatwick briefly on the evening of the storm. And I think the very rapid wrap around warm occlusion is the basis of the same characteristic that this one has. However I think Nick F on his blog last night cited some differing ocean contrasts in temp this season in terms of the waters that this particular low is migrating from that are a main part of the catalyst for the rapidly deeping the low?Might be worth visiting his blog to see what he says. I might again after this post lol!

Edited February 26, 2010 by North Sea Snow Convection

[snowray]

MO just have just issued warnings for Sunday, they are going for wet and windy for the South and EA, Winds are being played down so it would appear that the LP will be further East.

NAE also seems further East.

Edit: Local London forecast for Sunday just said wet and a bit windy, could all change though of course.

Edited February 26, 2010 by snowray

[johnholmes]

I've read a few posts over the past 48 hours saying it is quite different to the October 1987 windstorm. Is it that much? I agree that the Rapid cyclogenesis is highly likely to occur at a lower latitude and track more NE but wasn't that pretty much what was supposed to happen to the 1987 one?

yes it is quite different, somewhere in the files of NW is a fairly long explanation from me of what caused the rapid deepening of the 87 storm. I was part of the official Met O inquiry into finding out what occurred and why UK Met ended up with a forecast not as good as the French in the last few hours leading up to the event. For about a week they had given first class guidance then not so good 12 hours out. A team of over 50 meteorologists from UK and about 6 European countries spent 4-5 days at the Met O College at Shinfield. There is a large booklet available from HMSO with its findings.

[Weather-history]

I'm wondering if the snow potential of this storm has been upped?

UKMO 72hrs precipt

72hr temps

[Guest North Sea Snow Convection]

Chris Fawkes on the latest online forecast said in a reassuring tome at the end of his forecast that the low for Sunday would bring ' just wet and fairly windy weather to the UK'.

I do hope he is right - some of the models look rather iffy to me this morning.

[Fitzwis]

Over here the higher tides are on the Tuesday so it looks like we should escape the worst !! Had this been on the Sunday i can say for sure that we would be submerged big time !!! Oh, our top scale is 10m and they predict a 10.3m on Tuesday !! Oh dear !! Dont look good for the harbour of St Peter Port !!

Hey TMS ... saw this on the local news a day or two ago where they stated some of Guernseys coastal roads will be closed during the highest tides. Luckily, our highest occur on Tuesday also but even so, with a 37.1 footer (11.3m) predicted Sunday morning and evening coupled with deep low pressure and high winds, the tide will be much higher than this. Our main concern will be if the sea wall is breached again like last year. One thing going in our favour though will be the wind direction. If the low follows the models projected path, our strongest winds will come from the west and northwest which should spare our south coast and the town centre. Definately keeping an eye on this one due to the uncertainty surrounding the exact track and depth of the system. Good luck over there my boy!

[Harry]

With all due respect, IMO we are still far too far away to say either way what will happen. It is this sort of over-confidence which caught people off guard in 1987 - "well, we're likely to get some rain and some fairly strong winds, but the worst will stay over the continent" - lets not be complacent here, all it would take is a 100 mile shift West (which is nothing in meteorology terms) and parts of the SE could be slammed, just as in 1987. Or, judging by the current MetO pressure charts, we could already be in for more than "fairly strong winds". Heavy rain on to saturated ground seems a fair certainty at this stage too, which is enough of a concern for some.

The storm hasn't even begun to evolve as yet - there is a long way to go yet peeps.

[Guest North Sea Snow Convection]

With all due respect, IMO we are still far too far away to say either way what will happen. It is this sort of over-confidence which caught people off guard in 1987 - "well, we're likely to get some rain and some fairly strong winds, but the worst will stay over the continent" - lets not be complacent here, all it would take is a 100 mile shift West (which is nothing in meteorology terms) and parts of the SE could be slammed, just as in 1987. Or, judging by the current MetO pressure charts, we could already be in for more than "fairly strong winds". Heavy rain on to saturated ground seems a fair certainty at this stage too, which is enough of a concern for some.

The storm hasn't even begun to evolve as yet - there is a long way to go yet peeps.

I think there is also an element of the 'storm enthusiast' in you speaking there too in terms of you hoping it does take a different track.

Of course no-one should be over confident or complacent, and I'm not sure anyone is either anyway, but although the track and style of development of this low has some similarities with 1987 this low rapidly deepens much earlier than that storm and arrives towards the UK as an already 'mature low'. In that sense its track will be relatively easier to monitor. The midnight NAE has the low slightly shifted SE of the latest METO model for t48 and the METO model itself moves the strongest winds through western and northern areas of France even on its suggested track. The truth is it would be much more preferable if no-one had to experience strong winds such as this imo, but I guess I come from a different angle and perspective than you as I am not a weather extreme fan. Watching storms etc from a safe distance is exciting and interesting - having them on your doorstep and causing problems and havoc is something else.

Hopefully this low causes as few problems as possible for anyone whether over the channel or anywhere else.

[Fitzwis]

The storm hasn't even begun to evolve as yet - there is a long way to go yet peeps.

I believe it has, albeit in its embryonic stages. Track and depth still very uncertain at this time though

[Guest North Sea Snow Convection]

Latest NAE 06z for t48 Sunday Morning

[John London]

Who's going to be the first to say that this could be a _ _ _ _ _ _ _ _ _?

[West Sussex Kate]

It's all looking a bit close right now!

[Thundery wintry showers]

I'm not sure that Harry's latest post necessarily suggests that he wants it to hit the southeast more full-on, just making the reasonable point that it's easy to get too complacent in these situations with the low being progged to have its main thrust miss us- we still cannot rule out slight changes in positioning in future runs which could make a great deal of difference to south-eastern areas. From what I've seen of Harry he strikes me as more of a convective storm enthusiast than a wind storm enthusiast, and I can certainly say the same for myself.

I'm up for the occasional gale but once winds exceed gale force the excitement hits a diminishing returns law and the risk level increases dramatically (it's rather like the situation that arises when an activity crosses the boundary between fun and downright recklessness/stupidity), so once a deep low is at risk of exploding to dangerous levels you'll invariably find me hoping for downgrades.

I do think we still need to watch this low. The current NAE shows winds perhaps approaching gale force but no more, but it only requires a small shift north to bring something pretty dangerous. I continue to think that heavy rain and flooding could be as big an issue as the strong winds in that case. Re. snow, it looks like being a sleet/rain event to me at low levels but higher-up parts are certainly in with a fair chance of seeing some significant snow.

[dallas]

Latest from BBC at 1300, is that they are keeping an eye on the system and used some pretty impresive graphics to show some wild conditions. You really know that your in the UK when there is different weather systems affecting different parts of the country!

[West Sussex Kate]

The bbc have some info on the storm.......

http://news.bbc.co.u...000/8536711.stm

[dallas]

The bbc have some info on the storm.......

http://news.bbc.co.u...000/8536711.stm

Nice one, not a bad little report that

[Iceberg]

Not had much chance to really study this development, it looks like the models have a pretty good agreement on track, with the low probably getting down to a centre of 965-970mb. NAE I think goes for 966mb.

EPS analyst indicates winds of 25-30kts as probably the highest widespread inland, gusts upto maybe 35-40kts, maybe 45kts on extreme coastal bits.

Now, what the models are showing and what happens are possibly two very different things.

The period 12-27hrs will be crucial to determine how the system initially forms down to a tighter 980mb low,

The key will be how it interacts with the warmer air thats thrown up at between T24 and T36. This will be the determiner IMO none of the models really mixes the much warmer air into the system and generally don't engage the JS as much as it could.

Still a 20% chance or so of something more spectacular occuring, but tbh the models seem to have a good steer on it.

[Damp and dreary]

The bbc have some info on the storm.......

http://news.bbc.co.u...000/8536711.stm

Aaaah, i noticed Mr Corbett sees deep low pressures in a similar way to me,add on the wind flow and it looks just like water being flushed down a toilet. Bless him.

[Coast]

UKMO projected 10M winds:

GFS:

London & South East England:Bracknell Forest Brighton + Hove Buckinghamshire E Sussex Gtr London Hampshire Isle of Wight Kent Medway Milton Keynes Oxfordshire Portsmouth Reading Slough Southampton Surrey W Berkshire W Sussex Windsor + Maidenhead Wokingham

Heavy Rain Sun 28 Feb

There is a moderate risk of severe weather developing over England and Wales on Sunday. A prolonged spell of wet and windy weather is expected, with heavy rain falling on already saturated ground. The rain may also turn to snow at times over hills.

Issued at: 1054 Fri 26 Feb

[jimben]

Are these winds likely to cause problems at Heathrow on sunday, please ?