Atlantic Storms - 12th December 2011 Onwards

[BleakMidwinter]

Can I ask a couple of idiot questions, please - I'm new to this wind stuff...

The place where the spirals meet in the centre is pale blue: is that the 'eye' of the storm and therefore it woud get storms on approach and on retreat, but a lull in the middle?

And, last Thursday's one was a Sting Jet which, did I get this right, typically forms very very rapidly, 24 hours sometimes or even less? So if this one is known and projected from a week ahead, is this one (well, both Mon-Tues and Friday) not Sting Jets?

If they are not Sting Jets, then does this type have a name? and from the very useful pages posted in the previous discussion, I understood that part of the danger of a Sting Jet is that it has some of the actual jet stream tacked onto already high winds - so will this coming storm(s) get their immense power from the jet stream or is it all happening at levels lower than the jet stream?

[edited because I got Sting Jet the wrong way round, oops...]

Edited December 11, 2011 by BleakMidwinter

[godber]

just picked my jaw up off the floor,after seeing the gfs charts for next thurs-friday! now i love severe weather, especially the cold variety.the reason i'm posting is that i work outdoors delivering the post for royal mail,so that is one storm i don't want to see verify!!!

[Iceberg]

Sorry on my phone now so no charts IMO the charts do show a sting jet developing during the early development racy stages

The positing of the jet though makes it almost a foregone conclusion that the stimg jet will develop as the system reaches up into the 300 layer

Given the above the models have a very good grasp of the system with the major incertains around when the sting and development occurs and how sharply

[VillagePlank]

Not so sure about the sting jet. For sure, there is a bit of dry air at 300hPa (which is required for increasing the density, and therefore flow of air), but the 300hPa heights simply don't drop enough over the expected time nominally being between 880dm and 920dm during the whole period. That's not to rule out local factors, of course.

[chionomaniac]

Just look how strong the jet stream is at it crosses the country. I have highlighted the area known as the left exit zone of the jet stream. Here the upper winds are leaving the jet stream and diverging. This creates an area of relatively lower pressure in the upper regions of the atmosphere due to this divergence. The winds need to be replaced somehow, so that area effectively hoovers up the lower air beneath it, hence the surface air becomes an area of lower pressure that surface winds rush into to replace. The stronger the jet streak the stronger the whole system becomes - and that is one very strong jet streak coinciding with the UK.

[knightrider]

An article on MSN says that somewhere during Monday night/ Tuesdays storm could see gusts of 80 to 100mph but their not entirely sure where but did indicate that the south-east could get hit hard for a time on Monday night. GFS indicates that Tuesday's low wont be that bad for my region with gusts of about 50mph but nothing exceptional but Friday's storm has been upgraded suggesting gusts around London and the Home Counties of 60-70mph perhaps more!

[chionomaniac]

Not so sure about the sting jet. For sure, there is a bit of dry air at 300hPa (which is required for increasing the density, and therefore flow of air), but the 300hPa heights simply don't drop enough over the expected time nominally being between 880dm and 920dm during the whole period. That's not to rule out local factors, of course.

Can you tell whether a sting jet is going to form just yet. How accurate are the models in showing the dry air?

[knightrider]

I'm a roadsweeper for my local council and if there's a risk that these lows could bring damaging and disruptive storm-force winds to SE then I'm not sure I fancy pushing a barrow bin around in that with loads of debri flying about lol

[Aaron]

An article on MSN says that somewhere during Monday night/ Tuesdays storm could see gusts of 80 to 100mph but their not entirely sure where but did indicate that the south-east could get hit hard for a time on Monday night. GFS indicates that Tuesday's low wont be that bad for my region with gusts of about 50mph but nothing exceptional but Friday's storm has been upgraded suggesting gusts around London and the Home Counties of 60-70mph perhaps more!

80 to 100mph gusts in the South East Monday night/Tuesday morning? Not a chance.

[camiscool]

Another member from the north I suspect . And now. You will be saying oh 120 mph for north easily

[NickR]

Another member from the north I suspect . And now. You will be saying oh 120 mph for north easily

That's a ridiculous statement. The models are simply not showing 80-100mph gusts for London and the SE. It's as simple as that.

[DanN]

Not so sure about the sting jet. For sure, there is a bit of dry air at 300hPa (which is required for increasing the density, and therefore flow of air), but the 300hPa heights simply don't drop enough over the expected time nominally being between 880dm and 920dm during the whole period. That's not to rule out local factors, of course.

This is more of a danger during the rapid deepening phase as well? The low looks about as deep as it gets by the time it crosses us...

[camiscool]

Us southerners look like we have nothing of interest then. We havent had snow or wind and all you can say is oh no chance of that? You never know the models could change still.

[NickR]

Us southerners look like we have nothing of interest then. We havent had snow or wind and all you can say is oh no chance of that? You never know the models could change still.

What is this north/south chip on your shoulder?? We're just saying what the models are showing. The south will have strong winds on MOn/Tues, don't you worry - just not in the order of 100mph gusts in London/SE.

EDIT: I'm perfectly happy to give you the storm if you want it - I could do without the worry about property and safety.

Edited December 11, 2011 by NickR

[VillagePlank]

Can you tell whether a sting jet is going to form just yet. How accurate are the models in showing the dry air?

Classically, it is related to cloud formations - ie the cloud looks like a scorpion's tail - so we can't tell for sure, right now.

The forecast is for dry air aloft where the jet is, but at 700hPa it's nice and moist below the dry 300hPa layer implying that the dry air will not descend enough to affect surface wind,

Outside chance of the factors coming together for the southern midlands, perhaps? The jet-stream is certainly one of the more interesting components, here, since whilst the system crosses the UK, we remain in area of PVA (ie pressure dropping) for the entire time, implying, perhaps, that GFS might have the pressure too high!

It will probably all be down to local factors on the day.

Edited December 11, 2011 by Boar Wrinklestorm

[knightrider]

What makes me laugh is all the northerners and and Scotts have been banging on about how it's them who are going to take the full force of Tuesday's storm when all the warnings have been suggesting Southern England, Wales and Ireland but hey they know best not the actual Met Office! I'm not saying what MSN said about 100mph winds will come true for SE cause I dont think it will but certainly the south-west approaches could see something simular with pottencial for 70mph in SE.

[chionomaniac]

Classically, it is related to cloud formations - ie the cloud looks like a scorpion's tail - so we can't tell for sure, right now.

The forecast is for dry air aloft where the jet is, but at 700hPa it's nice and moist below the dry 300hPa layer implying that the dry air will not descend enough to affect surface wind,

Outside chance of the factors coming together for the southern midlands, perhaps? The jet-stream is certainly one of the more interesting components, here, since whilst the system crosses the UK, we remain in area of PVA (ie pressure dropping) for the entire time, implying, perhaps, that GFS might have the pressure too high!

Thanks BW,

Quite difficult to judge at this range I imagine but at 24 hours we should therefore have a better idea.

It certainly doesn't look great for the middle part of the UK, that's for sure.

Suggestion for mods - is it possible to have a more technical storm discussion page. Posts like Icebergs and BW's are getting lost in the squabbles of will it be 80 or 90mph!!

[NickR]

What makes me laugh is all the northerners and and Scotts have been banging on about how it's them who are going to take the full force of Tuesday's storm when all the warnings have been suggesting Southern England, Wales and Ireland but hey they know best not the actual Met Office! I'm not saying what MSN said about 100mph winds will come true for SE cause I dont think it will but certainly the south-west approaches could see something simular with pottencial for 70mph in SE.

I think it's because most of the attention has been on Friday's system, which is more potent and looks like hitting N England. I haven't seen much talk about Scotland bearing the brunt, especially of Tuesday's storm.

[knightrider]

I think it's because most of the attention has been on Friday's system, which is more potent and looks like hitting N England. I haven't seen much talk about Scotland bearing the brunt, especially of Tuesday's storm.

Thankyou at last some agreement lol Yes I think Friday's low will be more northern although not exclusively so but Tuesday's is definately looking more like a Southern event unless the storm takes a drastic change in it's path.

[Coast]

OK, my first look at charts since yesterday morning at this time and looks like we are all still in for a lively time. I'll take the convective aspects first as I think the strong winds are odds on now, its just a case of where and how much.

Seems like a double-whammy of the two lows off Scotland and it starts early Tuesday morning when we should all be tucked up safe and warm. These charts are hi-res European HiRLAM that have now come into the time frame:

Notice where those convective gusts are this time and how big they are!!!!! :ph34r:

and here in Sussex along with Kent could see some of the worst of the helical activity:

Look at the rain that now extends across the South!

Let me dig out some other charts at different time periods and see what's going on

Suggestion for mods - is it possible to have a more technical storm discussion page. Posts like Icebergs and BW's are getting lost in the squabbles of will it be 80 or 90mph!!

Possibly, I'll check with the team. In the meantime we could help ourselves by sticking to the thread title!

[VillagePlank]

What makes me laugh is all the northerners and and Scotts have been banging on about how it's them who are going to take the full force of Tuesday's storm when all the warnings have been suggesting Southern England, Wales and Ireland but hey they know best not the actual Met Office! I'm not saying what MSN said about 100mph winds will come true for SE cause I dont think it will but certainly the south-west approaches could see something simular with pottencial for 70mph in SE.

An awful lot of internet forecasts (ie MSN etc) simply take unadulterated model output for a long and lat, and publish it. Best bet, in my view, is stay tuned here: you'll get plenty of comment, for and against, and you should be able to make your mind up!

[knightrider]

In know this is abit off topic but there's already an article about the Bawbag storm on Wikipedia, I do luv that website lol

[Liam J]

Still looking bad this week, Tuesdays storm a bit further north, GFS predicts gusts around 70mph here for these parts. Fridays storm is looking major over north and north west England, 80mph sustained over the Irish Sea! Gusts would be over 100mph across north England. Very severe.

[knightrider]

An awful lot of internet forecasts (ie MSN etc) simply take unadulterated model output for a long and lat, and publish it. Best bet, in my view, is stay tuned here: you'll get plenty of comment, for and against, and you should be able to make your mind up!

Or just watch the Countryfile forecast later on that'll be a good bet.

[NickR]

Still looking bad this week, Tuesdays storm a bit further north, GFS predicts gusts around 70mph here for these parts. Fridays storm is looking major over north and north west England, 80mph sustained over the Irish Sea! Gusts would be over 100mph across north England. Very severe.

In set ups like this, what would be the difference between what could be expected gust-wise in Cumbria/NW and the inland NE (other side of the Pennines)? I'm guessing slightly lower in the NE... and in every case, better if you're sheltered from W'ly winds by buildings, etc.