Atlantic Storms - January 2012

[Zenarcher]

Hmmm... so not much to get excited about then for the foreseeable future!

After such an active period over the last few weeks I think I might suffer withdrawal symptoms looking at the current outputs!

One wind event is looking game on for the far north by the end of the week, perhaps a chance of an upgrade weathermaster? I'm not hopeful but you just never now with our fickle weather what may be round the next corner.

Windless and snowless Christmas... at least people travelling for the holidays to family etc should have little weather related problems this year. (after Friday in the north)

It's hard to tell whether it will upgrade or downgrade at the moment and looking at the ECM ensemble members for some support most of them have the low where the ECM operational run has placed it, in fact there may be a higher chance of it moving further North and pretty much missing the UK altogether.

Yeah I agree travel this Christmas shouldn't be an issue with the weather being settled and mild which is good news.

Edited December 18, 2011 by weathermaster

[ZONE 51]

GFS 18z - it does look like events at the end of the week look like being across the far north at this stage, high pressure quite a feature in the south and the storms/lows running around the top of this high across the far north, also i do think Scotland is at risk at this stage, not out of the woods yet! depends on this high.

[ZONE 51]

Thursday evenings Jet,

then the Thickness 500-1000hpa,

The green strip/zone on the above chart is where we could see lows deepening, as you can see on the Jet chart thats where the jet is located at this time, its inbetween the warm air and very cold air

[Coast]

GFS still showing something in the air:

[Coast]

First charts coming through for +72 hrs and it does look like a Scotland event mainly:

Norway and Iceland get crunched though!

[Zenarcher]

Update on this mornings model runs,

For Thursday night and into Friday morning we are seeing good model agreement now on this event with all of the 3 main models pretty much agreeing on its path now. However how deep the low is still unknown the GFS 970mb, ECM 970mb and UKMO 975mb so at the moment around the 970mb to 980mb mark. So if this event was to come off only the Northern Isles of Scotland would see the worse of the winds perhaps 65mph to 75mph gusts. However Western parts of Scotland and exposed parts could see 55mph to 65mph gusts.

As for this weekend the low over Iceland and Greenland area is shown different on all the 3 models but GFS and UKMO show something more similar to each other. But I am feeling confident it will not affect the UK at all because high pressure will build up over the UK. This is shown on all models.

Overall today I feel we have pretty much nailed down the track of the Thursday/Friday wind event however how strong the winds will be is still unknown and we probably won't know until tomorrow or once the models all agree on something. As for the weekend high pressure will build up over the UK bringing mild conditions but settled as a low over Greenland and Iceland is looking unlikely at this time to affect Northern parts of UK that was the concern shown yesterday.

[johnholmes]

Update on this mornings model runs,

For Thursday night and into Friday morning we are seeing good model agreement now on this event with all of the 3 main models pretty much agreeing on its path now. However how deep the low is still unknown the GFS 970mb, ECM 970mb and UKMO 975mb so at the moment around the 970mb to 980mb mark. So if this event was to come off only the Northern Isles of Scotland would see the worse of the winds perhaps 65mph to 75mph gusts. However Western parts of Scotland and exposed parts could see 55mph to 65mph gusts.

As for this weekend the low over Iceland and Greenland area is shown different on all the 3 models but GFS and UKMO show something more similar to each other. But I am feeling confident it will not affect the UK at all because high pressure will build up over the UK. This is shown on all models.

Overall today I feel we have pretty much nailed down the track of the Thursday/Friday wind event however how strong the winds will be is still unknown and we probably won't know until tomorrow or once the models all agree on something. As for the weekend high pressure will build up over the UK bringing mild conditions but settled as a low over Greenland and Iceland is looking unlikely at this time to affect Northern parts of UK that was the concern shown yesterday.

a nice summary there w-thanks

[Liam J]

Interesting to see the ECM 00z doesn't agree with the GFS regarding how far north the high pressure can build and remain in control, 12z ECM isn't out yet but looking at the 00z run we would be looking at an unsettled pattern making a return much quicker than the GFS model is progging atm.

12z UKMO out to 144hrs would probably evolve into a less settled picture with depressions crossing the UK (perhaps)

So a potential downgrade to the settled period on the cards over future runs? We shall see...

[Zenarcher]

Thanks John

Update using 12z runs today,

Thursday night and Friday morning hasn't changed too much the track is still the same but still we are still unsure how deep it will get. But as I said earlier today only the far Northern Scottish Isles will see the worst of the winds now looking to be around 55mph to 65mph and 45mph to 55mph for Western or exposed parts in Scotland. Overall its a slight downgrade due to the system being pushed a bit to the North due to this high pressure building up over the UK.

As for the weekend yet again all the models show high pressure over the UK so it will be settled and mild. But the models do show an intense system between Greenland and Iceland the ECM has it down to 940mb, not often do you see it say that for the low pressure systems.

Overall its looking more and more likely that Scotland, mostly the North will see windy weather on Thursday night as the path is appearing more clear now but we are still unsure on the wind speeds at the moment but the models this afternoon do agree more on its deepness than this morning. The weekend is still looking mild and settled for all. Looking ahead after Christmas into next week where confidence starts to fall as all models have different ideas it does look like unsettled weather will return.

Edited December 19, 2011 by weathermaster

[Zenarcher]

Update using the 18z GFS

The GFS has shifted the low for Thursday night further South this has upgraded the winds for the event. The Western Isles could see gusts of 65mph to 75mph meanwhile I wouldn't be surprised if Stornoway at the top of the Western Isles got gusts into the 80mph range.

Its also still looking bad for the Northern Isles of Scotland as well with 70mph to 80mph gusts.

After this the GFS still has the mild and settled weather for the UK over the weekend and still has that low over Greenland and Iceland area. I believe by tomorrow the track of that low will be nailed down because the models have felt confident on its track all day.

Looking ahead into next week again confidence is low but the 18z has changed its mind slightly it shows the high pressure sticking to the UK more but with plenty of low pressure systems in the Atlantic.

Overall an upgrade on the wind event for Thursday night and Friday morning and the weekend still looking mild and settled. Meanwhile next week although uncertain at the moment mainly settled for most but Northern and Western parts may be unsettled at times.

Edited December 19, 2011 by weathermaster

[Liam J]

Thanks for the updates weathermaster

I Noticed another potential very windy spell for the north during Christmas day evening, by no means a storm but the current GFS output is progging 45-50mph mean wind speeds over NW Scotland with strong to gale force winds further south likely as short wave feature runs over the high pressure.

Maybe one to watch over the coming days, after that much calmer conditions look likely for a time unless the current modelling changes.

Edited December 19, 2011 by Liam J

[Coast]

HiRAM, hi-res model have this as two distinct lows merging with each other over Scotland to an extent:

Still looks like Iceland gets a battering:

But Scotland also in for some action:

Although not as much as recent storms:

But look at that arc around the Western North sea where more helical elements seem to concentrate.

Big gusts likely for Shetland and the Islands to the North of Scotland?

[Zenarcher]

Update on this mornings runs,

For Thursday Night the GFS has shifted the worst of the winds further North again and looking at the ECM and UKMO they both have the low slightly further North at the moment so perhaps the GFS may keep moving it slightly. As for the worst of the winds the West of Scotland are pretty much dodging a bullet from this as the worst of the wind for them is out at sea despite this 60mph or even 70mph gusts could be expected on the coasts and on higher ground.

Although Orkney and Shetland at the moment are starting to look like the worst may miss them as well, 65mph to 75mph is likely for them, its the Faroe Islands that look to take the worst of the winds.

For the weekend as Liam pointed out last night there is potential for another wind event then. With the high pressure to the South but in the North a low may be likely at the the moment it doesn't look anything too big with 45mph to 55mph gusts at least for parts of Scotland mainly Western and Northern parts. That's for the entire weekend and next Monday so unsettled outlook for the North of the UK.

Looking ahead to next week the GFS is keen to bring in high pressure for the UK meanwhile the ECM wants to keep it unsettled.

[Liam J]

Stormy conditions in the far north of Scotland later on Thursday as a deep depression moves close to the top of the mainland, affecting the NW then moving eastwards to affect the Northern Isles later in the night. Nothing too extreme for this part of the country, gusts around 70mph possible.

Remaining pretty windy throughout the weekend for northern areas as strong SW'ly winds persist with local gales around some coasts in the north and west, after this conditions should be settling down as high pressure tries it's best to exert it's influence over the UK. Still unclear just how much the high will be allowed to build, it may be that we end up with NW'ern areas staying breezy, dull and damp with a long reaching SW'ly flow (possible bartlett scenario)

Plenty of time for changes with the overall synoptic set-up, this is still a week or so away atm. (fingers crossed)

Just came across this case study on the Meto site which looks at the storm earlier in the month which battered Northern Britain.

http://www.metoffice.gov.uk/about-us/who/how/case-studies/atlantic-storm-2011

Edited December 20, 2011 by Liam J

[Zenarcher]

Update on this afternoons runs,

The GFS has shifted the Thursday night wind event further North and now all 3 models agree on the track now. The GFS is still showing the deepest at 975mb meanwhile ECM 980mb and UKMO 985mb. Perhaps the GFS may downgrade the low slightly over the next day.

Shown below Western Scotland just missing the worst of the winds but still seeing gusts around 60mph to 70mph. Stornoway at the top could see over 70mph.

Later into the early hours of Friday the worst of the wind will hit the Northern Isles bringing 70mph to 80mph gusts. I'm wondering if any warnings for there will be issued?

For the weekend the UKMO and ECM bring a low pressure over Northern Scotland bringing very windy conditions on Sunday night and into Monday morning for most of Scotland and perhaps Northern England. However there is disagreement between the models, the ECM is showing very windy weather, UKMO somewhat agree but not as bad and GFS doesn't show the low at all but still slightly windy for Western parts. This event will become more clear later in the week.

Overall the Western and Northern Scotland can expect windy weather on Thursday night with the far North seeing the worst of the winds. For Sunday night and Monday morning next week the two models show another wind event possible but with no agreement between the three its hard to know.

[Zenarcher]

Update with the 18z GFS,

It's kept the low for Thursday night in the same position but has downgraded the wind speeds. This is now closer to what the UKMO and ECM where saying earlier today so perhaps this is looking like the most likely outcome.

Western Scotland can expect 55mph to 65mph gusts at the moment and Northern Isles around 60mph to 70mph gusts. So about a 10mph drop since this afternoon.

The GFS is now showing that low for the weekend it would bring around 60mph gusts to parts of Scotland. We are still unsure on this but at the moment I think the GFS and UKMO are right and the ECM is overdoing that low (it overdone that low at 120 hours yesterday as well). Also looking at the ensemble members for the ECM most of them show something similar to the GFS. For now its one to watch.

For next week it looks more settled at the moment with high pressure around bringing mild and settled conditions for all.

Overall a downgrade for Thursday night and agreement between all 3 main models now as Thursday night comes into a more reliable time frame. For this weekend a possible low may pass over Scotland most models or ensemble members have a rather weak low bringing windy conditions but nothing stormy but the ECM is on its own and brings much higher winds 70mph to 80mph gusts would be likely if it were to come off.

Edited December 20, 2011 by weathermaster

[Cookie]

Brillaint updates mate keep up t he good work!

[Liam J]

Weathermaster, brilliant! Thanks again for the in depth updates.

At least we have some wind to talk about until the weekend, then after this I fear it will only be the wind resulting from all the excessive food and drink intake to talk of (or rather not)

I really hope we see some changes in the synoptic set up soon, I can't stand the thought of boring doom and gloom weather over Winter.

Edited December 20, 2011 by Liam J

[Zenarcher]

Thanks guys I don't mind doing these updates if people read and enjoy them

[Liam J]

Enjoyable and very informative WM, and I'm sure other members and guests having a browse will find the information very helpful and it'll give them a clear picture of what to expect and where.

Edited December 21, 2011 by Liam J

[Liam J]

Morning, some changes overnight on the GFS 00z run with an upgrade of sorts for the weekend which shows a more developed low pressure system crossing the UK during Xmas Day, as the low runs against the high to the south it will create a tight pressure gradient with a squeeze of the isobars over the UK, especially the north.

Still got Thursday on the cards but this seems to have been pushed slightly further north, potential for 60-70mph gusts over the extreme North of Scotland and later the Northern Isles.

Xmas day would bring widespread stronger winds over N&W UK with gusts of around 50-60mph over parts of Northern England with higher gusts over Western Scotland, another one to watch is late Boxing day night with potential for a repeat of the above. Not good news for anyone making any lengthy journeys in N Britain so please take note of the forecasts as any further upgrades with the intensity of these depressions would lead to pretty nasty conditions to say the least,

Edited December 21, 2011 by Liam J

[Zenarcher]

Update using this mornings model runs,

The GFS has continued to downgrade the wind event for Thursday night and looking at wind maps from the ECM and UKMO all 3 pretty much show the exact same wind speeds and position so confidence is now very high on this low. Western Scotland can expect 50mph to 60mph gusts at least mean with Northern Isles 60mph to 70mph gusts. Winds should start to increase at 9pm on Thursday and ease off around 9am on Friday morning. A more into depth forecast for this low will be made tomorrow.

As for Christmas day which I'm still feeling unsure about. As Liam mentioned in his post the GFS last night picked up on the low however this morning on the 06z run it has downgraded it again but it would still bring gusts around 45mph to 55mph for Scotland, Northern Ireland and Northern England. Also looking at the ECM wind charts it has given it a big downgrade as well compared to yesterday. The track of this low seems fairly confident though. The Met Office don't seem to think the wind will be much of a problem but the rain this low will bring might cause some problems for Western Scotland,

Persistent and sometimes heavy rain is likely to commence during Christmas Eve, and as this continues through Christmas Day, there is an increasing risk of localised flooding issues.

The public should be aware that it will be worth keeping up to date with warnings, which may be updated in the run-up to Christmas

Looking ahead into next week with the ECM and GFS like yesterday they are keen for high pressure to take over all parts of the UK for most of next week so perhaps a settled period ahead.

Overall Thursday night hasn't changed much a slight downgrade on wind speeds for Western Scotland but looking the same for the Northern Isles. We are still unsure on the Christmas day low but all models have downgraded it over night but at the moment it would still bring windy weather and as the Met Office said flooding may be an issue. Next week is looking more settled as the models seem to show this a lot over the past day.

[Coast]

Yep, looks to have scaled back somewhat from earlier thoughts:

Iceland still in the firing line for rain:

and some possibility of convective activity, maybe a small tornado or funnel risk in Scotland?

Far North of Scotland gets bigger gusts on Friday:

[Liam J]

12z GFS has really blown the low up for Xmas Day tracking just off the mainland bringing severe gales to the Western Isles and storm force winds through the Northern Isles later in the day. UKMO showing a much less intense depression tracking further to the south which would bring fairly strong winds more widely but nothing like as severe as the GFS is progging.

It could be rather interesting should the final track of the low follow the UKMO model and have the same intensity as per the GFS, but we know that the GFS loves to overdo these systems at times.

Let's what the 12z ECM will make of this feature.

Edited December 21, 2011 by Liam J

[Zenarcher]

Update with today's 12z model runs,

Thursday night and Friday morning again hasn't changed much at all since this morning so again its about 45mph to 55mph gusts for Western Scotland and Northern Scotland. The wind charts for all the models show now the worse of the winds should miss the Northern Isles and can expect the same wind gusts as Western Scotland. It looks like the Faroe islands will see the worse of the wind I would expect 70mph to 80mph gusts.

Worse of the winds seen just missing Scotland tomorrow,

Northern Isles of Scotland just missing the wind as well meanwhile Faroe Islands get the worse,

On Saturday morning the same area's affected by Thursdays low are yet again at risk of windy weather. The chart below shows around 40mph to 50mph mean wind speeds so gusts could be around 70mph.

For Christmas day this Sunday another low will head on over to the UK. All 3 main models still show something different so lets look at the situation. The ECM has shifted the low further North compared to its run this morning this has put the wind speeds up but it would miss the UK completely probably just giving strong winds for the coasts.

Chart below shows ECM,

The GFS has blown up this low and looking at its ensemble members only about 2 agree with it meanwhile about 18 show something less intense.

However both the ECM and GFS show a similar track but the GFS has it further North interacting with colder air and another low which is the reason why its gone for a deep one, meanwhile the ECM and UKMO have it further South not interacting too much with the cold air or pressure systems to the North making it less intense. For now I feel the UKMO and ECM have got a hold of it while the GFS has gone over the top. All eyes on the GFS 18z tonight.

Looking into next week again the models show high pressure around for all bringing settled weather for most of the week.

Overall tomorrow night the Western Scotland and Northern Scotland can expect gusts over 50mph or 60mph nothing severe for these area's. For Saturday its looking very windy for Western and Northern Scotland again with 60mph or 70mph gusts likely. Then for Christmas day another low passes by the ECM and UKMO show a similar track meanwhile the GFS shows a powerful storm. However the worst of the winds for that day do look like they will miss the UK at the moment. I think if this low does go further South it won't be as strong as shown on the ECM and UKMO but if it moves further North and connects with cold air it will be intense but too far North to affect the UK but Faroe islands can expect a violent storm if that happened.

Edited December 21, 2011 by weathermaster