Potential Storm - Sunday 28th Feb

Su Campu · 23-02-2010 11:13pm #1

The models are in good agreement about the prospects of a deep storm system coming near to Ireland some time on Sunday. It could possibly reach 960hPa and has the potential to cause damage should it hold its strength on reaching us.

At the moment the upper pattern is characterised by a deep trough stretching northeast-southwest through the north Atlantic down as far as 30-35N. A series of depressions will form on its eastern flank this week, all following a similar northeasterly track through northern France and the low countries. On Friday, upper divergence in the right rear quadrant and left front quadrant of two jet streaks near Madeira lead to sharp pressure falls at the surface, forming a rapidly deepening low pressure system tracking from Madeira northeastwards towards Portugal and the Bay of Biscay.

While some differences do exists between the models on the lowest pressure, there is good agreement on the general track it will take, clipping northern Iberia, through the Bay of Biscay and towards Brittany and southern England. However, there is a rule of thumb called the Rosenbloom Rule, that states that a rapidly deepening storm system will follow a track left of the track forecast by the models. This would put the storm on a more westerly track towards Ireland. The models have it reaching its lowest pressure of around 965hPa, with the ECMWF the most progressive solution, having it still at 962hPa in the English Channel. But with the Rosenbloom Rule, the storm will take a more westerly track away from the effects of terrain, therefore possibly sustaining its strength as it reaches Ireland. This could bring 45 knot sustained winds, with gusts above 70 knots, to its easterly flank as it moves northwards. If the storm centre were to pass near Cork, southeastern coastal districts could be liable to structural damage and coastal flooding, with storms surge and channeling effects in St George's Channel.

With high baroclinicity and upper QG forcing, there is also the potential of substantial precipitation for many areas, most probably in the form of rain, as the system would be occluding on reaching Ireland.

Definitely one to watch in the coming days.

Danno · 24-02-2010 12:33am

Looks Nasty, I wonder will there be much cold air around to turn the precip to snow, and creating a strong thermal gradient, thus feeding the storm, now this would keep Pat from Tuam happy, a massive wind storm and snow all at once. I must stop dreaming.

WolfeIRE · 24-02-2010 12:37am

Will be cold Danno. all of this will change in the meantime, for better or for worse

Min · 24-02-2010 1:09am

I'd take snow over a bad storm that could cause structural damage anyday....

Su Campu · 24-02-2010 11:44am

An interesting 48hr chart by the US NWS, valid 00Z Friday, showing the rapidly intensifying storm near Madeira, with potential hurricane force surface winds

thetonynator · 24-02-2010 12:43pm

Min wrote: »

I'd take snow over a bad storm that could cause structural damage anyday....

I'd rather if the summer would just come instead.

any snow that falls will melt quickly, so the sooner the spring arrives the better. At least the rain is warmer then

snow ghost · 24-02-2010 1:16pm

Sounds interesting for us, although those hurricane force surface winds are probably the last thing Madeira needs.

This winter has been notable - for me anyway - for the lack of howling winds.

Weatherwise I love a good storm, that's the beauty of Ireland's weather, it can always throw up something exciting and dramatic.

H2UMrsRobinson · 24-02-2010 1:21pm

snow ghost wrote: »

Weatherwise I love a good storm, that's the beauty of Ireland's weather, it can always throw up something exciting and dramatic.

'cept a decent bit of powder it seems :rolleyes:

snow ghost · 24-02-2010 1:43pm

H2UMrsRobinson wrote: »

'cept a decent bit of powder it seems :rolleyes:

Sometimes it can H2U - it may tease and flirt with us, but that's the fun of the chase, it was easy we'd tire of it.

Speak Now · 24-02-2010 2:39pm

Looks like missing us thankfully.

nacho libre · 24-02-2010 2:45pm

i think you're right snow ghost. if we we were getting snowfall of 4- 8 inches regularly we wouldn't appreciate the snowfall as much. certainly more people would begin to see it as a nuisance. that said while i enjoy the chase i hope it ends sooner rather than later and we end up with a siginifacnt snow event in the next few years. assuming i don't kick in the bucket, i'd love to experience what new york is set to experience, over the next few days, just once in my lifetime! yes, i could go to colder climates for a snowfest holiday, but it just isn't the same as seeing it pile up in your own backyard!

As for the storm, if this tracks in over France there is going to be widespread destruction and loss of life. The storms that track in over france are nearly always severe.

snow ghost · 24-02-2010 3:08pm

Too true Nacho - that which is commonplace becomes banal... and what you're saying about needing the snow in Ireland rather than travelling abroad for it.

Snowaddict · 24-02-2010 5:35pm

The latest 12Z UKMO Guidance takes the rather vigirous depression to our Southeast with a transient ridge to the variable North. Light Northeasterly winds develop over Ireland while the fairly vigirous development moves through the English channel, quite possibly causing some destruction in that region.

UW96-21.GIF?24-17

I think this development may herald the start of a pattern change going forward, with the start of a more HP dominated influence with potential blocking developing to the NNE & NE.

SA

pistolpetes11 · 24-02-2010 5:38pm

Snowaddict wrote: »

I think this development may herald the start of a pattern change going forward, with the start of a more HP dominated influence with potential blocking developing to the NNE & NE.

SA

When you say a pattern change , would you expect it to be come milder or would HP blocking keep the warm air away from us ?

North Cork · 24-02-2010 6:57pm

The old saying goes... if March comes in like a lion, it will go out like a lamb

Su Campu · 24-02-2010 9:01pm

This is a classic cyclonic bomb situation, with the pressure set to fall by some 26hPa (997 to 971hPa) in 24hrs, as the surface low centre lies just ahead of the upper trough early Saturday. Certainly looks like unfortunate Madeira, and all of continental Portugal, are in for some serious weather Friday and Saturday.

There's not much change in the main models regarding the track, with the 12Z ECMWF slowing it down slightly compared to yesterday's run. The NOGAPS is the crazy outlier today, with a 956hPa low right over the Wexford coast 12Z Sunday. :eek: An unlikely outcome, but the track is more in line with what I was saying last night re the Rosenbloom Rule. We'll see if the other models gradually start to correct their track westwards in the next day or so.

Redsunset · 24-02-2010 9:07pm

Yes Su it could cause problems if it decide to follow nogaps plans.

nogaps-0-90.png?24-18

Deep Easterly · 24-02-2010 9:40pm

North Cork wrote: »

The old saying goes... if March comes in like a lion, it will go out like a lamb

I have yet to see that happen in the actual though, although my weather love mood tends to switch off in March as it is probably the most boring month weatherwise in Ireland.

I have not looked at any model for the last couple of days and have only just briefly glanced at the ECM. A good storm would be appreciated very much but seen no sign of any storm on the model I looked at just now. I just see a continuation of the same banal, inactive, empty void we have put over the last couple of months. Hopefully though a serious upgrade in later runs.

kindredspirit · 24-02-2010 10:13pm

Senor Valor usually gets things right.

It looks like it's going to get rough around Biscay but it'll miss us. Let's hope he's right this time as well.

Min · 24-02-2010 11:32pm

Please God we won't get that storm, if we do I hope Deep Easterly is left without electricity for a few days to get over his love of "a good storm" :P

I saw the Christmas eve storm tear the roof off two separate buildings as if the roofing was a piece of paper, the phone was out for about 7 days and the electricity was gone for most of Christmas, it was scary bad.

I pity any region that gets this storm as it looks real nasty and of course I don't wish any bad on DE, he can have a localised bad storm to keep him happy or move to Brittany for the weekend

thetonynator · 24-02-2010 11:34pm

Min wrote: »

Please God we won't get that storm, if we do I hope Deep Easterly is left without electricity for a few days to get over his love of "a good storm" :P

I saw the Christmas eve storm tear the roof off two separate buildings as if the roofing was a piece of paper, the phone was out for about 7 days and the electricity was gone for most of Christmas, it was scary bad.

I pity any region that gets this storm as it looks real nasty and of course I don't wish any bad on DE, he can have a localised bad storm to keep him happy or move to Brittany for the weekend

something good comes out of everything though . . .the christmas eve storm of 97 provided about 5 years firewood!!!

Hope that storm doesnt come though , i hate rain and wind

but if it falls as snow . . .???

delw · 25-02-2010 1:44am

can understand not wanting a storm& but personaly i love a good storm,wind howling,rain belting,pressure dropping,throw in a bit of thunder&lighting to top off:D

Redsunset · 25-02-2010 6:44am

This was from yesterday morning,i missed it,
Mentions the dangerous storm towards the end.

http://www.youtube.com/watch?v=T04l3j58XXE

Min · 25-02-2010 8:07am

redsunset wrote: »

This was from yesterday morning,i missed it,
Mentions the dangerous storm towards the end.

http://www.youtube.com/watch?v=T04l3j58XXE

A vicious storm he says, where it hits there is no doubt it will kill people.

redsteveireland · 25-02-2010 8:59am

thetonynator wrote: »

Hope that storm doesnt come though , i hate rain and wind

but if it falls as snow . . .???

The much sought after thundersnow?

Speak Now · 25-02-2010 9:13am

delw wrote: »

can understand not wanting a storm& but personaly i love a good storm,wind howling,rain belting,pressure dropping,throw in a bit of thunder&lighting to top off:D

Depends where you live

Not so great in rural area's when it's a wide open fields around your house and you're always last on ESB's list to be fixed

NoodleMc · 25-02-2010 9:28am

Yikes - my uncle is in Madeira (arrived on Monday) and my sister is due to go on Sunday! Better tell her to stay indoors!

Snowaddict · 25-02-2010 10:05am

Overnight Guidance is consistent on the track of the main depression, taking it the Southeast of Ireland & removing the risk of associated disruption from it, however there is still scope for last minute changes in relation to it's track.

However, as mentioned a while back on the thread, it's quite possible now that this development is heralding a pattern change to a more HP dominated influence with a subsequent Easterly flow. While there have been tentative signs of this over the past few days on NWP Guidance, the trend is developing to quite an extent overnight on the latest Guidance.

Into the medium term, EMCWF 00Z Operational, GEM 00Z Operational & GFS 00Z Operational all model a deep cold pool being advected across the UK & Ireland with an Easterly flow. UKMO @ T+120 - T+144 also shows a gradually developing Easterly evolution with a blocking High to the NE/NNE.

It's getting a little late in the year now, but there is just about enough time left, if the cold is deep enough, for a decent Easterly flow, but it must take place within the timeframe modelled overnight & not any later as solar power will be increasing on a daily basis..

In summary, this significant development will highly likely herald a pattern change to a more HP dominated influence, that could well lead to a cold pattern developing during early March.

It's certainly something to watch going forward.

SA

25-02-2010 10:44am

Snowaddict wrote: »

Into the medium term, EMCWF 00Z Operational, GEM 00Z Operational & GFS 00Z Operational all model a deep cold pool being advected across the UK & Ireland with an Easterly flow. UKMO @ T+120 - T+144 also shows a gradually developing Easterly evolution with a blocking High to the NE/NNE.

It's getting a little late in the year now, but there is just about enough time left, if the cold is deep enough, for a decent Easterly flow, but it must take place within the timeframe modelled overnight & not any later as solar power will be increasing on a daily basis..

In summary, this significant development will highly likely herald a pattern change to a more HP dominated influence, that could well lead to a cold pattern developing during early March.

It's certainly something to watch going forward.

SA

For what it's worth,in my lifetime,I've seen disruptive blizzards on st patricks day in Ireland ,with the snow falling as far south as cork.
I've also seen a week long freezing spell in march,as good as the one we had in january with more snow though [a good 8 inches in Arklow on the coast that lasted the week and sub zero!]
I won't tell you the year but I suspect it was before most posting here were born

So yes anythings possible with the right syn optics.

p.s it was an Easterly iirc

Speak Now · 25-02-2010 10:58am

GFZ 06Z at T72 shows the storm well away from us, has risen from 976 to 984 also.

nacho libre · 25-02-2010 1:34pm

Has paddy1 gone off to France? is that why he hasn't been posting much of late;)

Min · 25-02-2010 2:08pm

nacho libre wrote: »

Has paddy1 gone off to France? is that why he hasn't been posting much of late;)

He must be on the ferry to Brittany

Su Campu · 25-02-2010 5:50pm

The 12Z GFS is a big downgrade of the storm Saturday, with the 2nd jetstreak weaker than previously progged, and the surface centre moving out of the left front quadrant as it nears Portugal, consequently filling and taking a more easterly track through central France and into Germany.

The 12Z UKMO still has it as before, a potent sub-970hPa low, therefore on a more northerly track, with its centre clipping Galicia and tracking into northern France and Denmark by Monday 12Z.

With only 18hrs to go before we see the first signs of it forming west of Madeira, there is still some uncertainty with it.

nacho libre · 25-02-2010 6:03pm

Poor paddy1 his ferry trip is all in vain so:D

I think it may well take a deep system to end this pattern of weather we're experiencing. So we could yet see a storm come close to Ireland sometime in March.

Su Campu · 25-02-2010 9:46pm

12Z ECMWF is still progressive on this system, keeping it at 969hPa as it reaches the English Channel Sunday morning, and a little to the right of previous runs. If it were to drift to the left, conditions would be marginal for wintry precipitation in the east, but so far there's no real sign of the models correcting track westwards.

Redsunset · 26-02-2010 1:39am

Birth of a storm

Su Campu · 26-02-2010 8:50am

Madeira and Porto Santo TAFs are giving some strong winds early tomorrow, southerly 30 gusting 50 knots. With a wind like that at Madeira airport, where turbulence can be severe, there'll be no flights landing there, that's for sure! Moderate rain and drizzle forecast for the 24 hours, so hopefully not a repeat of last Saturday.

[FONT=Monospace,Courier]LPMA 260730Z 21004KT 170V240 9999 SCT006 BKN013 17/16 Q1009 RS22002KT 0522004KT 2324006KT[/FONT]

LPMA 260500Z 2606/2706 VRB05KT 9999 SCT015 BKN030
TEMPO 2606/2706 4000 RADZ BR SCT008 BKN013
BECMG 2607/2609 20008KT
BECMG 2612/2614 20017KT
BECMG 2622/2624 20025G35KT
TEMPO 2700/2706 20035G50KT

Meanwhile, the 00Z GFS has the system back as a potent storm in the English channel again after yesterday's 12Z downgrade, but a lot further east than the UKMO. Still some indecision between the models, so still a small chance that it could track more westerly.

Su Campu · 26-02-2010 11:48am

The Portuguese IM are warning of sustained coastal winds of 60-85kmph (Force9-10), with gusts up to 150kmph (93mph) tomorrow in continental Portugal. :eek:

Previsão para Sábado, 27 de Fevereiro de 2010

Céu muito nublado ou encoberto, por vezes com abertas para o final
da tarde.
Períodos de chuva por vezes forte, passando gradualmente a regime
de aguaceiros a partir da tarde.
Vento forte (35 a 55 km/h) do quadrante sul, soprando
temporariamente muito forte a excepcionalmente forte (60 a 85 km/h),
com rajadas da ordem dos 150 km/h no litoral e terras altas e
rodando para oeste a partir do final da tarde.
Subida de temperatura.

ESTADO DO MAR
Costa Ocidental: Ondas de sudoeste com 3 a 4 metros, aumentando
temporariamente para 5 a 7 metros.
Temperatura da água do mar: 13/15ºC
Costa Sul: Ondas de sudoeste com 2 metros, aumentando
para 4 a 5 metros.
Temperatura da água do mar: 16ºC

Actualizado a 26 de Fevereiro de 2010 às 10:3 UTC

ALADIN model

Redsunset · 26-02-2010 1:10pm

This storm is already looking agressive on satellite,and i think it could be deeper than suggested.
The NAE has it on this path but could eventually skirting closer to south england coasts.

Needs to be watch very closely this one,as it contains lots of moisture and poor old maderia is getting no luck lately all down to our prodical son called the jet stream.

Su Campu · 26-02-2010 2:01pm

Remember the system is developing in an area with very limited observations between 30-60W, both surface and upper air, so initial discrepancies in the different model analyses will have a bearing on the dynamics of its evolution. We saw yesterday with the GFS that a small change in the jetstream positioning and strength led to a very different system come Sunday lunchtime. It won't really be until we get inside the 24hr timeframe tomorrow that we'll be fairly certain what way it's going to go.

DWD 00Z 300hPa Analysis

GFS 00Z 300hPa Analysis

Deep Easterly · 26-02-2010 2:53pm

AEMET's HIRLAM model keeps this feature away from hus baz.

Su Campu · 26-02-2010 4:41pm

Where or who is hus baz??!!

nacho libre · 26-02-2010 5:29pm

He's just expressing disappointment in Tuam vernacular:P

Redsunset · 26-02-2010 5:42pm

nacho libre wrote: »

He's just expressing disappointment in Tuam vernacular:P

Yeah tuam has a language of its own:D

Know a few people there and worked for a crowd based there

Deep Easterly · 26-02-2010 7:11pm

nacho libre wrote: »

He's just expressing disappointment in Tuam vernacular:P

Wide..

snaps · 26-02-2010 7:39pm

Tuam or Chooom? Its very quiet on here this evening. Perhaps everyone has gone to watch the rugby in twickenham?

nacho libre · 26-02-2010 8:53pm

Deep Easterly wrote: »

Wide..

"Shapes";)

Deep Easterly · 26-02-2010 9:22pm

nacho libre wrote: »

"Shapes";)

Stall the breeze! his gills is well wide for da spake :eek:

Have ye Mayoians (:D) broken the sacred code? :P

Su Campu · 26-02-2010 9:34pm

The first effect are getting into Madeira and Porto Santo now. Note the TAF is giving southerly winds, mean 45, gusting 60 knots, with heavy rain, from midnight to 8am. I'm sure it's going to be a long night for them after what happened last week....:(

METAR
[FONT=Monospace,Courier]LPMA 262000Z 22018KT 9999 -RA SCT010 BKN015 FEW016TCU 18/17 Q0999 RS20015KT 0521015KT 2323018KT[/FONT]

TAF
LPMA 261700Z 2618/2718 22025KT 8000 SCT010 BKN013
TEMPO 2618/2708 22030G45KT 4000 -RADZ BR SCT005 BKN010 FEW015CB
PROB40
TEMPO 2700/2708 22045G60KT 1500 +RA BR BKN003
BECMG 2706/2708 26025G35KT 9999 SCT015
TEMPO 2708/2718 8000 SHRA BKN015 FEW018CB
BECMG 2710/2712 32020KT

Meanwhile, look at the TAF for Porto Airport, southerly mean 50, gusting 65 knots, from midday tomorrow! :eek:

LPPR 261700Z 2618/2718 19015KT 9999 SCT015 BKN030
TEMPO 2618/2624 8000 -SHRA BKN015 FEW020CB
BECMG 2622/2624 14010KT 4000 RA SCT006 BKN012
TEMPO 2700/2712 1500 +RA SCT003 BKN006
BECMG 2707/2709 18025G35KT 8000 NSW SCT012 BKN020
PROB40
TEMPO 2712/2718 19050G65KT 3000 RADZ SCT006 BKN012 SCT018CB

Cabra · 26-02-2010 11:37pm

Heading to Madeira on Sunday - any thoughts on what we can expect weatherwise?

Speak Now · 26-02-2010 11:42pm

Cabra wrote: »

Heading to Madeira on Sunday - any thoughts on what we can expect weatherwise?

Dunno if you're taking the piss or not but the low will have passed through by then. Expect temps around 18-20c this time of year but possibly a bit showery with the current jet stream.

Potential Storm - Sunday 28th Feb

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