Atlantic Storm Watch: December 2013

JanuarySnowstor

Am unsure where you see the downgrades john icy?
It looks the same as this morning to me if not more severe!!

munsterlegend

JanuarySnowstor wrote: »

Am unsure where you see the downgrades john icy?
It looks the same as this morning to me if not more severe!!

Have the systems not veered more north though and away from Ireland?

JanuarySnowstor

munsterlegend wrote: »

Have the systems not veered more north though and away from Ireland?

Not from where I am sitting it looks very severe tues morning

je551e

Flying out on Tuesday Morning, really hope this isn't bad

munsterlegend

JanuarySnowstor wrote: »

Not from where I am sitting it looks very severe tues morning

Ok thanks...am just repeating what other posters have suggested. Will be interesting to watch how it unfolds.

John.Icy

JanuarySnowstor wrote: »

Am unsure where you see the downgrades john icy?
It looks the same as this morning to me if not more severe!!

Previous runs looked a much more frightening prospect for the North for Tuesday. Still very windy as I said but nothing out totally out of the ordinary for them, unless the stronger low means a much wider spread of strong winds instead of just close to the core.

Regarding the 27th it has most defiantly been downgrading tonight on the ECM and GFS 12z.

EDIT: If NAE is the final solution though, it will be a severe storm.

force eleven

Every run bringing subtle twists and turns. And this system is barely an embryo at the moment. Come back here tomorrow evening, you'll get a firm idea what track and intensity is expected.

maquiladora

12Z ECM has the low doing a loop between 48 hour and 72 hours.

http://en.vedur.is/weather/forecasts/atlantic/#type=prec

One thing we need to look out for is that loop swinging closer to us.

But seeing how different the NAE looks compared to the global models at 48 hours, maybe we shouldn't be looking at any details too closely yet.

maquiladora

Latest 48 hour NOAA OPC chart. Notice the 50 and 60 knot wind barbs off the east and southeast coasts: the cold front passing over the country on Monday could be very active regardless the what happens with the area of severe winds close to the center of the low.

http://www.opc.ncep.noaa.gov/shtml/A_48hrbw.gif

eigrod

Gerry Murphy at 9.40pm highlighting the potential storm alright. Said it's all down to how it tracks and to keep an eye on the forecast over the next couple of days.

Hooter23

eigrod wrote: »

Gerry Murphy at 9.40pm highlighting the potential storm alright. Said it's all down to how it tracks and to keep an eye on the forecast over the next couple of days.

Yes its almost certain at this stage it will be a very Intense storm which I think makes it track that more difficult to predict .....

Iancar29

Just some clarity before I hit the hay to be up at 5am .

Though the pressure looks nearly historic to have a sub 930 storm near our coast , this does not mean it's winds will be historic . As one can see the pressure gradient isn't as compact as one would think with such a storm. So as others say , wait till tomorrow's high res models to run and then examine again .

I don't think it's looking as bad wind wise atm . But certainly the cold front is gonna pack a punch !

Night all .

Frank Garrett

What about storm surge? The lower the pressure, the higher the seas, if I understand correctly.

branie

Haven't been affected where I'm living

maquiladora

18Z NAE at 48 hours. Look at the size of that wind field, multiple secondary features swirling around. And that area of hurricane force west of the center, is that swinging in our direction? Also it looks like NAE does not display pressure below 950mb on Weatheronline.

I'm not even going to attempt to hazard a forecast at this stage :pac:

squonk

HOLY F#%K Maq! If that comes off it'll be brown trousers time my neck of the woods!

Oscar Bravo

A 2248 update fro Met Eireann Outlook

The unsettled weather will continue, with some very wet and windy spells over the Christmas period. However there will be some drier and brighter weather too.

The very wet and windy weather will continue on Monday night, with further heavy falls of rain. The rain should start to clear away towards the morning and it will be quite cold with lows of 0 to 2 degrees.

Christmas Eve will be a very cool day with highs of only 3 to 7 degrees. There will be some wintry showers, and these will mainly affect parts of Munster, Connacht and Ulster. It will be drier and brighter in parts of the east. Another windy day with fresh to strong southwest winds. The showers will continue to affect western and northern areas overnight and it will become cold with lows of -2 to +2 degrees, so some icy patches will develop.

Christmas Day will be cold and bright, with sunny spells for much of the country but showers will continue to affect Atlantic coastal counties. Highest temperatures 4 to 7 degrees. It will be a cold night with temperatures falling to freezing or below, and frost and ice patches will form.

St Stephen's Day will be a similar day with showers along western coasts, but drier and brighter elsewhere. There is the risk that overnight some heavy rain will develop, and that some snowfalls will also occur.

The next few days will see the unsettled trend continuing.

branie

Oscar Bravo wrote: »

A 2248 update fro Met Eireann Outlook

The unsettled weather will continue, with some very wet and windy spells over the Christmas period. However there will be some drier and brighter weather too.

The very wet and windy weather will continue on Monday night, with further heavy falls of rain. The rain should start to clear away towards the morning and it will be quite cold with lows of 0 to 2 degrees.

Christmas Eve will be a very cool day with highs of only 3 to 7 degrees. There will be some wintry showers, and these will mainly affect parts of Munster, Connacht and Ulster. It will be drier and brighter in parts of the east. Another windy day with fresh to strong southwest winds. The showers will continue to affect western and northern areas overnight and it will become cold with lows of -2 to +2 degrees, so some icy patches will develop.

Christmas Day will be cold and bright, with sunny spells for much of the country but showers will continue to affect Atlantic coastal counties. Highest temperatures 4 to 7 degrees. It will be a cold night with temperatures falling to freezing or below, and frost and ice patches will form.

St Stephen's Day will be a similar day with showers along western coasts, but drier and brighter elsewhere. There is the risk that overnight some heavy rain will develop, and that some snowfalls will also occur.

The next few days will see the unsettled trend continuing.

No storms, then thankfully

Oscar Bravo

yes big downgrade from Met Eireann ,even on the radio forecast earlier they didn't mention much about storms and gave all the way to next Friday so they must be fairly confident. good to see an update from them this late on a Saturday night....not like them!

aisling86

Reckless n that met.ie are practising there calming techniques

Smidge

I just wanted to ask Maq et al if anything like whats showing up on the charts for Tuesday has ever made landfall in Ireland?
If so when?
Thanks

leahyl

This is so confusing - from Gerry Murphy's forecast after the 9 news and reading on here you would think that a big storm was possible and now there is no storm coming?!

pad199207

I think they are playing it safe with the fact that it could very likely go much further North than projected.
Gerry did mention IF the storm follows the forecasted path

Hooter23

Oscar Bravo wrote: »

A 2248 update fro Met Eireann Outlook
St Stephen's Day will be a similar day with showers along western coasts, but drier and brighter elsewhere. There is the risk that overnight some heavy rain will develop, and that some snowfalls will also occur.

When they say snowfalls do they mean snowfall on the northern side of the system for thursday

rilz

maquiladora wrote: »

18Z NAE at 48 hours. Look at the size of that wind field, multiple secondary features swirling around. And that area of hurricane force west of the center, is that swinging in our direction? Also it looks like NAE does not display pressure below 950mb on Weatheronline.

I'm not even going to attempt to hazard a forecast at this stage :pac:

Is all of Ireland going to get strong winds from that?

maquiladora

squonk wrote: »

HOLY F#%K Maq! If that comes off it'll be brown trousers time my neck of the woods!

Well there's actually no severe winds shown over land there at that time, and it's only one run of one model. The previous run 6 hours ago had a low spinning up along he west coast that now doesn't exist on this run, so nothing to panic about. :P But it does look like there would at least be potential for strong wings at times?

Maybe coastal flooding would be a bigger threat with low pressure nearby, a large windfield and prolonged gales?

Maybe the models will have better idea once the low starts deepening in the Atlantic tomorrow.

eskimocat

As its still all to play for regarding this particular storm, I was reminded of a nice little weather station that's located on a little island called Edernish, off the coast of Donegal.

They have a website that streams live webcams, and gives real time weather readings.

So if this thing takes a swing towards the Ulster coast it might be worth the watching. During the day that is!! Here it is.

Happy storm watching!

maquiladora

leahyl wrote: »

This is so confusing - from Gerry Murphy's forecast after the 9 news and reading on here you would think that a big storm was possible and now there is no storm coming?!

Well the ECMWF and the HIRLAM, two models that Met Eireann use both show a sub-930mb low. So a "big storm" is almost certainly going to develop to our northwest, the question though is in what way it will impact us, if at all? The exact track, the timing, the phasing with other areas of low pressure etc....thats all changing from run to run and model to model. Met Eireann usually don't issue warnings until the night before or on the morning of an event, when there is high confidence of what exactly will happen, and right now there isn't high confidence on what exactly will happen.

We'll have a better idea tomorrow.

Frank Garrett

Fúck me, I have seen a Winter this stormy since December 2004/January 2005. We had like 3 storms in a week around New Year's day with some flooding, too. Oh and that Christmas was a white one.

M.T. Cranium

Compared to 1839 "Big Wind" storm of 6-7 Jan, this has a similar central pressure on more developed versions of guidance (922 vs 918 for that historic storm) and the centre tracks fairly close although this one could wobble around and even do a slight counter-clockwise loop which is not what research has suggested about the 1839 storm.

The key comparison would be pressure gradient. Some of the GFS stronger perturbations are close calls, I estimated from the research maps that the Malin to Valentia pressure difference was 45 mbs in 1839, and has been 25-30 mbs in some recent minor damage type events, perhaps 35-40 in more comparable storms such as Dec 1886 and 26-12-1998. There are some GFS perturbations with a 35-40 mb gradient over the country north to south.

Looking at all model guidance, I continue to think that there could be just a narrow escape from what might be termed moderate damage, and have come up with these three stats to indicate range of probabilities:

In the table, A would indicate a maximum gust 90% likely to be exceeded. B indicates the most likely value for maximum gust and C indicates a more severe reading that could be considered 10% likely. I have also divided the country into three zones, Zone 1 being the most exposed (likely to include West Munster, coastal Connacht and north/west Ulster), Zone 2 being moderately exposed (rest of south coast, inland areas of Connacht, central Munster, well exposed to west areas of Leinster) and Zone 3 would be less exposed locations mainly inland northeast, east, southeast.

So here's how the probabilities break down:

Region __________________ A __ B __ C (max gusts, km/hr)

Zone 1 _________________ 120_145_180
Zone 2 _________________ 110_130_150
Zone 3 _________________ 095_110_130

Based on that and factoring in population, the risk exposure for the entire population would read out as 108_125_140.

This roughly translates into saying that the risk of significant damage (thresh-hold being structural damage exceeding 20k euros for at least 10 cases) is about 40% overall, and for very widespread damage (thresh-hold being structural damage in total exceeding ten million euros) about 20% overall.

Therefore this is a significant event and yet there is some chance that the vast majority will avoid any really significant impacts, if two things happen -- the centre fails to deepen below 940 and the gradient is not any tighter than about a 30-mb differential north to south.

There are obviously some intermediate cases. One would presume that a partial hit would involve mostly significant damage from Galway to Derry, but some variations place west Munster at greater risk or equal risk and perhaps spare some parts of the north.

The least likely places to see a lot of impacts would be sheltered areas (not well exposed to west) in hilly terrain anywhere in the country. If you have hills to your west and not the sort of terrain that would invite a lee wave formation (a long gentle downslope) then you should be okay regardless.

There is also some spread in timing of most severe gusts, the 90% range there is about 7 p.m. Monday to noon Tuesday. The most likely time is about 0200h Tuesday 24th.

Final point, storm surge potential is lower than last Wednesday even in worst case maps because luckily we are dead centre between full and new moon so that astronomical tides are fairly low in their maxima, and a rise of one metre in ocean levels could merely bring them up to normal "spring tide" levels. So it would have to be a very very strong westerly wind into Galway Bay to bring about any worse conditions than seen last week, and hopefully those few who parked in the wrong spot then will not be tempting the fates a second time.