*** Heavy Rain and High Winds for many as Storm approaches(Mon 24th - Tues 25th Sept)

Redsunset

Currently this thread is to watch the development of a weather system expected to come up from the Bay of Biscay and being a potential troublemaker.

There are No warnings and was only briefly mentioned tonight by Met Éireann's Jean Byrne as being a danger but not a cert by any means yet.

Here's a GIF I made and we can then compare later of how right or wrong the current forecasted track.



M.T's thoughts.
http://www.boards.ie/vbulletin/showpost.php?p=80852991&postcount=2626

maquiladora

Doesn't look too severe in terms of wind, on the GFS. Max gusts of about 30-40 mph on the coasts. I don't think we'll be seeing hurricane stories in the media this time. :rolleyes:

The low does look like it wants to hang around doing a few loops though, which could dump quite a bit of rain somewhere.

6pm Sunday:


6am Monday:


6pm Monday:


6am Tuesday:


6pm Tuesday:


6am Wednesday:

TURRICAN

Possibility of a muck bath for the Ploughing championship next week then!

Just imagine over 150,000 people expected and then a possibility of 30 - 50mm of rain and wind to blow your cap off.

Anyway back on topic:)

Cantona's Collars

Was mentioned on the forecast after the news,they aren't sure of the track.Jean Byrne said it may hit us or veer off through Southern England.Don't want it so let it head East.

maquiladora

zerks wrote: »

Was mentioned on the forecast after the news,they aren't sure of the track.Jean Byrne said it may hit us or veer off through Southern England.Don't want it so let it head East.

Yeah there is a huge difference at 96 hours on the global models. The GFS and ECM have it over UK/Ireland at that time while the UKMO and GEM have it over Germany, and the NOGAPS doesn't develop it at all. Unusual to see such a wide difference at that timescale.

Edit : Haha, did I put that thumbs down icon in this post or did someone not like it? :P

Redsunset

https://www.youtube.com/watch?v=Njdyz4h1qjY

Some Met Office thoughts.But nothing conclusive yet.

Mr Cumulonimbus

18Z GFS run coming out at the moment. At least for Sunday the rain appears to be missing Ireland to the South unlike the 12Z. Following the 12Z UKMO a bit it seems.

Redsunset

I'd say ECM will eventually fall into line very soon with the other models as they drag system further south and east away from us. However it would be a good victory for ECM if it stays stubborn and is proven correct.

maquiladora

Huge change on the 18Z GFS. It is now more in line with the UKMO and GEM. Ireland doesn't get impact at all from this low now as it heads much further east and much weaker.

We do get some rain from another system coming down from Iceland later though.

Edit: I see Spawn of Nadine Part 2 at 150 hours? Haha



Probably will be gone on the next run.

Redsunset

Yeah seen Joe Bastardi tweets today. Being dramatic as usual.

Nadine to slam Iberian peninsula middle of next week then turn north through western Europe.

Nadine: hits Portugal then turns north on the GFS through western Europe all the way to UK.. Anarchy in the UK weather pattern!

Oscar Bravo

And Met Eireann's 2300 update....Saturday night will remain dry over much of the country, but rain will spread into south Munster and south Leinster late in the night. The rain will become widespread and heavy during Sunday across Munster, Leinster and east Ulster but amounts will be small further west where it'll stay mostly dry. It'll be mild in a fresh northeast breeze. Monday will be a mostly cloudy day with further outbreaks of rain across Ulster and Leinster, while other areas will have sunny breaks and occasional showers. Northwest winds will be fresh and blustery. It'll stay cool, very changeable and unsettled for both Tuesday and Wednesday as an extensive low pressure area predominates over Ireland. Showers will be widespread and heavy with some prolonged, along with possible hail and thunder. Strong gusty southwest winds on Tuesday will turn to an east or northeast direction for Wednesday. Thursday will be a brighter and mostly dry day with lighter winds. The latter part of the week will be mostly dry also as winds swing to the northwest. However eastern counties will have showers on occasions, and overall temperatures will be below normal.

Redsunset

Interesting that NOAA still tracking low towards us in latest report.

The plot thickens. Until the next run at last.

maquiladora

Redsunset wrote: »

Interesting that NOAA still tracking low towards us in latest report.

The plot thickens. Until the next run at last.

Probably based on the 12Z GFS.

I think we'll have a clearer picture in the morning after the 0Z runs.

Mr Cumulonimbus

A divergence again it seems between the 0z GFS and 0z UKMO. UKMO still has the rain passing to the south of Ireland on Sunday evening while the GFS has rain spreading into the south and east.

7:55am forecast on Radio 1 this morning following the GFS line it would appear.

ninebeanrows

Some pretty intense precip coming if the GFS is to be correct.

Could be severe flood risk for the north and east if things move in that direction.

ninebeanrows

Weatherman2012 wrote: »

Folks looking at the latest 00z run on GFS and ECMWF the storm will be felt mainly across the Eastern / Southern areas of the country. Unless the intensity drops off (Very possible) the models are hinting at some very strong winds and savage rainfall over a 48 hour period. The UKMO still showing the storm tracking well south of Ireland????

I think the main focus is on rainfall and as we know forecasting rainfall intensity is notoriously difficult.

Larbre34

Its probably more interesting because of its early season arrival, but I think if this showed up in the first week of November it would hardly raise an eyebrow.

I'm expecting a dirty wet day as your Granny might say, no doubt it will give the autumn leaf fall a good start with some surface flooding but Id be surprised if the wind gusts and rainfall totals were anything remarkable

Prediction 35mm max 24hr total at Johnstown Castle, 38kt gust at Dublin Airport

maquiladora

06Z GFS showing it weaker and further east. No strong winds and heaviest rain in England/Wales on this run.

Redsunset

Well this is increasing looking very benign, however there is still time for it to revert back to what only the previous 00z run suggested.

Rainfall totals up to 75mm. May not happen of course.

maquiladora

A couple of the 06Z ensembles have some fun and bomb ex-Nadine herself over us. :pac: Chance of this happening at the moment is very remote though.

Redsunset

Wave developing. This one could be interesting to track on satellite.

maquiladora

Comparison between the 06Z GFS and the hi-res 06Z HIRLAM.

At 60 hours, HIRLAM has the low further northeast than the GFS and less potent.




Still a tricky one for the models.

Redsunset

Another view of it in water vapor form and H500.

maquiladora

Latest models.

12Z NAE vs 12Z GFS at 48 hours.

M.T. Cranium

Before the ECM appears, can already note that all other reliable global models have ended the experiment of Nadine heading into Europe and seem to be reverting to the southwest track.

As to the main event the trend seems to be holding for the N American models to suggest a wider loop than the UK or German competitors, in fact the UK model basically bounces the low off some sort of Dublin shield on its 12z run.

There is a continued trend towards slower evolution of the storm.

Now we await the verdict of the big kahuna (but keep in mind, the ECM reputation is based on a 5% or thereabouts edge over the GFS or GEM or UK models, so it's always best to take a consensus).

maquiladora

Looking quite windy for parts of Scotland on the 12Z ECM. At 93 hours the center of the low is down to 972mb over Northern England.

BBC have a video now explaining this system and how it might impact the UK. Still a fair bit on uncertainty with the exact details of track, timing and intensity.

http://www.bbc.co.uk/weather/features/19677758

Deep Easterly

If the current ECMWF evolution played out as forecast in January or February, we would have the threat near blizzard conditions for the north and west esp.



Anyway, back to reality...

maquiladora

Latest model runs are out.

Look at the difference between the new GFS and the NAE, at the same timeframe - just 48 hours.

So when something might actually happen the models still can't agree 48 hours out? That's reassuring.

ninebeanrows

0z GFS looks abysmal. Some intense rain and strong winds for prolonged period, get your wet gear at the ready.

snaps

Weathercheck wrote: »

0z GFS looks abysmal. Some intense rain and strong winds for prolonged period, get your wet gear at the ready.

so we still don't know what's happening in 48 hours time? That's gas.

DOCARCH

snaps wrote: »

so we still don't know what's happening in 48 hours time? That's gas.

What's new!

As WC says, atm, Monday through to Wednesday now looks very wet for the east coast. All my cahnge again of course!

maquiladora

0Z GFS is very different to the 18Z.

Accumulated rainfall to next Friday has over 120mm of rain for parts of eastern Ireland and over 130mm for parts of Wales.



Windy everywhere with gales in some coastal regions if this came off.



We'll see what changes with the 06Z models soon.

Just as a comparison, here is what the GEM is showing for the same time as the GFS above :

Redsunset

Yes horrendous conditions on the 00z. Here's a gif showing some of that proposed rainfall for the archives just in case it does happen. Probably be gone on next run.

maquiladora

ninebeanrows

Really looks wet Monday into Tuesday on the latest GFS east and northeast look most at risk. Potential for up to 50-100mm over a 24hr period so certainly worth keeping a very concerned eye on this set up.

Iancar29

Yep , could be bad if any of that rain arrives with gusty winds . Gusts in the 60mph region possible for the N & NW too. I think this warrants a Level One now at least.

maquiladora

No real change to track/intensity of the low on the 06Z GFS.

Redsunset

Iancar29 wrote: »

I think this warrants a Level One now at least.

I think the situation is still too uncertain for that. Needs beefing up in a few more runs. The heavy rain over east and north east and strong gusts could downgrade.

maquiladora

UK Met Office update.

maquiladora

Interesting 06Z HIRLAM. It tracks the low further west than the GFS, NAE etc.

A big difference in the rainfall.

Over 50mm of rain for parts of Ulster falling in less than 24 hours here.



Much more than what the GFS is showing for the same time:

ninebeanrows

Meteociel charts show widely 40-50mm and 70mm along northeast coast.

Look for accumulated precip in the high res GFS

Redsunset

Hi Res image of the developing low.

srmambo

Looks like a pretty exciting scenario unfolding. Does this storm bear any similarities to the storm on September 6th 2010 or the torrential rainfall on October 2011?

Deep Easterly

srmambo wrote: »

Looks like a pretty exciting scenario unfolding. Does this storm bear any similarities to the storm on September 6th 2010 or the torrential rainfall on October 2011?

Not really Srmambo, although those 2 systems you mention were relatviely similar in set up themselves. This one seems quite different in that it is moving up from south or SSW, which is most unusual (but not unprecedented) for such an intense depression in this part of the world.

Close up of the low center at 1200 UTC today. Beautiful looking structure.

maquiladora

Comparing the latest runs of hi-res models HIRLAM and NAE, there is a 400km difference on the position of the center of the low at midday Monday.

Trying to predict where the heaviest rain will be and for how long seems really hard when there is still disagreement like that.

Ireland could get away with very little rain compared to the UK, or we could get an absolute drenching.

Redsunset

Correct Maq, we could very well still escape the worst of this or be under a threat of some flooding with locally high rainfall totals in strong gusty conditions at times.
Surely by tomorrow the track will be nailed.

maquiladora

Redsunset wrote: »

Correct Maq, we could very well still escape the worst of this or be under a threat of some flooding with locally high rainfall totals in strong gusty conditions at times.
Surely by tomorrow the track will be nailed.

And that's exactly what the 12Z GFS is showing now. The precipitation accumulation for the east coast at 90 hours is now 14mm. On the last run the same spot shows over 60mm. Bit of a difference!

Will be interesting to see what the 12Z HIRLAM shows.

Edit : Here is the 12Z HIRLAM, showing a lot more rain for the North and East than the GFS is.

Redsunset

Latest BBC weather update video

http://www.bbc.co.uk/weather/features/19687222

up for anything

It better rain now and good. I just spent the best part of three hours clearing the accumulation and growth of what looks like twenty years out of the gutter. :mad:

maquiladora

up for anything wrote: »

It better rain now and good. I just spent the best part of three hours clearing the accumulation and growth of what looks like twenty years out of the gutter. :mad:

Are you in Kilkenny? I wouldn't expect much rain there at all. It's really the east/north that is at risk of the heavy rain.