The Week Ahead - Discussion - Potentially Storm Thursday

pauldry

Deep Easterly wrote: »

Tonight's ECM, if anything, has increased the forecast windspeeds for Thursday:



Full gales now in coastal areas ( strong gales in the NW and north) with possible gale gusts overland during heavy showers especially. Let's hope it will deepen even further in later runs.

Edit, just to add for those who may not be 'regulars' on boards.ie weather, please take charts this far out with a colossal pinch of salt. We are only speaking of possiblities here at the moment. We will know what the story is, for better or for worse, closer the time.

Yes DE the flabby part of the Low will hit us instead of the lines

Oh dont you love my weather knowledge.

Anyways in all seriousness I think this low is going North and its effects on us will be "normal" wind and rain

On another subject I swallowed some high gloss paint today and got electricuted yesterday and I still live. Some immune system Sligo people have.:)

Lumi

pauldry wrote: »

I swallowed some high gloss paint today
got electricuted yesterday

Pauldry - you can't leave us hanging like that - details please!! :eek::D

maquiladora

Deep Easterly wrote: »

Tonight's ECM, if anything, has increased the forecast windspeeds for Thursday

Yep, it certainly has DE.

Here is a closer look.



Not often you see ECM ramping up a storm more than the GFS but that is the case herel Centre of the low is further south and those isobars look nicely stacked.

Definite strong gales on the coasts and gales inland in parts there methinks.

maquiladora

CMC 12Z is a cracker.

Gales/strong gales on the coasts and inland in the NW at T78 and then at T84...



Gales and even strong gales inland in the east/southeast and storm force winds on the east coast.

Have to remember though...its only a model.

Su Campu

The 18Z HiRLAM has it reaching a minimum pressure of 948hPa at midnight Wednesday, which is the lowest of the models.



The ECM has a bit of a wobble in the track of the centre between 12Z and midnight Wednesday, which brings it on a track slightly more towards us as it deepens further, but it looks like Wednesday afternoon gales will start occuring along Atlantic coasts, moving to the Irish Sea after midnight, followed by some stronger winds for Thursday, increasing through the day, becoming strong gale force to storm force along Atlantic coasts, strongest in the northwest, where the trailing occlusion could be near enough to enhance gustiness. Overall, all areas will get winds as strong, and in some cases, stronger, than yesterday, and for a longer duration.

A lot of variables yet that could change things. The low spawns from a deep cutoff low currently over the US east coast, and gets caught up in an as yet unformed jet that forms Tuesday night as a blast of low thicknesses shoots down from Baffin Bay. This jet will be around 50kts weaker than the one over the weekend, but its peak strength coincides with the surface low located in its left exit region, which causes that wobble and further strengthening during Wednesday. A slight change in the exact dynamics of the formation of this jet could cause enough of a change to the surface deepening to affect its rate of occlusion and hence its track. As occlusion occcurs, the low will tend to track to the left, away from us. But the models seem pretty consistent with this system, and there's no reason not to have full confidence in them, especially after they handled Becky so well.

And for any journalists reading - THIS WILL NOT BE A HURRICANE!!!

km79

what kind of rainfall can be expected from this? i cant remember the last dry day :eek:

maquiladora

Su Campu wrote: »

And for any journalists reading - THIS WILL NOT BE A HURRICANE!!!

Hopefully after the Becky/Tomas fiasco the media will ignore this.

ninebeanrows

18z for what it's worth pushed this abit further south as compared to its 12z.

Pushes a tight gradient south through southern Scotland, Northern Ireland.

parths of Northwestern England/ Wales, look set to be battered as indeed Northwestern Ireland in particular.

Central pressure progged at ~950mbar

Su Campu

km79 wrote: »

what kind of rainfall can be expected from this? i cant remember the last dry day :eek:

A band of moderate rain will race across the country Wednesday night, bringing around 20mm on average. It will clear to blustery showers for Thursday, heaviest in the northern half of the country. Possibly longer periods of rain in the far north from the back bent occlusion

maquiladora

18Z GFS is indeed an upgrade on the 12Z.

Gales/strong gales in many coastal area from the NW around to the SE if that came off, though inland winds would probably not be a lot higher than last night in most places.

Still needs to come further south a bit more though...

TheInquisitor

Harps

What direction will the wind be in west Donegal? Supposed to be getting a ferry on Friday so north or north west winds will put an end to that

ninebeanrows

maquiladora wrote: »

18Z GFS is indeed an upgrade on the 12Z.

Gales/strong gales in many coastal area from the NW around to the SE if that came off, though inland winds would probably not be a lot higher than last night in most places.

Still needs to come further south a bit more though...

Yes for anything really severe we need another 100mile push south on the GFS and another 50-70 miles on the UKMO.

Deep Easterly

This system is entering hi res territory on the 18z runs. Here is what the 18z HIRLAM is showing (subject to much change in later runs) for 0000utc Thursday:

Cloud forecast:



Front crossing Ireland with a classic swirling low to the northwest.


Wind forecast:



Tighening gradient south of the Atlanitc depression with gale to strong gales surging forth!

nacho libre

maquiladora wrote: »

18Z GFS is indeed an upgrade on the 12Z.

Gales/strong gales in many coastal area from the NW around to the SE if that came off, though inland winds would probably not be a lot higher than last night in most places.

Still needs to come further south a bit more though...

but in reality, as alluded to earlier, it's more likely to track further north than what the models are currently showing. in any case it's a timely reminder just how difficult it is to get a proper storm to effect most of the country these days. so, as was mentioned earlier, anyone new to the forum, who lives inland, don't get your hopes that you'll see windier weather than last night you likely won't. i could be wrong, though:)

M.T. Cranium

This one appears to have loads of potential for developing strong winds on Thursday, and I don't see the usual tell-tale signs of a northward drift in track, if anything, would be watching for the opposite drift here, but the 18z GFS and 12z GEM (CMC) both show the core of strong winds right over northwest Ireland about 12-15z Thursday. Would say there is potential from these charts for sustained 55 kt winds with gusts to 80 kt at places like Belmullet and Malin Head, that would probably imply 40 gusting 60 over most of inland Connacht and Donegal unless well sheltered, and direction of these strongest winds would be 240 deg (WSW).

The potential further south drops off a bit, however it would probably generate 45-50 kt gusts even in the southwest and along the south coast, and 50-55 kt gusts in Dublin.

Rainfall potential (from about 2100h Wed to 1200h Thurs mostly) appears to be 20-30 mms with the heaviest falls across central Ireland.

Temperatures during the strong winds would peak around 11-12 C then fall off to about 7-8 C by late afternoon Thursday, so not much potential for snow on hills, but probably some hail showers mixed in especially in the colder WNW flow that wraps around late Thursday.

Just another random comment, the whole 18z GFS run past Friday looks very chilly, I would estimate the mean "IMT" or "CET" values near 3.5 C from all that blue lurking nearby -- and the entire sector from eastern Canadian arctic to central Russian arctic looks very cold throughout. This tends to argue for potential snowfall events down the road.

maquiladora

nacho libre wrote: »

but in reality, as alluded to earlier, it's more likely to track further north than what the models are currently showing. in any case it's a timely reminder just how difficult it is to get a proper storm to effect most of the country these days. so, as was mentioned earlier, anyone new to the forum, who lives inland, don't get your hopes that you'll see windier weather than last night you likely won't. i could be wrong, though:)

Oh I know. Ive seen enough of these curve away to the north as we get closer to crunch time! But the trend at the moment has been a southward drift on the models, and the the models performed very well on the rather unusual track of Becky at an even earlier stage than this storm.

Deep Easterly

maquiladora wrote: »

and the the models performed very well on the rather unusual track of Becky at an even earlier stage than this storm.

Very true Maq, but that unfortunely does not necessarily mean that they will perform as good this time, but I am hoping (as we all are I guess) that they are onto something!

nacho libre

maquiladora wrote: »

Oh I know. Ive seen enough of these curve away to the north as we get closer to crunch time! But the trend at the moment has been a southward drift on the models, and the the models performed very well on the rather unusual track of Becky at an even earlier stage than this storm.

well they have that's true and hopefully they won't do about turn. i tend to be pessimistic in my outlook anyway, as i don't like to get my hopes up only to be left disappointed. my attitude is probably quite annoying if you're an optimist

maquiladora

18Z GFS ensembles for Dublin :



Even though the 18Z was an upgrade the mean had lower pressure at the peak of the storm and only 2 or 3 ensemble members had higher pressure than the operational run.

Wouldnt be surprised if it tracked a bit further south on the 0Z going by that!

So far so good lads.

Deep Easterly

nacho libre wrote: »

my attitude is probably quite annoying

It is, but I would not have you any other way Nacho Libre.

Sierra Oscar

Will high tides be of concern for coastal flooding with the potential storm?

maquiladora

18Z NOGAPS similar to the GFS/ECM but is a bit more intense.

Min

I hope it flops and is a major disappointment, living on an hill exposed to the west, I hate storms and the potential damage they do.
I have insurance but having seen roofs lifted like sheets of newspaper in the past, I don't like storms.
Too much potential for injury and no electricity.

At least the storm last night was a flop...

maquiladora

18Z NAE at 48 hours has the centre of the low at almost the exact same spot as the GFS ( about halfway between Greenland and Ireland ) but with the pressure a little bit lower.

M.T. Cranium

We'll see what the consensus is around here, but I think the 00z model runs have slightly upgraded the wind potential. The consensus track shows a tendency to peak around 59N 18W then takes the centre slightly south of due east across Scotland. That is a very favourable track for strong winds in Donegal and Connacht. There's only a slight scatter in model track and central pressure estimates (mostly mid-950s) and all of them share timing (most intense gradient over Ireland around 12-15z).

Unless we get downgrades later today, I think this may turn into something moderately severe. Have indicated this over in the forecast.

I suspect this one won't get away to the north because of two or three factors -- first this current storm which will force the jet stream to stay tight rather than letting it wander north ... second, there is no sizeable warm sector or warm advection ... third, the set-up in general favours a ridge between 20-30 W long term which is why this storm seems to be hitting its high point of latitude out around 20 W.

Factors favouring delivery of strong winds would be presence of strong jet stream over Ireland, good isobar pattern (a slight flabby core in this case would actually get the stronger winds over Ireland), daytime event for better mixing, and cold air advection for mixing and instability (gets a higher gust to sustained ratio).

However, that's just one opinion, interested in how the group sees this ... and of course there's time for this to change. System is currently just getting organized near east coast of Newfoundland.

Min

Met Eireann say winds gusting to 70 knots or 130km/h.

So one can probably say it will be higher...

Deep Easterly

No real change on the 00z runs as MT points out. Most if not all are still showing gales threatening coastal Ireland on Thursday with the north and northwest most at risk from being hit by severe gales force winds which could gust up to storm force.


Off topic, but the 00z runs are also showing secondary wave potential developing out in the Atlantic on Friday. UKMO & GFS not really keen to develop it in a major style but the ECMWF has it developing rapidly and heading towards Ireland later Friday:



Good chance that they may back away from this idea in the 12z run or have it spinning off more to the south but might be something to keep an eye on all the same.

irish1967

Ok folks.. don't anyone jinx this one. If you are thinking it. Don't say it.

Min

irish1967 wrote: »

Ok folks.. don't anyone jinx this one. If you are thinking it. Don't say it.

I think it will be crap, maybe a lot of people will be having bad hair days!