This Week's Storms - FORECAST, MODEL DISCUSSION ONLY

nacho libre

M.T. Cranium wrote: »

Have to say on reflection I am very dubious about the ECM downgrade, as the other models have much faster development of the storm at 72h and much depends on model performance over the sector from central North America to the central Atlantic, one place where the ECM does not have a demonstrated edge (in fact on American forums there have been extensive questions raised about recent changes to ECM model input and subsequent 2011 performance). So it would not surprise me to find later that there is a return to the plan A for the ECM and no changes on the other models.

Not that the 18z GFS is always the best indication of anything, but I guess that's our next clue, there is no 18z GEM except for their 48h regional which might at least tell me something about developments in the central Atlantic as a slight clue.

Just one other note before I head out for a while (it's a lovely day here) -- the incoming storm has been somewhat lost in the shuffle here and it is more than just a minor deal, especially in terms of the cold squally conditions likely to follow in its wake. So we still have that on the go.

Thanks M.T for the update. I hope you have an enjoyable day.

bb1234567

so storms probabaly not going to happen now? sorry if thats an annoying question...i just want to know:pac:

Harps

I was going to mention Tuesday's storm but then all this happened so changed my post

Stronger for the north again on the ECM. Obviously this run is a bit questionable so there's still no definite solution as to how it'll play out

Kippure

bb1234567 wrote: »

so storms probabaly not going to happen now? sorry if thats an annoying question...i just want to know:pac:

O yeh, there still going to happen. Batten down the hatchs.

irish1967

Ah we need a 'little mix' of charts to keep up the interest !

Min

This could be like the Christmas eve storm.

Met Eireann were warning about it then nothing really about how severe it would be as the time came for it to hit - it deepened rapidly as it moved in - something the models have been showing happening with this storm.

One weather model in one run is not something to get too worked up about, we have to wait and see what the rest do, but it is hard to believe the UK met as well as Met Eireann who have been warning people about this storm are suddenly wrong.

Su Campu

The ECMWF has missed an an upper shortwave feature that's appeared in water vapour imagery this evening, above tomorrow's developing surface low. The image below is the actual image, the image on the right is the "pseudo-wv image", generated by the model. The feature appears as a dark kink in the white jet cloud.

I think this feature will have a large influence on the development of the low and could be a sign that its developing faster than the model had thought. If that is the case then it should occlude earlier and hence curve further north than forecast, slowing down south of Iceland. This could have a knock-on effect for Wednesday and the even the path Thursday's low will take. The 00Z run will pick this up and will tell a lot.

sparrowcar

Following on from Irish Steve's post on Dublin airport, the max airbridge operation speed in pier B is 60kts. I am not sure if that is slightly raised in the new pier E but if it is it's only minor (65kts)

I work for a large company in the airport and we have a wind phase system in place that ceases all ground handling in winds in excess of 60kts.

In fact over 50kts in any direction and things start going pear shaped. ULD bins and cargo hold doors don't like winds in and above that figure. Smaller aircraft like ATR's and Dash's that Aer Arann/Aer Lingus regional/Flyby start to suffer in those winds, most flights in that size aircraft would be cancelled or delayed in winds above 50kts. Also some of the smaller regional airports have smaller/shorter runways leaving less room for error than say Dublin. To put things in perspective Loganair who now operate to CFN in Saab aircraft cancelled lasts week during the Scottish storm as CFN was outside operating limits.

If the winds get into the 80kts+ range in Dublin you might be looking at a mass relocation of aircraft out of Dublin airport to somewhere out of the path.

hotwhiskey

Sorry of topic!

Watch channel 4 tsunami in Japan all new.

Wine Goddess

Su Campu wrote: »

The ECMWF has missed an an upper shortwave feature that's appeared in water vapour imagery this evening, above tomorrow's developing surface low. The image below is the actual image, the image on the right is the "pseudo-wv image", generated by the model. The feature appears as a dark kink in the white jet cloud.

I think this feature will have a large influence on the development of the low and could be a sign that its developing faster than the model had thought. If that is the case then it should occlude earlier and hence curve further north than forecast, slowing down south of Iceland. This could have a knock-on effect for Wednesday and the even the path Thursday's low will take. The 00Z run will pick this up and will tell a lot.

Can I just say Su Campu - I learn a huge amount about weather from what you - as well as others - post, and thanks very much for bothering.

No icon for big sloppy kiss - LOL

Su Campu

I have set up another thread for general reports and chit-chat on this week's "storms"...... Can we use this thread just for forecast discussion only.

Bog Butter

Is Friday's storm going be at it's strongest in the NW? Or is it too early to say?

ninebeanrows

PJB on UKWW just posted and has access to alot of charts.

Has seen the ECMWF EPS

1/3 follow the ECM OP idea and 2/3 follow the UKM/GFS idea.

He doesn't believe the low split at 96hrs but says confidence on the storm is just moderate.

Tom Cruises Left Nut

The 0z will be interesting

TheMilkyPirate

I'm sorry straying off topic here, But the archives on meteociel only seem to go back as far as 2007, Where do i go to go back further??

Tom Cruises Left Nut

baraca wrote: »

I'm sorry straying off topic here, But the archives on meteociel only seem to go back as far as 2007, Where do i go to go back further??

This what you need ?

http://www.meteociel.fr/modeles/archives/archives.php

Vizual Pics

Snow risk on Tuesday from GFS - the GFS might not be that accurate and tends to over exaggerate but as alot of the other posters alluded to, its not only the wind that could be an issue during the week.



and Snow Risk on Friday from GFS, these images are only snap shots in time and the coverage across the country varies hour by hour as you can imagine.

TheMilkyPirate

t|nt|n wrote: »

This what you need ?

http://www.meteociel.fr/modeles/archives/archives.php

Thanks tintin

maquiladora

Weathercheck wrote: »

PJB on UKWW just posted and has access to alot of charts.

Has seen the ECMWF EPS

1/3 follow the ECM OP idea and 2/3 follow the UKM/GFS idea.

He doesn't believe the low split at 96hrs but says confidence on the storm is just moderate.

Hmmm, 1/3 follow the op? Thats too many to discount the op. 0z will tell the tale.

#rollercoaster

PixelTrawler

Su Campu wrote: »

Sometimes it's not the severity of the wind but the direction in relation to the runway heading that's the problem. Airliners have crosswind limits (i.e. the maximum crosswind component that has been demonstrated as safe) in the region of 34-40 knots (depends on the plane). A severe gale right down the runway will be easier than a Force 7 Strong Breeze at 45 ° to it.

Dublin has 4 runway directions - 28 (westerly), 01 (easterly), 16 (southsoutheasterly) and 24 (northnorthwesterly). As these winds will be coming from somewhere between a SW and SE direction, it will be between 28 (over Portmarnock) and 16 (over Garristown, Oldtown, Rolestown direction). Sometimes a strong wind of say 230 ° (SW) can be what closes the airport, as it's an equally strong crosswind on both 28 and 16. Winds will vary in direction during Thursday night, becoming strongest in the early hours of Friday morning, going on latest indications. It should be ok for Friday night, but Thursday morning could be iffy.

Watched the farming forecast and their glimpse of Friday in the animation looked like Friday night might be past the worst alright. Didn't realise Dublin had 4 runway approaches. Thanks

ninebeanrows

maquiladora wrote: »

Hmmm, 1/3 follow the op? Thats too many to discount the op. 0z will tell the tale.

#rollercoaster

Looks like things need to come together in a certain window in the Atlantic. They have to come together at the precise time to create the 'perfect storm' !!

M.T. Cranium

I followed the lead of the ECM and went out to lunch ...

ha ha ...

since we have lots of time before next model run, snowfall potential ... likely to be entirely elevation-dependent rather than regional. The air mass is just barely cold enough to sustain snow but highly unstable, so plenty of mixed precip can be expected. I think it will play out as rain near sea level, hail and sleet for many, and snow coming and going throughout but sticking mainly above 200m. This time it will not be a north-south divide, but more of a west to east dilution as the land mass slowly exhausts the sea effect, although by no means totally.

So how much snow for your location? Above 200m and west of Athlone to Cork, expect 5-10 cms. Above 200m and east, expect 3-7 cms.

In the range of 100-200m, west, expect 3-7 cms ... east expect 1-3 cms.

In the range of sea level to 100m, west, expect trace to 2 cms. ... east, expect zero to 1 cm.

Some very exposed (to west) upland locations could see as much as 20 cms and severe icing is possible on summit installations. Contrast that with melting snow or sleet near sea level.

The image in my mind is a sort of blizzard of fog, but perhaps if I have another coffee ...

Spindle

Before toys are thrown out of prams from Thursday/Fridays storm, just something to note on the great storm of 1987

Four or five days before the storm struck, forecasters had predicted bad weather on the following Thursday or Friday. By midweek, however, guidance from weather prediction models was somewhat equivocal.

I think models find it very hard to get these type of systems right.

Sponge Bob

Spindle wrote: »

I think models find it very hard to get these type of systems right.

Exactly. Models can overpredict an epic storm that happens to be nothing, particularly the GFS

Course they can underpredict...but are they programmed to underpredict. I don't think so.

Min

Looking like a very complex system at 1900hrs on Tuesday (GFS), two low centres in the centre of the depression and closer to Ireland by the looks of things than the previous run.

Sponge Bob

Two coalescing low centres were a feature of the mid January 1995 storm that hit Galway. I remember that was as bad as the 1997 and 1998 christmas storms where I was.

TheMilkyPirate

Thursdays storm is still intact on the 18z as far as i can tell so far.

Min

Sponge Bob wrote: »

Two coalescing low centres were a feature of the mid January 1995 storm that hit Galway. I remember that was as bad as the 1997 and 1998 christmas storms where I was.

The second low in the depression does put a quite a sqeeze on the isobars for Wednesday, on this GFS run.
A lot of wind to come...

ninebeanrows

18z downgrages the storm massively!

haha.

See ya in the morning folks!

cherryghost

Jaysus Thursdays storm has just dissipated.