This Week's Storms - FORECAST, MODEL DISCUSSION ONLY

ninebeanrows

M.T. Cranium wrote: »

No go there, the GEM 12z has the same evolution as the GFS. Would say that the global 48h is somewhat less focused than the regional 48h was, so there might be a faint hope of something much different to come in later runs (a more powerful storm taking longer to eject).

Here's what is currently happening in the storm's formation zone south of Nova Scotia and just to the northeast of Bermuda. The system was an inverted trough at 06z and is slowly developing a 1010 mb centre which you can see in this animation:

http://www.weatheroffice.gc.ca/satellite/animateweb_e.html?imagetype=satellite&imagename=goes_ecan_1070_m_..................jpg&nbimages=1&clf=1

(the 48h GEM shows this plodding northeast and deepening to 984 mbs).

So far all of the models want to take the leading edge of this system and shear it off, producing a fast-moving wave into northern France Friday, then bring along the bulk of the system around Saturday or Sunday into France.

The only scenario that would now work to create a stronger storm affecting Ireland would be in two parts, first the short wave tomorrow needs to track a bit further north and get pulled northeast towards the remnants of today's deep centre, then the jet needs to start rebounding and give the western Atlantic low somewhere to go instead of limiting its eastward progress and shearing it in half. It would not be totally unprecedented for that sort of model miscalculation to verify, but chances are probably about 10-20 %.

Have had a look at the GFS EPS and a few play with deepening the storm more in our southwest approaches. A few very severe for central and southern England.

Sponge Bob

Business end of the Jetstream forecast south of Ireland Thursday

corkman123

wow! so how strong would the winds be in cork ?

Deep Easterly

No sign of the UKMO 12z run yet? (on my usual sources anyways..)

M.T. Cranium

GME and UKMO both show same evolution of Channel low (00z Friday) to Holland (12z Friday). That track almost invariably brings about over-predictions of wind speeds in southeast England as the meso-scale factors work against the gradient and everyone says "where's our windstorm" the following morning.

Now that's not to say this track will verify, but that's what seems to happen when the track is operational.

I would like to wait for the 00z runs when the various players are better described by initial data. This could still turn out quite a bit different from how the models are saying at 12z today. If this short wave out to the west of Ireland misbehaves then there could be a last minute scramble towards explosive cyclogenesis as the final outcome. Today's storm also underwent last-minute (by model standards) changes to a more intense outcome than was perhaps expected on Saturday or 72h ago.

Not expecting anything different on 12z ECM but we'll see if there's any new trends there.

maquiladora

Deep Easterly wrote: »

No sign of the UKMO 12z run yet? (on my usual sources anyways..)

Its out on Meteociel.

Deep Easterly

Yep, track almost inevitable now:

munsterlegend

Deep Easterly wrote: »

Yep, track almost inevitable now:

it could have a late unexpected twist even if unlikely!

corkman123

what does this mean for cork?

munsterlegend

corkman123 wrote: »

what does this mean for cork?

it means for once we are not south enough!

corkman123

typical!

maquiladora

12Z ECM and 12Z GFS are slightly different at 72 hours... :pac:





ECM got the tipex out for that low.

ninebeanrows

ECM doesnt even have the storm for the channel!

leahyl

Come on storm move northwards!! :-D

Derfil

leahyl wrote: »

Come on storm move northwards!! :-D

Ye're some craic in Cork. When its snowing your too far south. And when there's potential for the mother and father of a wind storm you's are too far north. How'd ye manage that:pac:

snaps

But look at all that cold air being dragged down over us;)

Iancar29

LOW WRAPPING UP NICELY!!

only one

Is Thursday's storm ment to hit us? I've been asleep all day and only woke up. I'm hoping for snow in south and south east tomorrow

maw368

Hail and wind started again this eve in South Wales and now a couple cm's of the snow stuck on the ground. Surprisingly considering everything is so wet and its been warm.

skelliser

What are the chances of a significant if short snow event from thursday onwards.

With the jet stream further south then normal could colder artic air sweep in behind thursdays storm and plaster ireland with snow?

Sponge Bob

You point the moisture out to me on some model so.

blackius

skelliser wrote: »

What are the chances of a significant if short snow event from thursday onwards.

With the jet stream further south then normal could colder artic air sweep in behind thursdays storm and plaster ireland with snow?

At best,though it's uncertain still,all this will pull in is polar maratime air.
Very cold yes but with too much atlantic mix in it,put simply.
Meaning,1000ft asl and higher for your snow chances.

ninebeanrows

fergieweather Ian Fergusson
Worry re Thurs-Fri development is models may not resolve rapid deepening/perturbations adequately; UKMO not convinced by benign solutions

blackius

Weathercheck wrote: »

fergieweather Ian Fergusson
Worry re Thurs-Fri development is models may not resolve rapid deepening/perturbations adequately; UKMO not convinced by benign solutions

Interesting.
Human Forecaster brains in play tweaking the faxes over the coming days will be fascinating to watch.

ninebeanrows

My small chance forecast for the Low :eek::o

bb1234567

blackius wrote: »

At best,though it's uncertain still,all this will pull in is polar maratime air.
Very cold yes but with too much atlantic mix in it,put simply.
Meaning,1000ft asl and higher for your snow chances.

1000ft, hoping you mean 100 ft, do you?

Deep Easterly

Latest thinking from Exeter: (2 frames: 48hr & 60hr)



To the south as per model consensus with southern England & Wales still in with a chance.

maquiladora

This is absolutely uncanny...

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. Instead of stormy weather over a considerable part of the UK, the models suggested that severe weather would reach no farther north than the English Channel and coastal parts of southern England.

Except it's from....

http://en.wikipedia.org/wiki/Great_Storm_of_1987#Development

WolfeIRE

Very interesting Maq. Just goes to show you how dramatic a change can occur within a short time frame.

It obviously shifted 300 kms or so north which is incredible.



You can see storm here
http://www.meteociel.fr/modeles/archives/archives.php?day=16&month=10&year=1987&hour=12&map=1&mode=0

You can backtrack in the archive to see how quickly it developed

whataboutnow

ffarrell7 wrote: »

You are deluding yourself...the 'hills of donegal' rather than mountains. Ring MET Eireann and they will put you straight. I was in Letterkenny last week and there was not a patch of snow in the 'hills' when I was there. The east is generally a colder region away from the milder Atlantic with more extremes when easterly or north-easterly winds arrive. Donegal or other ranges of elevation just do not get the same savage snowfall as the Wicklow uplands...youtube it and you will see for yourself. Th coldest temperatures are also in Wicklow, midlands and occasionally Cavan/Monaghan.

Youtube it,how scientific.Granted there was no snow in the hills at letterkenny but there are two mountain ranges in donegal and letterkenny isn't one of them.try and google mountains of ireland.also in response to you saying the coldest temperatures are in wicklow have u ever watched the weather,usually the further north u go in ireland is colder and anyway who disagrees with that is looped,malin head is on the coast so therefore its mild.I will agree with you on one point you made regarding eastern donegal being colder,castlederg which is a few miles from recorded exceptional low temperatures last december almost beating the all ireland record which was set in sligo-another place u failed to mention in irelands coldest locations-what a surprise.I shall link u castlederg which had similar readings to my weather station.if u can show me proof of wicklow being as cold i would appreciate it.a youtube clip of it snowing in wicklow is hardly mind boggling in fairness.have a nice day..as u can see castlederg had it worst than anywhere in ireland last december http://www.metoffice.gov.uk/climate/uk/interesting/dec2010/ enjoy