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Weathercheck · 25-04-2012, 17:59

Another interesting fish being progged to develop this weekend. Develops as an interaction between some tropical air mass that gets dragged up over the continent and the cool maritime airmass over Ireland.

The combination is a large moisture ladden depression approaching from southern France and the Med. A very strange source for a system affecting Ireland.

At the moment the system is bring progged to the south of Ireland but it remains a real threat and is forecast at just T90hrs.

It is of particular interest as it is a very untypical type of system that has a small chance of bringing exceptional windspeeds from a easterly direction, not what we are used to.

Here are few charts.

#1 Illustrating the moisture in this thing south of Ireland

#2 Illustrating the pressure map, showing the small tight circulation.

#3 Illustrating the current forecast sustained winds

JanuarySnowstor · 25-04-2012, 18:52

Whilst it is certainly one to watch I couldn't see it happening as progged.
Seems to go against the natural law of physics

Worth seeing what ECM does

Weathercheck · 25-04-2012, 18:59

Quote:

Originally Posted by JanuarySnowstor

Whilst it is certainly one to watch I couldn't see it happening as progged.
Seems to go against the natural law of physics

Worth seeing what ECM does

Sure looks a strange one! Surely a storm can't strike Cork!

Weathercheck · 25-04-2012, 19:23

ECM goes for the interesting system to experience a intensification.

I reckon it will be a tricky one to forecast and still at T96hrs, so will be
very interesting to follow over next 3 days.

ECM has threat of flooding written all over it/ nevermind our consideration for wind.

JanuarySnowstor · 25-04-2012, 22:33

The system opens out quickly as it moves close to Ireland.
I'll give it tomorrow to see but in general it looks all wrong as how systems develop in this part of the world

Su Campu · 25-04-2012, 23:06

Although it is unusual there is nothing that says it can't happen. It all depends on how the large upper trough that is now deepening towards Iberia cuts off on Friday/Saturday.

The strong 150 knot polar jet currently over the north Atlantic feeding this trough will cause it to deepen southwards and become cut off by Saturday. At the same time the sub-tropical jet interacts this polar jet at the base of this trough over southern Iberia, and this interaction causes deepening at the surface near the Balearics. The upper cut-off process causes southeasterly flow steering flow at the cut-off zone, which drives the surface system northwards over France and swings it northwestwards towards us, where it pivots around the cut-off upper low.

Incindentally, this upper low meanders around northern Iberia next week and could lead to thundery events to our south in the unstable easterly flow. The south could see some action if all goes to plan.

Mr Cumulonimbus · 25-04-2012, 23:17

18Z GFS not bringing the low as far north as the 12Z run did. Might be a nice day on Sunday yet.......

pauldry · 26-04-2012, 00:15

yeah we might even get an April high to rival 14.9c!!!!!!

alfa beta · 26-04-2012, 00:46

Quote:

Originally Posted by pauldry

yeah we might even get an April high to rival 14.9c!!!!!!

is that the highest april has managed so far?

M.T. Cranium · 26-04-2012, 08:04

At the present time, whatever outcome you would like is there for the taking on one model or another. The most rain and wind available on 00z model runs is on the GEM. The UKMO is somewhat more subdued, the GFS has shifted south for a likely miss, and the ECM wants to take a weaker version of the system more north at first into Britain. The GME ends at 72h and looks headed for Ireland with a rather strong system.

I think we'll have to admit that there is no clarity in this situation but as a betting man (just collected on that Barcelona-Chelsea tie and some overtime hockey) I would say ECM. The others involve too much retrogression and in most cases cyclonic curvature that doesn't seem to follow the previous event (the departing storm). So the most likely outcome would be low cloud and drizzly light rain. Everything else is still on the table.

Weathercheck · 26-04-2012, 11:11

6z leans things a little further north.

It's track is very much unknown at this point.

Iancar29 · 26-04-2012, 11:29

Just goes to show the difference the jump north can have.

00z for 3pm Sunday

06z for 3pm Sunday

Mr Cumulonimbus · 26-04-2012, 17:27

Compact looking system for Sunday on the 12z run.

BEASTERLY · 26-04-2012, 17:38

Looks interesting, oh the havoc this could have caused in January.

Mr Cumulonimbus · 26-04-2012, 18:14

12h UKMO has the system fairly near to Iberia on Sunday.

25-04-2012, 23:06	#6
Su Campu Closed Account Join Date: Dec 2009 Posts: 4,258 Adverts \| Friends	Although it is unusual there is nothing that says it can't happen. It all depends on how the large upper trough that is now deepening towards Iberia cuts off on Friday/Saturday. The strong 150 knot polar jet currently over the north Atlantic feeding this trough will cause it to deepen southwards and become cut off by Saturday. At the same time the sub-tropical jet interacts this polar jet at the base of this trough over southern Iberia, and this interaction causes deepening at the surface near the Balearics. The upper cut-off process causes southeasterly flow steering flow at the cut-off zone, which drives the surface system northwards over France and swings it northwestwards towards us, where it pivots around the cut-off upper low. Incindentally, this upper low meanders around northern Iberia next week and could lead to thundery events to our south in the unstable easterly flow. The south could see some action if all goes to plan. Last edited by Su Campu; 25-04-2012 at 23:10.

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25-04-2012, 17:59	#1
Weathercheck Registered User Join Date: Nov 2004 Location: Portmarnock Posts: 8,044 Adverts \| Friends	Potential Storm Sunday April 29th , Rainy period till May 02nd Another interesting fish being progged to develop this weekend. Develops as an interaction between some tropical air mass that gets dragged up over the continent and the cool maritime airmass over Ireland. The combination is a large moisture ladden depression approaching from southern France and the Med. A very strange source for a system affecting Ireland. At the moment the system is bring progged to the south of Ireland but it remains a real threat and is forecast at just T90hrs. It is of particular interest as it is a very untypical type of system that has a small chance of bringing exceptional windspeeds from a easterly direction, not what we are used to. Here are few charts. #1 Illustrating the moisture in this thing south of Ireland #2 Illustrating the pressure map, showing the small tight circulation. #3 Illustrating the current forecast sustained winds Last edited by pistolpetes11; 01-05-2012 at 23:48.

25-04-2012, 18:52	#2
JanuarySnowstor Registered User Join Date: Feb 2008 Location: East of Cork City Posts: 893 Adverts \| Friends	Whilst it is certainly one to watch I couldn't see it happening as progged. Seems to go against the natural law of physics Worth seeing what ECM does

25-04-2012, 19:23	#4
Weathercheck Registered User Join Date: Nov 2004 Location: Portmarnock Posts: 8,044 Adverts \| Friends	ECM goes for the interesting system to experience a intensification. I reckon it will be a tricky one to forecast and still at T96hrs, so will be very interesting to follow over next 3 days. ECM has threat of flooding written all over it/ nevermind our consideration for wind.

25-04-2012, 22:33	#5
JanuarySnowstor Registered User Join Date: Feb 2008 Location: East of Cork City Posts: 893 Adverts \| Friends	The system opens out quickly as it moves close to Ireland. I'll give it tomorrow to see but in general it looks all wrong as how systems develop in this part of the world

26-04-2012, 00:15	#8
pauldry Registered User Join Date: Jul 2009 Location: Sligo 54.26N 8.46W 34M 111.5FT Posts: 1,418 Adverts \| Friends	yeah we might even get an April high to rival 14.9c!!!!!!

26-04-2012, 08:04	#10
M.T. Cranium Registered User Join Date: Apr 2007 Location: across from the neighbours Posts: 4,460 Adverts \| Friends	At the present time, whatever outcome you would like is there for the taking on one model or another. The most rain and wind available on 00z model runs is on the GEM. The UKMO is somewhat more subdued, the GFS has shifted south for a likely miss, and the ECM wants to take a weaker version of the system more north at first into Britain. The GME ends at 72h and looks headed for Ireland with a rather strong system. I think we'll have to admit that there is no clarity in this situation but as a betting man (just collected on that Barcelona-Chelsea tie and some overtime hockey) I would say ECM. The others involve too much retrogression and in most cases cyclonic curvature that doesn't seem to follow the previous event (the departing storm). So the most likely outcome would be low cloud and drizzly light rain. Everything else is still on the table.

26-04-2012, 11:11	#11
Weathercheck Registered User Join Date: Nov 2004 Location: Portmarnock Posts: 8,044 Adverts \| Friends	6z leans things a little further north. It's track is very much unknown at this point.

26-04-2012, 17:38	#14
BEASTERLY Registered User Join Date: Jul 2010 Posts: 1,756 Adverts \| Friends	Looks interesting, oh the havoc this could have caused in January.