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Storm Ellen - 19th/20th August 2020

M.T. Cranium

I just finished my forecast prep and discovered that various models are toying with strong developments in the Biscay region within 24-36 hours affecting some parts of Ireland within 36-48 hours, but details vary from model to model so at this early stage it's not possible to give a very precise alert for which regions may see the strongest winds.

The developments are somewhat similar to a near-tropical storm scenario that I recall from this time of year several years ago. That one moved into the Irish Sea.

Impacts are likely to be winds of at least 60 to 90 km/hr and possibly a lot stronger than that, possibly in more than one wave around Thursday and Friday, and locally intense rainfalls rapidly increasing in totals to reach 30-50 mm.

My expectation is that some clarity and model consensus may emerge as early as the 12z model runs later today but it may not be that straight forward.

At the moment, the ECM seems to favour the southwest for peak development while the Arpege model favours the southeast. While the GFS and some other models have considerable wind and rain in their output, they don't necessarily pick up on these particular developments from Biscay, keeping more of a southwesterly origin for their trajectory and no discrete lows.

This may of course be a false alarm so at the moment I am going with a level 1 tag although if some maps verify we will definitely be seeing level 2 impacts at least.

Heavy rainfalls over several days will be falling on top of considerable rainfall that hit similar areas in recent days and this needs to be factored into flooding potential.

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leahyl

pad199207 wrote: »

The trend is there this evening for Cork to be taken out of the highest risk zone for wind.

Ah no don’t say that! I’m aware I sound like a complete nutter actually hoping for strong winds btw!

RobertKK

M.T. Cranium wrote: »

The reason for the calm or light winds in west Cork and Kerry is that this storm has no cold air advection, it is moving along through the broader warm sector ahead of the more distant Atlantic low. Therefore as it approaches, wind potential from northeast is cancelled by the southwest flow around the more distant low. This calm phenomenon may be noted later up along the coast into Connacht for some period of time. Eventually even where the low passes to the east, strong southwest to west winds will develop around the circulation of Ellen. The centre is most likely to hit where winds stay moderate southerly. It will be very close to a direct hit on the Cobh/Cork metropolitan region but I suspect the actual location of landfall will be something like 20 miles east of there and west of Youghal. The only good thing about that for Cork might be that coastal flooding would be somewhat reduced as the storm surge will be higher to the east of the landfall. However I understand that the coastal flooding around Cork is mainly from runoff in the river Lee backed up by higher than normal tides so that part of the equation would still be operational if heavy rain was falling all through county Cork tonight.

There will very likely be some scattered wind damage in exposed coastal and inland higher south-facing locations, this is why I suggested a wider extent of the red alert to include those exposed locations. Our forum member RobertKK is on a south-facing hill (I think I recall him saying) in Kilkenny, that sort of location could pick up higher gusts than most of the surrounding county.

North, west and southwest facing hill.

ninebeanrows

TAFS are a point forecast....obviously CORK Airport was in the bullseye on the HARMONIE earlier, that has changed or moved in the subsequent run. It doesn't mean somewhere 10 miles further east isnt expected to receive a wind of that level

Oscar Bravo

leahyl wrote: »

Ah jeez, another damp squib? Or is it unwise to go on just the one source?

I tend to go with the TAF's and of course looking at various models. Shall be interesting to see max gusts. Valentia ? Roaches point? Somewhere in that area

Sephiroth_dude

leahyl wrote: »

just now in Garretstown and it already looks pretty miserable down there tbh!

Nothing new there so :pac: :pac:

EmmetSpiceland

leahyl wrote: »

Ah no don’t say that! I’m aware I sound like a complete nutter actually hoping for strong winds btw!

Stick around, lots of “hot air” being blown in here!

squarecircles

markjbloggs

If these trends continue, this should be hugely embarrassing for Met Eireann. Not the first time they have cried wolf in recent years of course but the impact of their warning on struggling tourism businesses should leave them open to some very difficult questions

endainoz

leahyl wrote: »

Ah jeez, another damp squib? Or is it unwise to go on just the one source?

froog wrote: »

ICON and GSF still showing a non event.

If your playing the boards.ie storm thread bingo be sure to mark off "damp squib" and "non event". Amazing it's being written off before it even starts.

munsterlegend

If Met Éireann are wrong whatever about cork what are galway and Mayo doing in the orange wind warnings?!

leahyl

endainoz wrote: »

If your playing the boards.ie storm thread bingo be sure to mark off "damp squib" and "non event". Amazing it's being written off before it even starts.

Not writing it off myself, I don’t have a clue, I’m only going on what regulars in here are saying.

ninebeanrows

munsterlegend wrote: »

If Met Éireann are wrong whatever about cork what are galway and Mayo doing in the orange wind warnings?!

I guess when it swings away to the north coastal parts will probably get gusts close to Orange level? Maybe tipping on 110kph

This could yet wallop the east coast.....Dublin not out of the game yet.

ChikiChiki

markjbloggs wrote: »

If these trends continue, this should be hugely embarrassing for Met Eireann. Not the first time they have cried wolf in recent years of course but the impact of their warning on struggling tourism businesses should leave them open to some very difficult questions

Then if someone is killed you'd probably be crying they didn't do enough.

Met Éireann will never win.

Cw85

The weather forecast on RTE seems to be that Cork is red, a few counties on the west coast are orange and the rest of the country yellow. The social media build up had this as a huge event which just shows that stick to Met Eireann and the facts.

Whehey!

markjbloggs wrote: »

If these trends continue, this should be hugely embarrassing for Met Eireann. Not the first time they have cried wolf in recent years of course but the impact of their warning on struggling tourism businesses should leave them open to some very difficult questions

Hardly hugely embarrassing now like. And what very difficult questions? Theres plenty of campers in these areas, I'd gladly prefer to pack up my tent for the night as a precaution than be blown up the country like Mary Poppins. If it's a non event so be it, but they have possibly saved a few lives maybe in the process.

highdef

Oscar Bravo wrote: »

Big downgrades on TAF's,Cork ,for example now going for max gust of 45 knots with 40 percent chance of 60 knots,way down from the 75 knots mentioned earlier.

Most likely because the eye is now forecast to pass over very close to Cork airport or just to the east of it. Winds are to be stronger to the east of the eye so that would explain the downgrade in this one particular location, I would imagine.

squarecircles

munsterlegend wrote: »

If Met Éireann are wrong whatever about cork what are galway and Mayo doing in the orange wind warnings?!

its hilarious when you read the met eireann regional forecast for connaught and compare it to MT's mentioning some heavy rain a brief spells of some gusty winds along the coast.

spent the day securing everything.well that was pointless.

token56

markjbloggs wrote: »

If these trends continue, this should be hugely embarrassing for Met Eireann. Not the first time they have cried wolf in recent years of course but the impact of their warning on struggling tourism businesses should leave them open to some very difficult questions

I don't understand what people are expecting Met Eireann to do. They are making the most informed judgement at a point in time with the information they have there and then, b . Everyone can see how quickly this event has progressed, if it turns out to be a non event, great less significant damage and less risk of people loosing their lives.

CruelSummer

markjbloggs wrote: »

If these trends continue, this should be hugely embarrassing for Met Eireann. Not the first time they have cried wolf in recent years of course but the impact of their warning on struggling tourism businesses should leave them open to some very difficult questions

Been following this thread with interest but this quote demonstrates just how ignorant some people are re the weather and it’s forecasts. Met Eireann are not fortune tellers, they’re using the best available models & forecasting accordingly with threats to safety and life at the forefront of their minds. If there’s a last minute downgrade, good. Less damage at the height of summer that Ireland can really do without right now.

M.T. Cranium

Sleety_Rain wrote: »

TAFS are a point forecast....obviously CORK Airport was in the bullseye on the HARMONIE earlier, that has changed or moved in the subsequent run. It doesn't mean somewhere 10 miles further east isnt expected to receive a wind of that level

Exactly right and if there was an airport around Fermoy (Moorepark) or just south of there, they could have a TAF indicating peak gusts of 70 knots.

The peak wind gust on land at weather stations may be at Roches Point around 77 knots or around 140-150 km/hr. Some place along the coast east of there might hit 160-170 km/hr briefly, Waterford a little uncertain but 120-140 km/hr possible, mickger844posts get ready you may have a new station record.

Johnstown Castle could even hit 100 at this rate (not known for being well exposed there) meaning about 130 on exposed Wexford coasts.

Will be interesting to see how Moorepark and Gurteen do with wind gusts as the core moves inland. Will predict peaks around 55 knots for them. That could mean some better exposed locations (and around Lough Derg) could hit 60-65 knot gusts.

There will be trees down here and there in that general area even into eastern Galway, whether it's a moderate impact or major remains to be seen.

Needless to say I would stay off the roads tonight in most areas, after dark you can't see road obstructions until you're too close to stop.

As to ICON not picking this up, unfathomable really, the main meteorological detail of interest to me is that upper level conditions change very rapidly around the time Ellen approaches the south coast, a signature for explosive development potential. That upper level low that has been out to the west of Ireland for days is scheduled to reposition in a capture position leading to a rapid phase of Ellen into the larger circulation. Ellen then effectively becomes the main centre with the former main centre rotating around it from the southwest. That could then deepen when Ellen loses steam and lead to a second round of wind warnings this time for the west coast later Thursday.

jackboy

squarecircles wrote: »

its hilarious when you read the met eireann regional forecast for connaught and compare it to MT's mentioning some heavy rain a brief spells of some gusty winds along the coast.

spent the day securing everything.well that was pointless.

It’s not over yet.

Actually, it’s not started yet.

screamer

ChikiChiki wrote: »

Then if someone is killed you'd probably be crying they didn't do enough.

Met Éireann will never win.

It’s not their job to win....... with every alert issued they either gain the public’s trust or lose it.
Lately, with the calls they’ve made, they’ve lost a lot of trust and so when they call the next event, people don’t believe it and so they don’t heed the warnings, which can lead to awful consequences.
In any event, high up here on the north Kilkenny/ Laois border I’ve been putting away all the outdoor toys, moving and securing the trampoline and making sure the gullies are clear. Who knows what will come, maybe nothing, maybe a huge storm.....

M.T. Cranium

squarecircles wrote: »

its hilarious when you read the met eireann regional forecast for connaught and compare it to MT's mentioning some heavy rain a brief spells of some gusty winds along the coast.

spent the day securing everything.well that was pointless.

Our expectations may not be that different, you may not regret taking those precautions. Some places in Mayo could see gusts above 60 knots briefly, especially if the centre curved a little further west and emerged there instead of heading for Donegal Bay.

HeyV

Charging my phone and tablet, should the electricity go later... got caught out before with that

DOCARCH

Bear in mind that Met E issue their warnings on the basis of evaluating potential impact and risk.

We are still in full swing holiday time so there are lots of tourists in places they are not familiar with. People are camping and in caravans/mobile homes.

In addition, trees are in full leaf and the storm coincides with high (spring) tide, so there is high risk of coastal flooding.

Maybe in mid Winter this storm might have a yellow warning for most with a number of counties with orange warning as impact/risk would be less.

ninebeanrows

The lack of windspeeds in the warnings is indicative they are impact based warnings.

irishrover99

JCX BXC wrote: »

TAF's aren't generally the best indicator, I've seen them be wrong many many times.

I’ve seen them being wrong too, usually on air crash investigation.

M.T. Cranium

From my point of view there was no real eastward trend, the models most trusted by met E happened to be those with the furthest west tracks. Also a slight shift east is not a downgrade except in the limited sense that places now to the west of the developing track will have a downgrade in their peak gusts. They will on the other hand get more rain than might have been predicted previously.

Take this very seriously indeed if you live or are situated between Cork and Wexford and all the way inland up to east Galway, Sligo, Roscommon.

munsterlegend

Sleety_Rain wrote: »

The lack of windspeeds in the warnings is indicative they are impact based warnings.

Yeah it’s unusual no speeds mentioned at all.

josip

Vessels at seas don't seem to have cleared out of the path like in other storms.
Is this an indication of the expected severity and sea area forecasts are not predicting anything dangerous?
Some of those are small fishing boats drawing 3m.