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Extratropical Storm Ophelia - Technical Analysis Only - MOD NOTE post #1

M.T. Cranium

Mod note

This is a busy thread and as a result the Mod Team will be taking a zero Tolerance approach to trolling and flaming

Don’t say you weren’t warned!!

And please don’t feed
Thanks

Just briefly for now, recent model runs (12z Wed 11th) have shown a track near Ireland for strong extratropical low (Ophelia) with timing converging on Monday 16th during the daytime hours.

The GFS model was of some concern but the ECM now has a very high impact low depicted at 965 mbs just about 70 miles southwest of Valentia by mid-day Monday.

This would evidently track through Ireland and Scotland on a generally NNE to NE path, which would bring damaging wind gusts into most of Ireland.

Too early to get very specific about impacts or peak wind speeds but these maps got my interest and look as intense as storm "Darwin" in 2014.

I wanted to get a dedicated thread into existence so that we can focus on this storm rather than using the tropical seasonal thread. Also, please note, obviously if this verifies a level 3 warning would be justified and at some point we will consider upgrading the current level 1 which is appropriate mainly because of the uncertain outcome, but an event of at least level 1 status seems almost locked in given the model consensus.

The GEM model is currently an outlier, like the rest of the pack it shifted east but that took its earlier eastern Ireland windstorm into Britain instead. It would be unusual for the GEM to beat out all these other models at five days so I don't give that much weight. However, it needs to be mentioned that this storm is currently a long way away (southwest of Azores) and relatively small for a hurricane, which it is about to become later today (last advisory had it as a high end tropical storm).

We shall see how the models respond to developments. The track towards Ireland makes sense when you consider how warm it is likely to be on the weekend and the position of the long-wave trough slowly moving east from the central Atlantic.

This could be a high impact windstorm for Ireland and the forum will be buzzing from now until the event comes into clear focus, after which it may be hyperactive, so post wisely with useful info as it comes along.

Mods, I will get in touch if I feel that a higher level or title change is needed. Get ready for a very busy few days.

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Video

Fully expect someone from met eireann on the six one news, they kind of have to at this stage.

M.T. Cranium

I will update this from time to time, predicted maximum sustained winds and gusts at selected locations based on model output to date and my own subjective impressions of how the storm will play out. All values in knots, km/hr is double minus 10%.

LOCATION ________ Max sustained _____ Gusts

Valentia ______________ 60 ___________ 85

Sherkin ______________ 68 ___________ 90

Roches Point __________ 66 ___________ 87

Kinsale energy _________ 80 __________ 105

Waterford _____________ 62 ___________ 87

Cork _________________ 62 ___________ 87

Shannon ______________ 58 ___________ 80

Oak Park ______________ 50 __________ 70

Gurteen _______________ 52 __________ 73

Mullingar ______________ 52 __________ 73

Casement ______________58 __________ 78

Dublin A _______________ 56 __________ 73

Dunsany _______________ 50 __________ 70

Athenry ________________ 60 __________ 80

Galway city _____________ 62 __________ 82

Mace Head ______________ 70 __________ 90

Newport ________________ 65 __________ 83

Belmullet ________________ 50 _________ 70

Claremorris ______________ 52 _________ 72

Finner ___________________ 58 _________ 78

Donegal A ________________ 58 _________ 78

Malin Head _______________ 65 __________ 85

Ballyhaise ________________ 55 __________ 75

These weather stations give a good representation of conditions that various regions will face but of course there are big variations in exposure from one place to another and airports tend to be located in exposed locations generally so quite often the overall exposure of the population is less than might be implied by assuming these winds will affect everyone in each region.

OTOH if you're a lighthouse keeper or a farmer on a hill, you might get stronger winds than any of these (except Kinsale energy).

I have assumed a GFS-GEM blend track something like 50 miles west of Valentia to landfall between Clifden and Westport, placing Belmullet on the west side of the track but all other locations to the east. If ICON is correct some of my estimates in the northwest will be reduced considerably.

To save space on the thread, if responding don't copy the whole table, just comment on it. Thanks. I will update this at least once before the storm arrives.

Spanish Eyes

I don't know if it's connected or not, but the wind here has just whipped up a great deal.

I'm looking out the back at the trees in the park and they are heaving and swaying.

But I'm probably on high alert now!

I need to calm down.

mel.b

Thanks to MTC and others who answered my question about why Ophelia is headed east and not west

I'm just back from a walk in Dromore Woods in Co.Clare which sustained a lot of damage in Storm Darwin and sadly I think will sustain more damage on Monday. This is one tree that fell - the shallow root system for a tree that size amazes me, but after less the 3yrs, the rest of the downed tree is almost invisible.

cherryghost

Pangea

Just seen BBC weather it said it was a Cat 2, it's apparent that the TV weather forecasts are relying on old data, social media is where it's at.

sdanseo

Top headline on the Six One.

Finally some proper broadcast acknowledgement.

jArgHA

Six One News on RTÉ leading with the story. Good to see it's being treated seriously finally.

h7nlrp2v0g5u48

Update now on RTE News.

Cantona's Collars

jArgHA wrote: »

Six One News on RTÉ leading with the story. Good to see it's being treated seriously finally.

Most of the focus was on cancelled school buses.

sdanseo

Met.ie - This is a bit fishy. It was about 12.45 when they first posted this, and there was outcry on here that the 1pm news had nothing of it.

They've since updated the issue time but the warning itself hasn't changed.

Wind Warning for Galway, Mayo, Clare, Cork and Kerry
Hurricane Ophelia is expected to transition to a post tropical storm as it approaches our shores on Monday bringing severe winds and stormy conditions . Mean wind speeds in excess of 80 km/h and gusts in excess of 130km/h are expected, potentially causing structural damage and disruption, with dangerous marine conditions due to high seas and potential flooding.

Issued:Saturday 14 October 2017 13:18
Valid:Monday 16 October 2017 09:00 to Tuesday 17 October 2017 03:00

_Whimsical_

cherryghost wrote: »

Does this suggest winds are now looking stronger on the east coast than on the west?

M.T. Cranium

_Whimsical_ wrote: »

Does this suggest winds are now looking stronger on the east coast than on the west?

On that model yes, but it is running east of consensus so generally not the trend of all guidance (yet).

antodeco

Very windy the last while here in Dublin. I put stuff out on the line earlier and it wasn't too bad. Last half hour it has them flying horizontal!

Romantic Rose

irish1967 wrote: »

Monday morning will be fine. Peak winds won’t be effecting us here in Donegal Town area until Monday evening given current timings.

Thank you Irish1967, my old friend

What time is it due to hit Donegal on Monday? I'm hoping to get back home mid afternoon.

Spanish Eyes

antodeco wrote: »

Very windy the last while here in Dublin. I put stuff out on the line earlier and it wasn't too bad. Last half hour it has them flying horizontal!

Glad it's not just me.

See my post #1144 above.

Oh me nerves! :eek:

M.T. Cranium

Looking at that ICON map, you know something is up when the map has winds stronger than anything in the legend (that dark patch in the white zone). hope everyone grasps that the white zone is gusts of 200 km/hr being predicted so the dark patch is either seaweed from the Sargasso Sea, or 220 km/hr wind gusts.

Meteorite58

Met Eireann

Weather News

Update on Storm Ophelia

14 October 2017

As of midday Saturday, Hurricane Ophelia situated at approx. 2,500km southwest of Ireland and 500km south-southwest of the Azores in the Atlantic Ocean is currently tracking east-northeast. The latest information from our colleagues in the National Hurricane Centre in Miami indicates that Ophelia will become a powerful post-tropical cyclone (from thereon in ex-Hurricane Ophelia) by Monday, and there is now generally high confidence that the centre of this system will track close to and possibly even over some parts of the west coast of Ireland.

Ex-Hurricane Ophelia is expected to be near the southwest tip of Ireland by Monday morning. From there it looks set to track northwards close to the Atlantic Seaboard at a fast pace to be roughly situated 100-200km northwest of County Donegal by midnight on Monday.

This will be a significant weather event for Ireland with potentially high impacts – structural damage and flooding (particularly coastal) - and people are advised to take extreme care Keep up to date with the warnings.

Met Éireann forecasters have been monitoring this situation closely all week. We have been liaising with our international colleagues, especially at the UK Met Office, and as we are now in the 48 hour window, with access to our high resolution models, we have decided to issue specific warnings. The warnings will be updated as required.

For further information on the evolution of this system, please continue reading.

What will happen with Hurricane Ophelia?

Hurricane Ophelia is expected to undergo an extra-tropical transition over the next 24 to 36 hours. That means its structure and appearance is going to undergo drastic changes as it approaches Ireland. It will lose its hurricane status but will become a powerful extra-tropical storm. Current indications are suggesting that Ex-Hurricane Ophelia will likely engage with an upper trough of low pressure in the mid-Atlantic at some point tomorrow afternoon. This engagement will cause the storm system to accelerate somewhat north-northeast towards Ireland and the UK.

Why will this happen?

As Hurricane Ophelia tracks north from its current position, it will encounter cooler seas and it will eventually come under the influence of the westerlies. The westerlies of the mid-latitudes increase in strength with height, a phenomenon known as vertical wind shear. This shear almost literally chops off the upper part of the hurricane and sweeps it away. Along with the lower sea temperatures of the mid-latitudes this destroys the positive feedback processes within the hurricane. What remains is the former hurricane’s low-level circulation which, if conditions are right, becomes the focus of further development.

What weather is expected?

Rain can be expected over the country on Sunday night and into Monday, though the heaviest and most significant rain will remain out to sea in the Atlantic on the western side of the surface low pressure. But there will also be some heavy and possibly thundery bursts rotating around the low centre itself, so it can be reasonably assumed that counties closest to the centre of the low will see the heaviest rainfall.

At the same time, damaging winds will accompany the low centre with wind gusts of 130km/h or more. The most severe winds will be in coastal counties, with lower impacts likely for central areas. In addition, we can expect very high waves. Sea conditions will be dangerous and large waves may lead to coastal flooding.

greysides

leahyl

M.T. Cranium wrote: »

Looking at that ICON map, you know something is up when the map has winds stronger than anything in the legend (that dark patch in the white zone). hope everyone grasps that the white zone is gusts of 200 km/hr being predicted so the dark patch is either seaweed from the Sargasso Sea, or 220 km/hr wind gusts.

:-O

TheMilkyPirate

Who is your one doing the weather she's awful

Jobs OXO

M.T. Cranium wrote: »

Looking at that ICON map, you know something is up when the map has winds stronger than anything in the legend (that dark patch in the white zone). hope everyone grasps that the white zone is gusts of 200 km/hr being predicted so the dark patch is either seaweed from the Sargasso Sea, or 220 km/hr wind gusts.

Joanna Donnelly looking very spooked on RTÉ. Stumbling and stuttering over words. Not like her at all. Something isn't being shared. Possibly to avoid panic.

sunbabe08

TheMilkyPirate wrote: »

Who is your one doing the weather she's awful

I was thinking that as well. Need a more steady hand for this situation

Nettle Soup

I think the RTE news and Met Eireann were very open, informative and clear about Ophelia just now. They've handled it well.
I was at a hurling match earlier and everyone is talking about it.

leahyl

Have to say, just can’t take to that Joanna Donnelly at all.

Meteorite58

https://twitter.com/pppapin/status/919231886744080385

https://twitter.com/pppapin/status/919235137681920001

https://twitter.com/pppapin/status/919240140811390978

RoisinClare6

Weather lady seemed a bit under pressure.

shmaupel

Nettle Soup wrote: »

I think the RTE news and Met Eireann were very open, informative and clear about Ophelia just now. They've handled it well.
I was at a hurling match earlier and everyone is talking about it.

Ditto.

I think they've been quite sensible and measured about the whole thing so far.

cyclops999

TheMilkyPirate wrote: »

Who is your one doing the weather she's awful

She's just excited after conference call from NHS, NWS they don't often get to forecast incoming hurricane

flaneur

Theresa is on standby !!