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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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leahyl

Kermit.de.frog wrote: »

If this is not a CATEGORY 3 at the next advisory i'll eat my hat.

Red warning on ME site now, someone has prob already said this...so ignore me if that’s the case haha

Kermit.de.frog

If this is not a CATEGORY 3 at the next advisory i'll eat my hat.

MJohnston

mel.b wrote: »

That talks about how/why Ophelia has survived but not what caused her to come east in the first place which is what I'm curious about.

The thing to know about hurricane movement is that they generally would be absolutely stationary under their own power, ie. they have no natural "inclination" to moving anywhere.

Their structure makes them very easily moved by external systems however - so they tend to get pushed around a lot. So to understand why Ophelia came east, you need to look not at the hurricane itself, but the jet stream and nearby pressure systems that pushed it along that particular course.

Gaoth Laidir

Early 12Z intensity forecast initialises it at 100 knots.

511

Stephen Hawkins football boots wrote: »

The weather is so warm at the moment, excuse the cliche but is this calm before storm?Is the hurricane the reason it's so warm?

The warm southerly airflow is guiding this tropical storm into Ireland's path: https://earth.nullschool.net/#current/wind/surface/level/orthographic=-15.77,42.59,981

mel.b

Nettle Soup wrote: »

https://www.popsci.com/hurricane-ophelia-british-isles#page-3

That talks about how/why Ophelia has survived but not what caused her to come east in the first place which is what I'm curious about.

Nettle Soup

Kai Rotten Shipwreck wrote: »

Interesting question.. hope someone can answer it!

https://www.popsci.com/hurricane-ophelia-british-isles#page-3

Hurricane Ophelia is an odd storm. It’s a picture-perfect hurricane with winds around 90 MPH, but that’s not the odd part, of course. What makes this storm weird is its location. It’s way out in the Atlantic, where it’s usually too cool for hurricanes to develop—much less survive. Ophelia is so far off the beaten path that instead of heading for the Americas (as so many storms have this season), the system will evolve and threaten Ireland and the United Kingdom early next week.

Met Éireann—Ireland's meteorological service—is advising residents to keep a close eye on the storm as it approaches the Isles, emphasizing the uncertainty in the forecast. A statement by the agency on Thursday noted that "it won’t be possible to quantify the exact timing, nor the strength or intensity of the wind and rain, in any great detail until later in the weekend." Weather alerts issued by the U.K.'s Met Office read much the same, noting the potential for damaging winds, heavy rain, and scattered power outages in Northern Ireland and along the western coast of Great Britain.

4068ac1elhodqr

Cloudio9 wrote: »

The chart in post 894 shows a scenario where the east gets hit as hard as the west and this is going to peak around the evening rush hour.

Agree, (according to two charts) 4-5pm Monday could be the worst for the SE, which means going into rush-hour on the (exposed) M1, some lorries will take a tumble, again.

Peak traffic & peak population significantly increases incident exposure risks.
Screen_Shot_2017-10-14_at_15.10.08.png

Of course still early, and many think this is a storm of one part, and not two?

M.T. Cranium

Well that was a fast jump by ME to level 3 and a fast jump by me out of bed.

Anyway, I think we knew this was almost inevitable if models kept tracking the storm towards west Munster and the 06z GFS probably tipped the balance of near-inevitability that the storm would be high impact.

As to the impact on Azores, here's the current situation -- the cold front has moved through the western half of the Azores with 15-25 knot northwest winds reported at Flores and falling temps (to 15 C). The southeastern islands have seen winds backing from south to southeast, still moderate at Santa Maria (southeast 18 knots) with a warm and humid 25/21 temp/dew point, and Ophelia will be within 50 miles of there by about 21z so those islands including Punta Delgada may reach 120-140 km/hr northeast winds as the centre goes past to their south.

I agree it looks close to cat-3 now.

Debbie which was never moving as slow as Ophelia did for much of this past week moved through the central Azores and was at 22W when it reached 42 N, Ophelia is predicted to be near 17W by 42N so its angle of approach is more SSW than Debbie's SW, however the results may be similar although details will be different.

Some talk about Donegal -- it all depends on whether the track cuts inland far enough to take the centre east of Donegal (which would likely mean Mayo and some parts of west Galway as well) -- in that scenario, winds over those counties would be more moderate, southeast backing to northeast 60-100 km/hr then shifting rapidly around to northwest 80-130 km/hr as the centre passed. But if the centre moves up the west coast and west of Donegal, then all those areas are exposed to stronger southerly winds, albeit not as strong as Kerry, Clare and other parts of west Munster might see -- would estimate 100-140 km/hr for Donegal in that scenario, and possibly 120-160 for Mayo, 130-170 might be the peak further south.

Storm surge potential should not be underestimated. The peak winds appear to be timed close to high tides on the south coast and this is a long duration, long fetch storm that will be rolling in with 10-15 metre battering waves and a storm surge that could be as high as 2 to 2.5 metres in some places between Sherkin and Waterford, 1.5 to 2 from Waterford to Rosslare and 1.0 to 1.5 up the east coast. Storm surges on the west coast would be somewhat less than other events with most track scenarios but would increase if the track is further west than consensus.

One other note of interest, the centre of the storm will pass very close to an ocean buoy located around 49N 13W about 06z Monday so we'll get very good data from that if it survives the encounter.

Gaoth Laidir

12Z wind analysis showing 75 knots as the max winds, but the radius of 64-knot+ winds has increased out to 70 miles from the centre.

Stephen Hawkins football boots

The weather is so warm at the moment, excuse the cliche but is this calm before storm?Is the hurricane the reason it's so warm?

Cloudio9

Weathercheck wrote: »

At present the Greater Dublin area looks least exposed so may lessen slightly the coverage of the storm.

The chart in post 894 shows a scenario where the east gets hit as hard as the west and this is going to peak around the evening rush hour.

uck51js9zml2yt

mel.b wrote: »

Just wondering what has caused this hurricane to travel east towards us, rather than west as they typically do? Is it due to where it first formed?

Interesting question.. hope someone can answer it!

Discodog

RobertKK wrote: »

I wouldn't be surprised if like with Storm Darwin, we ended up with a red warning.
We only got the red warning upgrade during that storm when we were in the middle of the worst conditions and trees were falling down everywhere, power cuts happening and conditions that were just too dangerous to be out in.

Be prepared for the worst, and hope for the best.

I think that power cuts could be the biggest problem.

Meteorite58

luimneachboy wrote: »

For those that have a good knowledge, at the moment what's this looking like for West limerick /north kerry

RobertKK

channaigh wrote: »

How will Kilkenny fair in this Robert ?

I wouldn't be surprised if like with Storm Darwin, we ended up with a red warning.
We only got the red warning upgrade during that storm when we were in the middle of the worst conditions and trees were falling down everywhere, power cuts happening and conditions that were just too dangerous to be out in.

Be prepared for the worst, and hope for the best.

Discodog

mickger844posts wrote: »

Anyone who suggests this will just be another windy day are in for a shock. This is looking like a once in a lifetime event. Its a stronger storm than Debbie in 1961.Be ready and prepared and hopefully it wont be as bad as its looking now.

I have a live Youtube stream set up for the event here in Waterford City. You can also check live data on my website www.waterfordweather.com

Might be hard to judge the windspeed as the trees are in the distance. Maybe put some wheelie bins of different weight

Akrasia

For anyone not aware of the excellent live wind map, here's the link for that

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-30.28,41.46,649

ascophyllum

Meteorite58 wrote: »

WRF- NMM

Gusts

This shows a very different scenario to Met's red warning, Mayo and Galway not so affected at all in this model

Harry Palmr

Just watching the repeat of the lunchtime weather, you'd hardly guess the windapocalypse was on the way

Monkeynut

mickger844posts wrote: »

Anyone who suggests this will just be another windy day are in for a shock. This is looking like a once in a lifetime event. Its a stronger storm than Debbie in 1961.Be ready and prepared and hopefully it wont be as bad as its looking now.

I have a live Youtube stream set up for the event here in Waterford City. You can also check live data on my website www.waterfordweather.com

i wonder how the bunting flags will do.

Colser

I'm starting to feel nervous about this,I've already told the kids that they're not going to school and they think I'm losing it but I'm really getting a bad feeling about it...hopefully it won't be as bad as its looking at the moment.

Strangegravy

This is a bit surreal really...

https://twitter.com/NWSWPC/status/919186027465515009

luimneachboy

For those that have a good knowledge, at the moment what's this looking like for West limerick /north kerry

4068ac1elhodqr

Concerned that Red has only been issued for 4 counties in the SW/W (of course likely 11am Monday).
the 'MaxGust' on two models show the SE&E (population dense) getting a fair whack from the Lady round about 4pm Monday.

Screen_Shot_2017-10-14_at_14.46.57.png

Dare even say it could more of an Irish Sea storm than an Atlantic Coast?

The UKMO have just a 'yellow' wind warning for Monday (Wales/NI/Scot), will it be another 'Fish' forecast?
Either the models are (both) wrong, or the forecasters...

Meteorite58

Definitely Cat 3.

Looks Close.

Saffir-Simpson Hurricane Wind Scale
Category Sustained Winds
1 74-95 mph 64-82 kt 119-153 km/h
2 96-110 mph 83-95 kt 154-177 km/h
3 (major) 111-129 mph 96-112 kt 178-208 km/h
4 (major) 130-156 mph 113-136 kt 209-251 km/h

https://twitter.com/splillo/status/919194553562775552

mickger844posts

Anyone who suggests this will just be another windy day are in for a shock. This is looking like a once in a lifetime event. Its a stronger storm than Debbie in 1961.Be ready and prepared and hopefully it wont be as bad as its looking now.

I have a live Youtube stream set up for the event here in Waterford City. You can also check live data on my website www.waterfordweather.com

iguana

ellieh1 wrote: »

Just curious as to why Met Eireann has not included Limerick in the Red warning......seems strange when they have included Cork, Kerry, Galway etc..

Presumably because we don't have any direct coastal areas? I'm sure parts of Limerick will fare identically or worse to parts of counties with red alerts (I live about 700 meters from the Clare border and high up hill of it so will probably be hit as hard if not harder than the parts of Clare near me). But the more coastal regions of those counties are possibly at risk of worse damage.

Discodog

I thought that this would be Sunday night into Monday but now seems to be Monday late afternoon. Based on the current estimates when would peak winds arrive in Galway ?

Hooter23

With the Hurricane becoming stronger than expected perhaps the track will move west again as it aprroaches Ireland...