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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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Reckless Abandonment

http://magicseaweed.com/UK-Ireland-Surf-Chart/1/?type=surf
Surf should be good

Meteorite58

12Z UKMO

Meteorite58

:eek: Don't see that every day. This could or is becoming a serious matter me thinks.

M.T. Cranium

This is mostly for mods, but open to general discussion -- if all guidance looks this intense after the 00z model runs, and if GFS starts to drift back towards consensus, then I think level 2 is justified and if that continued into 12z Saturday then level 3, with the original post edited to reflect the upgraded level of concern.

Our philosophy has always been to go with the highest level likely to affect any significant part of the country so it doesn't have to be level 3 in Dublin to justify that designation, but maps can be produced to show what level applies to each part of the country. From the current guidance excluding GFS, would say level 3 would apply to almost all of Munster, some parts of Connacht and perhaps southwest Leinster, level 2 would apply to almost all other regions. Some tracks might put Donegal into only a level 1 exposure and there could be sheltered parts of the southeast in level 1 also.

For your planning, the strongest winds would likely come from nearly due south veering to southwest during the event. You can do some harmless (costless) advance planning simply by inspecting your location for possible tree falling potential, trees are most likely to fall towards the north through northeast, and make sure your vehicle won't be parked in any such location, also if you think you are susceptible to roof tile damage, same concept applies, flying debris will head towards north-northeast. A lot of vehicle damage at least can be avoided by choosing a parking spot (if you can't park indoors) that is unlikely to be impacted by falling or flying debris. It's going to be a nice warm weekend for many so lots of time to get as ready as possible if this continues to be the model trend.

Gaoth Laidir

A nice image at 1540Z. Notable is the absence of a central dense overcast, so it seems to have an appearance more like a medicane (Mediterranean hurricane).

cherryghost

ARPEGE is going for 150kmph+ gusts further east and along the south coast. Inland gusts nationwide over 130kmph

Akrasia

Any tips on securing windows if this comes to the worst?

Irish houses don't have storm shutters. Is there anything we can do to protect windows that won't just blow off and become flying debris themselves?

pad199207

Just curious, but would this be as strong as Darwin in 2014?

Eaglebridie 32

What volume of rain could this conceivably dump on us?

Meteorite58

not 100% sure on the reliability of this site but it seems to be endorsed by some in the know in the US

__..__

pad199207 wrote: »

Just curious, but would this be as strong as Darwin in 2014?

Much stronger

Gaoth Laidir

I think people need to remember that the system will be racing northwards at over 50 km/h so the duration of max winds won't be prolonged, just like Debbie in 1961.

These were the max winds reported during that event. The problem was the storm's motion northwards at around 60 km/hr, otherwise winds would have been much less.

cherryghost

Eaglebridie 32 wrote: »

What volume of rain could this conceivably dump on us?

I dont think thats the concern right now but if it tracks further east the West could be on for a dumping instead of the nightmarish winds

Meteorite58

Very much like the ECM track

The NHC forecast at these times is similar to the previous
one and lies on the right side of the deterministic guidance
envelope but is near the middle of the ECMWF, UKMET and GEFS
ensemble members. Regardless of the exact track, post-tropical
Ophelia is likely to bring some impacts to Ireland and the United
Kingdom as a powerful extratropical cyclone in 4 to 5 days.

KEY MESSAGES:

1. Ophelia is expected to transition to a hurricane-force post-
tropical cyclone by Monday when it moves near Ireland and the
United Kingdom. While post-tropical Ophelia will likely bring some
direct impacts from wind and heavy rain to portions of these areas,
as well as dangerous marine conditions, given the forecast
uncertainty at these time ranges it is too soon to determine the
exact magnitude, timing and location of the impacts. Residents in
Ireland and the United Kingdom should monitor the progress of
Ophelia for the next several days. For more information on local
impacts, residents of Ireland should refer to products issued by Met
Eireann and residents in the United Kingdom should refer to products
issued by the Met Office.

FORECAST POSITIONS AND MAX WINDS

INIT 12/1500Z 30.5N 35.6W 80 KT 90 MPH
12H 13/0000Z 30.9N 34.9W 80 KT 90 MPH
24H 13/1200Z 31.6N 33.4W 80 KT 90 MPH
36H 14/0000Z 32.7N 30.8W 75 KT 85 MPH
48H 14/1200Z 34.4N 27.3W 75 KT 85 MPH
72H 15/1200Z 40.9N 18.8W 75 KT 85 MPH
96H 16/1200Z 51.0N 12.5W 65 KT 75 MPH...POST-TROP/EXTRATROP
120H 17/1200Z 60.5N 5.5W 55 KT 65 MPH...POST-TROP/EXTRATROP

Spanish Eyes

Oh God. I am here alone from Sunday night till Wednesday, and quite frankly I am mighty scared about this.

I know this is a weather forum, and lots of you like chasing storms and praying for snow and so on, but on this occasion given the potential severity of this event, maybe we should hope and pray that it veers West and fecks off into the Atlantic.

I'm in Dublin, and hoping against hope that it stays out to sea somewhere between here and America.

It is a great thread to remind people of the dangers. But there is only so much you can do apart from battening down the hatches and taking the precautions that MT has so kindly posted. I will be terrified either way.

JCX BXC

cherryghost wrote: »

ARPEGE is going for 150kmph+ gusts further east and along the south coast. Inland gusts nationwide over 130kmph

Basically a nationwide red warning!

sdanseo

Spanish Eyes wrote: »

Oh God. I am here alone from Sunday night till Wednesday, and quite frankly I am mighty scared about this.

I know this is a weather forum, and lots of you like chasing storms and praying for snow and so on, but on this occasion given the potential severity of this event, maybe we should hope and pray that it veers West and fecks off into the Atlantic.

I'm in Dublin, and hoping against hope that it stays out to sea somewhere between here and America.

It is a great thread to remind people of the dangers. But there is only so much you can do apart from battening down the hatches and taking the precautions that MT has so kindly posted. I will be terrified either way.

At the moment the very worst case prediction for Dublin has been 130km/h gusts. We've seen that several times in the last few years, so unless it takes a hefty swing east, I wouldn't be too worried. By no means complacent either, but it wouldn't be catastrophic here by any means.

Western and southern coastal areas would be a totally different story however.

Donegal Storm

ECMWF seems to track further east that before, Dublin and the east coast suddenly could be in the danger zone yet.

Gonna be plenty of hype in the media that a hurricane is hitting us but even with a direct hit it'll be long transitioned to post tropical so rainfall amounts will be fraction of what you'd get in a real hurricane and the eyewall structure will be gone

To the guy asking whether it'll be worse than Desmond, on this evenings guidance I'd say potentially yes and there's the added problem that most trees are still full of leaves so will blow over much easier than in a similar storm in December. Again though, its still 4 days away so for now just keep an eye on forecasts, if we're seeing similar charts on Saturday evening then it's time to get more worried. We'll likely see plenty more shifts in track and intensity before then

__..__

The trees won't be full of leaves on Tuesday

Spanish Eyes

sdanseo wrote: »

At the moment the very worst case prediction for Dublin has been 130km/h gusts. We've seen that several times in the last few years, so unless it takes a hefty swing east, I wouldn't be too worried. By no means complacent either, but it wouldn't be catastrophic here by any means.

Western and southern coastal areas would be a totally different story however.

130kph winds :eek:

But thanks for the reassurance. Things can change from day to day, so let's hope for the best. Just got a brand new roof on the shed/garage two weeks ago. Feck sake. But as long as no lives are lost hopefully all will be ok.

Still scared witless, but will be watching this thread avidly.

MJohnston

Donegal Storm wrote: »

ECMWF seems to track further east that before, Dublin and the east coast suddenly could be in the danger zone yet.

Gonna be plenty of hype in the media that a hurricane is hitting us but even with a direct hit it'll be long transitioned to post tropical so rainfall amounts will be fraction of what you'd get in a real hurricane and the eyewall structure will be gone

To the guy asking whether it'll be worse than Desmond, on this evenings guidance I'd say potentially yes and there's the added problem that most trees are still full of leaves so will blow over much easier than in a similar storm in December. Again though, its still 4 days away so for now just keep an eye on forecasts, if we're seeing similar charts on Saturday evening then it's time to get more worried. We'll likely see plenty more shifts in track and intensity before then

I know we aren't expecting much rain, but how good are we in Ireland about predicting storm surges? Genuine question!

Malayalam

West coast here. I have stocked up on Polytunnel repair tape and a major reinforcement will be made to the structures over next couple of days. It's kind of scary to be honest ...following for info :eek:

DOCARCH

sdanseo wrote: »

...130km/h gusts. We've seen that several times in the last few years...

Not in Dublin!

dacogawa

__..__ wrote: »

The trees won't be full of leaves on Tuesday

What trees?

Chicken Run

Akrasia wrote: »

Any tips on securing windows if this comes to the worst?

Irish houses don't have storm shutters. Is there anything we can do to protect windows that won't just blow off and become flying debris themselves?

We lived in a rental house with a couple of massive west-facing windows.... Taped them with criss-crossed masking tape to prevent shattering (like WWII style)

Dunno how effective it actually is.... Gave us something constructive to do I guess

thomasj

https://twitter.com/liamdutton/status/918552931368161282

CJhaughey

I'd better check the generator, get some fuel and sharpen the chainsaws and some spare chains just in case.
Drum of water wouldn't be stupid either.
It may amount to nothing but I'd rather be ready than not in this case if the worst forecasts are half accurate.
This time of year trees are still carrying a lot of leaf and will be very susceptible to high winds, not alone that the ground has had a lot of rain as well in the last week.
It could be interesting.

sdanseo

DOCARCH wrote: »

Not in Dublin!

Maybe not, although without doing any digging online I can only be anecdotal, I've certainly seen >60kt gusts in Dublin Airport METARs a few times.

George Sunsnow

I remember the Xmas storms a couple of decades ago (90’s someone here will point the date,there was one two xmas’s in a row) and the main item on the BBC tv news was 100000 homes in the republic without power

JCX BXC

sdanseo wrote: »

Maybe not, although without doing any digging online I can only be anecdotal, I've certainly seen >60kt gusts in Dublin Airport METARs a few times.

You'd want 70kt+ gusts to be getting 130km/h gusts. Strongest I remember in recent years was 79kts at Shannon, that was a scarily windy Wednesday!(12/02/14).