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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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savj2

JJJJNR wrote: »

Could this bring about a cold snap once it heads north ?

I think it's going to north then east. Models showing a ridge just after the storm passes then back to westerlies.

Pangea

Will Ophellia be renamed according to the Met Eireann naming system?

M.T. Cranium

This concept of extratropical transition was not as developed in the 1960s or 1970s as it is now so that both Faith and Debbie (1961) were probably classified as hurricanes longer then compared to what would happen today.

Also the transition is not some instant development, no doubt if these models verify there will be remnants of the old tropical organization visible on satellite and radar but the wind field will definitely start to expand rapidly after 45N and fronts will rapidly develop, the GEM model for example has an upper low of 536 dm capturing Ophelia and that's going to result in very rapid occlusion. This will become the focus of the strongest winds with reinforcements rotating around the southern quadrant of the low into the dry slot feature.

Strong mid-latitude cyclones have eye features so the process will be for the eyewall to lose its localized intensity, rather than for the eye to disappear. I am almost certain there would be an eye visible in the storm as far north as 55N or beyond.

savj2

M.T. Cranium

The 06z GFS is very intense but not quite on the same track as other models, brings the strongest winds across outer Kerry then along Clare and Galway coasts. Pretty much the same track as Debbie took in 1961. Localized level 3 alert material with widespread level 2 south coast and inland.

Places like Newport, Westport and Clifden are now in a situation where a track difference of 30-50 miles could mean a huge difference in wind speeds, but Kerry, Clare and Galway (city) appear to be more certain to see severe winds. Cork to Limerick quite likely but some model tracks worse than others for them.

I have not seen any guidance yet that would be much more than 60 knot gusts for Dublin which is bad enough, but so far not a major impact.

Plenty of time for details to change and entire country needs to be on high alert.

Meteorite58

As above

davo2001

Is the above gusts or sustained wind speeds?

savj2

Meteorite58 wrote: »

As above

Sustained kph I think

smodgley

Would it be advisable to close schools yet especailly the rural ones as travel will be dangerous if event happens ?

Meteorite58

davo2001 wrote: »

Is the above gusts or sustained wind speeds?

gusts

pad199207

Meteorite58 wrote: »

gusts

We have had worse in these parts

Meteorite58

All charts subject to change but an idea of what it could look like

hatrickpatrick

davo2001 wrote: »

Is the above gusts or sustained wind speeds?

savj2 wrote: »

Sustained kph I think

Wind gusts and barbs, in knots per hour or kts (not to be confused with km per hour, which I think is what kph means)

Meteorite58

National Weather Warnings

STATUS YELLOW

Weather Advisory for Ireland
On Monday, an Atlantic storm from the remnants of Hurricane Ophelia will move northwards close to Ireland. There is still a high degree of uncertainty regarding the exact track and evolution of the storm. However, storm force winds, heavy rain and high seas are threatened. Met Eireann will continue to monitor this storm and will issue appropriate warnings as required.

Issued:Friday 13 October 2017 08:00
Valid:Monday 16 October 2017 06:00 to Tuesday 17 October 2017 06:00

savj2

hatrickpatrick wrote: »

Wind gusts and barbs, in knots per hour or kts (not to be confused with km per hour, which I think is what kph means)

Thanks. Wasn't sure.

Coax

smodgley wrote: »

Would it be advisable to close schools yet especailly the rural ones as travel will be dangerous if event happens ?

Yes it would.

There is a framework in place for this but I feel it needs improvement.

Meteorite58

https://twitter.com/weerenradar/status/918787123423178753

W4p1Bqs.png?1

Meteorite58

10m wind speeds (kt)

ZxzBudD.gif?1

Kermit.de.frog

A little bit of weakening of intensity in the projections but the zone of potential disruption is a bit wider too.

Still changes to come.

Iancar29

Friday midday and the forum is buzzing! :pac:

Storm 10

Surprised that ME would not at least have an Amber warning in place, they put up yellow for a small Gale yet they are saying storm force winds for Monday.

irish1967

Guess it’s time for my first visit since last winter. Hello from Donegal. 10meters from shoreline of Donegal Bay. ðŸŒŠ

MJohnston

Storm 10 wrote: »

Surprised that ME would not at least have an Amber warning in place, they put up yellow for a small Gale yet they are saying storm force winds for Monday.

People were saying that it's about how far out the storm is - that even if nothing changes with the predictions by tomorrow that they'll bump it to an Orange warning or perhaps higher.

jasper100

Storm 10 wrote: »

Surprised that ME would not at least have an Amber warning in place, they put up yellow for a small Gale yet they are saying storm force winds for Monday.

Bit early putting out warnings for something that may miss us by 100 miles.

They have flagged that a storm is a distinct possibility but I don't expect them to make rash calls prematurely.

my3cents

jasper100 wrote: »

Bit early putting out warnings for something that may miss us by 100 miles.

They have flagged that a storm is a distinct possibility but I don't expect them to make rash calls prematurely.

But do you believe it will miss us by 100 miles?

Malayalam

Iancar29 wrote: »

Friday midday and the forum is buzzing! :pac:

I have the page open and regularly refreshing...weather possibilities like this brings out the islander in us all I think.

jasper100

my3cents wrote: »

But do you believe it will miss us by 100 miles?

I don't know, we will have to wait and see. But there is, from what I can see, still a good chance that this could be a damp squib causing minimal damage.

MJohnston

jasper100 wrote: »

Bit early putting out warnings for something that may miss us by 100 miles.

They have flagged that a storm is a distinct possibility but I don't expect them to make rash calls prematurely.

That's reasonable enough, but there is some context to consider here - for example the schools may not have enough time to react if a Red warning is put out over the weekend, and then come Monday they'll have to scramble. Same with elderly folks picking up the correct supplies.

Nothing might come of this, but if ME are still being vague about this tomorrow, I would consider that more reckless than putting out an 'overhyped' warning.

Gaoth Laidir

Latest visible satellite image and recent SSMIS 37GHz microwave image, showing it losing the western half of its eyewall.

20171013.1115.goes13.x.vis1km.17LOPHELIA.90kts-970mb-309N-344W.100pc.jpg

20171013.1115.goes13.x.vis1km.17LOPHELIA.90kts-970mb-309N-344W.100pc.jpg

20171013.0912.f17.x.37h.17LOPHELIA.90kts-970mb-309N-344W.97pc.jpg

pad199207

Gaoth Laidir wrote: »

Latest visible satellite image and recent SSMIS 37GHz microwave image, showing it losing the western half of its eyewall.

EWRC?