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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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Irish Steve

Well, for me, that puts this in context, ME are trending towards calling RED for the entire country, for winds.

They have been cautious up till now, but the way I am seeing this now is that while it is transitioning from Hurricane to Extra tropical storm, (or whatever) it has intensified more than was originally predicted, and as a result, will also diminish more slowly, with the result that what arrives here will be even stronger than was originally thought.

I am possibly going to tread on a few toes, but here goes.

Based on the clear indication from ME that this storm is going to be significant, and that it's not going to suddenly disappear, to put this event in context for anyone that's wondering what the fuss is all about.

The last storm of this magnitude that came over Ireland with the sort of intensity that is now being clearly forecast was nearly 60 years ago, and 19 People lost their lives as a result of it.
Traffic volumes were a fraction of what they are now, fast open motorways and similar did not exist then, and people did not commute the sorts of distances that are the norm now. The risks tomorrow have been very clearly delineated by a number of people during the news and subsequent weather forecast. Tomorrow WILL BE DANGEROUS. There is also the very real risk that public transport systems will be severely disrupted in the later stages of the day as this system moves up across the country. Please think about this very carefully before making decisions about tomorrow

Hastentoadd

Is there any understanding of what will happen when Opheilia hits the Jet Stream. Will it possibly sling Ophelia on a different course, will it dampen or strengthen Ophelia or will it have no impact at all?

Bsal

JCX BXC wrote: »

Dublin

Regular
BECMG 1607/1609 10015G25KT
BECMG 1610/1612 16025G40KT
BECMG 1612/1614 16035G50KT
BECMG 1616/1618 21030G45KT

Decoded
8am-10am 100 degrees 15kts gusting 25kts
11am-1pm 160 degrees 25kts gusting 40kts
1pm-3pm 160 degrees 35kts gusting 50kts
5pm-7pm 210 degrees 30kts gusting to 45kts

Shannon

Regular
BECMG 1605/1607 09025G35KT
BECMG 1609/1612 14035G55KT
BECMG 1612/1614 17040G60KT
BECMG 1614/1616 23030G45KT

Decoded
6am-8am wind 090 degrees 25kts gusting to 35kts
10am-1pm wind 140 degrees 35kts gusting 55kts
1pm-3pm wind 170 degrees 40kts gusting 60kts
3pm-5pm wind 230 degrees 30kts gusting 45kts

Cork

Regular
BECMG 1603/1606 07020G30KT
BECMG 1607/1609 17035G50KT
BECMG 1609/1611 17040G60KT
TEMPO 1611/1614 18048G70KT
BECMG 1614/1616 23035G50KT

Decoded
4am-7am wind 070 degrees 20kts gusting 30kts
8am-10am wind 170 degrees 35kts gusting 50kts
10am-12pm wind 170 degrees 40kts gusting 60kts
12pm-3pm wind temporarily 180 degrees 48kts gusting 70kts
3pm-5pm wind 230 degrees 35kts gusting to 50kts

Knock

Regular
BECMG 1603/1605 05018G30KT
BECMG 1608/1610 08025G40KT
BECMG 1610/1612 12025G40KT
BECMG 1612/1614 12035G50KT
BECMG 1614/1616 23030G45KT
BECMG 1616/1618 24025G35KT

Decoded
4am-6am wind 050 degrees 18kts gusting 30kts
9am-11am wind 080 degrees 25kts gusting 40kts
11am-1pm wind 120 degrees 25kts gusting 40kts
1pm-3pm wind 120 degrees 35kts gusting 50kts
3pm-5pm wind 230 degrees 30kts gusting 45kts
4pm-6pm wind 240 degrees 25kts gusting 35kts

*----*----*----*----*----*----*----*----*----*----*

Nothing spectacular at Knock, Shannon and Dublin, however I've never seen 70kts at Cork!

I was expecting the airport forecasts to be worse. Will see if the 23z TAF's are any different.

Donegal Storm

Still a bit of a spread across the hi res models for max gusts, wrf only showing 120-130kph, ICON saying 160-180kph. Track is more consistent with Cork, Waterford and Wexford seeing the strongest winds though some models are showing a brief and short lived peak closer to the centre over Kerry, Clare and Galway

If I were to guess I'd say the Arome is closest to what we'll see with about 150kph on the south coast and 100-120kph more generally across the southern half of the country. Nothing record breaking but still potentially very dangerous with countless trees likely coming down

spookwoman

18.50

JanuarySnowstor

spookwoman wrote: »

18.50

Still looks a hurricane wow!

Discodog

So which site, apart from here

, will have the position updated during the day. We have the 15 min updates from ME for rainfall but not pressure etc. Is it best to find a local weather station that's linked to the web ?

sdanseo

JanuarySnowstor wrote: »

Still looks a hurricane wow!

It is still a hurricane.

redsteveireland

Donegal Storm wrote: »

Still a bit of a spread across the hi res models for max gusts, wrf only showing 120-130kph, ICON saying 160-180kph. Track is more consistent with Cork, Waterford and Wexford seeing the strongest winds though some models are showing a brief and short lived peak closer to the centre over Kerry, Clare and Galway

If I were to guess I'd say the Arome is closest to what we'll see with about 150kph on the south coast and 100-120kph more generally across the southern half of the country. Nothing record breaking but still potentially very dangerous with countless trees likely coming down

What time does that translate to?

Gaoth Laidir

The centre is set to pass near or over Buoy K1 (62029) overnight so keep an eye on the reports here. Unfortunately it doesn't report windspeed but its pressure is falling now.

garyha

Meteoalarm has most of the country under red alert.

lucernarian

I'd extend the red warning to around most coastal areas and more exposed areas but I feel like nationwide red warnings might be too much after seeing the 12z Hirlam today. 130 kph gusts aren't covering the entire country in the forecasts I've seen.

Or am I missing something else?

spookwoman

list of other bouys here M3 is off the coast of cork http://www.marine.ie/Home/site-area/data-services/real-time-observations/irish-weather-buoy-network

Meteorite58

Mod Note

This thread is for technical analysis only please - there’s a general discussion thread available for everything else

Thanks

Gaoth Laidir

Latest track, showing it at the south coast with 65-knot 1-minute speeds (in the southern half of the circulation) and gusts to 80 knots at 12Z tomorrow. This would not suggest support for the higher gusts being forecast by the Arpege and ICON. We'll wait and see.

al172017.17101506.gif

sdanseo

garyha wrote: »

Meteoalarm has most of the country under red alert.

That's because Meteoalarm gives warnings at provincial level not by county. So because Wexford has red, all of Leinster has red on that view, etc.

Middle Man

New Wind Map Update...

https://earth.nullschool.net/#current/wind/surface/level/orthographic=-9.59,48.33,3000/loc=-13.553,43.571

Max average winds just above 100kph now it seems...

mayo.mick

https://twitter.com/CorkHarbourWX/status/919599381774561281

garyha

Latest ECMWF, those gusts are looking pretty severe.

Donegal Storm

redsteveireland wrote: »

What time does that translate to?

Its showing the max gusts for the whole event

Hooter23

That latest ECMWF chart looks worse than ever with violent gusts well inland

[Deleted User]

Image at 7pm. The last time Ophelia will be seen as a tropical system in the visible spectrum.

dacogawa

And maybe another storm (a bit less but power) on the way for Saturday, ECM running slightly north of this, anyway back to tomorrow #headsup

gfs-0-132.png?12

Villain

garyha wrote: »

Latest ECMWF, those gusts are looking pretty severe.

Just FYI those are not surface winds?

ch750536

Villain wrote: »

Just FYI those are not surface winds?

Correct , approx 5000 ft

firemansam4

Sat24 getting very interesting to watch now, it needs to be set to infrared mode, but the storm seems to be approaching fast now heading straight to the south coast

sdanseo

Villain wrote: »

Just FYI those are not surface winds?

I got very worried for about 5 seconds until I saw 850hPa. :pac:

pad199207

She is literally bombing it along now!

Kermit.de.frog

Euro4

60 kts just off Dub coast. If that is in any way onshore then that would merit a red warning.

drunkmonkey

pad199207 wrote: »

She is literally bombing it along now!

Looking at sat 24 it's moving very fast over the last 15 minutes.. https://en.sat24.com/en/eu/infraPolair are the times correct were seeing here if it keeps going that quick will it hit tonight rather than tomorrow.