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

Longboard · 12-10-2017 5:32pm

cherryghost wrote: »

Pinch of salt

pad199207 · 12-10-2017 5:36pm

GFS could be going on it’s own with this one!

12-10-2017 5:54pm

11am (4pm Ireland) NHC 5 day graphic outlook.

Kermit.de.frog · 12-10-2017 6:01pm

Gas

PukkaStukka · 12-10-2017 6:06pm

Met Eireann 6pm forecast has issued a preliminary warning re this event, but advise that that this is a developing situation and people need to follow the forecasts till then.

+1 to Met, this is the right call even if this turns out to be a non event.

TitianGerm · 12-10-2017 6:11pm

First time poster here but looking at the above graphs would I be right thinking Waterford/Wexford could be hit quite hard by this one?

jasper100 · 12-10-2017 6:11pm

That chart says 3 day error is 105Nm. There is a very good chance this could miss us completely.

M.T. Cranium · 12-10-2017 6:13pm

12z GEM has moved west to direct hit on Ireland, cyclone moves from 48N 11W at 00z Monday to intense stacked low near Belmullet 12z. This would be a high impact track for most of Ireland.

This removes the one eastern outlier from the model guidance suite.

12z GFS is comparatively slower and further west. This would be a level one alert for parts of Connacht and sub-alert for rest of Ireland.

More clarity after 12z ECM registers its vote perhaps.

jasper100 · 12-10-2017 6:13pm

emmetkenny wrote: »

First time poster here but looking at the above graphs would I be right thinking Waterford/Wexford could be hit quite hard by this one?

Cork, Kerry, Waterford and Wexford would potentially be where it reaches landfall on Irish shores from what I can see. That's if it lands a direct hit here at all.

Kermit.de.frog · 12-10-2017 6:16pm

http://edition.cnn.com/2017/10/12/world/hurricane-ophelia-ireland/index.html

CNN have got this. Expect Anderson Cooper and Wolf Blitzer to arrive over the weekend.

59b5944fe4b0f22e0e9f0145_1455589917779-yrd15k_t_1505072275660_640_360_400.gif

JCX BXC · 12-10-2017 6:17pm

jasper100 wrote: »

Cork, Kerry, Waterford and Wexford would potentially be where it reaches landfall on Irish shores from what I can see. That's if it lands a direct hit here at all.

Looks alot worse in Clare than Waterford and Wexford!

JCX BXC · 12-10-2017 6:19pm

Kermit.de.frog wrote: »

http://edition.cnn.com/2017/10/12/world/hurricane-ophelia-ireland/index.html

CNN have got this. Expect Anderson Cooper and Wolf Blitzer to arrive over the weekend.

We have Tereasa Mannion, we're fine!

server down · 12-10-2017 6:26pm

jasper100 wrote: »

That chart says 3 day error is 105Nm. There is a very good chance this could miss us completely.

IS the error not in the cone, though? If not whats the point of the cone.

EDIT:

Of course if it tracks to the west of that cone of probability it wont affect Ireland much at all. The centre -- presumably the most probable - will.

M.T. Cranium · 12-10-2017 6:46pm

Right, the actual track usually falls within the cone, in rare cases it has shifted further than the edges of the cone which is what the NHC have found operationally to be something like the 95% certain to verify zone. Don't forget that the cone uncertainty is also operating in elapsed time, in other words, there is uncertainty at each of the cone-bisecting elapsed times such as 72h, 96h, and that is not visually apparent, the error there is probably a little larger in spatial terms than the spread of tracks.

The timing uncertainty can be seen comparing GEM and GFS, already at least 8 hours in the vicinity of Ireland, and 4 deg of longitude.

sdanseo · 12-10-2017 6:56pm

M.T. Cranium wrote: »

Right, the actual track usually falls within the cone, in rare cases it has shifted further than the edges of the cone which is what the NHC have found operationally to be something like the 95% certain to verify zone. Don't forget that the cone uncertainty is also operating in elapsed time, in other words, there is uncertainty at each of the cone-bisecting elapsed times such as 72h, 96h, and that is not visually apparent, the error there is probably a little larger in spatial terms than the spread of tracks.

The timing uncertainty can be seen comparing GEM and GFS, already at least 8 hours in the vicinity of Ireland, and 4 deg of longitude.

I remembered reading this earlier this year on NHC's website:

Historical data indicate that the entire 5-day path of the center of the tropical cyclone will remain within the cone about 60-70% of the time. To form the cone, a set of imaginary circles are placed along the forecast track at the 12, 24, 36, 48, 72, 96, and 120 h positions, where the size of each circle is set so that it encloses 67% of the previous five years official forecast errors. The cone is then formed by smoothly connecting the area swept out by the set of circles.

That 67% is over five years so I guess the certainty in a given year would be relatively higher? (I'm no mathematician, nor will I ever be).

Gotta hand it to the Americans. They can be very officious - but their official websites and information sources are very well explained.

Edit: NHC's interactive map. If this was to come off, all of Sligo, Mayo, Donegal and Kerry as well as most of the western side of the country would experience a true Category 1 Hurricane. The green is 1min. sustained 64kt (75mph) wind.

jasper100 · 12-10-2017 7:14pm

sdanseo wrote: »

I remembered reading this earlier this year on NHC's website:

That 67% is over five years so I guess the certainty in a given year would be relatively higher? (I'm no mathematician, nor will I ever be).

Gotta hand it to the Americans. They can be very officious - but their official websites and information sources are very well explained.

Edit: NHC's interactive map. If this was to come off, all of Sligo, Mayo, Donegal and Kerry as well as most of the western side of the country would experience a true Category 1 Hurricane. The green is 1min. sustained 64kt (75mph) wind.

The people of Rosslare must be wondering why they are being left out!

pad199207 · 12-10-2017 7:15pm

Looks like ECM has the perfect storm for Ireland this evening. Worst case scenario for the South Coast.

dacogawa · 12-10-2017 7:16pm

The 96 on the ECM is out, it didn't go west... :eek:

ECM1-96.GIF?12-0

Kermit.de.frog · 12-10-2017 7:17pm

ECM 12z

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Meteorite58 · 12-10-2017 7:18pm

A few interesting observations

https://twitter.com/pppapin/status/918534724712325121

https://twitter.com/MattHugo81/status/918533282077315072

https://twitter.com/RyanMaue/status/918493506800406528

https://twitter.com/RyanMaue/status/918493732336435202

https://twitter.com/metoffice/status/918504887775842309

Qw5800h.png?1

M.T. Cranium · 12-10-2017 7:18pm

Did anyone earlier mention the 12z Arpege? It rocks the house and moves a touch to the east of the NHC track (by perhaps 50 miles). Well here comes the 12z ECM ...

... and it's heading for west Munster with very strong winds depicted at 96h -- a touch slower than previous pace, worst of the storm would be 15-18z presumably.

Iancar29 · 12-10-2017 7:18pm

ECM

UKMO

GFS

GEM

I think we can see what the current outlier is...

JanuarySnowstor · 12-10-2017 7:19pm

Looks like a direct hit for here. WOW!

Cee-Jay-Cee · 12-10-2017 7:22pm

JanuarySnowstor wrote: »

Looks like a direct hit for here. WOW!

Best disassemble the kids trampoline on Saturday :eek:

Meteorite58 · 12-10-2017 7:22pm

The 96 on the ECM is out, it didn't go west...

Note 850 hPa Winds

M.T. Cranium · 12-10-2017 7:22pm

It should be noted, the Met Office commentary of course only applies to the UK and their maximum wind gusts would be for Derry and western Scotland, parts of (Republic of) Ireland could expect 80-100 mph gusts consistent with their scenario.

Frankly, some of this guidance looks worse than Debbie 1961, don't you agree?

dacogawa · 12-10-2017 7:23pm

Looks like a swing east on the 120?!?

ECM1-120.GIF?12-0

km79 · 12-10-2017 7:25pm

Only seen this thread now
12 pages in a day
I'm scared

JCX BXC · 12-10-2017 7:26pm

Expecting downgrades, got the opposite. Plenty of time yet for it to change completely however some of that guidance looks quite frankly scary!

I'd love to give wind updates from West Clare but if that comes off I'm not confident of my current weather station set up so it would be coming inside for safe keeping!

Meteorite58 · 12-10-2017 7:28pm

My money is on the ECM and the other European models

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

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