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

Itssoeasy · 12-10-2017 4:49am

squarecircles wrote: »

Oscar Bravo wrote: »

Joanna donnelly on Radio 1 just now saying that more or less its been hyped in the media and that it will more than likely just a wet and windy episode however they will be keeping an eye on it. she perhaps should of said nout until a day or two more passes.

Isn't that her style generally, blaze,about this kind of stuff.

Also how many wet and windy episodes have ever been given a track by the NHC ? I mean MT from what I can see doesn't hype things.

Kermit.de.frog · 12-10-2017 4:58am

Yes, this is a hurricane chart. Who'd have thunk it?

M.T. Cranium · 12-10-2017 6:43am

The 00z GFS has a very intense low just a little further west than the 12z run, but a respected forecaster once mentioned that the better comparison at this time scale is from the previous 00z run to this one, and on that comparison there is not much of a shift. The strongest winds would be out to sea but still a level one or perhaps two impact on land from this version.

The 00z GEM made a slight shift west as well and is also similar to the track it had 24 hours ago (eastern Ireland, but not a very strong storm left at that point).

The 00z Arpege has shifted east of any of its earlier output and is also a bit weaker than before, once again, would suggest a level one to two event up through the central counties.

Now waiting for the 00z ECM to update.

Ophelia has been spinning her wheels out to the southwest of the Azores, for about six hours there was almost no forward progress, but this was anticipated and a very slow eastward drift has resumed with hints of a northward component (30.1 N 35.2 W last time I looked at the satellite imagery). It's a strong cat-1 or perhaps a weak cat-2 now, NHC is frank about having an approximate estimate from satellite presentation.

Still thinking that we won't have a lot of clarity on this outcome until Friday afternoon at the earliest and perhaps Saturday morning. Once Ophelia accelerates and makes a northeast move we should have a better idea.

Kermit.de.frog · 12-10-2017 7:04am

Remember this.

Unbelievable.

DL6Zwk0VQAAFqmv.jpg:medium

That is a hurricane chart showing landfall in Ireland.

Could conceivably be at or near Cat 1 - would be historic and hugely damaging near the center.

I see some UK weather watchers are seriously considering making the trip to the south coast just to see it make landfall! (if it does of course!)

mirrorwall14 · 12-10-2017 7:05am

Yes! Distraction from the joys of trying to conceive. Love the weather

. Looking forward to all the updates and thanks in advance to all the weather posters for sharing their knowledge

I’m thinking it would be prudent to start the garden toys clear up for the winter and to pick up a torch (we don’t have one)

Gaoth Laidir · 12-10-2017 7:36am

Currently 75 knots and moving slowly over increasingly colder waters. The NHC chart shows it as a hurricane strength extratropical low (white icon) as opposed to a proper hurricane (black icon) south of Ireland, and as storm force over Ireland. 55 knots by Monday evening. Kermit's chart doesn't show a hurricane landfall either.

This is similar to Debbie in 1961, which had already become extratropical well before Ireland but its lightning fast forward speed (~60 kph) is what brought those strong winds. Ophelia won't be moving quite as fast (~35-40 kph) but this foward speed is what will increase the winds felt at the surface.

Still a lot of uncertainty at this stage and a lot depends on what happens in the next 2 days as it sits over cold waters.

Kermit.de.frog · 12-10-2017 7:47am

Gaoth Laidir wrote: »

55 knots by Monday evening. Kermit's chart doesn't show a hurricane landfall either.

Never said it did. But it could make landfall with or near Cat 1 winds near the center.

Gaoth Laidir · 12-10-2017 8:00am

Kermit.de.frog wrote: »

Never said it did. But it could make landfall with or near Cat 1 winds near the center.

I know, I was just clarifying the difference between the two types structures-wise.

Latest intensity guidance. Official forecast (red) is at the bottom of the consensus. Certainly hurricane gusts possible come Monday but I can't see hurricane-force sustained.

fraxinus1 · 12-10-2017 8:49am

Joanne Donnelly being very blasé about this potential storm. I hope she isn't about to have her Michael Fish moment.

Reckless Abandonment · 12-10-2017 9:11am

fraxinus1 wrote: »

Joanne Donnelly being very blasé about this potential storm. I hope she isn't about to have her Michael Fish moment.

Way to early to be calling anything . Personally I'll only get excited if it's showing this strength on Sat afternoon. Even Met can wait till Then before warnings are needed . Then I'll start thinking a road trip

Ave Sodalis · 12-10-2017 9:16am

Following this thread, I've a ferry crossing from Pembroke to Rosslare early next week and wouldn't mind being kept up to date

star gazer · 12-10-2017 10:07am

Not much change from NHC advisory 13 just a slightly further west forecast track coming towards Ireland.

At 500 AM AST (0900 UTC), the center of Hurricane Ophelia was
located near latitude 30.3 North, longitude 35.6 West. Ophelia is
moving toward the northeast near 3 mph (6 km/h). This general
motion is expected today, followed a by faster motion toward the
east-northeast or northeast on Friday.

Maximum sustained winds are near 85 mph (140 km/h) with higher
gusts. Some slight strengthening is possible over the next day or
two.

Hurricane-force winds extend outward up to 25 miles (35 km) from the
center and tropical-storm-force winds extend outward up to 70 miles
(110 km).

The estimated minimum central pressure is 986 mb (29.12 inches).

Cureently 1,165km South West of the Azores.

Donegal Storm · 12-10-2017 10:42am

Reckless Abandonment wrote: »

Way to early to be calling anything . Personally I'll only get excited if it's showing this strength on Sat afternoon. Even Met can wait till Then before warnings are needed . Then I'll start thinking a road trip

I can already picture the post mortem arguments here on Tuesday after we end up with a typical windy day..

Potential is clearly there for a major storm but as you say it's far too early to talk of battening down the hatches. Yesterday evenings ECMWF was a worst case scenario, this mornings runs are either further west or less severe so nothing worth getting worried about yet.

Certainly an interesting one to watch evolve at least, this is the first time in a long long time I've been watching each model run as it rolls out!

fraxinus1 · 12-10-2017 10:51am

I think many including mysled got over excited yesterday with the charts.The general feeling today is that it will be normal autumn gales on the west coast. And very mild. Panic over.

dacogawa · 12-10-2017 11:03am

Pulled a bit west on the GFS run

gfs-0-108.png?6

Stephen Hawkins football boots · 12-10-2017 11:05am

Apologies for question,I'm flying to isle of man on mon Oct 16 on one of those propeller planes, with this storm due that day, do you reckon flight will go ahead?

ronnie3585 · 12-10-2017 11:14am

I've been looking at the NHC's five day cones for years with fascination, it's a very different feeling when the cone is aimed at us!

pauldry · 12-10-2017 11:16am

I think it will be pulled out further to the W and NW but only surmising.

Itll only start moving up Saturday with the strong airflow from the HP

I think the HP will keep it out in the Atlantic.

Normally these storms only become issues when theres a jet to our South.

Ill be wrong of course

PukkaStukka · 12-10-2017 11:19am

Stephen Hawkins football boots wrote: »

Apologies for question,I'm flying to isle of man on mon Oct 16 on one of those propeller planes, with this storm due that day, do you reckon flight will go ahead?

Largely depends on the "crosswind" component, or to put it plainly, whether the wind is blowing straight along the runway, and if not, how far of centre it is. Different aircraft and companies have varying limits.

pad199207 · 12-10-2017 11:25am

What’s the storm surge potential with this?

RubyK · 12-10-2017 11:55am

Any idea of what kind of rainfall amounts would be expected with this (I know its a long way away yet!)?

Gaoth Laidir · 12-10-2017 11:57am

Latest track.

al172017.17101200.gif

Gaoth Laidir · 12-10-2017 12:00pm

RubyK wrote: »

Any idea of what kind of rainfall amounts would be expected with this (I know its a long way away yet!)?

Not much. The rain looks like it will probably be confined mostly to the west of the centre, so out over the sea, and with the storm's fast movement it will not hang around enough to dump much water.

12-10-2017 12:03pm

Cork City tidal barrier ruled out on cost basis

They might change their mind if this storm makes landfall just to the west of Cork during high tide.

Jimmy 3 times · 12-10-2017 12:19pm

PukkaStukka wrote: »

Largely depends on the "crosswind" component, or to put it plainly, whether the wind is blowing straight along the runway, and if not, how far of centre it is. Different aircraft and companies have varying limits.

How do you think Aerlingus might decide in this situation? Flying in from mainland Europe at about 6 Monday evening. Might be better off not flying out in the 1st place!

Gaoth Laidir · 12-10-2017 12:23pm

Latest LGEM forecast has the following winds at these locations:

MON 06Z 48.9N 12.8W 57 KT
MON 18Z 54.1N 10.0W 44 KT

So decreasing from 57 to 44 knots as it reaches around Belmullet. The distance between the two points is 609 km, so it will be moving up the west coast at an average speed of around 50 kph during Monday.

Gaoth Laidir · 12-10-2017 12:48pm

Latest satellite representations.

Visible,
20171012.1115.goes13.x.vis1km_high.17LOPHELIA.75kts-986mb-302N-357W.100pc.jpg

SSMIS 37 GHz (0926Z, shows lower structure),
20171012.0926.f17.x.37h.17LOPHELIA.75kts-986mb-302N-357W.89pc.jpg

85 GHz (0926Z, shows upper structure)
20171012.0926.f17.x.91hw.17LOPHELIA.75kts-986mb-302N-357W.87pc.jpg

SSMIS Multisensor (0926Z)
20171012.0926.f17.x.composite.17LOPHELIA.75kts-986mb-302N-357W.84pc.jpg

squarecircles · 12-10-2017 1:11pm

Met Eireann forecaster Liz Walsh told Independent.ie: "It is coming towards Ireland, basically the hurricane is south-west of the Azores right now and it is tracking towards Portugal.

"As it comes north over the weekend it will change into an extra-tropical cyclone and it is tracking towards Ireland and the UK.

"It does look like it will hit Ireland on Monday, heading into Tuesday will be very stormy days."

She said that Met Eireann has predicted gusts in "excess of 120kph

She said: "At the moment this is more of a wind event than a rain event but of course the possibility of heavy rainfall with an extra-tropical cyclone cannot be ruled out."

Independent.ie

Irish Steve · 12-10-2017 1:32pm

ME forecast on RTE 1 has just mentioned Monday as "being worth keeping an eye on the forecasts, with significant weather warnings likely to be issued for strong winds".

Gaoth Laidir · 12-10-2017 1:56pm

GFS ensemble boxplot chart.

Current windfield

Rulmeq · 12-10-2017 2:04pm

Will they give this storm one of the North Atlantic names, or will this keep it's current name?

squarecircles · 12-10-2017 2:09pm

It wont be renamed,it will be known as Ex- hurricane Ophelia

cherryghost · 12-10-2017 2:13pm

GFS has been consistently off-mark for these predictions so I'd be focusing on ECM tbh

squarecircles · 12-10-2017 2:14pm

https://mobile.twitter.com/GregPostel?ref_src=twsrc%5Egoogle%7Ctwcamp%5Eserp%7Ctwgr%5Eauthor

Rougies · 12-10-2017 2:25pm

Yellow "Weather Advisory" issued by Met Éireann

STATUS YELLOW

Weather Advisory for Ireland

A combination of a vigorous Atlantic weather system and the remnants of Hurricane Ophelia will pass close to Ireland on Monday, and has the potential to be a high-impact event in parts of the country. There is a lot of uncertainty as to the exact evolution and movement of this weather system during the coming four days, but storm-force winds, outbreaks of heavy rain, and very high seas are threatened. Met Éireann will maintain a close watch on the evolution and issue further advisories and warnings as these are warranted.
Issued:
Thursday 12 October 2017 14:00
Valid:
Thursday 12 October 2017 14:05 to Tuesday 17 October 2017 06:00

https://www.met.ie/nationalwarnings/default.asphttps://www.met.ie/nationalwarnings/default.asp

squarecircles · 12-10-2017 2:27pm

Rougies wrote: »

Yellow "Weather Advisory" issued by Met Éireann

https://www.met.ie/nationalwarnings/default.asphttps://www.met.ie/nationalwarnings/default.asp

High impact event, a term met eireann rarely use...

Just a Slight bit of egg on Joanna's face...

Vinculus · 12-10-2017 2:32pm

I was hoping Ophelia would dump a load of rain over Galicia as we really badly need it, especially here in the south. Doesn't look like she will though.

pilly · 12-10-2017 2:34pm

squarecircles wrote: »

High impact event, a term met eireann rarely use...

Just a Slight bit of egg on Joanna's face...

Only a yellow warning though?

squarecircles · 12-10-2017 2:43pm

pilly wrote: »

Only a yellow warning though?

It's not a warning,more an advisory for now,Weather advisory's are yellow by default,given we are four days out,they want to bring it to the public's attention first before issuing any warning.

FutureGuy · 12-10-2017 3:14pm

Hi all,
If this does hit Ireland, will it be worse than Storm Desmond?

JanuarySnowstor · 12-10-2017 3:24pm

My thoughts before the 12zs come out is that there's a clear nudge West by the gfs since this time yesterday. I'm very surprised the Met didn't wait until this evening to do a warning. If the ecm moves more towards gfs then let's be clear there is no storm!

We'll know a good bit more by tonight but the trend this morning is West and away from our shores

goat2 · 12-10-2017 3:27pm

JanuarySnowstor wrote: »

My thoughts before the 12zs come out is that there's a clear nudge West by the gfs since this time yesterday. I'm very surprised the Met didn't wait until this evening to do a warning. If the ecm moves more towards gfs then let's be clear there is no storm!

We'll know a good bit more by tonight but the trend this morning is West and away from our shores

hoping not to lose some of my roof again this Monday as happened a few yrs ago, when MT warned us, trees came down also, missing the home, but have kept things at safe height since

Gaoth Laidir · 12-10-2017 3:30pm

12Z Early guidance out. 96-108 hours is what we're looking at.

Seems like a westward shift in track compared to the official track (red).

[img][/img]

fraxinus1 · 12-10-2017 3:37pm

JanuarySnowstor wrote: »

My thoughts before the 12zs come out is that there's a clear nudge West by the gfs since this time yesterday. I'm very surprised the Met didn't wait until this evening to do a warning. If the ecm moves more towards gfs then let's be clear there is no storm!

We'll know a good bit more by tonight but the trend this morning is West and away from our shores

That's good to hear. I was going to ask a neighbour to have a look at the shed roof but no need to. I hope Met Eilean feel silly now with their hype about high impact weather. Meet a neighbour earlier and it was all talk about a big storm. I told him the word is it will stay out to sea to the west.

George Sunsnow · 12-10-2017 3:42pm

Oh for fcuks sake
Met Éireann have only issued a yellow and only said theyre watching it
That it has the potential to be high impact etc

Often criticized here for no mention of uncertainty’s
You guys,a lot of you guys are never happy

Iancar29 · 12-10-2017 3:46pm

fraxinus1 wrote: »

That's good to hear. I was going to ask a neighbour to have a look at the shed roof but no need to. I hope Met Eilean feel silly now with their hype about high impact weather. Meet a neighbour earlier and it was all talk about a big storm. I told him the word is it will stay out to sea to the west.

Seriously???????

Bsal · 12-10-2017 3:58pm

Met office latest forecast

https://www.youtube.com/watch?v=TGThwsLopXY

star gazer · 12-10-2017 4:14pm

Wind speed up a bit, pressure down and track similar, not much change forecast for the next two days or so.

...OPHELIA MEANDERING SOUTHWEST OF THE AZORES...
...EXPECTED TO BEGIN MOVING NORTHEASTWARD LATER TODAY...

SUMMARY OF 1100 AM AST...1500 UTC...INFORMATION
LOCATION...30.5N 35.6W
ABOUT 715 MI...1145 KM SW OF THE AZORES
MAXIMUM SUSTAINED WINDS...90 MPH...150 KM/H
PRESENT MOVEMENT...NNE OR 20 DEGREES AT 2 MPH...4 KM/H
MINIMUM CENTRAL PRESSURE...978 MB...28.88 INCHES

NHC advisory 14
It's still too early to predict the exact impact Ophelia will have on Ireland, but it's important to at least be aware of the potential danger.
For those interested in the way the US National Hurricane Centre deals with uncertainty in their track forecast cone

Ophelia Water vapour image. Yellow is drier air.

cherryghost · 12-10-2017 4:18pm

FORECAST POSITIONS AND MAX WINDS

INIT 12/0900Z 30.3N 35.6W 75 KT 85 MPH
12H 12/1800Z 30.7N 35.2W 80 KT 90 MPH
24H 13/0600Z 31.3N 34.0W 80 KT 90 MPH
36H 13/1800Z 32.2N 32.0W 75 KT 85 MPH
48H 14/0600Z 33.7N 28.6W 75 KT 85 MPH
72H 15/0600Z 38.5N 20.5W 75 KT 85 MPH
96H 16/0600Z 49.0N 13.5W 70 KT 80 MPH...POST-TROP/EXTRATROP
120H 17/0600Z 59.0N 7.0W 55 KT 65 MPH...POST-TROP/EXTRATROP

Gaoth Laidir · 12-10-2017 4:32pm

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

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