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

Meteorite58

The ICON ( German model ) I have noticed that this can overestimate a tad higher then other models, to pay attention to nonetheless.

Meteorite58

The ARPEGE track of potential Max winds ( still about 80 hrs away so open to change )

Beechwoodspark

Gerald Fleming of Met Eireann has just been on RTÉ radio. He said that there's still a chance that the winds miss landfall.

JCX BXC

Beechwoodspark wrote: »

Gerald Fleming of Met Eireann has just been on RTÉ radio. He said that there's still a chance that the winds miss landfall.

That's looking less and less likely however, I'd think they're just trying to ensure that the forecasts are as severe as they look at the moment in a more reliable time frame before issuing severe warnings.

Meteorite58

Arpege Mean Wind Speeds










Gust Speeds

Meteorite58

Worth reading from the NHC

000
WTNT42 KNHC 130250
TCDAT2

Hurricane Ophelia Discussion Number 16
NWS National Hurricane Center Miami FL AL172017
1100 PM AST Thu Oct 12 2017

Remarkably, the hurricane has continued to strengthen this evening.
Satellite images indicate that cloud tops in the eyewall have cooled
in the past several hours, with a warm eye remaining. Dvorak
estimates from TAFB, SAB and CIMSS range between 90 to 95 kt, so the
initial intensity is raised to 90 kt.

It seems that the marginal SSTs that Ophelia has been moving over
have been offset by the cold upper-level temperatures and low shear
environment. SSTs only slightly cool in the next 24 hours with
similar shear conditions, so a minor decrease in strength is in the
forecast. After that time, while the hurricane should move over
colder waters, it will likely be accelerating to the northeast and
experiencing favorable mid-latitude jet dynamics, which will help to
maintain the cyclone's intensity. All of the guidance show
extratropical transition by 3 days with the cyclone keeping
hurricane-force winds, as indicated in the new forecast. Little
change was made to the previous prediction, except to account for
the higher initial wind speed.

Ophelia is finally moving, estimated at 6 kt to the east-northeast.
This general motion with an increase in forward speed is expected
for the next couple of days as the hurricane gets picked up by a
large mid-latitude trough. Confidence in the track forecast remains
fairly high for the first 72 h, although the spread increases after
that time. The GFS-based guidance generally then show a more
northward track to the west of Ireland then over the far North
Atlantic, while the UKMET/ECMWF show a track over Ireland and Great
Britain then eastward and dissipating over northern Europe.
The forecast is close to the consensus at long range, but some large
changes could be required for later forecasts.

While the NHC track keeps the center of Ophelia south and east
of the Azores, tropical-storm-force winds are possible throughout
the Azores by Saturday night due to an approaching front. In
addition, the wind field of Ophelia will likely expand as the
cyclone begins extratropical transition, and any deviation to the
left of the forecast track could bring stronger winds to the
islands. Interests in the Azores should refer to products issued by
the Azores Weather Forecast and Watch Center.

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 13/0300Z 30.7N 34.7W 90 KT 105 MPH
12H 13/1200Z 31.2N 33.5W 90 KT 105 MPH
24H 14/0000Z 32.2N 31.1W 85 KT 100 MPH
36H 14/1200Z 33.7N 27.5W 80 KT 90 MPH
48H 15/0000Z 36.0N 23.0W 80 KT 90 MPH
72H 16/0000Z 45.0N 14.5W 75 KT 85 MPH...POST-TROP/EXTRATROP
96H 17/0000Z 56.0N 7.0W 55 KT 65 MPH...POST-TROP/EXTRATROP
120H 18/0000Z 64.0N 0.5W 50 KT 60 MPH...POST-TROP/EXTRATROP

$$
Forecaster Blake

coillsaille

dacogawa wrote: »

And a huge thanks to M.T., Iancarr, Kermit, Gaoth and too many others to name on this forum for all their in depth information and opinions, it is priceless coming towards something like this (or it's a non event :rolleyes: ).

Stay safe!

Too many to mention but have to mention Meteorite who keeps up a constant supply of charts for us through the boring times and the exciting ones.

Meteorite58

https://twitter.com/RyanMaue/status/918724512169865216

Donegal Storm

Meteorite58 wrote: »

The ICON ( German model ) I have noticed that this can overestimate a tad higher then other models, to pay attention to nonetheless.

I recall a short but very intense storm a few years ago (Jan 2012 I think?) where none of the models were showing anything too severe except the German model, turned out to be hurricane force in Donegal with gusts above 90kts and fairly widespread damage so its definitely worth paying attention to their model

goat2

coillsaille wrote: »

Too many to mention but have to mention Meteorite who keeps up a constant supply of charts for us through the boring times and the exciting ones.

very much appreciate them, giving us the thumbs up, they save us untold damage, getting outside and putting garden furniture and plant pots as well as taking down tree limbs and topping to keep disaster as low as possible, thanks to all of ye great people

Donegal Storm

Wind forecast looks to be slightly down this morning overall, I'd say its more in line with a typical severe (1 in 5-10 year) storm now though a big difference between this hitting coastal Donegal and Mayo in mid winter compared to large swathes of the most populated parts of the country with trees still in leaf so still worrying times

magicbastarder

random aside, but interesting to note that at least one map includes county lines for ireland, but not the UK?

SEPT 23 1989

My main concern is the strength of the unregulated cr@p that was thrown up during the celtic tiger

littlema

I'm offski to buy in candles for the 2 houses I have to manage (!) and muchos bottles of water....high ridge here in S Sligo always gets a battering so we have had a gennie for years.

jamo2oo9

Correct me if I'm wrong but from looking at the gifs of the models on previous page, the storm is to dissipate completely on Monday night, Tuesday morning?

We're due to fly out on Tuesday afternoon and I'm hoping this won't affect us as bad as it seems to be on this thread.

Reckless Abandonment

jamo2oo9 wrote: »

Correct me if I'm wrong but from looking at the gifs of the models on previous page, the storm is to dissipate completely on Monday night, Tuesday morning?

We're due to fly out on Tuesday afternoon and I'm hoping this won't affect us as bad as it seems to be on this thread.

It will be gone by tuesday. Airports should be back to normal by then.

Coax

Hi Guys & Girls,

Many thanks for all the knowledge and information that's being shared on this thread.

As an avid weather watcher and lover of extreme weather and being well experienced in travelling and working outdoors in storm conditions even I'm dubious about wanting this one...

In general its probably too late for any decent preparations to lessen structural damage in certain situations e.g. already damaged farm buildings etc (I still observe many damaged sheds etc...), trees in need of attention etc, however stowing the garden furniture, trampoline, bins and anything else that can easily be moved by a person on their own is a must.

Consider moving any vehicles where possible away from debris fall zones e.g. tiles slates from roofs, fence panels etc...Top up fuel tank.

Remember that in the event of structural damage to the building or home a person is in, along with the probable loss of electricity that a vehicle with a few essential supplies onboard can provide refuge, heat, a means of charging a mobile phone (networks may go down due to site and infrastructure damage and exhaustion of generators or batteries), car radio (a means of obtaining information from local and national radio stations, RTE Radio 1 is the method that the government will use to keep the population informed during times of emergency).

A few simple common sense precautions are wise.

Obviously don't travel during the peak winds or immediate aftermath. Your first responsibility is to look after yourself. If you become a casualty or person in need of urgent assistance then that's a further burden on emergency services.

With the weekend approaching I've heard little in the way of planning in general for this potential event which strikes me as virtually criminal. There is no harm in preparing for the worst and hoping for the best.

The schools in my area haven't uttered a word yet and I'll be in contact this morning with the principal of the school which my kids attend as three years ago parents were summoned to collect their kids during the height of the wind. There were trees down and more falling at this time in West Limerick, bringing people out onto the roads was a potentially disastrous situation. If the situation unfolds in a negative way in line with the various forecasts I'll be making a decision to keep the kids at home that day.

Anyhow, all the updates from those with the knowledge of forecasting is highly appreciated as are the responses and banter from all the participants.

As ye've probably gathered, I'm not a newbie here. It's been close on 18 months since I've posted and have not recovered my login details so I re-registered.

__..__

Reckless Abandonment wrote: »

It will be gone by tuesday. Airports should be back to normal by then.

Isn't there high wind forcast for Thursday or Friday to effect flights too though. Hope it doesn't effect you coming back.

munsterlegend

Still a lot of uncertainty as to exact track and a small movement can have a huge impact for a country our size.

At least over the weekend most people get a chance to move any items outside to safety.

Meteorite58

Still a spread in the tracks but bginning to narrow

Colser

Could someone compare this storm to Darwin (could it be as bad or worse)?

Great thread as always,thanks to all the usual posters.

Drumpot

Great thread , really helpful and thanks to posters. I’ve passed a link to this
Thread to anybody I can.

Meteorite58

Good site here for quick access to key information.

http://www.convectiveweather.co.uk/HurricaneLive.php?Wallet=2

Coax

Colser wrote: »

Could someone compare this storm to Darwin (could it be as bad or worse)?

It all depends on the track and where you're located.

It could potentially be as bad or worse subject the the above.

Best advice is prepare for the worst, hope for the best. Keep an eye on the thread, heed any Met Eireann weather warnings or advisories and take appropriate action.

average_runner

Before this thread goes haywire about a non-event, I just want to say thanks for all the information.

Making people aware of this is more important than a non event if it is one.

Thanks.

star gazer

NHC 17 advisory

...OPHELIA MOVING FASTER TOWARD THE EAST-NORTHEAST...


SUMMARY OF 500 AM AST...0900 UTC...INFORMATION

---

LOCATION...31.1N 33.9W
ABOUT 615 MI...995 KM SW OF THE AZORES
MAXIMUM SUSTAINED WINDS...105 MPH...165 KM/H
PRESENT MOVEMENT...ENE OR 70 DEGREES AT 8 MPH...13 KM/H
MINIMUM CENTRAL PRESSURE...970 MB...28.65 INCHES

INIT 13/0900Z 31.1N 33.9W 90 KT 105 MPH
12H 13/1800Z 31.8N 32.5W 85 KT 100 MPH
24H 14/0600Z 33.1N 29.7W 85 KT 100 MPH
36H 14/1800Z 35.0N 25.5W 80 KT 90 MPH
48H 15/0600Z 37.9N 20.8W 80 KT 90 MPH
72H 16/0600Z 47.9N 13.7W 75 KT 85 MPH...POST-TROP/EXTRATROP
96H 17/0600Z 57.5N 6.0W 50 KT 60 MPH...POST-TROP/EXTRATROP
120H 18/0600Z...EAST OF THE PRIME MERIDIAN

Met Eireann 5 day Atlantic forecast.

sideswipe

A track that creates a storm surge onto the east coast could be disastrous for us here in Wicklow. Last few winter storms from that direction caused massive erosion along the coast from Wicklow town.

DominoDub

354 people in the Weather forum on a work day is it Snowing ?

snusie

165kmh winds? Is that a category 5?
Is this stronger than previously expected or on track with the forecast?

Reckless Abandonment

DominoDub wrote: »

354 people in the Weather forum on a work day is it Snowing ?

We've gone form lamppost watching to . Where is the lamppost