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

star gazer

Hurricane Ophelia Discussion Number 23
NWS National Hurricane Center Miami FL AL172017
500 PM AST Sat Oct 14 2017

Ophelia continues to have an impressive appearance in satellite
imagery. The eye has remained clear all afternoon, surrounded by a
very symmetric ring of cold cloud tops. Since the cloud pattern has
not changed significantly over the past few hours, the intensity has
been held at 100 kt. Microwave imagery and scatterometer retrievals
indicate that beneath the cold canopy, Ophelia's structure is
beginning to deteriorate, at least slightly. A GMI overpass around
1700 UTC indicated that the vortex is beginning to tilt toward the
east with height, probably a result of increasing southwesterly
shear associated with a large upper-level trough to the west.
Furthermore, a pair of earlier ASCAT passes suggested that an
approaching cold front is already infringing on the NW quadrant of
the circulation, within about 80 n mi of Ophelia's eye. Given the
close proximity of the cold front and upper-level trough,
extratropical transition will likely begin within about 12 hours. A
favorable baroclinic environment may allow the cyclone to deepen as
the wind field increases in size, so only a slight decrease of the
maximum wind is expected through 36 hours. After that time, the
post-tropical cyclone will likely occlude and interact with land,
causing a faster rate of weakening and resulting in the eventual
dissipation of the surface circulation in about 96 hours.

Ophelia continues to pick up forward speed and the initial motion
estimate is now 055/24 kt. The hurricane remains embedded within
the southwesterly flow ahead of the aforementioned mid-latitude
trough, and this will keep Ophelia on a northeast or north-northeast
heading through the next 72 hours. The track guidance remains in
fairly good agreement, though it has shifted southward a little for
the first 24 hours. The new NHC track forecast has been adjusted in
that direction, and is close to the GFS/ECMWF consensus throughout
the forecast period.

Although the center of Ophelia is not forecast to reach Ireland or
the UK until Monday, wind and rains will arrive well in advance of
the cyclone center. Individuals in those locations should consult
products from their local meteorological service for more
information on local impacts.

Tropical-storm-force winds are possible throughout the Azores
after Ophelia passes to the south and east tonight as a cold front
moves through 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 be a powerful extratropical cyclone with
hurricane force winds Monday while it moves near Ireland and the
United Kingdom. Direct impacts from wind and heavy rain in portions
of these areas are likely, along with dangerous marine conditions.
For more details on the magnitude, timing, and location of impacts
from post-tropical Ophelia, residents in 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 14/2100Z 35.9N 23.7W 100 KT 115 MPH
12H 15/0600Z 38.0N 20.0W 95 KT 110 MPH
24H 15/1800Z 42.8N 15.3W 85 KT 100 MPH
36H 16/0600Z 48.8N 12.3W 75 KT 85 MPH...POST-TROP/EXTRATROP
48H 16/1800Z 54.0N 9.3W 60 KT 70 MPH...POST-TROP/EXTRATROP
72H 17/1800Z 59.5N 3.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
96H 18/1800Z...DISSIPATED

$$
Forecaster Zelinsky

Discussion 23

piplip87

Bloomberg reporting that this storm could have damages of 600 Million Dollars.

https://www.bloomberg.com/news/articles/2017-10-14/hurricane-ophelia-set-to-pick-up-speed-as-it-heads-for-ireland

Gaoth Laidir

For all those bitching about who's getting what colour warning, it is coming into the time frame of the hi-res models. We have already seen a HiRLAM chart posted earlier and tomorrow tonight they will have the Harmonie output too. It is then that they can home in on the finer detail. Until then they are not in a position to go red on anywhere other than where they've already gone, which was based on the ECMWF output.

As for those bitching about RTE, get a life.

ingalway

adox wrote: »

Weather on RTE finished with the line " we have got something to look forward to on Monday" :eek:

I think this will be Joanna's Michael Fish moment...

star gazer

Still on track



50 Knot:

Paully D

In the south-east and really not looking forward to the damage this is going to bring.

Trying to warn people about the seriousness of what's on the way as per latest models and it is being laughed off by almost all. :rolleyes:

sword1

Is that a bit further west than earlier?

Gaoth Laidir

star gazer wrote: »

Discussion 23

A slight downgrade in language in that discussion. Confirmed the erosion of the western eye. 60 knots at 54N (around Mayo), which is about 55 knots in old money. Storm 10 to violent storm force 11 possible early on in the south and southwest, but weakening all the while.

h7nlrp2v0g5u48

sjb25 wrote: »

Yeah do we really need a reporter standing on the coast of Kerry somewhere telling us the same thing hour by hour

Surely RTE wouln'd send Teresa out into a storm of this magnatitue or would they?

sword1

A tv coverage thread would be an idea

Red Nissan

My daughter is named Ophelia, my storm chasing anemometer is rusted solid, by storm chasing vehicle has flat tyres, but i'm in Cork, so m

uck51js9zml2yt

Cushtie wrote: »

I have a mobile on a site on Dingle Penninsula. It survived Darwin in 2014. Not so sure this time......

Potential for firewood.

UsBus

First time in ages a proper weather storm might hit us and the rte weather girl has a complete brain fart today both at 6.00 and 9.00 o'clock weather report.
She'll be on the Saturday evening graveyard shift for a while yet. ....

mirrorwall14

Can anyone summarize the important roll out of modeling results times tonight Irish time and tomorrow. I’m an insomniac but I try and steer clear of the phone. I may break that rule tonight....

I used to be more familiar with them but I confess to not following the weather forum as much since I had the toddler!

Lissavane

yr.no have updated their forecast and I don't see anything too scarey there.

floorpie

Is this bad enough to not bother going into work in Dublin city on Monday? I presume I wont blow away but, how do the roads from the city typically cope after events like this? Floods, fallen trees...?

uck51js9zml2yt

Agustin Limited Hatchet wrote: »

Surely RTE wouln'd send Teresa out into a storm of this magnatitue or would they?

She might talk it into submission

TheMilkyPirate

"A favorable baroclinic environment may allow the cyclone to deepen as
the wind field increases in size, so only a slight decrease of the
maximum wind is expected through 36 hours."

Not expecting it to weaken much if at all before it reaches Ireland judging by that snippet.

sword1

mirrorwall14 wrote: »

Can anyone summarize the important roll out of modeling results times tonight Irish time and tomorrow. I’m an insomniac but I try and steer clear of the phone. I may break that rule tonight....

I used to be more familiar with them but I confess to not following the weather forum as much since I had the toddler!

It's for Monday, hopefully it will be downgraded tomorrow

Romantic Rose

This is so nerve wrecking!

Gaoth Laidir

Looking forward to readings from Sherkin Island and Roches Point. Also, could have anomalously high Föhn readings from Valentia. Later on, Mace Head and Belmullet will be interesting.

marno21

Gaoth Laidir wrote: »

Looking forward to readings from Sherkin Island and Roches Point. Also, could have anomalously high Föhn readings from Valentia. Later on, Mace Head and Belmullet will be interesting.

Kinsale Energy readings on Monday morning will be quite interesting too.

Lissavane

UsBus wrote: »

First time in ages a proper weather storm might hit us and the rte weather girl has a complete brain fart today both at 6.00 and 9.00 o'clock weather report.
She'll be on the Saturday evening graveyard shift for a while yet. ....

I don't think she's an "RTE weather girl". AFAIK she's a Met Éireann meteorologist.

Red Nissan

TheMilkyPirate wrote: »

"A favorable baroclinic environment may allow the cyclone to deepen as
the wind field increases in size, so only a slight decrease of the
maximum wind is expected through 36 hours."

Not expecting it to weaken much if at all before it reaches Ireland judging by that snippet.

Yup, except its got too strong, it'll as likely just fall apart in two hours as its engine stalls/ ?

mirrorwall14

sword1 wrote: »

It's for Monday, hopefully it will be downgraded tomorrow

I know it’s for Monday? I also know that models roll out overnight and I’m wondering what times so I can check them since I’ll likely be awake anyways. I knew all the times way back in the big freeze but I’ve forgotten

Jpmarn

Just to remind you tha NHC has advised us to pay attention to Met Eireann or if you living in the U.K. Their Met Office. A lot of you were posting models from French and German weather sites which seems to give good guidance. Is Ophelia going to affect France or Germany?

Pangea

Cannon_fodder wrote: »

Nervous, she is bloody woeful on delivery of what could be a seismic event. I do wonder what Met Eireann are at sometimes, the quality of delivery varies so much from presenter to presenter

Steady on, She's actually a meteorologist, at least knows what she's talking about more than someone who is just reading the script.

clawback07

ingalway wrote: »

I think this will be Joanna's Michael Fish moment...

Just two points ; one , she has not given an inaccurate forecast . She has delivered the forecast as she should ,and as all the previous excellent posts and models are forecasts and nobody can accurately predict a final outcome to all this .Mr fishs' disaster should not be compared to a cautious forecasters' report .
Two, I lived in Ballyshannon in 1961 as a kid and to this day I can see the slates coming off the roofs of houses across the river Erne and coming through our windows nearly a quarter of a mile away , and in the aftermath dead crows stuck in the branches of the tress that withstood the force of the winds of Debbie .

Lumi

UsBus wrote: »

First time in ages a proper weather storm might hit us and the rte weather girl has a complete brain fart today both at 6.00 and 9.00 o'clock weather report.
She'll be on the Saturday evening graveyard shift for a while yet. ....

Mod Note

Can we focus on the discussing Weather and the Storm Potential & cut out the personal attacks on RTÉ and it’s Weather presenters please
Thanks!

Gaoth Laidir

marno21 wrote: »

Kinsale Energy readings on Monday morning will be quite interesting too.

But the anemometer there is I think over 100 metres above the sea so really not of any use.