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Old October 10th 17, 07:28 AM posted to uk.sci.weather
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Default TS Ophelia

Looks like an interesting 30th birthday, for the 1987 Great Storm of
15/16 Oct, with TS/TD Ophelia taking the role , along the same track,
where's Michael Fish when you need him.
All the global met models agree she will at least get to Portugal.
This is the latest National Huricane Centre assessment


000
WTNT42 KNHC 100252
TCDAT2

Tropical Storm Ophelia Discussion Number 4
NWS National Hurricane Center Miami FL AL172017
1100 PM AST Mon Oct 09 2017

Ophelia's center is just south of a broad curved band of deep
convection. At synoptic time, the subjective Dvorak
classifications from TAFB and SAB were both at 2.5, or 35 kt, while
the CIMSS SATCON was at 43 kt. Given the increasingly curved
structure of the bands during the last couple of hours, the initial
intensity is set at 45 kt, a bit higher than the previous advisory.

While the tropical storm is fighting some moderate vertical shear
currently, the global models suggest that this should lighten some
between now and about day 4 as Ophelia resides between the
mid-latitude and subtropical westerlies. Even though the system
will be traversing cool 26C SSTs, upper-tropospheric temperatures
likely will also be cool, allowing for deep convection to continue.
The mid-level moisture analyzed in the SHIPS guidance appears to be
somewhat dry, though the total precipitable water imagery shows
distinct moistening near the system during the last couple of days.
The official intensity forecast shows gradual intensification
through day 3, then slow weakening thereafter. This is close to a
blend of the LGEM statistical guidance and the HWRF dynamical model
and is slightly above that of the previous advisory.

The initial position has fairly small uncertainty as the
low-level center is along the southern edge of the deep
convection, as seen in the GOES-16 shortwave infrared imagery.
Ophelia is moving toward the northeast at about 6 kt - somewhat
unexpectedly - this evening. Despite this, the model guidance
suggests that a ridge will soon build in strongly north of Ophelia
and force the tropical storm to the southeast and then south
during the next couple of days. Around day 3, Ophelia should get
kicked out toward the east-northeast by an approaching trough in the
mid-latitude westerlies. The official track forecast is north of
the previous forecast in the short term and east-northeast in the
long term, and is in between the HFIP Corrected Consensus Approach
(HCCA) and the previous forecast.

The initial tropical-storm-force wind radii was adjusted outward
based upon a 2137Z AMSU size analysis. The official size forecast
is based upon the RVCN consensus technique.

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Old October 11th 17, 07:13 AM posted to uk.sci.weather
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Default TS Ophelia

On 10/10/2017 08:28, N_Cook wrote:
Looks like an interesting 30th birthday, for the 1987 Great Storm of
15/16 Oct, with TS/TD Ophelia taking the role , along the same track,
where's Michael Fish when you need him.
All the global met models agree she will at least get to Portugal.
This is the latest National Huricane Centre assessment


000
WTNT42 KNHC 100252
TCDAT2

Tropical Storm Ophelia Discussion Number 4
NWS National Hurricane Center Miami FL AL172017
1100 PM AST Mon Oct 09 2017

Ophelia's center is just south of a broad curved band of deep
convection. At synoptic time, the subjective Dvorak
classifications from TAFB and SAB were both at 2.5, or 35 kt, while
the CIMSS SATCON was at 43 kt. Given the increasingly curved
structure of the bands during the last couple of hours, the initial
intensity is set at 45 kt, a bit higher than the previous advisory.

While the tropical storm is fighting some moderate vertical shear
currently, the global models suggest that this should lighten some
between now and about day 4 as Ophelia resides between the
mid-latitude and subtropical westerlies. Even though the system
will be traversing cool 26C SSTs, upper-tropospheric temperatures
likely will also be cool, allowing for deep convection to continue.
The mid-level moisture analyzed in the SHIPS guidance appears to be
somewhat dry, though the total precipitable water imagery shows
distinct moistening near the system during the last couple of days.
The official intensity forecast shows gradual intensification
through day 3, then slow weakening thereafter. This is close to a
blend of the LGEM statistical guidance and the HWRF dynamical model
and is slightly above that of the previous advisory.

The initial position has fairly small uncertainty as the
low-level center is along the southern edge of the deep
convection, as seen in the GOES-16 shortwave infrared imagery.
Ophelia is moving toward the northeast at about 6 kt - somewhat
unexpectedly - this evening. Despite this, the model guidance
suggests that a ridge will soon build in strongly north of Ophelia
and force the tropical storm to the southeast and then south
during the next couple of days. Around day 3, Ophelia should get
kicked out toward the east-northeast by an approaching trough in the
mid-latitude westerlies. The official track forecast is north of
the previous forecast in the short term and east-northeast in the
long term, and is in between the HFIP Corrected Consensus Approach
(HCCA) and the previous forecast.

The initial tropical-storm-force wind radii was adjusted outward
based upon a 2137Z AMSU size analysis. The official size forecast
is based upon the RVCN consensus technique.


So NHC has it up to a huricane tomorrow and
96H 15/0000Z 35.7N 23.2W 70 KT 80 MPH
120H 16/0000Z 41.0N 14.0W 65 KT 75 MPH
So 75mph to within 10 degrees lat and long of the UK.
GFS has sustained 65mph gusting to over 90mph winds for the Channel
Approaches, oo-er.

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Old October 11th 17, 08:11 AM posted to uk.sci.weather
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Default TS Ophelia

SNIP

So NHC has it up to a huricane tomorrow and
96H 15/0000Z 35.7N 23.2W 70 KT 80 MPH
120H 16/0000Z 41.0N 14.0W 65 KT 75 MPH
So 75mph to within 10 degrees lat and long of the UK.
GFS has sustained 65mph gusting to over 90mph winds for the Channel
Approaches, oo-er.


I'm beginning to think your latest dire warning might be onto something this time, if only for Cornwall & western Ireland (going by GFS & ECMWF) .

I'm not sure that 90mph gusts in the SW approaches are that rare, there were certainly a few 90mph gusts at Gwennap Head when I lived on the cliff top at Sennen (Talking of which I've just come across this https://geographic.org/global_weathe...060_99999.html though the decimal points are in the wrong place ) Certainly 80mph gusts at JCs Lands End site are far from rare, and that would indicate 90mph over the open sea.

THowever there is a brief period of very big waves forecast, in the 25-30' range at Sevenstones with a 15sec period. Certainly big but unexceptional, and with a low degree of certainty.

Time will tell.

Graham
Penzance
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Old October 11th 17, 08:20 AM posted to uk.sci.weather
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Default TS Ophelia

On 11/10/2017 09:11, Graham Easterling wrote:
SNIP

So NHC has it up to a huricane tomorrow and
96H 15/0000Z 35.7N 23.2W 70 KT 80 MPH
120H 16/0000Z 41.0N 14.0W 65 KT 75 MPH
So 75mph to within 10 degrees lat and long of the UK.
GFS has sustained 65mph gusting to over 90mph winds for the Channel
Approaches, oo-er.


I'm beginning to think your latest dire warning might be onto something this time, if only for Cornwall & western Ireland (going by GFS & ECMWF) .

I'm not sure that 90mph gusts in the SW approaches are that rare, there were certainly a few 90mph gusts at Gwennap Head when I lived on the cliff top at Sennen (Talking of which I've just come across this https://geographic.org/global_weathe...060_99999.html though the decimal points are in the wrong place ) Certainly 80mph gusts at JCs Lands End site are far from rare, and that would indicate 90mph over the open sea.

THowever there is a brief period of very big waves forecast, in the 25-30' range at Sevenstones with a 15sec period. Certainly big but unexceptional, and with a low degree of certainty.

Time will tell.

Graham
Penzance


Strange to see the Daily Excess under-playing Hurricane Ophelia. They
have some weird input to their WWW weather section, saying it is going
overland at Portugal. Any old bod on usw could do better than whoever it
is on their deask.
All the global met models, currently have it going through Biscay and
centre going just to the west of Ireland.
As a large change from the concensus yesterday, I wonder what the 30th
anniversary of the 1987 Great Felling will have for mainland UK
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Old October 11th 17, 01:35 PM posted to uk.sci.weather
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Default TS Ophelia

How come nothing in the proper media about this looming hurricane ?
or at least hurricane force winds
http://www.nhc.noaa.gov/graphics_at2...?cone#contents
They must have a long memory
"a woman rang the BBC and said she had heard that there was a
hurricane on the way. Well if you are watching, don't worry there isn't"



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Old October 11th 17, 01:59 PM posted to uk.sci.weather
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Default TS Ophelia

On 11/10/17 14:35, N_Cook wrote:
How come nothing in the proper media about this looming hurricane ?
or at least hurricane force winds


Perhaps because the UK will miss the strong winds? Strong winds from
Ophelia are forecast to graze Eire on Monday but the strongest winds
won't hit UK until Tuesday and Wednesday when the decaying Ophelia will
be near Iceland.



--
Graham P Davis, Bracknell, Berks. [Retd meteorologist/programmer]
Web-site: http://www.scarlet-jade.com/
“Like sewage, smartphones, and Donald Trump, some things are just
inevitable.” [The Doctor]



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Old October 11th 17, 02:38 PM posted to uk.sci.weather
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Default TS Ophelia

On 11/10/2017 14:59, Graham P Davis wrote:
On 11/10/17 14:35, N_Cook wrote:
How come nothing in the proper media about this looming hurricane ?
or at least hurricane force winds


Perhaps because the UK will miss the strong winds? Strong winds from
Ophelia are forecast to graze Eire on Monday but the strongest winds
won't hit UK until Tuesday and Wednesday when the decaying Ophelia will
be near Iceland.




I thought part of the problem with Hurricanes, is the difficulty in
predicting their meandering tracks. So powerful , they influence the
Jetstream, which then influences this that and the other.
Wasn't that why the NHC was set up , as global met models did not work
well predicting hurricane tracks.
I would not like to say that this expected hurricane was going to to
stick to the current concensus of the global models, relatively safely
to the west of Ireland.
Or, for that matter, the NHC could be well outside its comfort zone,
this side of the Atlantic.
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Old October 11th 17, 03:04 PM posted to uk.sci.weather
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Default TS Ophelia

It's still 5-6 days out from any potential UK impact isn't it (assuming no
sudden speed-up in track)? So presumably all the usual health-warnings that
far out still apply, whether or not it achieves hurricane status near its
present position. Interesting that the absence of hurricane-hunter
lights - unsurprising perhaps given how far east of the US it is - seems to
be hampering the interpretation and forecasting by the NHC a little.

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Old October 11th 17, 03:16 PM posted to uk.sci.weather
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Default TS Ophelia

'lights' = flights of course.
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Old October 11th 17, 03:46 PM posted to uk.sci.weather
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Default TS Ophelia

On 11/10/2017 16:04, JohnD wrote:
It's still 5-6 days out from any potential UK impact isn't it (assuming
no sudden speed-up in track)? So presumably all the usual
health-warnings that far out still apply, whether or not it achieves
hurricane status near its present position. Interesting that the absence
of hurricane-hunter lights - unsurprising perhaps given how far east of
the US it is - seems to be hampering the interpretation and forecasting
by the NHC a little.


Not just the numerical model being outside its compfort zone.
I suppose those USA craft and pilots are the only ones who could go near
, let alone through, hurricanes.
I doubt these people
http://www.faam.ac.uk/
could go anywhere near


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