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Hurricane Ophelia


Wannabehippie

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

National Weather Warnings

 

STATUS RED

Wind Warning for Galway, Mayo, Clare, Cork and Kerry

Ex-hurricane Ophelia is expected to bring severe winds and stormy conditions on Monday. Mean wind speeds in excess of 80 km/h and gusts in excess of 130km/h are expected, potentially causing structural damage and disruption, with dangerous marine conditions due to high seas and potential flooding.

Issued:
Saturday 14 October 2017 12:00
Valid:
Monday 16 October 2017 09:00 to Tuesday 17 October 2017 03:00
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6 hours ago, Windspeed said:

Ophelia has been putting on a show this morning. I am in awe at the appearance of this hurricane considering its location. The northern semicircle is pushing nearly -70° C cloudtops right now with a clear and stable eye. Just insane...

4d48ac01b3af3b44821620b7cf6b85ca.jpg03d4f718f64a6ae5a6c8043aafe13cb6.jpg

Sweet momma....Like someone just poured a bunch of steroids into the Atlantic this season! How does this happen that far east? Lol Now, regardless, will this still be considered "extra tropical" if the winds stay at Cat 1 or more when it makes landfall?

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1 hour ago, Amped said:

It was supposed to weaken, guess not. Luckily this isn't hitting France or Spain.  It does havesome time to weaken before Ireland.

Yeah this would be a huge problem if it was going to track into the Iberian peninsula. Likely could still be tropical and quite strong in an area that is not equipped to handle it 

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This has the structure of a 110 kt hurricane. Convection is not going to reach -80° C like you see at lower latitudes in tropical cyclones and mesoscale convective complexes due to 300-200 mb pressure heights and tropopause. You have to realize that what you are seeing out of Ophelia is the absolute maximum efficiency in thermodynamics for the atmosphere and sea surface temperatures at work here. Post analysis should be fun.cc1e9cc4e946b277668c12926c9f661c.jpg

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3 minutes ago, Windspeed said:

This has the structure of a 110 kt hurricane. Convection is not going to reach -80° C like you see at lower latitudes in tropical cyclones and mesoscale convective complexes due to 300-200 mb pressure heights and tropopause. You have to realize that what you are seeing out of Ophelia is the absolute maximum efficiency in thermodynamics for the atmosphere and sea surface temperatures at work here. Post analysis should be fun.cc1e9cc4e946b277668c12926c9f661c.jpg

I think the fact that it is in the entrance region to a jet streak off to it's NE is doing it a lot of favors and allowing it to reach this intensity. Pretty much evacuating all the outflow this storm is generating on the north side.

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I think the fact that it is in the entrance region to a jet streak off to it's NE is doing it a lot of favors and allowing it to reach this intensity. Pretty much evacuating all the outflow this storm is generating on the north side.
Absolutely. Just like Charley. Ophelia is positioned in the right front entrance region of a strong mid-latitudinal trough. The dynamics involved here are mass evacuation to the north at height while the entire steering column from 900 to 400 mb has the same general vector of motion. Therefore, low shear even at rapid motion, amazing divergence aloft. Obviously the 2-3° C cooler tropospheric mean is helping to get the maximum latent heat vaporization out of 24-25° C SSTs to sustain Ophelia's eyewall. Pretty incredible meteorological phenomenon to see even if it can be explained scientifically.

 

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14 minutes ago, Windspeed said:

Absolutely. Just like Charley. Ophelia is positioned in the right front entrance region of a strong mid-latitudinal trough. The dynamics involved here are mass evacuation to the north at height while the entire steering column from 900 to 400 mb has the same general vector of motion. Therefore, low shear even at rapid motion, amazing divergence aloft. Obviously the 2-3° C cooler tropospheric mean is helping to get the maximum latent heat vaporization out of 24-25° C SSTs to sustain Ophelia's eyewall. Pretty incredible meteorological phenomenon to see even if it can be explained scientifically.

 

Yeah this is the second storm to have a 20mph+ movement with virtually no shear,  very well aligned flow.   EPAC storms never have this kind of tropospheric instability, 25.9C ssts, and the EPAC TC kill switch usually engages.

I can't wait to see what funny name the Irish/British tabloids come up with for this, they are usually pretty funny.

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51 minutes ago, Amped said:

Yeah this is the second storm to have a 20mph+ movement with virtually no shear,  very well aligned flow.   EPAC storms never have this kind of tropospheric instability, 25.9C ssts, and the EPAC TC kill switch usually engages.

Timing is also critical. I suspect you are referring to Nate. Nate had higher SSTs to work with, warmer troposphere and colder convective tops, but there are some other big differences. Ophelia has greater divergence aloft and the hurricane already had a well-established core vortex before gaining rapid forward motion and, as such, has had significantly less problems with its opposing cyclonic flow competing against the strong mid-level steering column driving it at 25 mph. It's worth noting that Nate took a long time to seperate from the larger surface gyre it was imbedded within. Had Nate been able to establish its core vortex faster, its western semicircle may have faired better and it may have been able to reach major hurricane intensity as well. Too much competition with competing mesos within its core versus a more developed eyewall in storms like Alex (2004) and Charley that were also rapidly moving systems. But it's speculation at this point. Trough interaction is tricky business besides. Ophelia just happened upon a perfect atmospheric setup. Perhaps forward motion and radial heat flux in tropical cyclones could make a terrific thesis for some grad student down the road.

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I keep instinctively waiting for Ophelia to fall apart as if she were about to drive over the edge of a cliff with the hammer down. With all that has been discussed, it is still insane seeing a hurricane look so well-organized and intense passing by the freaking Azores!

 

A few hours ago, I thought: This structure will probably degrade before the NHC can increase the intensity further. It has to be on the brink of weakening, no? Ophelia is not showing any of those signs yet.

 

The NHC probably will bump up the intensity on the 5 PM advisory to reflect the overall spread in satellite estimated guidance. I'm going to say 110 kts / 125 mph.

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7 minutes ago, Windspeed said:

I keep instinctively waiting for Ophelia to fall apart as if she were about to drive over the edge of a cliff with the hammer down. With all that has been discussed, it is still insane seeing a hurricane look so well-organized and intense passing by the freaking Azores!

 

A few hours ago, I thought: This structure will probably degrade before the NHC can increase the intensity further. It has to be on the brink of weakening, no? Ophelia is not showing any of those signs yet.

 

The NHC probably will bump up the intensity on the 5 PM advisory to reflect the overall spread in satellite estimated guidance. I'm going to say 110 kts / 125 mph.

Nope NHC being conservative. Still 100 kts.

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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.


Well there is the professional reasoning in bold. Hard to argue that that. Still an impressive major hurricane.
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SAB at 1745 was still 5.5 / 100 kts so even with TAFB and ADT a spread wouldn't have yielded 110 kt. 105 kts would have been more accurate. But the NHC analysis was solid. The look of a hurricane on satellite can be deceiving and I got excited. I will be absolutely shocked out of my mind if Ophelia is able to hold on to current structure through the 11 pm advisory. It's likely running out of time. Even if it is stronger than 100 kts, I doubt it ever will be officially.

We still have the fascinating next stage to watch: baroclinic forcing and warm seclusion. How deep can Ophelia's surface vortex drop? GFS has shown as low as the lower 940s on some runs. The ECMWF hasn't shown much deeper beyond what the tropical warm core has already attained IRL.

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Don't think Ireland sees forecasts like this very often.

Sunday night will continue cloudy with patchy rain in the early night. The rain will become heavier overnight, especially over the southern half of the country. Northeasterly winds will strengthen in the south towards morning. Lowest temperatures of 9 to 12 degrees.

Monday: On Monday stormy conditions are expected to develop especially in southern and western areas. Current indications suggest that Ex Hurricane Ophelia will track northwards close to the west coast of Ireland, bringing storm force winds, heavy possibly thundery rain and very high Seas during Monday and Monday night to southern and western coastal counties especially. Some flooding is likely due to heavy rainfall and very high seas.
The storm will move away to the north later Monday night. 

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Imagine it doesn't turn north... shows that a major hurricane hit of Portugal is possible 

 

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Even with Ophelia's perfect environment for sustaining eyewall convection, there is still a threshhold in which to adhere. Yes, the lower tropospheric mean temperature and higher divergence aloft has aided in the impressive presentation today. But I am not willing to concede the possibility of a major hurricane hitting the Iberian Peninsula. The Portugal Current is just way too cold. Even in this unique set of circumstances, the above normal 20-22° SSTs that extend hundreds of miles west of Portugal are not going to cut it. You again would need a rapid baroclinic warm seclusion extra tropical system to get hurricane force impacts. Perhaps a strong tilted trough to get the transitioning cyclone to the Portuguese coast fast enough without fully occluding. But the cyclone is not going to be a purely tropical hurricane at that point. If it is purely tropical, it is going to be a weaker tropical storm without the warm seclusion. Just my opinion. Perhaps someone else would like to weigh in..
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