Jump to content

  • Member Statistics

    17,506
    Total Members
    7,904
    Most Online
    SnowHabit
    Newest Member
    SnowHabit
    Joined

Hurricane Ophelia

Wannabehippie

By Wannabehippie,
in Tropical Headquarters

Recommended Posts

  • Replies 121
  • Created
  • Last Reply
Windspeed

Windspeed

Posted
Posted

Still classified a tropical hurricane per NHC with the presence of core convection over the surface vortex. Ophelia is transitioning rapidly though and probably will be a Post-Tropical Hurricane by 11 PM AST.

We're a little more than 14-16 hrs from landfall based on forward motion. Looks like a pretty hard hit for southern Ireland, especially the SE coast. The Irish Sea may have the strongest winds as pressure gradient increases away from the center with strong southerly low-level flow at the surface. The Isle of Man will be just a bit breezy tomorrow. Probably not a good day for motorcycling.

FORECAST POSITIONS AND MAX WINDS

INIT 15/2100Z 44.6N 13.3W 75 KT 85 MPH

12H 16/0600Z 49.2N 11.3W 70 KT 80 MPH...POST-TROP/EXTRATROP

24H 16/1800Z 54.3N 7.5W 55 KT 65 MPH...POST-TROP/EXTRATROP

36H 17/0600Z 58.5N 2.0W 40 KT 45 MPH...POST-TROP/EXTRATROP

48H 17/1800Z...DISSIPATED

Quote
Ophelia's cloud structure is declining rapidly, and microwave and shortwave IR imagery indicate that the low-level and mid-level centers are becoming separated. However, some deep convection is still present near Ophelia's center, and an SSMIS pass from 1827 UTC indicated that the hurricane still has an inner core that is separated from a front to the north and west. The estimated maximum winds have been decreased slightly to 75 kt given the overall decay of the cloud structure. However, the cyclone's favorable position relative to an upper-level jet streak is likely contributing to deepening of the low as the wind field expands substantially. Only a slight decrease in the maximum winds is therefore expected before the post-tropical cyclone reaches Ireland. After that time, interaction with land while the cyclone occludes should cause it to weaken more rapidly. Around 48 h, the cyclone's circulation is likely to become ill-defined and dissipate near the western coast of Scandinavia.
Link to comment
Share on other sites
bluewave

bluewave

Posted
Posted

http://www.estofex.org/

A mesoscale discussion was issued for parts of the NE-Atlantic Ocean mainly for extreme wind gusts.

This off-topic MD highlights a non-convective but very dangerous setup over offshore areas of the NE-Atlantic Ocean. The cloud pattern of category-1 hurricane "Ophelia" detoriates rapidly but still indicates a better organized core with weakening convective banding (supporting the idea of and ongoing but tilting deep warm-core structure). Extratropical transformation however is imminent and a vigorous post-tropical depression is forecast during the end of the forecast (and onwards).
Latest WV loops (comparison of two WV channels) show a broadening/lowering and rapidly warming tongue of dry low-stratospheric air to the west of "Ophelia", and this surge is about to approach the southern part of the cyclone's center. Combined with favorable upper dynamics (as described in the extended forecast), another deepening phase is anticipated during the MD forecast period.

Overall synoptic conditions for a potential sting jet or major cold-conveyor belt (CCB) jet event seem to be in place, also supported by numerous fine-mesh models and even global models. Near BL flow exceeds 50-65 m/s in numerical guidance just south of the cyclone's center with a speed maximum near/just below 850 hPa. It's speculative to try to forecast the BL thermal stratifiaction in such an environment (and offshore), but given this wind speed magnitude, gusts in excess of 150 km/h are likely with some models indicating gusts in excess of 180 km/h. The core of the strongest winds will be narrow and probably short-lived compared to the MD's validity, but due to subtle model discrepancies (timing and placement of the cyclone, its deepening rate and transformation into a warm seclusion), a rather broad MD was issued. Convection should not play any role for this event. The most extreme winds should weaken during the end of the MD but intense CCB jet winds approach S-Ireland later-on from the S.

 

Link to comment
Share on other sites
KPITSnow

KPITSnow

Posted
Posted

I'm saving a couple of the graphics just because I don't really think we see this again anytime soon, where we have a storm still classified as tropical off the Iberian peninsula.

Honestlu too it looks like it is still holding onto a small center of convection, so still looks at least to be holding onto some tropical characteristics. 

 

Still just really impressive to watch and definitely one of the most unusual places I have seen a tropical system.

Link to comment
Share on other sites
Windspeed

Windspeed

Posted
Posted

Ophelia's broadening surface vortex is moving faster than the forecast points. This thing has gained forward motion and is screaming N faster than 35 kts. The mid-level vortex looks to have finally seperated as well. I think Ophelia will definitely be classified a PT Hurricane on the 11 PM AST. But just going on satellite plots from the past three hours, the LLC is going to landfall on the left of the forecast cone. Perhaps even left of guidance further up the western coast.

4dd9083e3ed63f5fdbb0b1f543aada71.jpg

Link to comment
Share on other sites
Windspeed

Windspeed

Posted
Posted

Ophelia's strong southerly surface flow combined with negligible precipitation over Portugal and NW Spain created a horrible high wind environment for flaring up and expanding ongoing wildfires. Pretty dramatic images coming out of that region of the Iberian Peninsula tonight.

 

http://observador.pt/2017/10/16/as-fotografias-brutais-do-dia-com-mais-incendios-do-ano/

Link to comment
Share on other sites
Windspeed

Windspeed

Posted
Posted

Ophelia has completed extra-tropical transition and as such, the NHC has issued their final advisory. For posterity...


ZCZC MIATCDAT2 ALL
TTAA00 KNHC DDHHMM

Post-Tropical Cyclone Ophelia Discussion Number 28
NWS National Hurricane Center Miami FL AL172017
1100 PM AST Sun Oct 15 2017

Within just the past six hours, the last bit of deep convection near Ophelia's center has been sheared off well to the north, and the cyclone has acquired a definitive extratropical structure. Ophelia has completed its transition to an occluded low, with an attached warm front extending northeastward across Ireland and a cold front draped southeastward toward Spain and Portugal. The powerful cyclone continues to produce hurricane-force winds, with recent ASCAT data showing wind vectors as high as 70 kt to the east of the center. Based on these data, the initial intensity remains 75 kt to account for undersampling. The occluded low is forecast to gradually fill and weaken during the next couple of days, and it is likely to dissipate near the western coast of Norway by 48 hours. Despite the expected weakening, the post-tropical cyclone is still likely to bring hurricane-force winds, especially in gusts, to portions of western Ireland on Monday.

Ophelia has accelerated and retrograded slightly during the past 6-12 hours during the occlusion process, and the long-term motion estimate is northward, or 010/38 kt. Now that occlusion is complete, the post-tropical cyclone should resume a north- northeastward motion, with some decrease in forward speed, within the next 12 hours. That heading should continue for the ensuing day or two, bringing the center of the cyclone near the western coast of Ireland on Monday and then near northern Scotland Monday night. The dynamical track models remain in good agreement on this scenario, and the updated NHC forecast is not too different from the previous one.

This is the last advisory issued by the National Hurricane Center now that Ophelia has become post-tropical. Local forecasts, warnings, and other communications regarding the post-tropical cyclone that are pertinent to Ireland and the United Kingdom will continue to be available from Met Eireann and the UK Met Office.

KEY MESSAGES:

1. Ophelia will remain a powerful extratropical cyclone with hurricane-force winds while it moves near Ireland and the United Kingdom Monday and Monday night. Strong winds and heavy rain are likely in portions of these areas, 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.

2. Individuals are urged to not focus on the exact track of Ophelia since strong winds and heavy rainfall will extend well outside of the NHC forecast cone.

FORECAST POSITIONS AND MAX WINDS
INIT 16/0300Z 49.2N 13.3W 75 KT 85 MPH...POST-TROP/EXTRATROP
12H 16/1200Z 53.2N 10.1W 65 KT 75 MPH...POST-TROP/EXTRATROP
24H 17/0000Z 57.4N 5.9W 50 KT 60 MPH...POST-TROP/EXTRATROP
36H 17/1200Z 61.9N 0.1W 40 KT 45 MPH...POST-TROP/EXTRATROP
48H 18/0000Z...DISSIPATED

$$
Forecaster Berg

NNNN
Link to comment
Share on other sites
donsutherland1

donsutherland1

Posted
Posted

At 5 am, now post-tropical Hurrican Ophelia was centered near 51.3°N 11.4°W. Ophelia still had a large area of 75-knot (85 mph) winds as it headed north-northeast and was poised to turn somewhat more to the northeast toward Ireland.

At 6 am, Cork Airport was reporting sustained winds of 41 knots (47 mph) with gusts to 67 knots (77 mph). Roches Point had sustained winds of 50 knots (58 mph) with gusts to 70 knots (81 mph). 

Based on the EPS, ECWMF, and GEFS, later today, Ophelia will likely pass near or over the Beara and Dingle Peninsulas and then likely somewhere between Clifden and Galway as it tracks northeastward. Ophelia should remain at hurricane strength as it passes over those areas.
 

Link to comment
Share on other sites
klw

klw

Posted
Posted

  1. Avg Wind:67kts, Gust:84kts, Wind Dir:257 °(W), Gust Dir:254 °(W) at 16/10/2017 13:26:00

     
  2.  

    Avg Wind:70kts, Gust:86kts, Wind Dir:258 °(W), Gust Dir:247 °(SW) at 16/10/2017 13:02:00

     
  3.  

    Avg Wind:72kts, Gust:87kts, Wind Dir:249 °(W), Gust Dir:242 °(SW) at 16/10/2017 12:44:00

     
  4.  

    Avg Wind:80kts, Gust:102kts, Wind Dir:235 °(SW), Gust Dir:237 °(SW) at 16/10/2017 12:26:00

     
  5.  

    Avg Wind:79kts, Gust:100kts, Wind Dir:230 °(SW), Gust Dir:228 °(SW) at 16/10/2017 12:08:00

     
  6.  

    Avg Wind:82kts, Gust:101kts, Wind Dir:220 °(SW), Gust Dir:222 °(SW) at 16/10/2017 11:50:00

     
  7.  

    Avg Wind:75kts, Gust:95kts, Wind Dir:210 °(SW), Gust Dir:215 °(SW) at 16/10/2017 11:32:00

     
  8.  

    Avg Wind:76kts, Gust:102kts, Wind Dir:194 °(S), Gust Dir:183 °(S) at 16/10/2017 11:08:00

Link to comment
Share on other sites
CheeselandSkies

CheeselandSkies

Posted
Posted

I wonder if Ireland will request retirement of Ophelia? Obviously it remains to be seen exactly how much damage it will do but I think this is one of those situations where it will do a lot more cumulative damage to Ireland than, for example, Nate did at its U.S. landfall despite having similar advisory reported MSW.

At landfall, it was similar in structure to past strong extratropical cyclones that have affected the area, but like Sandy was still close enough after transition that its true hurricane phase was still fresh in everyone's mind. Was Sandy retired on its U.S. impacts as a post-tropical cyclone or would its impacts on Cuba and other islands have been enough on their own?

If Ireland does request retirement, it would be an exceptionally rare case for (a) impacts on the east side of the Atlantic and (b) impacts that occurred after extratropical transition.

Link to comment
Share on other sites

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.
×
×
  • Create New...