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

24567…89

Comments

  • #32
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,813 Mod ✭✭✭✭Meteorite58


    From the NHC

    DISCUSSION AND 48-HOUR OUTLOOK
    At 500 PM AST (2100 UTC), the center of Hurricane Ophelia was
    located near latitude 30.0 North, longitude 36.1 West. Ophelia is
    moving toward the east near 3 mph (6 km/h). A slow northeast drift
    is expected tonight and tomorrow, followed by an acceleration
    toward the east-northeast or northeast.

    Maximum sustained winds are near 75 mph (120 km/h) with higher
    gusts. Some strengthening is possible over the next 48 hours.

    Hurricane-force winds extend outward up to 25 miles (35 km) from the
    center and tropical-storm-force winds extend outward up to 70 miles
    (110 km).

    The estimated minimum central pressure is 990 mb (29.24 inches).



    https://twitter.com/convectivewx/status/918226602198265861


    https://twitter.com/MattHugo81/status/918198033480912898


  • #33
    Floki
    Closed Accounts Posts: 951 ✭✭✭Floki


    Oscar Bravo wrote: »
    Also coming up on 30 years since this

    That storm was the 16th October 1987.
    Our storm forecast for the 16th October 2017.

    30 year anniversary.
    Happy anniversary everyone!


  • #34
    star gazer
    Moderators, Society & Culture Moderators Posts: 1,706 Mod ✭✭✭✭star gazer


    Hurricane Ophelia:
    vis0.gif

    Minimum central pressure 990mb, max sustained winds 120km/h and moving East at 6km/h. 1,200km South West of the Azores.

    NHC Discussion
    Since it isn't clear exactly how strong Ophelia is, the intensity
    forecast is low confidence. All of the intensity guidance indicates
    that strengthening is likely for the next 24 to 36 hours, however
    the near stationary motion of the hurricane could induce some
    upwelling and limit the extent to which the hurricane may
    strengthen. Around 72 hours, the shear should begin to increase
    substantially as Ophelia begins to interact with the approaching
    trough, and extratropical transition will likely begin, accompanied
    by a broadening of the wind field and a gradual decrease of the
    maximum winds. The global models indicate that this process will
    complete by 96 h. The new NHC intensity forecast is slightly higher
    than the previous forecast, but lies on the lower end of the
    intensity guidance for the first 72 h. It is near the consensus
    aids thereafter.


  • #35
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,813 Mod ✭✭✭✭Meteorite58


    I think we are all a bit skeptical of getting extreme weather in Ireland but this seems to be shaping up to be the real thing. Track will be everything. When you have the NHC / NOAA putting out guidance like above it is definitely time to sit up and take notice.

    mNPEOE9.png?1


  • #36
    [Deleted User]
    Posts: 0 ✭ [Deleted User]


    18Z GFS.

    gfs-0-120_tgt9.png

    gfs-0-126_ywm5.png


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  • #37
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,813 Mod ✭✭✭✭Meteorite58


    xbshZOO.png?1

    E42g5Ct.jpg?1


  • #38
    sdanseo
    Registered Users Posts: 9,233 ✭✭✭sdanseo


    It's almost as if all the models have gone and asked the NHC what they think.


  • #39
    server down
    Closed Accounts Posts: 1,613 ✭✭✭server down


    Is this storm considered to be ex hurricane on Sunday merely because it has left the tropics, or because it will weaken, or do other factors come into play?

    Could it have hurricane speed winds?


  • #40
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,813 Mod ✭✭✭✭Meteorite58


    This is interesting as ex Tropical Ophelia phases with the trough on Sun evening


    https://twitter.com/RyanMaue/status/918234156743712768

    https://twitter.com/RyanMaue/status/918235494533746689

    fYGKoJI.gif?1


    meD6qBp.gif?1


    LXfaKqD.png


    WwGyAMw.png


  • #41
    fraxinus1
    Closed Accounts Posts: 240 ✭✭fraxinus1


    This is worrying. If this materialises then we need to prepare for major damage and fatalities. I'm cancelling a drive to Galway planned for early next week and getting in supplies as power will be lost. I'm warning folk.


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  • #42
    tomcosgrave
    Registered Users Posts: 320 ✭✭tomcosgrave


    Have to say I'm sceptical. Have been looking at this system since it formed and especially since it started to head east - firstly it was aimed at North Africa. Then Spain. Then France yesterday. Now Ireland. My guess is the models will update and it will head towards Iceland and will miss Ireland.


  • #43
    Donegal Storm
    Registered Users Posts: 2,023 ✭✭✭Donegal Storm


    fraxinus1 wrote: »
    This is worrying. If this materialises then we need to prepare for major damage and fatalities. I'm cancelling a drive to Galway planned for early next week and getting in supplies as power will be lost. I'm warning folk.

    It's still nearly 5 days away, no point cancelling anything yet, theres every chance it'll just end up a typical windy day


  • #44
    George Sunsnow
    Closed Accounts Posts: 2,043 ✭✭✭George Sunsnow


    server down wrote: »
    Is this storm considered to be ex hurricane on Sunday merely because it has left the tropics, or because it will weaken, or do other factors come into play?

    Could it have hurricane speed winds?

    Yes it could have hurricane aka force 12 speeds
    Whether they’re in Ireland or not is debatable but looking likely


  • #45
    Oscar Bravo
    Registered Users Posts: 10,059 ✭✭✭✭Oscar Bravo


    Joanna donnelly on Radio 1 just now saying that more or less its been hyped in the media and that it will more than likely just a wet and windy episode however they will be keeping an eye on it. she perhaps should of said nout until a day or two more passes.


  • #46
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,813 Mod ✭✭✭✭Meteorite58


    Met Eireann remaining calm : Current indications suggest a stormy day for Monday is possible, but uncertainty on the detail remains, due to the nature of the track of the Atlantic storm system. The situation will be monitored throughout the weekend but at the moment it looks like it will be a windy day with further spells of rain.

    The GFS showing weaker winds than the ECMWF, usually the other way round.


  • #47
    squarecircles
    Registered Users Posts: 1,981 ✭✭✭squarecircles


    Oscar Bravo wrote: »
    Joanna donnelly on Radio 1 just now saying that more or less its been hyped in the media and that it will more than likely just a wet and windy episode however they will be keeping an eye on it. she perhaps should of said nout until a day or two more passes.

    Isn't that her style generally, blaze,about this kind of stuff.


  • #48
    Meteorite58
    Moderators, Science, Health & Environment Moderators Posts: 11,813 Mod ✭✭✭✭Meteorite58


    For the record, can see how the ECM is showing much stronger winds.

    Yr0MXYG.png?1

    niZdddm.png?1


    Note 850hPa winds

    VKUz9rF.jpg?1


  • #49
    M.T. Cranium
    Registered Users Posts: 14,325 ✭✭✭✭M.T. Cranium


    Ophelia looks better organized and it may be as strong as 80-90 knots (next update due around 0400h). I don't mean to imply this would lead to a stronger low near Ireland, the ECM has pretty much maxed out that potential.

    Latest position about 30.0 N and 35.6 W.


  • #50
    George Sunsnow
    Closed Accounts Posts: 2,043 ✭✭✭George Sunsnow


    M.T. Cranium wrote: »
    Ophelia looks better organized and it may be as strong as 80-90 knots (next update due around 0400h). I don't mean to imply this would lead to a stronger low near Ireland, the ECM has pretty much maxed out that potential.

    Latest position about 30.0 N and 35.6 W.
    I presume MT that the NHC doesn’t overfly hurricanes this Far East or on this kind of track,so we’ll be without their handy eye data?


  • #51
    M.T. Cranium
    Registered Users Posts: 14,325 ✭✭✭✭M.T. Cranium


    They mentioned not flying into this storm earlier today, but their satellite techniques should be fairly reliable, maybe the UK or France could get their hands on a dropsonde and get a reading on Saturday. If the ECM is right there's an ocean buoy in its path for Sunday night's readings.

    The 1987 under-prediction (for England) was mostly due to the failure of forecasting models to pick up on the rapid deepening, you can see from Michael Fish's 24-48h maps that the wave was expected to deepen gradually as it crossed England but instead it bombed out in the first six hours and reached the eventual forecast central pressure somewhere near Coventry instead of Bergen. That made all the difference.

    With this one, we're in the opposite situation, how long will this low retain a deep central pressure that we should know within 5 mbs by Saturday.


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  • #52
    Itssoeasy
    Registered Users Posts: 39,437 ✭✭✭✭Itssoeasy


    squarecircles wrote: »
    Oscar Bravo wrote: »
    Joanna donnelly on Radio 1 just now saying that more or less its been hyped in the media and that it will more than likely just a wet and windy episode however they will be keeping an eye on it. she perhaps should of said nout until a day or two more passes.

    Isn't that her style generally, blaze,about this kind of stuff.
    Also how many wet and windy episodes have ever been given a track by the NHC ? I mean MT from what I can see doesn't hype things.


  • #53
    Kermit.de.frog
    Registered Users Posts: 23,442 ✭✭✭✭Kermit.de.frog


    024405_5day_cone_no_line_and_wind.png


    Yes, this is a hurricane chart. Who'd have thunk it?


  • #54
    M.T. Cranium
    Registered Users Posts: 14,325 ✭✭✭✭M.T. Cranium


    The 00z GFS has a very intense low just a little further west than the 12z run, but a respected forecaster once mentioned that the better comparison at this time scale is from the previous 00z run to this one, and on that comparison there is not much of a shift. The strongest winds would be out to sea but still a level one or perhaps two impact on land from this version.

    The 00z GEM made a slight shift west as well and is also similar to the track it had 24 hours ago (eastern Ireland, but not a very strong storm left at that point).

    The 00z Arpege has shifted east of any of its earlier output and is also a bit weaker than before, once again, would suggest a level one to two event up through the central counties.

    Now waiting for the 00z ECM to update.

    Ophelia has been spinning her wheels out to the southwest of the Azores, for about six hours there was almost no forward progress, but this was anticipated and a very slow eastward drift has resumed with hints of a northward component (30.1 N 35.2 W last time I looked at the satellite imagery). It's a strong cat-1 or perhaps a weak cat-2 now, NHC is frank about having an approximate estimate from satellite presentation.

    Still thinking that we won't have a lot of clarity on this outcome until Friday afternoon at the earliest and perhaps Saturday morning. Once Ophelia accelerates and makes a northeast move we should have a better idea.


  • #55
    Kermit.de.frog
    Registered Users Posts: 23,442 ✭✭✭✭Kermit.de.frog


    Remember this.

    Unbelievable.


    DL6Zwk0VQAAFqmv.jpg:medium

    That is a hurricane chart showing landfall in Ireland.

    Could conceivably be at or near Cat 1 - would be historic and hugely damaging near the center.

    I see some UK weather watchers are seriously considering making the trip to the south coast just to see it make landfall! (if it does of course!)


  • #56
    mirrorwall14
    Closed Accounts Posts: 6,751 ✭✭✭mirrorwall14


    Yes! Distraction from the joys of trying to conceive. Love the weather :). Looking forward to all the updates and thanks in advance to all the weather posters for sharing their knowledge

    I’m thinking it would be prudent to start the garden toys clear up for the winter and to pick up a torch (we don’t have one)


  • #57
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Currently 75 knots and moving slowly over increasingly colder waters. The NHC chart shows it as a hurricane strength extratropical low (white icon) as opposed to a proper hurricane (black icon) south of Ireland, and as storm force over Ireland. 55 knots by Monday evening. Kermit's chart doesn't show a hurricane landfall either.

    This is similar to Debbie in 1961, which had already become extratropical well before Ireland but its lightning fast forward speed (~60 kph) is what brought those strong winds. Ophelia won't be moving quite as fast (~35-40 kph) but this foward speed is what will increase the winds felt at the surface.

    Still a lot of uncertainty at this stage and a lot depends on what happens in the next 2 days as it sits over cold waters.

    430373.png

    2017AL17_OHCNFCST_201710120000.GIF


  • #58
    Kermit.de.frog
    Registered Users Posts: 23,442 ✭✭✭✭Kermit.de.frog


    Gaoth Laidir wrote: »
    55 knots by Monday evening. Kermit's chart doesn't show a hurricane landfall either.

    Never said it did. But it could make landfall with or near Cat 1 winds near the center.


  • #59
    Gaoth Laidir
    Registered Users Posts: 8,219 ✭✭✭Gaoth Laidir


    Kermit.de.frog wrote: »
    Never said it did. But it could make landfall with or near Cat 1 winds near the center.

    I know, I was just clarifying the difference between the two types structures-wise.

    Latest intensity guidance. Official forecast (red) is at the bottom of the consensus. Certainly hurricane gusts possible come Monday but I can't see hurricane-force sustained.

    aal17_2017101200_intensity_early.png


  • #60
    fraxinus1
    Closed Accounts Posts: 240 ✭✭fraxinus1


    Joanne Donnelly being very blasé about this potential storm. I hope she isn't about to have her Michael Fish moment.


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  • #61
    Reckless Abandonment
    Registered Users Posts: 1,492 ✭✭✭Reckless Abandonment


    fraxinus1 wrote: »
    Joanne Donnelly being very blasé about this potential storm. I hope she isn't about to have her Michael Fish moment.
    Way to early to be calling anything . Personally I'll only get excited if it's showing this strength on Sat afternoon. Even Met can wait till Then before warnings are needed . Then I'll start thinking a road trip


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