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Post Tropical Storm Helene 17/18 Sep 2018

  • 13-09-2018 5:16am
    #1
    Registered Users Posts: 21,818 ✭✭✭✭ Kermit.de.frog


    Expected to transition to a tropical storm soon from a hurricane.


    It would be worthwhile keeping an eye.

    Ex-Helene looks set to bring strong winds and heavy rain close to Ireland within 120 - 136 hrs after effecting the Azores as a tropical storm.

    023954_5day_cone_no_line_and_wind.png

    023954.png

    NHC discussion

    https://www.nhc.noaa.gov/text/refresh/MIATCDAT3+shtml/130238.shtml?


    MOD NOTE: Updated title and included a yellow warning at this stage. Can update title if needs be as forecasts become clearer.


«1345678

Comments

  • Registered Users Posts: 13,209 ✭✭✭✭ M.T. Cranium


    In fact, I suspect that if that output persisted to the next NHC update, they might consider keeping Helene closer to cat-1 hurricane past the Azores. The GFS depiction is the only one with damaging wind gust potential for Ireland, the track is broadly similar to Ophelia and timing of strongest winds is around 10 p.m. Monday to 0400h Tuesday from Munster into the southeast portions of Connacht. Isobars are packed and gusts could be as strong as 130 km/hr if these maps verified. Once again Cork appears to be in the crosshairs of this as yet hypothetical storm.

    At the moment, UKMO brings a significant wind potential from Helene about 24h later (Tuesday night into Wednesday morning), not quite as strong as the GFS. The GEM shows Helene dying gradually embedded in the southwest flow ahead of a distant northern low, and almost an extinct circulation crossing southern Britain by Tuesday. Waiting to see the ECM take in just less than an hour from now.

    Also the GFS has gusty winds by Thursday 20th from remnants of Florence which gets slowly captured over the lower Great Lakes around Monday and Tuesday then rockets eastward -- the isobars would suggest southwest gusts to about 110 km/hr.

    Apparently what has changed for the GFS is that new TS Joyce southwest of the Azores does little more than wave hello and goodbye to Helene and there's a bit of a slingshot effect near the end of the encounter during which Joyce ceases to exist, while Helene seems to deepen somewhat again.

    We must stress that in the absence of broader model consensus, the GFS is so far pretty much a lone wolf on this outcome with weak support from UKMO, not really enough to trigger a robust alert but more like notice of a watch situation.


  • Registered Users Posts: 10,347 ✭✭✭✭ MJohnston


    This seems a bit too early for a thread, especially as you were complaining about premature threads recently Kermit! Anyway...

    What I find interesting about the GFS is how for Florence, a lot of American sources are ignoring it and relying primarily on the ECM. I can't remember where I read it, but I do recall reading that the GFS doesn't include SSTs in its storm modelling - is that correct?


  • Registered Users Posts: 1,789 ✭✭✭ squarecircles


    The Midland Weather Channel has issued a severe weather warning as Hurricane Helene continues its track towards Ireland.

    Meteorologist Cathal Nolan told the Offaly Express, "having assessed the latest weather models and based on my own numerical calculations it looks increasingly likely that hurricane Helene will make landfall in Ireland at some point between 14:00 on Monday and 02:00 on Tuesday next."

    "Currently, Helene is 2000km southwest of the Azores and remains a category 1 hurricane, with sustained winds of 130kph and gusts in excess of 170 kph," he continued.

    The latest guidance suggests that the strongest winds will occur along the south and west coasts, where gusts could exceed 130-140 kph.

    "Overland gusts of between 110-120 are possible. The storm itself is still some time away and therefore it’s exact track and intensity remain difficult to pin down," Cathal explained.

    "Helene has taken a very similar track to that of Ophelia last year, which is extremely unusual for an Atlantic hurricane," Nolan told us.

    "My concern at present is that the storm could deepen during its approach to Ireland, transforming from a Post Tropical Cyclone into a very powerful Atlantic Storm, which would potentially increase the winds along the west and south coast given the storms angle and interaction with the jet stream," he concluded


  • Moderators, Technology & Internet Moderators Posts: 17,098 Mod ✭✭✭✭ cherryghost


    Nothing crying out for anything beyond Orange if models come good.


  • Registered Users Posts: 633 ✭✭✭ REBELSAFC


    Nothing crying out for anything beyond Orange if models come good.

    Agree. Early days but Helene doesn't look a patch on Ophelia......yet

    This was Ophelia at a similar timeframe to Helene now

    430432.jpg


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  • Registered Users Posts: 4,306 ✭✭✭ SleetAndSnow


    REBELSAFC wrote: »
    Agree. Early days but Helene doesn't look a patch on Ophelia......yet

    one to keep an eye on though. Ophelia was forecast to weaken a lot before hitting us, it didn't really (or well not as much as forecast). Infact it wasn't really known the strength until the day before because of the rarity of it happening.


  • Registered Users Posts: 30,532 ✭✭✭✭ Graces7


    Grateful for the updates and warnings. In the line of fire out here on the West Coast offshore island. Although Ophelia missed us very neatly as after Clare it turned east into the Midlands.


  • Registered Users Posts: 2,357 ✭✭✭ amandstu


    Is it beginning to feel as if these particular "hurricane" events are going to become regular (yearly?) and some of them may be even worse than Ophelia?


  • Registered Users Posts: 2,499 ✭✭✭ frash




  • Registered Users Posts: 6,447 ✭✭✭ pad199207


    Now downgraded to Tropical storm


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  • Registered Users Posts: 2,549 ✭✭✭ refusetolose




  • Moderators, Science, Health & Environment Moderators Posts: 10,466 Mod ✭✭✭✭ Meteorite58


    ECM and GFS tracking ex Helene more over the UK ( ECM trending this the last two runs ).

    A few wobbles on the track so this will take a few days to know for sure. On latest runs it looks quite windy but a much diminished system by the time it reaches our Islands.

    2tKPfRJ.gif


  • Registered Users Posts: 10,347 ✭✭✭✭ MJohnston


    It's crazy how knife edge this could be - while Helene is making its passage on Tuesday, there's a tremendous large low pressure system hanging around near Iceland that was heading our way. The interaction between it and Helene seems to actually keep us somewhat protected, but you could imagine a small shift either way being....exciting.


  • Moderators, Science, Health & Environment Moderators Posts: 10,466 Mod ✭✭✭✭ Meteorite58


    MJohnston wrote: »
    It's crazy how knife edge this could be - while Helene is making its passage on Tuesday, there's a tremendous large low pressure system hanging around near Iceland that was heading our way. The interaction between it and Helene seems to actually keep us somewhat protected, but you could imagine a small shift either way being....exciting.

    Yea that Low coupled with the Jet seems to be giving Ex Helena that gentle nudge over towards the UK.


    WvOmxCD.png


    tempresult_aas8.gif


  • Registered Users Posts: 746 ✭✭✭ GeneHunt


    A storm of any size next week could be very costly, as the National Ploughing Championships starts on Tuesday in Offaly (A Tented Village), with thousands expected to attend - could it be cancelled on safety concerns.


  • Banned (with Prison Access) Posts: 3,829 Cork Boy 53


    GeneHunt wrote: »
    A storm of any size next week could be very costly, as the National Ploughing Championships starts on Tuesday in Offaly (A Tented Village), with thousands expected to attend - could it be cancelled on safety concerns.

    I would imagine there would need to be at least an orange, more likely a red warning for that to happen. A case of wait and see I guess.


  • Registered Users Posts: 2,904 ✭✭✭ cian1500ww


    NHC 5pm update:

    vfRb3Qc.png


  • Registered Users Posts: 746 ✭✭✭ GeneHunt


    Sorry I didn't mean the whole show - All three days, but the first day cancelled. However the second day could be in jeopardy too. An Agricultural show in the UK last January (LAMMA) had to cancel it's second day on safety grounds following high winds overnight. This storm is still a long way off, it maybe even miss us (fingers crossed) but we need to keep an eye on it.


  • Registered Users Posts: 10,347 ✭✭✭✭ MJohnston


    cian1500ww wrote: »
    NHC 5pm update, the cone of uncertainty has widened:


    The cone is pretty much the same compared to the earlier NHC update, but the track is a little bit further east and a good bit later. Be interesting to see what happens if Helene delays long enough to escape the influence of that Iceland low - we could end up getting hit by the low and Helene in a 2 day period.


  • Registered Users Posts: 1,376 ✭✭✭ Reckless Abandonment


    GeneHunt wrote: »
    A storm of any size next week could be very costly, as the National Ploughing Championships starts on Tuesday in Offaly (A Tented Village), with thousands expected to attend - could it be cancelled on safety concerns.
    Farmers are Well used to bad weather. Would need to be very bad to cancel it. Would be a real shame after the summer we've had for a storm to wreck their big day out.


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  • Closed Accounts Posts: 18,277 ✭✭✭✭ Maximilian Muscular Supplies


    Farmers are Well used to bad weather. Would need to be very bad to cancel it. Would be a real shame after the summer we've had for a storm to wreck their big day out.

    They'll be grand. Sure haven't they been crying out for a bit of rain :D


  • Moderators, Science, Health & Environment Moderators Posts: 10,466 Mod ✭✭✭✭ Meteorite58


    Nice deep Low, moving along quickly. Track a bit closer to the SE, E coast on this run.

    tempresult_euw5.gif

    tempresult_xew6.gif


  • Registered Users Posts: 12,653 ✭✭✭✭ ninebeanrows


    Looks fairly nasty there. I think the timing is very uncertain yet as the system will move very erratically over the next 72 hours, I could easily see this being a Wednesday event.


  • Registered Users Posts: 10,347 ✭✭✭✭ MJohnston


    The Netweather GFS charts has the 3 hour frames in between the 6 hours on Meteociel, and it helps here because most of Ireland's impact from Helene will be in one of those missing frames:

    bpYLmaN.png

    That (as forecast) would be right up there in Red-level warning rainfall amounts for parts of the west.


  • Registered Users Posts: 10,347 ✭✭✭✭ MJohnston


    That Icelandic low swinging its tail around on Wednesday would also bring quite cool temperatures for the time of day (3pm here):

    ukmintemp.png


  • Moderators, Science, Health & Environment Moderators Posts: 10,466 Mod ✭✭✭✭ Meteorite58


    What is going on here. ICON 18Z has Ex Helene arriving Monday. Seems to have it whipped along by the Jet and re intensifies as it gets phased with the large Icelandic Low ? Can see pressure dropping as it gets closer to the SW.

    An Outlier or on to something ?

    4O9FvEt.png

    af90zKd.png


    YgP5koW.png

    bhIbUNc.png





    tempresult_xhh9.gif


  • Moderators, Science, Health & Environment Moderators Posts: 10,466 Mod ✭✭✭✭ Meteorite58


    ICON shifted the storm further E more in line with the ECM keeping the strongest winds off / along the E coast. GFS and WRF keeping strong winds with high gusts over Ireland.

    GFS brings it late Mon / early hours of Tues , ECM more towards 07.00 Tues.

    To Note very strong winds possible later Tues or Weds more so on Atlantic coastal counties .


  • Registered Users Posts: 3,994 ✭✭✭ giveitholly


    Will there be much rain associated with helene


  • Registered Users Posts: 2,545 ✭✭✭ hairyslug


    Can anyone tell me what I should be expecting for Wales early next week, am off camping.


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  • Registered Users Posts: 25,907 ✭✭✭✭ Wanderer78


    hairyslug wrote:
    Can anyone tell me what I should be expecting for Wales early next week, am off camping.


    I'd be keeping an extremely close eye on weather reports, particularly for the UK, and have alternative accommodation plans just encase


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