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Storm Lorenzo: October 3/4 2019 **Technical Discussion Only**

  • 26-09-2019 11:12pm
    Registered Users Posts: 1,472 ✭✭✭

    Starting a new thread on what is a tropical Hurricane Lorenzo which is in the middle of the Atlantic Ocean south of the Azores. More details can be found in the Hurricane season Thread. I am giving Lorenzo it's own thread because at present models are bringing the Storm towards Ireland. Models at present are keeping out to sea with only minimal impact on Ireland at the moment. The latest model run are bringing the storm a bit closer to the west coast. If the storm in it’s extra tropical state should have a direct hit on Ireland it could generate wind gusts of over 160 Kmh. The storm is due nearest us next Thursday or Friday.

    Mod Note:This thread is going to get very busy over the coming days and we would ask posters to adhere to the forum charter. Most importantly keep it civil and friendly. There will be no time for messing and it is imperative that the thread is not dragged off topic.



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

    The rapid intensification this morning happened just as it was passing into an area of very low wind shear (5 knots), as seen in this sequence of images from 00Z, 06Z and 12Z (far right, east of 40W, south of 20N). It's since been passing into that area of slightly higher shear, and the SHIPS model has it up to 20-25 knots late tomorrow.

    The latest forecast track has storm intensity around 90 knots at 18Z on the 1st, about 300 NM southwest of the Azores. Looks like a direct hit for them a few days later but most likely in a much-weakened state by then.





  • Registered Users Posts: 14,245 ✭✭✭✭M.T. Cranium

    Even with the weakening it would still be in the cat-2 range possibly, or higher end cat-1 when passing through the Azores. Latest GFS has its centre coming no closer to Ireland than 22 deg W and I would estimate peak gusts on west coast around 60-70 km/hr if the current maps verified. But there would likely be some large swells and surfers might be getting excited by the prospects of this outcome. Still plenty of time for this to veer off the predicted track though.

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

    Two recon aircraft are due to leave Barbados for Lorenzo in a few hours.


  • Registered Users Posts: 2,873 ✭✭✭JanuarySnowstor

    Icon gives a direct hit with Ireland. Ecm much closer to us also than gfs

  • Registered Users Posts: 2,873 ✭✭✭JanuarySnowstor

    Actually ECM IS A DIRECT HIT ALSO! !

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  • Registered Users Posts: 1,472 ✭✭✭Jpmarn

    Just looking at the gfs on As Lorenzo approach our part of the Atlantic Ocean it is going to break up partially during its extra tropical transformation. It's energy is going to spawn some secondary storm depressions giving a relatively high risk of stormy weather over the next 2 weeks or so.

  • Registered Users Posts: 15,944 ✭✭✭✭Villain

    The ECMWF track has been moving it further East, last 5 runs here.


  • Closed Accounts Posts: 1,220 ✭✭✭Davaeo09

    Been living on Sherkin for the summer and planning on moving back to Kilkenny this coming week.

    Had planned on 2 trips up and back to get all my stuff across on the ferry.
    If those latest models come through i will be rethinking my plans incase of ferry cancelation :(

  • Registered Users Posts: 32,634 ✭✭✭✭Graces7

    Davaeo09 wrote: »
    Been living on Sherkin for the summer and planning on moving back to Kilkenny this coming week.

    Had planned on 2 trips up and back to get all my stuff across on the ferry.
    If those latest models come through i will be rethinking my plans incase of ferry cancelation :(

    Wise idea anyways as equinoctial gales cause havoc. I am well stocked here so whatever happens, no worries. Just got more supplies in .

    west mayo offshore island

  • Moderators, Computer Games Moderators Posts: 15,223 Mod ✭✭✭✭FutureGuy

    How does this compare to the last hurricane that came our way.

    It's nuts that we are even using the words "hurricane", "Ireland" and "again" in same sentences.

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  • Registered Users Posts: 6,814 ✭✭✭pauldry

    I think this storm will miss to our West but in the days after id be concerned that it may drag up further distubances of heavy rain and strong winds.

    However with a washout of August, wet September and wet start of October we must be due a dry month soon.

    On graphs on Met Eireann rainfall seems to equalize itself over the course of the year

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

    Just the usual disclaimer that this will not be a hurricane at our latitude, but may have hurricane-force winds.

    The ECMWF ensembles show that slight shift eastwards in the 00Z run versus yesterday's 12Z. The majority still offshore but some creaping eastwards and also to Iberia. Still no real change in net intensity at our latitude.



    This morning's SHIPS LGEM has it at around 70 knots on reaching the Azores, with shear at 42 knots and increasing at that stage.

  • Registered Users Posts: 1,472 ✭✭✭Jpmarn

    Looking at Atlantic charts and it shows Lorenzo affecting southern counties in the early hours of next Friday morning. But it looks a bit weaker and would generate no more than Status Yellow warning winds according to the present chart.

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

    Thar he blows


  • Registered Users Posts: 15,944 ✭✭✭✭Villain

    A thing of beauty!


  • Registered Users Posts: 4,139 ✭✭✭PokeHerKing

    Absolute Unit!

  • Registered Users Posts: 32,634 ✭✭✭✭Graces7

    Villain wrote: »
    A thing of beauty!

    Gives me the creeps and the heebie jeebies and I am not easily scared. shudders

  • Registered Users Posts: 80 ✭✭octsol

    What are the chances this storm will hit the south west of ireland

  • Registered Users Posts: 18,065 ✭✭✭✭JCX BXC

    octsol wrote: »
    What are the chances this storm will hit the south west of ireland


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

    Latest tracks and intensity. Intensity is fairly tightly clustered around a Cat 1 at T +120 hrs, which is around the time it reaches the Azores, but there is a few hours timing difference between the models.



    The 12Z SHIPS LGEM has it at 63 knots at that stage and weakening, with 48 knots of shear, moving at 25 knots over SSTs of 21 °C.


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  • Moderators, Science, Health & Environment Moderators Posts: 11,738 Mod ✭✭✭✭Meteorite58

    From the Met Office :

    Hurricane Lorenzo is the strongest hurricane on record to exist this far east in the Atlantic (Category 4, 145 mph). Whilst it is set to weaken to some extent before reaching the Azores, hurricane force winds and heavy rain are likely for these mid-Atlantic Portuguese islands.


    Tropical Tidbits


  • Registered Users Posts: 6,235 ✭✭✭Oneiric 3

    This might look a bit trippy but a good comparison between the 12z runs of yesterday and the 0z runs of this morning regarding forecast track of this storm from both the GFS and the ECMWF:

    GFS: 12z (yesterday) vs 00z:


    ECMWF 12z (yesterday) vs 00z:


    All over the gaff, not only between the two models, but between different runs of the same model.

    New Moon

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

    Comparison of ICON output for both Lorenzo and Ophelia. At the moment Ophelia is the big sister.



    Ophelia 2017


  • Registered Users Posts: 23,299 ✭✭✭✭



  • Moderators, Science, Health & Environment Moderators Posts: 11,738 Mod ✭✭✭✭Meteorite58

    ECM 12Z rolling out and quite similar to the last run if bringing the remnants of Lorenzo a bit closer to the South of Ireland. Still the strongest winds offshore on this run .

    Note showing 850 hPa winds below ( roughly a height of 1.5 km's )




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

    A huge difference between the various models' pressure and wind analyses of Lorenzo at 12Z today. These are not forecasts, they're the actual initial starting conditions for the 12Z runs. The GFS is different to all the rest, but it may be closer to reality, as the microwave scans showed no real deep convection in that southwestern quadrant. The latest scan at 6 pm shows that the eyewall has actually dismantled further (bottom image, deep red colour) but a second one may be replacing it (to the south).





  • Registered Users Posts: 6,814 ✭✭✭pauldry

    Will definitely be a windy few days at the end of next week.

    Too far away to determine whether it will be fierce but its interesting

  • Moderators, Science, Health & Environment Moderators Posts: 11,738 Mod ✭✭✭✭Meteorite58

    NHC mentons that Lorenzo has being passing over a slightly cooler surface temperature and is forecast to reach warmer water in 12- 24 hrs. After that, it stays over sea surface temperatures near 28C through about 72 h.

    Mentions will be going through various eye wall replacement cycles.

    NHC 'After 72 h,the cyclone will become embedded in the mid-latitude westerlies and
    move over much colder water. This, and the approach of the
    aforementioned deep-layer trough, will lead to extratropical
    transition that will be underway, but likely not complete, by 120 h.'

    UKM0 12Z +144 more to the SW/ W of Ireland on the latest run, filling on its approach.


  • Moderators, Science, Health & Environment Moderators Posts: 11,738 Mod ✭✭✭✭Meteorite58

    I think with the remnants of Lorenzo entering the fray next week and bringing up so much energy with it that it has the possibility of interacting with other areas of LP's as shown in the GFS 12Z and could be seeing quite an unsettled period around next weekend.

    GFS not far off the UKMO and closer now to the ECM track than other runs but showing it stronger than the other models with a center pressure of around 930 hPa which is very much at odds with the ECM and UKMO.



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

    This microwave scan just in shows that eyewall replacement cycle well underway. We might see a slight weakened intensity in the 10 pm discussion.