Thankfully by the time it is over the British Isles it’s central pressure is forecast to be around 996mb.
Plenty of rain and gusty winds will be still present.

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The ECM 00z run has the centre of the storm over the west of Ireland at 976hPa

https://weather.us/model-charts/euro/united-kingdom/sea-level-pressure/20191004-0000z.html 

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It astounds me this board is so quite. Its a fekking hurricane.. at the same latitude and perhaps 400 miles west of Liverpool.

A hurricane!?

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It astounds me this board is so quite. Its a fekking hurricane.. at the same latitude and perhaps 400 miles west of Liverpool.

A hurricane!?

I think that's called the calm before the storm, Russwirral.

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It astounds me this board is so quite. Its a fekking hurricane.. at the same latitude and perhaps 400 miles west of Liverpool.

A hurricane!?

No it wont be a hurricane, but a post tropical cyclone

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Quite a lot of high cloud now approaching from the South and West. Presumably, that's the outermost edge of the storm now showing up. Hard to believe that it's visible already having barely cleared the Azores. MetEireann only have Orange warnings in place and those only for Western coastal counties of Ireland, with Yellow for the rest. That surprises me a little as I would have thought that a Red warning would be appropriate for prone areas with an Orange warning for the rest of us. That might still come, I suppose.

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Lorenzo might not technically be a hurricane when it is forecast to hit the west coast of Ireland, but the NHC forecast chart shown or linked to in previous posts does show it as having hurricane force winds (74-110mph) at the time (2pm Thurs).  Maybe locations on the west coast of County Mayo, on the Mullet Peninsula or Achill Island, could report record-breaking wind speeds.  This surely is something remarkable, isn't it?

By the time that Lorenzo is forecast to leave the east coast of Ireland (2am Fri), its wind strength is shown to have reduced to gale/storm/violent storm force (39-73mph), which could still be very disruptive.  Does anyone else have information about how Met Éireann are calling this one? [ETA] While composing this post Lionel has answered this question.  Thanks Lionel! You're not the only one watching how this turns out. [End edit]

From reading a post by DEW in the MO thread, I understand that the NHC forecast model has the highest wind speeds for England out of the range of model output, so I wonder whether maybe that model tends to err on the side of forecasting higher wind speeds because of its specialization in forecasting hurricanes.  But Great Britain seems to be only protected from damaging winds by the very rapid reduction in intensity of the storm.  No way am I suggesting that the pros (MetO et al.) are wrong in forecasting this, but it could be very interesting to watch.

 

By the way, where is everyone?  In UIA talking politics?  There's some interesting weather going on ...

 

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No it wont be a hurricane, but a post tropical cyclone

 

Its forecasted to be a Hurricane just off the coast of ireland. Thats bloody imptessive!! Haha

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Its forecasted to be a Hurricane just off the coast of ireland. Thats bloody imptessive!! Haha

If you look at this chart: https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/055036.shtml?cone#contents

you will see that the small circles indicating Lorenzo's position are white, indicating a post-tropical cyclone, as The Beast from the East has stated.  When Lorenzo was classified as a hurricane, these circles were black, showing it to be (as per the key bottom right) a tropical cyclone.  The letters inside the circles indicate the wind speed, with H showing hurricane-force 12 winds (74-110mph). The distinction between a hurricane, and a storm with hurricane-force winds, may be technical (and a distinction of which the general public are commonly ignorant) but it is an important one.   

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If you look at this chart: https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/055036.shtml?cone#contents

you will see that the small circles indicating Lorenzo's position are white, indicating a post-tropical cyclone, as The Beast from the East has stated.  When Lorenzo was classified as a hurricane, these circles were black, showing it to be (as per the key bottom right) a tropical cyclone.  The letters inside the circles indicate the wind speed, with H showing hurricane-force 12 winds (74-110mph). The distinction between a hurricane, and a storm with hurricane-force winds, may be technical (and a distinction of which the general public are commonly ignorant) but it is an important one.   

Lorenzo has now gone ex-tropical so no more NHC updates https://www.nhc.noaa.gov/text/refresh/MIATCPAT3+shtml/021435.shtml?

A pity that there are no more updates as it really is the best site for graphics when a storm is bearing down on you.

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If you look at this chart: https://www.nhc.noaa.gov/refresh/graphics_at3+shtml/055036.shtml?cone#contents

you will see that the small circles indicating Lorenzo's position are white, indicating a post-tropical cyclone, as The Beast from the East has stated.  When Lorenzo was classified as a hurricane, these circles were black, showing it to be (as per the key bottom right) a tropical cyclone.  The letters inside the circles indicate the wind speed, with H showing hurricane-force 12 winds (74-110mph). The distinction between a hurricane, and a storm with hurricane-force winds, may be technical (and a distinction of which the general public are commonly ignorant) but it is an important one.   

Indeed. There is a really nice description highlighting the differences here: https://www.aoml.noaa.gov/hrd/tcfaq/A7.html 

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Interesting to see that the latest NHC update has been picked up by "Google SOS". Go to Google Maps, for example, and you'll see a "Hurricane Lorenzo" option on the left which overlays the forecast track. I knew they did this in the States but it's the first time I've seen it over here!

As the storm is now extratropical I'd imagine it'll be dropped from Google's coverage the next time an update would have come through.

EDIT: And FWIW, the latest GFS retains a low-level warm core until the system crosses the Irish Sea.

http://www.meteociel.fr/modeles/gfs/royaume-uni/theta-e-850hpa/51h.htm

The storm may officially be extra-tropical, but there are still the odd tropical influences even on Friday afternoon.

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Interesting to see that the latest NHC update has been picked up by "Google SOS". Go to Google Maps, for example, and you'll see a "Hurricane Lorenzo" option on the left which overlays the forecast track. I knew they did this in the States but it's the first time I've seen it over here!

As the storm is now extratropical I'd imagine it'll be dropped from Google's coverage the next time an update would have come through.

EDIT: And FWIW, the latest GFS retains a low-level warm core until the system crosses the Irish Sea.

http://www.meteociel.fr/modeles/gfs/royaume-uni/theta-e-850hpa/51h.htm

The storm may officially be extra-tropical, but there are still the odd tropical influences even on Friday afternoon.

Great info from you as usual 

 

The official classification works off whether a storm is 'deep warm core' i.e. warm all the way up to the tropopause or thereabouts.

Once a cyclone becomes shallow warm core, convection ceases to be as deep as well, and peak sustained winds tend to be unable to get much past weak cat 1 strength. 

That warm core is down by the surface where we all live though, so if someone was to somehow locate themselves within it tomorrow, they'd find some weirdly warm temperatures for the time of year.

It'll be really interesting to see how well the storm holds onto a distinct belt of stronger winds around its core. The NWP modelling shows it doing that well on the eastern side right out to tomorrow eve as it starts to drift into Ireland. The result is wind gusts as high as 90 mph, for quite a number of hours, hammering the central-western coast of Ireland from about 6 pm tomorrow.

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Great info from you as usual 

 

The official classification works off whether a storm is 'deep warm core' i.e. warm all the way up to the tropopause or thereabouts.

Once a cyclone becomes shallow warm core, convection ceases to be as deep as well, and peak sustained winds tend to be unable to get much past weak cat 1 strength. 

That warm core is down by the surface where we all live though, so if someone was to somehow locate themselves within it tomorrow, they'd find some weirdly warm temperatures for the time of year.

It'll be really interesting to see how well the storm holds onto a distinct belt of stronger winds around its core. The NWP modelling shows it doing that well on the eastern side right out to tomorrow eve as it starts to drift into Ireland. The result is wind gusts as high as 90 mph, for quite a number of hours, hammering the central-western coast of Ireland from about 6 pm tomorrow.

Sorry to ask a "will it snow in my backyard question", but presumably, gusts shouldn't be quite as bad as that here in South East Ireland?

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Sorry to ask a "will it snow in my backyard question", but presumably, gusts shouldn't be quite as bad as that here in South East Ireland?

This is what the ECM 12z has for peak gusts (in kph) for your area. https://weather.us/model-charts/euro/ireland/gusts-3h/20191004-0900z.html 

 

Further NW a few hours early it looks a good deal higher around western Galway https://weather.us/model-charts/euro/ireland/gusts-3h/20191004-0300z.html 

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Sorry to ask a "will it snow in my backyard question", but presumably, gusts shouldn't be quite as bad as that here in South East Ireland?

 

The 'wind forecast' on the Met Eireann home page should keep you updated Lionel. Good zoom in option too. 

https://www.met.ie/

 

 

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Something very interesting about Lorenzo with shallow warm core traits even as an extra tropical feature as it trundles towards the British Isles. I would think there will be some huge wave and surf action off the Irish west coast and wonder just how much rain it will give. Is this about the closest call we will ever see for a hurricane to make it to our part of the world, or do I remember someone posting anecdotal evidence of a near intact inner wall making it to the Irish coast with reported bangs and crashes and whistling sounds in antiquity (can’t remember who posted this some time ago)

Interesting table of swell periods and heights from storms with various wind speeds and at various distances - immediately ABOVE the 'Dissipation' heading (quicker than a long scroll down through the previous section).

I was slightly disappointed that the regular swell at Bognor today with an 8 sec period must have been due to something more local than Lorenzo

https://en.wikipedia.org/wiki/Swell_(ocean)#Dissipation

 

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Thanks very much for those links, Chunky and doctormog. That weather.us one is especially good - definitely one to bookmark. Hopefully not too much damage in my part of the world.

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The swell will start building tomorrow afternoon onwards peaking here in west Cornwall around dawn on Friday. Porthleven should get a good hit as most of the swell formed to the SW.
Usually mid Atlantic storm swells have to wrap around Ireland before hitting us. 10-15ft at the beach 25+ in open water.

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