Storm Lorenzo: October 3/4 2019 Technical Discussion Only

Gaoth Laidir · 02-10-2019 01:09PM

Preliminary maximum official gusts from the Azores (IPMA).

Corvo (aeroporto) - 163 km/h às 08:25h UTC

Flores (aeroporto) - 142 km/h às 05:00h UTC

Faial (Horta) - 145 km/h às 04:00h UTC

Images here

mickger844posts · 02-10-2019 01:12PM

Mod Note: Chat belongs in its own thread "Technical Discussion Only" in here please.

Mount Vesuvius · 02-10-2019 01:12PM

Euro4 brings centre in at 978mb . Mayo ,Galway and Clare probably feeling worst of winds, however the storm surge will be pushed in strong by those winds, so flooding a given.

Strongest gusts potential to reach 130+ on west coast

bnt · 02-10-2019 01:13PM

HIRLAM forecasts some moderate southerly winds on the east coast tomorrow afternoon, but with the worst coming overnight. It's not going to stop me going in to Dublin tomorrow.

Gaoth Laidir · 02-10-2019 01:17PM

This station is on the central island of Horta, about 250 km from the westernmost islands of Corvo and Flores. Highest mean speed of 145 kph and highest gust 178. I'm not sure how high up this is but it would appear to be on a very exposed south-facing coast.

easypazz · 02-10-2019 01:32PM

Mount Vesuvius wrote: »

Euro4 brings centre in at 978mb . Mayo ,Galway and Clare probably feeling worst of winds, however the storm surge will be pushed in strong by those winds, so flooding a given.

Only if it coincides with a high tide, and also a spring tide will effect it.

Does anybody know if the tides are similar to expected peak storm time?

igCorcaigh · 02-10-2019 01:33PM

Widdensushi wrote: »

struggled to se an orange warning for cork on any forecast, it was always going to be worse from north kerry up the west coast

Does the orange warning factor in flooding risk or just wind?

Also, will the direction of the wind favour pushing the water up Cork Harbour?

TIA.

m17 · 02-10-2019 01:37PM

The azores 02/10/19

SeaFields · 02-10-2019 01:38PM

easypazz wrote: »

Only if it coincides with a high tide, and also a spring tide will effect it.

Does anybody know if the tides are similar to expected peak storm time?

High tides on the west coast tomorrow night between 8-9pm approximately depending on the exact location.

Gaoth Laidir · 02-10-2019 01:38PM

Current intensity now 70 knots and over water of 20 °C, cooling by about 2 degrees every 6 hours from now on. The 12Z SHIPS has it weakening to around 43 knots off the west coast at 12Z tomorrow, then weakening to 33 and 30 over the next 12 hours as it moves inland. Probably a bit on the low side.

Villain · 02-10-2019 01:39PM

igCorcaigh wrote: »

Does the orange warning factor in flooding risk or just wind?

Also, will the direction of the wind favour pushing the water up Cork Harbour?

TIA.

Sadly flooding isn't covered by Met Eireann warnings but they are working on a flood warning system with the OPW however ETA on it being available.

See https://www.met.ie/weather-warnings for more details on what they cover, mind you trying to cover rainfall in this setup is tricky as depends on track and intensity, Evelyn said 80-100mm is possible in some local areas of West and Northwest!

SeaFields · 02-10-2019 01:49PM

Villain wrote: »

Sadly flooding isn't covered by Met Eireann warnings but they are working on a flood warning system with the OPW however ETA on it being available.

See https://www.met.ie/weather-warnings for more details on what they cover, mind you trying to cover rainfall in this setup is tricky as depends on track and intensity, Evelyn said 80-100mm is possible in some local areas of West and Northwest!

I would imagine the ESB will be emptying the reservoirs in so far as possible so that the can restrict water flow either side of the high tide hitting Cork city. With regard flooding it is a massive management aid having the ability to do that. Of course the low pressure itself in the storm will increase flood risk along with the wind and rain.

Rebelbrowser · 02-10-2019 01:58PM

igCorcaigh wrote: »

Does the orange warning factor in flooding risk or just wind?

Also, will the direction of the wind favour pushing the water up Cork Harbour?

TIA.

Think its a SE wind that causes Cork city flooding

Villain · 02-10-2019 02:00PM

The Met Eireann Meteorologist’s Commentary was updated at 13:20 at https://www.met.ie/forecasts/meteorologists-commentary and includes the Harmonie charts below which also brings center of storm in around Mayo/Sligo.

sdanseo · 02-10-2019 02:06PM

Nothing over 48kts mean there coming onto land bar very exposed coastal parts in Galway and Mayo. Hard to justify any warning at all for the eastern half of the country based on the mean speeds also.

Would be interested to see the same chart for gusts. Presumably showing higher than the various thresholds.

igCorcaigh · 02-10-2019 02:07PM

Rebelbrowser wrote: »

Think its a SE wind that causes Cork city flooding

I think so, given the geography.
Looks like the charts showing a SSE?

One to watch for us.

Oneiric 3 · 02-10-2019 02:08PM

Looking at the latest ECM offering, nothing too concerning (away from outer west coasts that is) seems to be the 'take away'.

Hairy enough in places for a while for sure, but nothing out of the ordinary for the time of year really. Still a long way to go though.

Oneiric 3 · 02-10-2019 02:13PM

sdanseo wrote: »

Nothing over 48kts mean there coming onto land bar very exposed coastal parts in Galway and Mayo. Hard to justify any warning at all for the eastern half of the country based on the mean speeds also.

Would be interested to see the same chart for gusts. Presumably showing higher than the various thresholds.

You can find the latest model gust speeds on the 'Weather.US site for any location really. Just type in nearest town or village and you'll get the graph of a range of parameters:

https://meteologix.com/ie/forecast/2964180-galway/essentials/rapid-euro

igCorcaigh · 02-10-2019 02:14PM

Not looking like a big wind event for most is seems, but ME did emphasise storm surge.

Also trees in full leaf. Enough to avoid journeys by car, and be careful around coasts, would be my reading of it at this stage.

But don't listen to me, or anyone here.
Keep to the official channels for info.

topcat77 · 02-10-2019 02:25PM

The ECMWF model looks scary for Galway around Friday 1am.

https://www.windy.com/?2019-10-04-00,52.666,-9.470,7

Oneiric 3 · 02-10-2019 02:27PM

Sat animation since midnight. Fairly fast moving feature now.

Jpmarn · 02-10-2019 02:33PM

We now have a high confidence that the centre of Storm Lorenzo will hit Ireland tomorrow night. But the question is which county is it, Mayo or Donegal. GFS suggests that the centre will it Donegal and in it's 06z run it is pretty much North Donegal. Met Eireann has gone for a Co. Mayo landfall and the warnings it issued reflect that. Just to point that yellow status warnings come into effect at 9 AM tomorrow morning. Status Orange comes in at 6 PM in the evening. A Mayo Landfall would mean top gust of 120kmh for Limerick City. A Donegal landfall would mean the gusts are not likely to exceed 100kmh in Limerick. I would reckon that Mayo, Galway and Maybe Clare to be upgraded to red. If Met Eireann backs off onto a Donegal landfall status Orange maybe cancelled for Limerick and Cork but added to Sligo and Donegal. The only other good news is the depression will start filling in just before landfall and continue so after that so it intensity will decrease.

DOCARCH · 02-10-2019 02:38PM

Oneiric 3 wrote: »

Sat animation since midnight. Fairly fast moving feature now.

Looks quite unimpressive already!

squarecircles · 02-10-2019 02:39PM

hopefully it will pack a punch as it is moving fast,and doesnt fill too quickly as it crosses the country.

The thought of all the whinging the next day is worst than a hangover.

looking foward to upgrades later also for all those that revel in downgrading and deflating everything
as much as possible always.

easypazz · 02-10-2019 02:44PM

squarecircles wrote: »

hopefully it will pack a punch as it is moving fast,and doesnt fill too quickly as it crosses the country.

The thought of all the whinging the next day is worst than a hangover.

looking foward to upgrades later also for all those that revel in downgrading and deflating everything
as much as possible always.

I am hoping for downgrades on this one. Lots of people on about cancelling journeys, storm surge flooding, upgrades to red etc.

Lets see what happens.

Laurali · 02-10-2019 02:46PM

Lorenzo maintains hurricane status at 39.1N 32.7W 135 km WSW of Flores Island in the Western Azores with maximum sustained winds of 155 km/h and minimum central pressure of 960hPa, present movement is NE at 65km/h. Lorenzo will undergo extra-tropical transition within the next 24 hours as it engages with the polar jet-stream.

Got this from ME website - Saying it still maintains hurricane status, which is conflicting from comments in this thread, saying it had hurricane force winds but is not a hurricane anymore?

Oneiric 3 · 02-10-2019 02:49PM

squarecircles wrote: »

looking foward to upgrades later also for all those that revel in downgrading and deflating everything

As much as I'd like to see an upgrade myself, I don't really see the point of hyping stuff up either. We have enough gob****es in the media doing that for us already.

DOCARCH · 02-10-2019 02:50PM

Laurali wrote: »

Got this from ME website - Saying it still maintains hurricane status, which is conflicting from comments in this thread, saying it had hurricane force winds but is not a hurricane anymore?

Not sure how ME classify hurricanes, but officially, according to NHC, it is now Post Tropical Cyclone Lorenzo.

AirBiscuit · 02-10-2019 02:52PM

New Advisory (#41) from the NHC

MJohnston · 02-10-2019 02:57PM

Laurali wrote: »

Got this from ME website - Saying it still maintains hurricane status, which is conflicting from comments in this thread, saying it had hurricane force winds but is not a hurricane anymore?

I think people are saying that it will be that way at landfall in Ireland.

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

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Storm Lorenzo: October 3/4 2019 Technical Discussion Only