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

dermiek

From met.ie website. I did look- apologies if it's been posted already.

https://www.met.ie/forecasts/meteorologists-commentary

Tap the top one, "tracking hurricane Lorenzo".

igCorcaigh

Any upgrade could impact on current warning levels

https://twitter.com/rtenews/status/1179329112344875014?s=19

Villain

The Met Eireann commentary on Lorenzo was updated this morning and includes some Harmonie Model images, full details at https://met.ie/forecasts/meteorologists-commentary

Villain

Well ICON-EU wants to keep Lorenzo away, not sure I'd even share the latest images from it as I don't think it has much support!

Villain

Villain wrote: »

Well ICON-EU wants to keep Lorenzo away, not sure I'd even share the latest images from it as I don't think it has much support!

Well actually GFS shifts it further north too!

Laurali

Widdensushi wrote: »

looking at those I can't see how cork gets an orange warning

or anywhere.. can see gusts of 100km or more anywhere.. maybe briefly on the Mayo/Limerick coast

Danno

South Midlands (Laois and surrounding areas) Weather Warning: https://www.facebook.com/LaoisWeather/photos/a.274326212681505/2442837485830356

UPDATE - WEATHER WARNING: ExHurricane/Extra-Tropical Storm Lorenzo - Wed Oct 2nd 2019 10Z: Storm Lorenzo is currently pushing northeastwards from the Azores Islands and is on track towards Ireland to affect the country from Thursday evening until Friday morning. Met Eireann have issued two yellow level warnings for Ireland: Wind and Rain. The wind warning is for 30mph to 40mph (50kmph to 65kmph) mean wind speeds with gusts up to 62mph (100kmph) possible. The rainfall warning is for up to or in excess of 50mm in parts of the northwest, however amounts are expected to be smaller elsewhere.
With recent above average rainfall, grounds are already saturated so the possibility of local flooding is enhanced. While rainfall amounts from the frontal bands associated with Lorenzo are not expected to be very high, heavy thundery showers will follow once the frontal bands clear and these could lead to localised downpours causing spot flooding.
With the trees still in full leaf and the predicted longevity of the winds, some downed trees are possible leading to road blockages and possible disruption to power supplies. In addition, western coastal counties have been issued with an Orange warning for stronger winds and coastal inundation associated with high tides and large sea swell.
Wednesday presents an opportunity to prepare for the storm as the weather is forecast to be cool, dry and near calm.

MJohnston

Widdensushi wrote: »

looking at those I can't see how cork gets an orange warning

Cork got an orange warning based on earlier charts which are shown on the Met Eireann website. Those warnings will be adjusted if the situation changes. Pretty simple!

Laurali

ICON model showing potential wind gusts of 150kph in Doolagh Achill Thurs night/Fri morning. LOL

NotToScale

Widdensushi wrote: »

looking at those I can't see how cork gets an orange warning

The granularity is on county by county basis and Cork's almost half the size of Northern Ireland. Some of it is basically western Atlantic Coast, the majority of it isn't.

We don't really have any way of getting better granularity as counties aren't uniformly sized or shaped and there's no real way of making statements about areas that aren't counties.

They're trying to get a clear safety message out. There isn't really much other way of doing it anywhere in the world as referring people to highly nuanced maps about undefined areas isn't really helpful.

Also the path and impact is still not entirely locked down.

Unfortunately, Met Éireann are always damned if they do and damned if they don't. People need to be a little more forgiving about the need to communicate clear information and inability to be accurate on a house by house basis.

Mount Vesuvius

Might miss us altogether now, WRF up to it max range has it way out west.

hatrickpatrick

The new NHC cone keeps it at Cat 1 hurricane wind speed directly before landfall in Mayo, very surprised areas near there haven't been upgraded to a red alert O_o

m17

The azores 02/10/19

NotToScale

You could define it as within X km of the coasts of the following counties and perhaps define big coastal counties like Cork as east and west. The problem is it's not all that well defined and you have to divide a map up somehow and we don't have smaller units like "communes" in France or so on.

The UL example is just the kind of thing you'll get on county lines. I mean, if you go to the US, a police chase can stop at the county lines. Even here different bylaws apply in different local authorities. If you walk down the road in Donegal near the border, the entire constitution and jurisdiction changes one minute you're in a Republic, the next a constitutional monarchy.

Common sense can apply, but at the same time, people who can make the calls on the weather aren't university administrators. If you don't close the north campus during a red alert and a tree comes down on someone or they're hit by some bit of debris, you're the one making that call as a university administrator, without any specialist skills to forecast weather. Ultimately, that's what it will come down to.

Unfortunately this is just the nature of maps and mapping. Unless we get down to sending alerts based on individual eircodes or come up with official descriptions of coastal regions for weather forecasting information purposes, we aren't going to be able to solve this to everyone's satisfaction.

cherryghost

Surprised to see NHC still classify Lorenzo as a hurricane at landfall.

sdanseo

cherryghost wrote: »

Surprised to see NHC still classify Lorenzo as a hurricane at landfall.

They aren't. The white circle indicates an extratropical storm, but with hurricane force winds.

Much more interesting to me is this part of the commentary:

Lorenzo passed near Flores in the Azores a few hours ago where
hurricane-force winds, at least in gusts, were observed. Winds
are now decreasing across those islands. The current intensity
estimate, 75 kt, assumes only slow weakening since late yesterday.

Essentially they are saying that nowhere the Azores recorded hurricane force sustained winds and on that basis their intensity estimates might be generous.

irishgeo

cherryghost wrote: »

Surprised to see NHC still classify Lorenzo as a hurricane at landfall.

Doesn't the white h mean a ex hurricane with possible hurricane force gusts

TTLF

Does anyone have a rain chart we can base off? Wind is one thing, but Rain is another, and MÉ only specified excess of 50mm on the West coast. What about like... everywhere else? 30mm?? 15mm?

Mortelaro

hatrickpatrick wrote: »

The new NHC cone keeps it at Cat 1 hurricane wind speed directly before landfall in Mayo, very surprised areas near there haven't been upgraded to a red alert O_o

The flaw in the colour scheme is,you have to put entire counties the same warning colour
It is being said that areas near the coast in the west could have red level conditions but other parts, if not most parts of the same county might not

Icyseanfitz

Mortelaro wrote: »

The flaw in the colour scheme is,you have to put entire counties the same warning colour
It is being said that areas near the coast in the west could have red level conditions but other parts, if not most parts of the same county might not

That's my issue, I'm very coastal so don't know whether to treat this as red or orange/yellow

Mortelaro

TTLF wrote: »

Does anyone have a rain chart we can base off? Wind is one thing, but Rain is another, and MÉ only specified excess of 50mm on the West coast. What about like... everywhere else? 30mm?? 15mm?

Can't do that either because there will be random pockets of heavier rain,monsoon like maybe,those could be anywhere even in the yellow areas
That is being mentioned,highlighted in oral forecasts even but its Impossible to do anything other than say they'll be around somewhere

Mount Vesuvius

Storm 10 wrote: »

I seen it this morning and another poster and myself were wondering why Donegal was not there given how close it is to Sligo may have been up for a short time

Sligo was never orange I took this as soon as warnings were released.

pauldry

Sligo will have a gust of 109kph so is not Orange

Somewhere else further inland might have a peak gust of 90kph but its the same colour

Everything above 100kph should be Orange

Below that yellow.

pauldry

Looking at the Satellite now the Jetstream seems to have got hold of Lorenzo now as it becomes extratropical i dont see much more weakening

Peak gusts probably around 130kph on West coast

JanuarySnowstor

If it was me I would have Sligo down as the sweet spot for this storm. I said this 2 days ago. Sligo in the yellow and Cork in the orange is quite simply wrong imo.
Time will tell the gfs and icon were never gone on the idea of this storm turning right across the country and neither am I.
I think the Northwest will get hammered and Sligo will get the highest gust and for us in Cork it'll be a normal 24hours though we will have overlapping high tides

m17

jamesbere

JanuarySnowstor wrote: »

If it was me I would have Sligo down as the sweet spot for this storm. I said this 2 days ago. Sligo in the yellow and Cork in the orange is quite simply wrong imo.
Time will tell the gfs and icon were never gone on the idea of this storm turning right across the country and neither am I.
I think the Northwest will get hammered and Sligo will get the highest gust and for us in Cork it'll be a normal 24hours though we will have overlapping high tides

Well I doubt South West Cork will be normal by the looks of it. The fear of house damage is always a concern where we live

m17

The azores 02/10/19

Akrasia

Based on the latest NHC guidance, I would expect the Warning period to be brought forward. This would bring Tropical force winds to the coastal counties by noon, while the alerts only start at 6pm

TTLF

Akrasia wrote: »

Based on the latest NHC guidance, I would expect the Warning period to be brought forward. This would bring Tropical force winds to the coastal counties by noon, while the alerts only start at 6pm

NHC map broadcast is in a different timezone

I think -4 hours behind