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

J6P

Really hoping the eye tracks a little further south so i can get a nice stadium effect pic here in dublin.

MJohnston

sdanseo wrote: »

There's barely a red warning on the 18Z Icon going by wind speed. Maybe western counties will get red on merit.

Let alone anything resembling 64kt + mean winds.

It's as we were.

I don’t think we can say that Met Éireann will be basing their warning levels on any individual criteria meeting a particular range - there has to be consideration of how wind plus rain plus tides as a combination will effect things.

m17

Pangea

Seeing as Lorenzo could deviate at the last minute, I would imagine that the same colour coded warning would be issued for western counties to cover any deviation.

Meteorite58

Mod Note : Please use the other thread for general chit chat https://www.boards.ie/vbulletin/showthread.php?t=2058019653


and keep this thread free for technical discussion.

Villain

Latest ICON-EU model shifts it a little North with northwest seeing bigger impact but overall less impact compared to 12z.

https://twitter.com/carlowweather/status/1179146930020110341?s=21

sdanseo

Comparison of the NHC graphics at the same time frame (+48hrs) Ophelia (1st image) vs Lorenzo.

Again, this is the 50kt windspeed probability.

froog

looks like galway's going to take an absolute smashing

Meteorite58

ICON 18Z slower moving so expending most of its energy off the coast and keeping strongest winds to the coasts.

Not as strong as previous run.

Kermit.de.frog

Slight adjustment of the center east and south on the GFS 18z run but as we were in terms of depth and intensity.

Gaoth Laidir

Interesting comparison between the ECMWF ensembles for Lorenzo today and those for Ophelia when it was at about the same stage out from us.

Note how the HRES and mean for Ophelia were on the right of the envelope, whereas they're straight down the middle for Lorenzo. Opelia's intensity on landfall was around 65 knots as opposed to around 55 knots for Lorenzo.

JanuarySnowstor

18z gfs is close to nationwide red warning

Macy0161

I wouldnt rule out higher warnings given the ground conditions already in place. Surprising number of "tree down/ road blocked" posts in my timeline here in Wicklow with today's relatively benign conditions .

ninebeanrows

JanuarySnowstor wrote: »

18z gfs is close to nationwide red warning

No it isn't.

typhoony

JanuarySnowstor wrote: »

18z gfs is close to nationwide red warning

has it not weakened a small bit on previous run, apart from the coasts the wind gusts over land look to be in the 90 to 110km max range

SleetAndSnow

JanuarySnowstor wrote: »

18z gfs is close to nationwide red warning

It’s more like high yellow low orange everywhere besides the west coast

sdanseo

JanuarySnowstor wrote: »

18z gfs is close to nationwide red warning

It's nowhere near national red.

Calls for widespread gusts up to 110km/h.
Widespread 110-120km/h on western coasts combined with the storm surge will probably tip the balance to Red for those counties.
Orange elswehere at most, there is nothing on any 18Z GFS chart to warrant more than a yellow in eastern parts but we'll probably see orange from Thursday evening & for Friday given all the other factors.

JanuarySnowstor

The isobars are packed tight together.
These ex hurricanes usually pack a different virw

Meteorite58

Again going a bit more N before turning and moving down across the country, GFS keeping the isobars tight, will be interesting to see if it will bring a stripe of very strong winds across the country during it's transit.

Gaoth Laidir

Latest NHC track, showing extent of 34 and 50-knot wind radii.

Meteorite58

sdanseo

Gaoth Laidir wrote: »

Latest NHC track, showing extent of 34 and 50-knot wind radii.

Correct me if I'm wrong, but that doesn't take terrain into account, so some areas may not see 34kt wind at all.

Meteorite58

Looks like heavy or very heavy rain in places in the Northern half of the country.

Gaoth Laidir

To see live station data from the Azores click here. The two westernmost islands are Flores and Corvo.

http://www.ipma.pt/en/otempo/obs.superficie/#Flores (Aeródromo)

Flores data now (28 amsl)

sdanseo

Convenction intensifying again? Seems to be unwrapping itself on the southern side, but colder could tops in the core over the last 1-2hrs.

(GL I'm hoping you might explain this, I'm new to TTB and messing around with all they have on there)

John.Icy

What is this places obsession with Ophelia comparisons? Besides Cork there's every chance other areas will see winds like they did with Ophelia with Lorenzo.

And that's because bar exposed southern places Ophelia delivered yellow level winds to many, orange to some (3 stations red, all Cork S.coast, 5 orange and the rest yellow).

Out and out max intensity Lorenzo won't match what Opehlia did down in Cork BUT you should be looking at what Lorenzo is going to do in your area and cross compare to previous storms not max vs. max gusts of systems. Most of the time you're looking at what various storms have done at Malin Head or Bellmullet or the likes then!

Just like how Storm Ali caught some by surprise in Dublin. It was only a yellow yet it matched the 104km/h gust achieved during Ophelia so it was a tasty little storm.

Follow the forecasts and regional wind speed estimates rather than dismissing a storm because the answer to "will Lorenzo be as strong as Ophelia" is no technically. Trees are in leaf and the ground is damp, trees can fall with yellow level gusts, as seen today in Dublin - don't even think we hit yellow level gusts.

TTLF

John.Icy wrote: »

What is this places obsession with Ophelia comparisons?

Exactly, here’s something I wrote out earlier to show how this storm can be devastating in its own ways.

1. More rain with this system, so already waterlogged soil gets worse and weakens trees
2. Still some pretty sustainable gusts up to 90 or 100KMH here (Dublin) at some point
3. Heavier trees due to leafs on trees with weakened soil
4. Already high rivers

This storm will still pack a punch, even if it’s not Ophelia intensity, because of the setup this time.

John.Icy

TTLF wrote: »

Exactly, here’s something I wrote out earlier to show how this storm can be devastating in its own ways.

1. More rain with this system, so already waterlogged soil gets worse and weakens trees
2. Still some pretty sustainable gusts up to 90 or 100KMH here (Dublin) at some point
3. Heavier trees due to leafs on trees with weakened soil
4. Already high rivers

This storm will still pack a punch, even if it’s not Ophelia intensity, because of the setup this time.

Hurricane Charley remnants, case and point. Nothing noteworthy wind wise but the floods were bad (not saying this is coming!!). 13 deaths attributed on the island to the storm.

More than max wind speed for the weather to get ya.

snowgal

PokeHerKing wrote: »

From game over to county specific landfall!

So meant to post this earlier too!

Gaoth Laidir

sdanseo wrote: »

Correct me if I'm wrong, but that doesn't take terrain into account, so some areas may not see 34kt wind at all.

Correct.