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

AirBiscuit

New Advisory (#41) from the NHC

MJohnston

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.

endainoz

High tide in Lahinch due tomorrow night at 9.22pm. combined with the big swell and the winds, it will be a big test for the coastal armour recently installed.

I had thought Clare might miss most of this one, we will have to wait and see.

Laurali

DOCARCH wrote: »

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

Yup, NHC downgraded it 26 mins ago it seems.

Mickeroo

Laurali wrote: »

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?

That was posted almost three hours ago I think, might have degraded since?

DOCARCH

Mickeroo wrote: »

That was posted almost three hours ago I think, might have degraded since?

Looking quite degraded!

drunkmonkey

endainoz wrote: »

High tide in Lahinch due tomorrow night at 9.22pm. combined with the big swell and the winds, it will be a big test for the coastal armour recently installed.

I had thought Clare might miss most of this one, we will have to wait and see.

Showing 20 footers barreling in,. What did Christine bring size wise that caused all the damage?

Villain

GFS and ICON-EU are pretty much sticking to their guns bringing center in at Northwest Donegal, with Harmonie and other high resolution models not agreeing it will be interesting to watch this unfold as the GFS and ICON-EU outcome would see strongest winds early tomorrow.

endainoz

drunkmonkey wrote: »

Showing 20 footers barreling in,. What did Christine bring size wise that caused all the damage?

I think the storm you are referring to is Hercules from January 2014, that's the one that had the iconic photo of Lahinch prom getting battered. Not sure about the size of the waves, but it made for spectacular pictures.

Gaoth Laidir

So from the Harmonie animation we're looking at Force 9 and 10 sustained winds at its worst point around Galway Bay tomorrow night. All eyes on Mace Head gusts. I'm going for 75 knots.

sdanseo

NHC has issued its last update. No longer a hurricane, although it does (barely) have hurricane force sustained winds.

000
WTNT43 KNHC 021436
TCDAT3

Post-Tropical Cyclone Lorenzo Discussion Number 41
NWS National Hurricane Center Miami FL AL132019
1100 AM AST Wed Oct 02 2019

Lorenzo has completed its transition into a powerful extratropical
cyclone and this will be the last NHC advisory on this system. The
center has become exposed on the southwestern edge of the cloud
shield, and recent ASCAT data indicate that the system has acquired
frontal features. The initial intensity is set at 70 kt, which is
a little above the scatterometer data since there is typically a
low bias in that instrument at these wind speeds. The global
models suggest that the post-tropical cyclone will only gradually
weaken during the next 24 to 36 hours as it approaches Ireland. A
faster rate of weakening is expected Thursday night and Friday when
the cyclone moves southeastward over Ireland and the United Kingdom.
The low should dissipate over southeastern England by late Friday.

The cyclone continues to move rapidly northeastward or 040/37 kt,
and this general motion should continue into Thursday. After that
time, the cyclone is expected to turn eastward and then
southeastward within an area of weaker westerly flow. The global
model guidance is in good agreement, and the NHC track forecast is
in closest to the ECMWF model.

Future hazard information on Lorenzo for Ireland and the United
Kingdom can be found in products issued by Met Eireann and the
United Kingdom Met Office.

Local forecasts and warnings for Ireland can be found on the
website of Met Eireann, the Irish Meteorological Service, at
http://www.met.ie/.

Local forecasts and warnings for the United Kingdom can be found on
the website of the UK Met Office at http://www.metoffice.gov.uk/.

Lorenzo's expansive circulation is producing very large seas over
the north Atlantic. Full information can be found in High Seas
Forecasts from the following agencies:

The NOAA Ocean Prediction Center under AWIPS header NFDHSFAT1, WMO
header FZNT01 KWBC, and online at
ocean.weather.gov/shtml/NFDHSFAT1.php

The UK Met Office under WMO header FQNT21 EGRR and online at
https://www.metoffice.gov.uk/weather/specialist-forecasts/coast-and-
sea/high-seas-forecast

Meteo France under WMO header FQNT50 LFPW and online at
http://www.meteofrance.com/previsions-meteo-marine/bulletin/
grandlarge/metarea2

FORECAST POSITIONS AND MAX WINDS

INIT 02/1500Z 44.4N 25.8W 70 KT 80 MPH...POST-TROPICAL
12H 03/0000Z 48.6N 20.8W 70 KT 80 MPH...POST-TROP/EXTRATROP
24H 03/1200Z 52.8N 14.3W 65 KT 75 MPH...POST-TROP/EXTRATROP
36H 04/0000Z 54.0N 9.5W 60 KT 70 MPH...POST-TROP/EXTRATROP
48H 04/1200Z 52.5N 3.5W 40 KT 45 MPH...POST-TROP/EXTRATROP
72H 05/1200Z...DISSIPATED

$$
Forecaster Brown

Iancar29

Lorenzo is not a hurricane anymore, it lost its Hurricane status at roughly 3am Irish time.

12z UPDATE :

My thoughts.
Rain bands and increase in winds to arrive into the SW of the country tomorrow morning around daylight.
Noticeable strong winds around the west coast ( offshore winds ) and to a lesser extent the South coast ( onshore winds ) from midday. Light-moderate Rain bands spreading throughout the country.

2nd round of concern tomorrow evening in the west as it makes an easterly turn into the country bringing strong (onshore) winds and heavy rain to Atlantic coastal counties ( localised severe gusts of >120km/hr at extreme coastal spots/ high ground ) . Localised flooding also likely accompanying high tide.

Elsewhere main concern would be heavy rain and to a lesser extent fallen trees from moderate winds. Mountainous areas in leinster moderate to strong winds.


Max gust prediction 68knots - Bellmullet.


PS- cheers to the mod team for keeping this thread technical discussion posts only.

Gaoth Laidir

ASCAT wind scans from 11:21, 11:47 and 12:28Z today. The first one shows highest speeds of 55 knots in the southeastern quadrant, with max 50 knots in the other two scans after that. As the NHC said, scatterometer data have a low bias at high windspeeds and they've held it at 70 knots in their latest discussion. Still, it might be a little generous.

Oscar Bravo

Could we see any embedded thunderstorms in the second band of rain into Mayo/ Galway tomorrow evening?

pauldry

Think the West will get over 60 knots gusts. The rest 50 knots or less

Id expect looking at 8pm (approx) gusts on Met Reports tomorrow to see

Mace Head 64 knots
Belmullet 60 knots
Shannon 58 knots
Newport 55 knots
Sligo 48knots

Gaoth Laidir

For posterity.

...LORENZO BECOMES EXTRATROPICAL BUT STILL EXPECTED TO BRING WINDS AND RAINFALL TO IRELAND AND PORTIONS OF THE UNITED KINGDOM...

SUMMARY OF 1100 AM AST...1500 UTC

...INFORMATION

---

LOCATION...44.4N 25.8W
ABOUT 945 MI...1525 KM WSW OF CORK IRELAND
ABOUT 970 MI...1565 KM WSW OF GALWAY IRELAND
MAXIMUM SUSTAINED WINDS...80 MPH...130 KM/H
PRESENT MOVEMENT...NE OR 40 DEGREES AT 43 MPH...69 KM/H
MINIMUM CENTRAL PRESSURE...962 MB...28.41 INCHES

Meteorite58

A big spread again in the models with regards to track, timing and wind strengths. ECM 0Z and 6Z is very consistent , will be interesting to see if it maintains this when the next run comes out after 19.00

To Alcohol

Is it game over for a red flag 🚩 event and duvet day tomorrow and possibly Friday, if one could stretch the event for two days??

SleetAndSnow

https://twitter.com/eoinbearla/status/1179430279741616129?s=21

Esb releasing excess water from the dam, let’s hope they measure it properly unlike 2009

REBELSAFC

DOCARCH wrote: »

Looking quite degraded!

Looks alot more dissipated than Ophelia did.Looking at that again, visually Ophelia nearly looks like a hurricane when it reached Ireland

uck51js9zml2yt

Gotten bitterly cold after what was a nice day in Kerry.
Does the ex hurricane have any bearing on the temperature drop?

pauldry

Its gone shockn calm here

If one hadnt looked at forecast and just sat24 one would guess that its going to miss us completely bar the far Northwest but I suppose its the late swing east thats going to cause the widespread wind

Oneiric 3

Iancar29 wrote: »

Max gust prediction 68knots - Bellmullet.
.

It is great to see you back posting again Ian.
I'll go with 65 knots in Belmullet. It is a riskier prediction given the latest output but just the slightest nudge north will make all the difference.

squarecircles

Leila Eager Blowgun wrote: »

Gotten bitterly cold after what was a nice day in Kerry.
Does the ex hurricane have any bearing on the temperature drop?

No,the opposite,it will drag up air of tropical origins.

Meteorite58

72 kts Mace Head ( between 23.00 and 01.00 )

Meteorite58

https://twitter.com/ysaka42001/status/1179423907662749704?s=20


https://twitter.com/MJVentrice/status/1179450628919173128?s=20

https://twitter.com/ABC/status/1179403623140401154?s=20


https://twitter.com/MeteoOs/status/1179319633561698304?s=20

Meteorite58

Rainfall predictions










The GFS looks broken.

squarecircles

Tomorrow

Turning wet and windy on Thursday as the outer rain-bands associated with Storm Lorenzo track across
Ireland. Southeast winds will be strong and gusty with some damaging gusts. Very high seas are
expected along the Atlantic coast. Feeling increasingly humid with temperatures of 13 to 17 degrees.
During Thursday evening the centre of Storm Lorenzo will move closer to the northwest coast. Southerly
winds will veer west to southwest, with gales and severe damaging gusts, especially along
Atlantic coasts. Intense falls of falls of thundery rain will move into the west too.

Met.ie

JCX BXC

This storm probably won't be significant for wind speeds, however for longevity of winds it will be notable.

Hooter23

I fear this will be the scene around ireland Friday morning...