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

Naggdefy

The storm which produced a max gust of 107 km, 66 miles per hour. My goodneess such an amount of hyperbole and waffle, with people like George Lee and Eoin Murphy posing as meteorologists.

Ordinary people up and down the country being frightened, over gusts you get with any low pressure system. I live on a hill top in Laois over 330m, over 1050ft in old money. It gives us an extra 20-30km in wind speed gusts. My 85 year old mother, active, healthy, and most of all positive and not prone to moaning, said to me that grown men like George Lee and women like Teresa Mannion should grow up and stop running around like clocking hens. Couldn't agree more.

Chris_5339762

All failures of modelling and warnings aside, does anyone else think its actually quite awesome they managed to predict the fast moving storm taking a very sudden right hand turn?

Danno

Chris_5339762 wrote: »

All failures of modelling and warnings aside, does anyone else think its actually quite awesome they managed to predict the fast moving storm taking a very sudden right hand turn?

A double-edged sword question, but a very valid point/question too. Why? The art of forecasting in the more traditional sense has been replaced by computers to a certain degree now-a-days. I think that forecasters are less inclined to go with "gut feeling" (the art) and go with what the models are suggesting.

Perhaps I'm too harsh there in saying that, but I feel if "the computer says no" means it won't happen. Is the art of forecasting now becoming an art of interpreting charts that are computer simulations? Time will tell.

Just to add... the "art" of forecasting is by no means to diss the years of study, etc... put in to be a forecaster. Forecasting is a fine "art" in the highest of respect to the profession.

Donegal Storm

Oneiric 3 wrote: »

Ophelia ended up being stronger here too, even though we largely missed out on it, with higher mean and gust speeds (think my max was around 52kts) Ophelia was also notable for its angle of attack. It seems that, here in the west of Ireland at least, trees etc 'shaped' to tolerate strong winds from a westerly quarter, but not from an easterly one. That could be a nonsense theory though but for whatever reason, strong winds from an easterly direction always seem to be stronger and more 'robust' than they would appear to be in the actual stats.

That definitely is the case, I grew up around 100 metres from the Atlantic in West Donegal and the few trees that survived were all shaped to counter the prevailing wind, I suspect roots are also stronger/deeper. A northerly storm, even if not technically as strong always feels more intense than a westerly I find.


As for the event itself, I largely ignored it as could see early on it wouldn't amount to anything around here. Also find it really tedious how hyped and obsessive things get on here now so can't be arsed keeping up. The hysterical media/public reaction is sadly the new normal these days though with every strong breeze or snow shower so what can ya do...

Neddyusa

Oneiric 3 wrote: »

Ophelia ended up being stronger here too, even though we largely missed out on it, with higher mean and gust speeds (think my max was around 52kts) Ophelia was also notable for its angle of attack. It seems that, here in the west of Ireland at least, trees etc 'shaped' to tolerate strong winds from a westerly quarter, but not from an easterly one. That could be a nonsense theory though but for whatever reason, strong winds from an easterly direction always seem to be stronger and more 'robust' than they would appear to be in the actual stats.

Absolutely - half the wind from the south east can do twice the damage of a wind from the south west around here.
Wind speeds from Ophelia were not the problem here - the wind direction was.
I know - I lost a shed roof and a heifer to it.

Oneiric 3

Carol25 wrote: »

The calm after the storm in Salthill today.

Beautiful photo Carol25. Once the clouds cleared here this morning it almost had that mid-summer tone with strong sunshine and solid blue.

I agree with most others regarding the 'warning' system. It's a farce. If there is to be one, then what is currently considered the criteria for 'Red' should be a 'Yellow' and so on. Ireland does not get extreme weather very frequently, but it can and does happen, and given the amount of 'Orange' & 'Reds' given out over the last few years for weather events that were not all that out of kilter with the season they occur in, they will start to lose all their desired impact.

Meteorite58

Chris_5339762 wrote: »

All failures of modelling and warnings aside, does anyone else think its actually quite awesome they managed to predict the fast moving storm taking a very sudden right hand turn?

I dont know if you could say there was failures in modelling. Models will always be different, have weakness and strengths , look at any collection of precipitation charts for a given date and you will see a wide spread in predictions. Models are far from perfect, even the best ones, even with all the technology at hand. For me it is trying to learn each models traits in what they are good at and what they fall down on ( in different weather scenarios ) and how accurate are they at given timeframes .

Relatively quick moving systems are probably the least complicated to forecast I would think, it is ones like what we have seen over the last couple of days that prove to being the most testing, full of energy hurtling towards us in a NE'ly direction over cooling waters, losing energy... Hurricane 4,3,2,1, extra tropical , storm.... interacting with troughs and Jet Stream, moving up off the coast heading more N'ly , slowing down , running into Hp putting the breaks on and turning and heading SE / E'ly, how long will the turn take, interacting with the jet like a conveyor belt , friction against land , how much energy will be left etc etc

I think the models do an incredible job in general, they have their great moments and can falter at times but sometimes it is just trusting them especially in the short term and especially after a climb down . It takes guts to stand up and call a potential big event knowing how it is going to become a big news item and how preparations and possible anxiety at hearing warnings will impact peoples lives , but it takes even more courage to change the advice that was given initially when and if new information comes to hand saying that an earlier forecast will not materialize as strong as first thought and had been prepared for.

I was thinking that perhaps once the image of the Hurricane and how powerful it was gets into the mind then it is hard to shake that off and look at it with fresh objective eyes when new information comes to hand, no matter how late in the day.

I was wondering also is there some theory or a known practice about giving warnings and then there comes a point within a timeframe when you should not change them or cant ?

Oneiric 3

Donegal Storm wrote: »

That definitely is the case, I grew up around 100 metres from the Atlantic in West Donegal and the few trees that survived were all shaped to counter the prevailing wind, I suspect roots are also stronger/deeper. A northerly storm, even if not technically as strong always feels more intense than a westerly I find. .

We had strong northerly wind here back March (I think) one night and it was really boisterous and 'clattery', yet when I checked the wind speed readings, it wasn't registering anything out of the norm. It's just funny how it works and sort of hints that readings and stats are no substitute for the real life experience of things (not just weather).

Graces7

Donegal Storm wrote: »

That definitely is the case, I grew up around 100 metres from the Atlantic in West Donegal and the few trees that survived were all shaped to counter the prevailing wind, I suspect roots are also stronger/deeper.

On the road to the pier on the mainland here there is a single small tree... Bent sharply at an angle .. stark witness to the westerlies we get

west mayo offshore

Graces7

Oneiric 3 wrote: »

We had strong northerly wind here back March (I think) one night and it was really boisterous and 'clattery', yet when I checked the wind speed readings, it wasn't registering anything out of the norm. It's just funny how it works and sort of hints that readings and stats are no substitute for the real life experience of things (not just weather).

amen to that. It was storm out here . Have to start damage repair

Also the ocean took 36 hours to settle.

I have no tech things out here but I do have a keen vested interest in our weather, as on a small island it rules everything. Do not need "readings and stats" to define "storm". Observation and experience rule and are never wrong

sryanbruen

I wasn't going to include Lorenzo in the storm comparison table as it barely registered yellow warranted gusts for many - and Storm Hannah back in April produced stronger gusts mostly, but here it is anyway. Met Éireann have released the maximum mean wind speeds early too for Lorenzo so I have updated that table as well. In the gusts table, I have added Storm Doris also since I last posted it in April. The gusts are measured in km/h.





Data from Met Éireann.

Darwin

Thanks for the effort in keeping that table updated Syran, it interesting to see the impacts of each storm system by location. Someone had a sense of humour naming bawbag!

Donegal Storm

Hurricane bawbag (and another big storm around a week later) are I think the last 'good' storms I've experienced in Donegal, for whatever reason the general storm track seems to have shifted south since around 2012 or so.

Before then it was almost a given that Malin Head and Belmullet would record the strongest winds but in the past few years Mace Head and even the south coast stations seem to take the brunt a lot more often

weisses

Donegal Storm wrote: »

Hurricane bawbag (and another big storm around a week later) are I think the last 'good' storms I've experienced in Donegal, for whatever reason the general storm track seems to have shifted south since around 2012 or so.

I was getting the same impression ... It was mostly W, NW that got hammered ...

Snow Garden

That's a great comparison table Sryanbruen. Thanks.

Out of curiousity, where is Storm Brian? I thought that one was biggish or was it a false alarm?

Kamili

sryanbruen's table really adds fuel to the fire that this was totally over hyped by our national broadcaster

JCX BXC

I have to agree with the sentiments it was overhyped, it was to an insane degree.

It wasn't to be more than a regular orange wind warning for a few coastal Atlantic counties. Remember 2014? They were every few weeks.

Granted because it was a hurricane before it reached us it garnered extra attention, however this is, in my opinion, the most overhyped weather event we've ever had in this country.

Met Éireann play little or no part in this, they only issued a small number of orange warnings and that's exactly what the charts showed.

sryanbruen

Snow Garden wrote: »

That's a great comparison table Sryanbruen. Thanks.

Out of curiousity, where is Storm Brian? I thought that one was biggish or was it a false alarm?

Storm Brian wasn't as big in terms of max gusts as it was made out to be like most other storms we've had but I added it to the table for you there along with the depression that Donegal Storm speaks of (which is named Cyclone Hergen on wikipedia). See the post with the edited table.

The storms I had on the table were those added during event threads last year and random ones I picked out from the 2010s off the top of my head that I thought were notable (besides Dirk on 23 December 2013 which was more notable for being deep in the North Atlantic in terms of MSLP rather than wind gusts).

I find it amusing how the worst naming storm season was the first one we had, 2015-16 and how storms have seemingly become weaker since in terms of wind gusts. Like you see most of the red warranted ones (besides Ophelia in south, Doris and Eleanor in the NW) earlier in the decade before the whole naming storm debacle became a thing although even so, these generally don't compare to the likes of those from Jan 1974, Jan 1991, Dec 1997, Dec 1998 etc.

lleti

Todays weather is worse than during the week yet there's not even a yellow warning, nevermind national headlines warning of danger

M.T. Cranium

So here's a question about the warning system, if they (or we here at Boards) went to a more fine-tuned system breaking down counties into parts, which counties would you consider most in need of regions and what would you propose for them?

As a first draft of this, I would say that these counties do not need further dividing into regions for warnings:

Sligo, Leitrim, Roscommon, Cavan, Monaghan, Louth, Meath, Longford, Westmeath, Offaly, Dublin, Kildare, Laois, Carlow, Kilkenny, Wexford, Waterford.

For the rest, this would be the proposed sub-county grid for warnings:

Kerry north, Kerry south, Cork north, Cork south, Limerick west, Limerick east, Tipps north and south, Clare northwest, southeast, Galway west, central, east, Mayo northwest, southeast, Donegal south, Donegal north, Wicklow east, Wicklow west.

Then if this grid were in use, a warning that did not break down the county would apply to all parts.

Alternatively, you could make the system totally map-dependent, and just issue warnings for "all of" and "parts of" counties with a map published to show what zones were in what categories.

For this past storm, I would imagine the orange warnings might have been restricted to some parts of at least Clare, Galway, Cork and Mayo, with yellow for the more inland portions so the map would have looked more yellow and less orange basically. If no regions were being used and just the zones on a map, then probably the orange zone would have been most of the west coast within 20-30 miles of the ocean.

Also it might be helpful for maps to have two styles of shading for wind and rainfall, same colours but say solid orange for the wind warning and hatched orange for the rainfall (which in this case in hindsight may not have overlapped and in fact there was probably a zone of yellow wind and rain verifying in the space (north Mayo-Sligo) between them.

Can see that Sligo, Leitrim and Roscommon often have north-south differences that might add them to my list of possible divisions. Give this some input and I will get a base map created (if the prevailing opinion favours breaking down counties and not just the map based system) for use here, and we can help fine-tune these warnings.

Is this breakdown fine enough to make the system potentially more responsive, or would you need even more of a subdivision?

M.T. Cranium

Sryanbruen, it would be interesting to see Debbie (Sep 1961) on the same grid as the other storms, maybe Oneiric could collaborate and you could estimate some of the data from locations not then recording wind speeds. The map I saw early in the thread seemed to have a fairly regular looking wind pattern that would probably allow some reasonably good estimates.

Gaoth Laidir

M.T. Cranium wrote: »

Sryanbruen, it would be interesting to see Debbie (Sep 1961) on the same grid as the other storms, maybe Oneiric could collaborate and you could estimate some of the data from locations not then recording wind speeds. The map I saw early in the thread seemed to have a fairly regular looking wind pattern that would probably allow some reasonably good estimates.

These are from Debbie.

https://irishweatheronline.wordpress.com/2015/10/28/blast-from-the-past-hurricane-debbie-1961/

Kutebride

Oneiric 3 wrote: »

A reminder of the wind gust speeds from Hurricane Debby back in 1961, and these are in knots, not Km/h.



Entire forests were flattened around here in a matter of minutes during that storm.

Only recently my Dad mentioned this storm, that flattened forests, and he got a job gathering the trees/wood as a result of this, that year as a teenager in Galway.

Storm 10

Kutebride wrote: »

Only recently my Dad mentioned this storm, that flattened forests, and he got a job gathering the trees/wood as a result of this, that year as a teenager in Galway.

I was at school in Galway that morning when we were told to go home, we went straight to the Wolfe Tone bridge to watch the River Corrib getting blown in the opposite direction, Had to walk home to Salthill dodging slates coming off roofs and hardly able to stand ,The following morning Salthill was literally destroyed the main road and prom was gone three Houses near the sea front disappeared into the Sea a lovely harbour at Seapoint was gone massive rocks and sand everywhere our roof was gone I never want to see the likes again but it was exciting

JanuarySnowstor

Ireland is a very small country
County by county warnings is absurd.
It should be just simply done on a geographic spread as was done for the last 100 years before the softy millenials came along!!
Windy on west and north coasts etc is a typical phrase we used to hear before that worked fine
In the era of fake news folks always speak your mind not what you think will get you a 100 likes!!!

Snowc

Somebody is just back from the pub;)

SleetAndSnow

If we were do do what M.T is suggesting with warnings, from a cork perspective we would need cork north, south, east and west. The county is huge (like 1/3 of NI). It’s often shocking weather in the west and dry and sunny in the city (or East).

Meteorite58

M.T. Cranium wrote: »

So here's a question about the warning system, if they (or we here at Boards) went to a more fine-tuned system breaking down counties into parts, which counties would you consider most in need of regions and what would you propose for them?

/QUOTE]

I like the Met Offices warnings, think they work well as highlight areas of risk rather than county by county and as we all know weather events can be very much confined to a certain area such as winds for coasts or general coastal areas or as like mentioned say 10 to 20 km inland or rain for the far W of Galway or the far SW and W cork or snow along the E coast etc etc.

We must get away from county by county warnings I think, people want accessible , easy to read and understand forecasts that are area specific.

Included a few examples from the Met office below and link to Weather Warnings guide which gives further examples for warnings.

https://www.metoffice.gov.uk/weather/guides/warnings/










Also like the Convectiveweathers maps, as we know forecasting thunderstorms is difficult but again these maps give a good idea of areas of risk.





This guy https://twitter.com/metmonkey is doing some great work putting together risk outlook charts for both convection/ lightning, storms and snow worth a good look .

Examples

Gaoth Laidir

It would really help if Met Éireann presenters on RTÉ would put up an actual map of Ireland with the coloured counties in their broadcasts. Instead we have awful misaligned text of all the same font, no bold, etc., which really doesn't do much to put the overall message across. They have this map on their website ffs, just copy and paste it across.

I don't agree with having 4 levels of advisory, watch, warning and alert. There is much more room for confusion with that system imo. The general public are unable to properly read the current forecasts as is, so adding alliteration to the mix is a recipe for disaster. Keep it simple, stupid.

Donegal Storm

Naming storms is the single biggest driver of hype for me, the second a storm gets named it's all over social media and office conversations and regardless of strength or where it's due to hit, people just have the idea in their head that a big storm is on its way

Also most 'storms' this country amount to a few hours of rain followed by a windy day with heavy showers, they look dramatic on weather charts with bright colours and whatnot but the reality isn't all that different to a normal bad winters day.