Storm Ophelia in Mayo: The dangers of inappropriate forecasting


First I acknowledge the source of my data for actual wind speeds recorded and forecast bulletins as Met Eireann and have assumed the usage here to be acceptable under their copyright which states: The use of the web pages, and the information contained within them, for private and non-commercial purposes, for teaching, and for research, is allowed subject to the condition that the source of the information is always credited in connection with its use.

I ask readers to note that my censure is solely directed to weather forecasting and Television media as related to the Mayo area and not elsewhere. I do feel that the inclusion of Mayo in the Status Red warning was over the top and inappropriate in the light of other data that is freely available. It was very obvious from the data presented on Earth:NullSchool that Mayo was NOT in line for anything worse than that which we usually experience during Autumn and Winter storms.



On the video above the location is shown with the small green ring near the top right hand corner and just on the west coast of Ireland. The actual location is shown on the video in Lat/Lon.

In the run up to Storm Ophelia dire warnings were posted on the Met Eireann web site, and rightly so as ex-Ophelia was due to be severe in the south of Ireland.

Below are the three days Status warning and Connacht regional forecasts up to and including the 16th. Any emphasis is by me.

14th October

STATUS YELLOW: Weather Advisory for Ireland. On Monday an Atlantic storm from the remnants of Hurricane Ophelia will move northwards close to Ireland. There is still a high degree of uncertainty regarding the exact track and evolution of the storm. However storm force winds heavy rain and high seas are threatened. Met Eireann will continue to monitor this storm and will issue appropriate warnings as required. Issued: Friday 13 October 2017 08:00. Valid: Monday 16 October 2017 06:00 to Tuesday 17 October 2017 06:00. [This was appropriate]

Connacht: 14 October 2017- updated at 06:00. Today: Cloudy and misty at first today with scattered outbreaks of rain and drizzle. It will become dry in most parts by early afternoon but rain will affect parts of the west coast at times. Some bright spells will develop inland. Highs of 16 to 18 Celsius and mildest in the southeast. Light southerly breezes will increase moderate to fresh with strong winds developing near the west coast. Tonight: Cloudy and breezy overnight with outbreaks of rain and drizzle spreading from the west. Mild with lows 10 to 13 Celsius in fresh and gusty southerly winds which will be strong near the west coast. [This was appropriate]

15th October

STATUS RED: Wind Warning for Galway Mayo Clare Cork and Kerry. Hurricane Ophelia is expected to transition to a post tropical storm as it approaches our shores on Monday bringing severe winds and stormy conditions . Mean wind speeds in excess of 80 km/h and gusts in excess of 130km/h are expected potentially causing structural damage and disruption with dangerous marine conditions due to high seas and potential flooding. Issued: Saturday 14 October 2017 13:18. Valid: Monday 16 October 2017 09:00 to Tuesday 17 October 2017 03:00. [This was not appropriate for Mayo]
STATUS ORANGE: Wind Warning for The rest of the country. Hurricane Ophelia is expected to transition to a post tropical storm as it approaches our shores on Monday. Mean wind speeds between 65 and 80 km/h with gusts between 110 and 130km/h are expected however some inland areas may not be quite as severe. The winds have potential to cause structural damage and disruption with dangerous marine conditions due to high seas and potential flooding. Issued: Saturday 14 October 2017 13:21. Valid: Monday 16 October 2017 09:00 to Tuesday 17 October 2017 03:00. [This was appropriate]

Connacht: 15 October 2017- updated at 06:00. Today: Today Sunday will be mild and misty. Rain and drizzle will be fairly widespread this morning and with a few heavier bursts occurring in parts. Top afternoon temperatures of 15 or 16 degrees. Fresh and gusty southerly winds strong to near gale in western coastal areas at first this morning will become northwesterly and ease through the course of the day. Tonight: Further rain and drizzle tonight with the rain turning persistent and heavy with a risk of thunder. Winds will be generally light between northeast and southeast in direction at first but become increasingly gusty northeasterly by dawn. Overnight lows of 9 degrees Celsius. [This was appropriate]

16th October

STATUS RED: Wind Warning for Ireland. Latest Update Ex-Hurricane Ophelia is forecast to track up over western parts of Ireland during daytime today. Violent and destructive gusts of 120 to 150 km/h are forecast countrywide. These over Munster and south Leinster this morning will extend quickly to the rest of the country this afternoon. Also heavy rain and storm surges along some coasts will result in flooding. There is a danger to life and property. To recap Most severe conditions over Munster and South Leinster this morning and early afternoon Remaining areas this afternoon. Issued: Monday 16 October 2017 09:09. Valid: Monday 16 October 2017 09:00 to Tuesday 17 October 2017 01:00. [This was NOT appropriate as it was too all inclusive.]

Connacht: 16 October 2017- updated at 06:00. Today: Today will be a stormy day as Ex-Hurricane Ophelia moves over the country. Winds will vary in direction and strength through the day but there is the potential for structural damage. There will be heavy rain as well with local flooding. Highest temperatures of 16 to 18 degrees. Tonight: It will continue very windy for a time tonight with showers or longer spells of rain. Later in the night it will become mainly dry and winds will gradually ease a bit. Lowest temperatures of 9 or 10 degrees. Strong to gale force westerly winds will decrease fresh to strong overnight. [This was appropriate if possibly a little over the top and bears little relationship to the status warning of red also issued.]

On the video above you can see that the mean wind forecast speed reached a maximum of 40kph, or just about 25 miles an hour. I have to point out that this is well below mean wind speeds that we get in winter storms. I find it extremely difficult to believe that the Met Eireann and Met Office UK forecasting models can be giving them data that causes them to make such inappropriate all inclusive warnings.

The Met Eireann warning caused the local paper to print this on their Monday edition:

(Click the Image for a larger/clearer version)

Castlebar and probably many other business areas in Mayo and the schools were shut, most from 12 noon onwards presumably based on the last all inclusive Red warning issued by Met Eireann and the continual non-stop scaremongering on the TV about how bad this was going to be. No vective can be directed at these organisations as they were correctly reacting based upon the information that they received.

What did happen weatherwise? Pretty much EXACTLY as forecast on Null School. As I said the projected mean was 40kph and the actual reading at Knock Airport – 20 miles from the location on the projections but higher up (and usually windier) – was just over 37 kph, with a max gust of 50 knots or 57.5 mph which is 92.54 kph. This is a long way off the 120 to 150 kph ‘destructive gusts’ that were forecast and well within the range of gust we usually experience in winter.

(Click the Image for a larger/clearer version)

The real danger of this is that, due to what we actually experienced by comparison to the forecasts, people will be less likely to believe future forecast when they may be appropriate. We all know the story of the boy who cried ‘wolf!’.

Please note that I am not a trained meteorologist, although I did teach meteorology to Air Cadets in the past, and what is expressed above is my opinion based solely on my years as a citizen scientist and a deep interest in all things connected to the weather, earthquakes and volcanoes.

About PuterMan

A retired programmer.
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