Revenge of the weather nerds

Train spotting... plane spotting.... weather watching. Whether it's 747s, a freight train or a funny shaped cloud there's always going to be a group of geeks who are passionately into it.

And like most interests in life there's always a fine line between a geek...and a freak. The difference between the two? One is a healthy interest the other is an unhealthy obsession. There are some complete nut jobs out there in the weather world...and I'm starting to learn this as media outlets run press releases written by me or the Weather Watch team.

Since we launched the Weather Watch Centre last July I've had many comments. Some are from people who know their stuff (meteorologists & enthusiasts), others are just everyday kiwis who love the weather for no real reason, others need to know about it for their farms or vineyards or whatever their profession may be. Then, there are the freaks...who are quite obviously one frontal system short of a weather map. These are the ones who write to me, frequently, pointing out every mistake we make - even the mistakes TV presenters make. Now if I do make a mistake I don't mind being told - most people are polite when they tell me I've made a typo in a story, but the freaks are never polite. They demand retractions and apologies.

So, out of the complaints I get - which are valid and which are not? Let me share some of the things I've had complaints about over the past year:

- Using the term 'mini-tornado'. Small tornado was ok though. (pretty sure mini means small).
- Calling a storm a 'cyclone', when it wasn't in the tropics.
- Saying the temperature 'felt like 40 degrees' when it was probably more like the late 30s.
- Saying that 'Auckland had its hottest day', when even NIWA backed that up.
- Mentioning a 'front' had reached Cook Strait was when in fact I should've said 'frontal cloud'...the front was still back in Canterbury.
- Using the term 'gusting to gale force'.
- Allowing the media to use the term 'weather bomb' all the time (apparently I run the media).

Now some of those comments above are fair enough. Obviously I'm human and sometimes when being rushed in an interview you say something like "gusting to gale force"...which technically isn't correct. But does it really matter? I've found the majority of people glaze over the second I start talking in too much detail...and my job is to get people hooked to the weather. You don't do that by debating semantics.

SO...from the above complaints, let me respond. I also asked Bob McDavitt - weather ambassador at MetService - for his point of view on a few of this complaints. By the way he says he describes himself as a "guru" not a "geek". "Once the weather has turned your hair as white as mine, you can move from weather geek to weather guru" says Bob. Fair enough too. I'm starting to get a few greys myself so I feel like his apprentice.

- "Mini tornado". The geeks have this right - there is no such term. But tornados are classed using the Fujita system. An F0 is at the bottom of the scale...this is the smallest you can get. Most twisters in NZ would fall into the F0 category and F1. F5 is the highest...the Oklahama tornado back in the 90s was an F5. Considering we rarely get significant tornados the term "mini tornado" doesn't really worry me as in context F0 means nothing. I suspect this is why MetService also don't use the Fujita scale and usually just mention "weak tornados". I can accept the term mini-tornado isn't overly accurate - you either have a tornado or you don't. But a weak one, or small one, or 'mini' one is surely safer than just saying "tornado". I wouldn't want the public to think something from the movie Twister is on the way!

Bob, what do you think? "I don't mind the generic term twisters to describe the ones we can see. . Two passing trucks on the road make a spin in the wind, felt by the nearby cyclist but not actually seen. On the scale of a few metres for a few minutes we get "dust devils" (sometimes called Willy willys in Australia) and these can be seen by the debris they carry and sometimes do some damage- they can knock cyclists over. They occur naturally when the atmosphere is ripe and they don't need a cloud to form them. The name tornado should be reserved for those twisters that are formed by a cloud. By the look of them, they seem to start at cloud base and descend towards the ground. In NZ , the damage trail is usually a few metres wide, a kilometre long and within 10 minutes, and shows a twisting wind. That's F0 to F1. Cumulonimbus clouds can also produce downbursts - when the downdraft takes stronger upper winds down to the ground, winds in a downburst can be over 100km/hr and produce a swathe of damage several metres round showing straight wind directions. These downbursts should not be described as twisters, tornados, or mini-tornados. Their principle cause is different".

- Calling a storm a cyclone when it's not in the tropics. Well a high pressure system that forms outside the tropics in the southern hemisphere is called an anti-cyclone...so surely it stands to reason that cyclone is ok. If it's severe and can cause significant risk to property and life then the word cyclone is fine by me. I wouldn't want the term overused though...but often a big storm passing the South Island can easily match a moderately sized tropical cyclone. It's about putting those southern storms into perspective.

- "It didn't feel like 40, it felt more like the late 30s". I think a freak complained about this - not a geek. The late 30s and 40 would feel so similar. Besides, who can argue what a temperature feels like? It's subjective.

- Auckland's hottest day. Wow this got the geeks and the freaks excited...but for all the wrong reasons. While many forecasters were chuffed that Whenuapai airbase recorded its highest ever temperature last month, many weather geeks and freaks were more into a 'heated' debate about what defines Auckland's hottest day. So much for enjoying the moment. Some angrily argued that Auckland airport is the official reading for Auckland... yeah that makes sense, the temperature gauge that's furthest from the city. I find Whenuapai to be more accurate at representing Aucklanders as it's closer to the CBD and mirrors more of our inland suburbs. When I asked someone (can't remember if it was a geek or freak) what exactly defines Aucklands hottest day they couldn't answer me. Did every single thermometer in the Auckland region have to beat its record? Honestly, does the public of New Zealand care?. One thermometer broke a record, therefore it's a record breaker for that part of Auckland. My press release on that day pointed out exactly where the temperature was taken from too.

- Frontal cloud. The geek (and a nice geek at that) pointed this out to me was actually correct and I was wrong. Frontal cloud lies ahead of the front - to make this confusing the front is usually at the back. Confused? This is why I don't normally talk like this.

- Gusting to gale force. Geeks passionately argue this is wrong. Technically it is and, well, technically it isn't. In New Zealand and much of the world gale force is a wind speed averaging over 62km/h for a minimum of 10 minutes. In America, they go by 1 minute. So it depends on whether you think Americans do a good job at weather forecasting and covering weather news or not. If you think they're too hyped then you'd probably agree a 10 minute level is right. To me, 10 minutes is too long, 1 minute is too short. 3 minutes suits me just fine. At the end of the day the general public, you, probably couldn't care less - but our weather presenters on TV should avoid saying it as it can have an impact on how the public perceive gale force winds. A gust is simply that - a short burst of wind. A gale is a word used to define wind blowing for 10 minutes. (Although as I said, 3 minutes sits fine with me).

Bob, your thoughts again please? "Gale force" is a term from the Beaufort scale which refers to an AVERAGED WIND of 62-74 kph (Beaufort force 8 and 9 )(not a gust). The World Meteorological Organization was formed in part to set international standards for comparing weather observations around the world and sets the standard for an averaged wind at over at "over a ten minute period". This is the standard we use to report our wind observations and for or wind forecast. Mariners do not sit and watch their wind gear for ten minutes to work out the average speed of the wind, and usually, as you say, three minutes will do OK. .

Beware when using the "One minute wind" as this refers to a one-minute MAXIMUM SUSTAINED WIND as used in the US to classify the intensity of tropical cyclones. It applies to a maximum over the period of many hours, thus it isn't an average. It is a term that tangles our terminology. So when I say gale force, that's force 8 or 9 on the Beaufort scale and an AVERAGE of 62-87 kph, but has GUSTS of 90 to 120 kph. The term 'gusting to gale force' tangles the meanings of averaged wind and gust ".

- Use of the term "weather bomb". This is a kiwi term to describe a low that deepens at 1hPa an hour for 24 hours. It happened back in 2004 causing significant damage around the North Island. Since then journalists use the term "weather bomb" whenever there's been any damage related to weather. To be honest this term is so rare and unknown around the world I don't think it's a major problem if it's used incorrectly. The English language evolves and since Bob McDavitt used it so famously back in 2004 the general public and journalists have used the term "weather bomb" to describe a "generally nasty weather event". If that's how it's evolving then so be it. But in the interests of not wanting to promote inaccurate information - the term 'weather bomb' should probably only be used once in a blue moon. I'll always correct a journalist when they use that term with me, but really it doesn't upset me at all when I hear it used elsewhere. (Here's an indepth paper on the definition of "bomb").

But I don't believe that this term can confuse the public - they have no idea what a weather bomb technically is and they happen so rarely I doubt they'll ever need to know it.

Bob disagrees with me. "Misusing this term does upset me. Let's reserve it for Lows that deepen 24hpa in 24 hours (corrected to a reference latitude) . OK its then a technical geeky definition but it is useful to reserve this term to just classify the rapidly deepening lows. The amount of damage from a weather bomb may NOT be as much as other lows of lesser intensity. The Low of 26 July last year at 960hpa was the deepest low we have measured n in NZ and a definite BOMB, but only lasted six hours and just sideswiped Northland. There were five fatalities and $26 million in insurance payouts. The very next low was around 980hpa, and took three days to cross central NZ . It caused 2 fatalities, and $42 million in Insurance payouts including a slip that closed road and rail between Kaikoura and Cheviot for days. People may remember the YouTube of a tree falling on a car in Nelson. It was NOT a BOMB under this definition but had the greater impact"

Maybe we need to come up with another cool term like "Weather Bomb" that journalists and everyday kiwis can use to describe a nasty storm?.

Thanks for your contribution Bob - by the way MetService has a great wind poster, you can download for free, by clicking here. This explains wind speeds and the Fujita Scale too and is actually quite interesting.

So there we have it...are you a geek, a freak or a guru? I don't know what I am.......fine....as much as I hate to admit it I think I'm a geek. Sigh.

Top photo: Is it a tornado? Or a cyclone? Photo / Supplied