MetService gets call for an inquiry: One News

TonyT · Unread post by **TonyT** » Wed 25/01/2006 08:58

Yesterday's Fencepost forecast for Auckland did say "fresh" northeasterlies, but the risk of gales was mentioned for other regions, and most had predictions of winds "strong". I'm not sure why we didnt have the gale risk in for the Auckland region, so that could have been better I agree.

The rainfall amounts predicted were 20-50mm for the heaviest part of the rain (which we picked as later in the day) and 50-100mm total for the day (this for Northland, Auckland, Waikato, Bay of Plenty). Today's Herald reports rain of 40-60mm in most parts of Auckland, with up to three times that in the hills. So I would say our rainfall forecasting was spot on - how can anyone in Northland not be happy with that prediction? (minor timing error aside). All of the forecasts talked of heavy rain, easing late in the day. So that was pretty good too.

Asd for the maps, well Fencepost migrated to a new server last week and it has got issues whereby the maps (both the weather map and the warnings map) are not updating. So the maps on there are weeks old. The Fencepost admins know about this and tell us they are working on it. Its out of our control. The maps are most certainly not a rough guide, and are intended to be as accurate as possible.

And finally, I dont feel I "easily say when the met service gets things wrong" I usually button my lip, expect when I see people like yourself praising them to the skies and often blind to their mistakes. Their rainfall predictions were pretty good for this event, and someone in this thread rightly mentioned that. So for you to come along and rubbish our rainfall predictions, when they were also pretty good simply shows you are good at storing up grudges, a trait which other users of this forum have commented on in the past.

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Weathermad · Unread post by **Weathermad** » Wed 25/01/2006 09:51

Thanks for clarifying matters Tony regarding the temperatures and the new site too...

I had one email from a listener asking how the maximum and minimum temperatures are forecast/predicted...Could you please explain this and do you( Blue Skies), do it manually?

Ta muchly in advance!!

Richard

TonyT · Unread post by **TonyT** » Wed 25/01/2006 09:58

You can do it "numerically" by using a combination of what the models are predicting in terms of upper atmosphere temperatures (eg at 1500m altitude) and past statistics of what local temperatures have been. Or, you can do it "manually", by mentally taking into account local winds, expected cloud cover through the day, wind direction, etc (a whole lot of other factors too, some obvious things like time of year, some less obvious like the time of day the maximum is likely to be reached) and coming up with a number. I guess you could sum that process up in one word, "experience".

There are issues, as I alluded to before, in that there can be quite significant variations across quite small distances (eg some days the eastern suburns of Chch are 2-3 deg cooler than the west, some days its the other way around, most days they are the same). Also, where you measure your temps from is important - radio stations usually take their readings from the roof of the building, so if I were doing forecasts for radio I would probably add 2 degrees to the forecast max and 3-4 degrees to the forecast min, just to get them lining up with the temps the radio station will be reporting to its listeners.

RWood · Unread post by **RWood** » Wed 25/01/2006 10:24

Tony, on Monday 16th saw your 12-day forecast on the office wall of a Sounds launch cruise company. For Nels/Marlb. it has worked out very well. Though I fancy my own capability at filtering various published forecasts through my own judgement of local signs, these things are still very helpful. We were able to plan all our activities around the expected weather and the only slight kink was the rain arriving a little early (noon yesterday in Nelson area).

Thumbs up from me.

TonyT · Unread post by **TonyT** » Wed 25/01/2006 10:28

Thanks RWood. I also got a call yesterday from a pilot with Air Fiordland, very concerned that the weather map on Fencepost hadnt been updated for a while!

Perhaps we should have a competition for the most unusual use of a weather forecast. I'll start off with this one, the lady from the local speedway track who uses the forecast for Saturday evening to plan whether to make salad rolls (which are profitable, and sell well on mild evenings but are time consuming to make) or just rely on pies (which have a lower margin, sell well on cold evenings and take no time at all to prepare).

spwill · Unread post by **spwill** » Wed 25/01/2006 10:29

I glanced the Auckland weather forecast on Fencepost.com mid afternoon yesterday during our big blow and was very surprised to see their forecast was just for fresh gusty winds.

TonyT · Unread post by **TonyT** » Wed 25/01/2006 10:44

spwill wrote:I glanced the Auckland weather forecast on Fencepost.com mid afternoon yesterday during our big blow and was very surprised to see their forecast was just for fresh gusty winds.

Who'd be a forecaster, eh?

Willoughby · Unread post by **Willoughby** » Wed 25/01/2006 10:48

TonyT wrote: Perhaps we should have a competition for the most unusual use of a weather forecast. I'll start off with this one, the lady from the local speedway track who uses the forecast for Saturday evening to plan whether to make salad rolls (which are profitable, and sell well on mild evenings but are time consuming to make) or just rely on pies (which have a lower margin, sell well on cold evenings and take no time at all to prepare).

I sorta forecast for the manager at the restaurant I work at.. tell her how, e.g next week will shape up sales wise and to put more staff on when it's a wet cold day!
early October last year when we that very unstable cold westerly belt over us for a week or so gave us record sales for the year

TonyT · Unread post by **TonyT** » Wed 25/01/2006 10:56

Interesting, in Chch I believe its the other way around, wet cold days mean fewer people eating out, warmer sunny days have higher turnover. Perhaps it varies with the type of eaterie.

03Stormchaser · Unread post by **03Stormchaser** » Wed 25/01/2006 18:57

Now and again I'll get rung up about when its a good time to cut hay during summer or dig potatos from a couple of farms in N.Canturby. So far so good with my preditions, touch wood!