How accurate is weather forecasting in the media?

DMC

How many times have you cursed at the weather man on the TV saying "ya didnt say that was going to happen" or "that never came here today"?

How reliable and accurate do you think the weather forecasts on TV, radio or the newspapers are? Do you believe them half the time, or only when the weather is good?

Hell, lets have a poll!

daveg

I voted accurate most of the time which I think they are. For those in the West the Galway Advertiser's 5 days forcast is nealry always spot on........... but then again how difficult is it to predict it'll rain 90% of the time :rolleyes:

DeVore

Er.... study chaos theory for a start.

What level of confidence are you defining as "accurate" in predictions and what level of matching of prediction to outcome do you require for "accuracy" in retrospect?

Weather forcasts for tomorrow will generally have a high confidence value, probably something in the 95% range.
It drops off then every day as the influencing factors become more and more subtle and the calculations become larger and larger. Eventually you simply dont have the information to even process in the first place as its too subtle to capture.

The accuracy more or less breaks down at 5 days currently (afaik) though even at that extreme you are dealing with a fairly low confidence level in the prediction.

There are some people on boards from Met Eireann who might be able to shed some light on this as all of the above is purely my understanding from Maths.

DeV.

DMC

Getcha DeV The level of accuracy I was looking at was next day. I totally argee, the further away from the event, the more chance its not completely accurate

For me watching the farmers forecast on the telly on Sunday really only gives me "a guide" for the week. You would feel confident that what they are saying for Sunday-Wednesday should hold, then, being me, I'd get an update on Wednesday (BBC1 lunchtime forecast on Wednesdays is another farming forecast) to make sure that the rest of the week forecast hasnt changed.

Thats for short term planning, I'd still watch the night befores forecast to be sure.

Sleipnir

I think it's a lot tougher to forecast the weather than people think.
Basically, a meteorologist looks at all the current data, searches back for a day where the data was very similar. And then says
"ok, well when it was like this before, the weather 2 days later was like this, so it's reasonably likely that it will do a similar thing again"
Now that's basically what they do, but it ain't really that simple!

Chaos theory applies to the 24 hour forecast sometimes too, and more often than not, a wrong forecast is remembered more so than a right one.

The most recent example was last week when cloud and fog descended on the south East , whilst the rest of the country was roasting.
sure, it was forecasted for there, but it was impossible to predict when it would come or go.

So a 24 hour forecast predicted temperatures in the mid to high 20's and what they got there was a miserable 17 or 18.
You had people travelling from boiling hot inland towns to enjoy a day at the seaside and all they got was the fog.
Similarilly, the chaos at Dublin Airport last week end was caused by the same event , the extent of which was difficult to predict.

By and large though,they do get it fairly right imho, and are only let down by natures flooky behaviour at times.
mm

mike65

I voted option 2.

Chaos Theory eh? I bet Micheal Fish cited that very phenomena in 1987, the morning after the night before.....;)

http://www.dandantheweatherman.com/Bereklauw/Octstorm.html

I try to catch the RTE Farming Forcast as I like stats and it tends to be alot more right than wrong but as ever it cant foresee the unexpected...if you get me!

Mike.

Originally posted by mike65
I try to catch the RTE Farming Forcast as I like stats and it tends to be alot more right than wrong but as ever it cant foresee the unexpected...if you get me!

Mike.

On that note, when I first started recording rainfall here, friends of mine suggested I put the recording jug beside a down pipe from the corner of the house.
They wanted to hear "divil a bit" explain that apparently there had been a 1000% above average rainfall in this part of the East coast...
I didn't oblige:D
mm

sceptre

Originally posted by Man
and more often than not, a wrong forecast is remembered more so than a right one.

Certainly true.

And I knew someone was going to bring up the Michael Fish thing:D

Ah, don't worry love. Hurricane? Ha!

Fabritzo

Lisa Burke on sky news weather is great, I can never seem to be able to concentrate on the weather forecast she is presenting though, not to mention remember what's she's said....weather, we need weather....

DapperGent

In general next day forecasts are very accurate, forecasting becomes exponentially more difficult (and in accurate) as time goes on.

Current computer models give an output to 10 days ahead, the last three days of which can easily be completely and utterly wrong. By a rule of thumb three days is grand almost 100% grand, 5 is probably alright, 7 is difficult and the forecast must be very general anything after 7 has as much chance of being wrong as right.

Forecast accuracy also depend on the current weather, a situation like now with a large stable blocking high makes it a lot easier for models and human forecasters alike.

Normally Ireland's weather consists of various fronts coming in from the atlantic one after the other. A weather system that could be dominating Ireland' weather in four or five days may not even have formed yet. It's also a problem that it isn't easy to gather data over a body of water, weather buoys are horribly expensive so there aren't that many of them.

Whats certainly true is that predicting weather for bit of rock jutting out into the North Atlantic ain't easy!

Well, case in point last night:

My understanding from the forecast was that , Wicklow was going to have a dry night, but mother nature, unpredictable at times as she is, had other ideas.

At about 3 am last night I was awoken by a very noisy down pour,and as I type even though it is very sunny now, there are pools of water still on the tarmac outside.

Also during said downpour which went on for over an hour, I remembered I'd left the sunroof open:eek: so it's not just on the tarmac that there are pools of water.

I notice on the radar history for last night that, that "shower" travelled across the Irish sea from wales in almost as good a time as the fast ferry.

mm

Dude111

I voted option #2 (Almost always)

I cant believe how many times i have seen them BE QUITE WRONG!!!!

And day to day temperature forecasts ARE ALWAYS NOT THE SAME

For example in todays paper it says this EXPECTED HIGH FOR MONDAY IS: 0

In yesterdays paper the EXPECTED HIGH LISTED FOR MONDAY WAS: 2.22

Weather forecasting is a JOKE,you cant say what nature is gonna do..


They usually get it pretty close but its impossible to get it accurate!

thetonynator

Zombie thread? What the hell . . .. i'll vote anyway!

Fabritzo

The forecasting has come on a bit since 2003, I think Lisa has hung up her forecasting boots though

isle of man

i have to say all forcasts for us here, are well shocking,
does not matter if its BBC or local.

you would think the local met here would maybe be able to get it right a bit more taking in to accont local weather etc.
but nope they have no idea whats so ever.

The storms we had last month.
While all on here had them plotted out 2 weeks before that there was a chance.
then the week before it was a 70% chance of hitting.
to 3 days before it hit you were all 100% sure it was right. and you were right.
The local weather out put out a warning the night before it hit. :eek:.

I kid you not i was telling people to batten down the hatchs as it was going to be a strong winds etc. and most of the replys i got was, oo the weather man says it be fine. and i mean well over 75% said this.

So a lot were caught out by this. because of our weather men having not a clue.

Even me mum was going o bbc says it be fine, local weather says it be fine,
had a comp on who was going to be right. yep i won!!!

Once again i have to say a huge big thank you to the 4 or 5 that have given warnings and when i have asked for a report on what we may get have offerd this and it has been vary vary helpful. and i thank you for that.

problem is i know get phone calls and msg asking what the bloody weather is going to be, as they say i can give them more reliable results than the met. (told them i was going to charge them £1 a min ) I have told them its not my forcasting but some vary good people on a website:cool:

Because apart from the good advice i have got from this site about major weather movments, i have picked up a great deal on how to read the weather and im getting ok at it now. But im preety good at guessing when it will snow, the signs to look out for etc, and how the clouds seam to go around us now.
So much so i am the offical snow reporter for the island among my freinds.

But this is all down to you lot. so thanks again and please please keep up the good work.

you really are saving a lot of people a shock when they wake up in the moring be it from flooding winds or snow.
So you really are helping people well here on the island you are that know me.

keep it up

lord lucan

Holy Thread Resurrection Batman!!:eek:

isle of man

ha ha i diden see the date.

dear god thats some post from the agers.

Dublin_Gunner

Its about as accurate as predicting when someone will REVIVE A SEVEN YEAR OLD THREAD

Seriously, its not bad in the short term. Weather is one of those unpredictable things.

It can never really be said it will be 100% this or that, but usually it will be 'most likely' this or that.

So many factors to consider and model from all around the globe - and space that effect our weather.