Weather meteorological forecast

[0707]

From my search, meteorological 24 hour forecasts have 86% of accuracy. 5 day forecasts have 80 % accuracy. In the north hemisphere in the beginning of summer we always hear sensionalistic announces saying that heat waves will grew up on the contrary in winter the announces are for more and more cold.
With a four month delay usually all the forecasts for Europe are inaccurate and instead of heat we have cold and also the contrary. Most of the times this inaccuracy is attributed to Azores Anticyclone dislocation versus north or versus south.
For oil refineries, for air conditioning sellers, for tourism, for fire fighting, for civil protection and for clothing is important to know in advance how will be the weather behaviour during the summer and during the winter to adjust their business planning accordingly.
With all that geo stat ional meteorological satellites and computational programmes why cannot whether forecast be more accurate beyond 5 days?

luismarques

 

[PSE]

I would propose that there is much yet to be understood as to the various interrelationships between meteorological indicators. Temperature, Humidity, wind speed, direction, barometric pressure all have underlying factors that affect them. Seasonal changes bring in factors of solar cycles and their effects.

I think we know quite a bit, but there is much more to discover still.

Last week I was sitting out on my deck in the sunshine and got rained on. It was a partly cloudy day and my hypothesis is that upper level winds carried the precipitation away from the cloud and so kindly deposited it on me. There was only a slight breeze at ground level.

Regards,

 

[rb1957]

'cause it's difficult ?

seriously tho', weather is a chaotic problem, small differences in the initial conditions make significant differences to the future predictions. that and we don't know all the interactions (so we aren't measuring the right things).

but somehow ground hogs have managed to do this (at least once a year when people (well, americans) are watching).

 

[csd72]

If scientists cannot agree on the causes of something as straight forward as climate change then what hope have they got for the subleties of weather!

 

[sms]

Ever worked a multivariable problem? Just a few variables get complex quickly. Imagine doing a problem with thousands or hundreds of thousands of variables...

I also expect that weather models can be correlated to the sun, so a good 6 month predictive model of the sun would probably be required to do a good 6 month predictive model of our weather.

No offense cs72, but I don't agree that "straight forward" is a reasonable adjective to use with "climate change."





"Why don't you knock it off with them negative waves? Why don't you dig how beautiful it is out here? Why don't you say something righteous and hopeful for a change?" Oddball, "Kelly's Heros" 1970

Please see FAQ731-376 for tips on how to make the best use of the Eng-Tips Forums.

 

[zdas04]

We can't predict tomorrow's weather with much better than 80% accuracy anywhere on the planet (even in Death Vally and the Qattara depression they regularly get the wind speed and direction wrong). In the mountains it is much closer to being worse than a coin toss.

The climate is amazingly complex with hundreds of independent variables, and many thousands of dependent variables (most with varying dependencies). Hell, we can't agree on what happened last year, let alone tomorrow or next month.

On this canvas of complexity, I find it amazing that people say with a straight face that they know what will happen to the global climate over the next decade. Certainty in the global climate change discussion is the rankest form of hypocrisy.

David

 

[civilperson]

If a accurate prediction of solar energy variations could be made, then the climate questions might resolve into something solvable.

 

[epoisses]

What is 80% accuracy? 8 hours of sunshine instead of 10? 6 Beaufort instead of 5? What is 80% of no rain today?

In our region where the weather is extremely simple (binary: northern wind = dry, southern wind = wet, no other winds exist and the wind changes only after an odd number of days as old locals say) but 5 days forecasts are completely useless. 2 days is already stretching it.

Predicting climate change on a global level is fairly accurate, experts say, but regional (say: a continent) effects are still difficult to predict.

 

[rb1957]

"Predicting climate change on a global level is fairly accurate, experts say ..." ... do they ?

 

[prohammy]

0707,

A couple of words that haunt all the guys who work in meteorology etc

Navier Stokes Equation (summation of 5 Partial Diff Equn.s) + Non linear dynamics.....

Scary stuff, but the upshot of the whole thing is that your sampling size (in this case grid seperation, I read somewhere that the box size is 10km square) determines how good your prediction is going to be. Even with that 'huge' grid size, we are pushing what the best computers can do computationally with the NS equation. Throw in non-linear response and its very easy to lose your predictabilty as time goes by....


Kevin

“It is a mathematical fact that fifty percent of all doctors graduate in the bottom half of their class." ~Author Unknown

"If two wrongs don't make a right, try three." ~Author Unknown

 

[Tomfh]

Predicting climate is a lot easier than predicting weather.

Predicting climate is akin to putting a pot of water on the stove and solving a differential equation to determine when the water boils.

Prediction weather is like dropping a bit of food colouring into that same pot and trying to compute how the colour trails will unfold over the next 10 seconds.

 

[0707]

Meteorologists set June 1 to Nov. 30 as the Atlantic season because while a few hurricanes have formed outside that window, most happen in summer or fall, when waters are warmest. August and September historically have been the busiest months.

On this subject I share the sites bellow with all of you.

http://www.cpc.ncep.noaa.gov/products/outlooks/hurricane.shtml

http://www.nhc.noaa.gov/HAW2/english/marine_safety.shtml

luis

 

[jmw]

I can't help thinking that at the present level of understanding, Climate Change is to the weather what Astrology is to the stars.

JMW

http://www.ViscoAnalyser.com

 

[epoisses]

rb1957

Well some do:

http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Pub_SPM-v2.pdf

See table on page 8, see definitions of degrees of likeliness etc.

 

[sms]

If we are going to engage in qualitative assessments (likely, very likely, etc), 0.2 degree C per decade does not seem like the end of the world as we know it...




"Why don't you knock it off with them negative waves? Why don't you dig how beautiful it is out here? Why don't you say something righteous and hopeful for a change?" Oddball, "Kelly's Heros" 1970

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