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What does FI mean to people ?


stewfox

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Posted
  • Location: Napton on the Hill Warwickshire 500ft
  • Weather Preferences: Snow and heatwave
  • Location: Napton on the Hill Warwickshire 500ft

What does FI mean to people?

 

FI = Fantasy Island

I get confused what is FI ?

I always thought FI shortens when confidence levels (for the models) remains very low

If Shannon entropy has been low like most of December then forecasting will be better or more confident regarding specific trends ie westerly or south-westerly weather with high rain fall.

If Shannon entropy is high FI will shorten to  T94/T144 ?

We know ECM GFS etc verification stats drop of post T168 yet we place a lot of emphasis on long range forecasts and some folk write months off at a time for cold etc or is that because we have high confidence on trends to remain the same even at T368 ?

What I don’t understand based on ECM,GFS verification stats FI can be at the very best T168/T200

So if someone is writing off periods past that is that based on a confidence that trends wont change ?

 Ie what does FI mean ?? Is it at present T368 ??

 

 

 

Edited by stewfox
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Posted
  • Location: Alresford, Near Colchester, Essex
  • Weather Preferences: As long as it's not North Sea muck, I'll cope.
  • Location: Alresford, Near Colchester, Essex

It used to mean 'forced induction' to me, until I came onto this site...

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.

Fantasy Island: a movable area where the ensemble spread drowns out any useful signal...But means something-else entirely when used to describe Donald Trump!:D

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Posted
  • Location: Canmore, AB 4296ft|North Kent 350ft|Killearn 330ft
  • Location: Canmore, AB 4296ft|North Kent 350ft|Killearn 330ft

the Internet country code top-level domain for Finland

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Posted
  • Location: Napton on the Hill Warwickshire 500ft
  • Weather Preferences: Snow and heatwave
  • Location: Napton on the Hill Warwickshire 500ft

Ok for some folk its a short wave or long wave on a book, which leads to more confusion.

 

 

fi short wave.jpg

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Posted
  • Location: Wildwood, Stafford 104m asl
  • Weather Preferences: obviously snow!
  • Location: Wildwood, Stafford 104m asl
2 minutes ago, Ed Stone said:

Fantasy Island: a movable area where the ensemble spread drowns out any useful signal...But means something-else entirely when used to describe Donald Trump!:D

can guess that ed! lettuceing idiot? FI generally varies, 144 UKMO suppose normally is FI, the last chart, Fax charts tend to be 'reliable' anything after 120 FI

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.

For me it is when there becomes significant long wave differences or divergences either between models, between runs or between the ensembles. That timeframe is FI and it is a moveable feast.

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Posted
  • Location: Napton on the Hill Warwickshire 500ft
  • Weather Preferences: Snow and heatwave
  • Location: Napton on the Hill Warwickshire 500ft
Just now, chionomaniac said:

For me it is when there becomes significant long wave differences or divergences either between models, between runs or between the ensembles. That timeframe is FI and it is a moveable feast.

If we don't pick up a 'strong signal' for say cold does that mean FI is extended ?

I think there were only a few 'postage stamps' for December that showed 'cold snaps' so confidence of the same weather was strong ? 

Had the models shown 40% for cold does that shorten FI ?

Or can or do people use FI for almost anything e.g rain fall amounts in specific areas next week is at present FI ?

 

 

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Posted
  • Location: South Norfolk, 44 m ASL.
  • Weather Preferences: Varied and not extreme.
  • Location: South Norfolk, 44 m ASL.

Isn't Shannon Entropy higher when there is more variability and uncertainty, thereby reducing the period during which we have confidence and bringing FI closer to the present?

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Posted
  • Location: Beccles, Suffolk.
  • Weather Preferences: Thunder, snow, heat, sunshine...
  • Location: Beccles, Suffolk.
Just now, chrisbell-nottheweatherman said:

Isn't Shannon Entropy higher when there is more variability and uncertainty, thereby reducing the period during which we have confidence and bringing FI closer to the present?

I think so: the higher the entropy-value, the greater the degree of disorder?

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Posted
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
  • Weather Preferences: Snow and storms
  • Location: Hayward’s Heath - home, Brighton/East Grinstead - work.
6 minutes ago, stewfox said:

If we don't pick up a 'strong signal' for say cold does that mean FI is extended ?

I think there were only a few 'postage stamps' for December that showed 'cold snaps' so confidence of the same weather was strong ? 

Had the models shown 40% for cold does that shorten FI ?

Or can or do people use FI for almost anything e.g rain fall amounts in specific areas next week is at present FI ?

 

 

I don't think that FI has anything to do with cold and everything to do with confidence in the output.

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Posted
  • Location: Napton on the Hill Warwickshire 500ft
  • Weather Preferences: Snow and heatwave
  • Location: Napton on the Hill Warwickshire 500ft
4 minutes ago, chrisbell-nottheweatherman said:

Isn't Shannon Entropy higher when there is more variability and uncertainty, thereby reducing the period during which we have confidence and bringing FI closer to the present?

My mistake I have changed it

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