Jump to content

Archived

This topic is now archived and is closed to further replies.

stewfox

What does FI mean to people ?

Recommended Posts

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 ??

 

 

 

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

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

Share this post


Link to post
Share on other sites

the Internet country code top-level domain for Finland

Share this post


Link to post
Share on other sites

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

 

 

fi short wave.jpg

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites
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 ?

 

 

Share this post


Link to post
Share on other sites

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?

Share this post


Link to post
Share on other sites
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?

Share this post


Link to post
Share on other sites
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.

Share this post


Link to post
Share on other sites
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

Share this post


Link to post
Share on other sites

For me it's the point at which the models go from plausible to wacky and if you scan through every run you'll see it. GFS is an expert at this one, usually early on the 18z.

Share this post


Link to post
Share on other sites

  • Warm run-up to Easter but a destabilising low means sunshine and showers at the weekend

    High pressure is keeping our weather settled at the moment, and in the main it'll stay that way until the end of the week. But with low pressure helping to destabilise the atmosphere this weekend, the sunshine will be joined by some heavy showers. Read the full update here

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather

    Lockdown Gardening - Top Tips for New Gardeners

    Lockdown Gardening - Top Tips for New Gardeners - Blog by Jenny Bell WWW.NETWEATHER.TV In the first in a regular series of gardening articles, Jenny Bell gives her top tips for new gardeners who are maybe taking their first gardening steps during the lockdown.  

    Netweather forecasts
    Netweather forecasts
    Latest weather updates from Netweather
  • Recently Browsing   0 members

    No registered users viewing this page.

×
×
  • Create New...