Help

Hi SaKhan , 
Look that in this image nothing was selected and the gauge is full filled with Max Sales:

Now look that when i select a segment in slicer the the fill change in gauge but it keep my maximium value of my sales:

To achive this aproach, Try the follow steps:

I imagine that you have a measure to calculate weight forecast like this:

Sales Amount = SUM(financials[ Sales])

Now create a second measure for static Max Weight, something like this:

Max Sales = 
CALCULATE(
    [Sales Amount], //measure created before
    ALL(financials) //removing all applied filters in table, replace the table with your own
)

Now in your Gauge, put the [sales amount] measure (in my case) in the value field, and Max Sales in Maximum value as you can see below:

Note: replace table and column names with your owns.

If this post help you, please consider to mark as solution and give a Kudo.

thank you