How to change scrollbar position in AppleScript?
Based on the additional information you provided in the comments, let me offer the following example code of how I'd do it. (At least until I learned a better way.)

set myURL to "https://weather.com/weather/hourbyhour/l/12345"

tell application "Google Chrome"
    set bounds of front window to {0, 23, 1440, 850}
    tell front window to make new tab at after (get active tab) with properties {URL:myURL}
    repeat while (loading of active tab of front window is true)
        delay 1
    end repeat
    activate
    tell application "System Events"
        repeat 9 times
            key code 125 -- # Down Arrow
            delay 0.1
        end repeat
    end tell
end tell




Notes:


The value of the delay command in the repeat while ... loop can be adjusted to something more or less as you see fit based on how fast that page actually loads, you'd want to minimize the number of times the event triggers just so you don't unnecessarily over trigger the event. It's necessary for the page to finish loading, otherwise the next repeat loop will not scroll the appropriate amount. (I'm obviously using the term scroll figuratively.) 
In the tell application "System Events" statement/block, you might need to adjust the number of time the repeat loop triggers. The delay command in this repeat loop is necessary otherwise the key code event, in this use case, does not register on the page properly.