Trapped Catch of Throw

[bwbuddy]

Batter hits grounder and F5 throws low to F3. Umpire was in C. Catch of throw forces F3 to catch close to ground and momentum causes her catch "followthrough" to touch the ground. Is umpire allowed to use his best judgement to determine if catch was caught and ball accidently touched the ground after the catch? Or, in this case, should it automatically be called a trap if the ball touches the ground at all after the catch?