How to date match "January 16th 2019, 07:00:09.257"?

This should be easy, but for some reason I am unable to do this. Can someone help, please?

January 16th 2019, 07:00:09.257

Logstash 6.3.2

where do you which a match? in the date filter or in grok?

if it is the date filter there is a previous question with an untested solution

Yes, like you have in the match, however, MMM is for Jan, would MMMM be for January?

It worked with four digit MMMM. Thanks!