Sorry but philly has over 1.5 million residents compared to Westmorelands 360k. 20,000 provisional or absentee ballots in philly is absolutely correct and believable.
Hillary also got over 80% of the vote there winning by more than 450k.
There is always fraud in philly, and the fact she performed as well in philly as Barack, even though she managed not to do that anywhere else in the country is a pretty good indication fraud once again happened there, but these 20k votes or so aren’t evidence of it.
Most absentee votes are counted on election day by precinct election boards. They are supposed to be in the Friday before the Tuesday election so they can be delivered to each election judge to be canvassed after the machine totals are tabulated. We use a group of at least three to do that with representation from both major parts-- one opens and reads, one watches and one tabulates. The results are turned in with the machine counts the same night. The election judge or other designated person actually drives them over to the court house.
Any absentees which do not arrive in time for the precinct count must be verified by the county canvassing board along with each provisional ballot. You can actually go to this site and see a breakdown of ballots counted in the county totals and on the precinct level on election day. There were a total of 316 ballots which were not tabulated by precinct on election day (roughly 3 times the 100 figure which I stated because there was roughly 3 times the turnout).
So, if you don't make totally weird assumptions, the Philadelphia total should be 4.17 x 316 or 1,317. Yes, I know. Maybe they have worse mail service than we do, or a greater proportion of people serving in the military overseas or just a lot more turnout than our measly 75%.