For most BMA members, you will see on your October 20th paycheck retro pay and retro medical. Because of this, your gross salary will be increased and thus increasing how much tax is taken out.
If you want to avoid the extra tax that will be taken out, you do have the option of changing your withholding allowances (increase the number of them) for that one paycheck. You can even go EXEMPT for no tax taken out if you want!
What you need to do is go visit the payroll office in the ASB building and fill out a W-4 now, but no later than Monday October 10th. You will also need to know your social security number and employee ID. Then after October 20th, you need to go back in and fill out another W-4 to put back the number of allowances you normally take.
How many allowances should you take for the October 20th paycheck? That depends on your tax situation and you might want to consult your tax preparer. You could use this salary calculator to play with the numbers, you just need a pay stub in front of you to enter everything including your before and after tax items.
Remember, if you do this, make sure to put everything back after the October 20th paycheck.