My mom pays estimated taxes. She makes the entire years payment with the first payment. Over the last 6 weeks she has had to move into a dementia care unit and we needed to raise funds. We cashed out an annuity that had accumulated approx. $10k in tax deferred interest. I do not believe the estimated taxes will be enough to cover this unexpected gain and I would like to make an additional $2k payment to the IRS to cover this deferred interest.
My question is how to do this? I have tried googling but can't seem to find the information. Can I just create another 1040-ES form with TurboTax and pay it using the 4th Quarter payment even though she has already paid the estimated taxes for the year including all coupons with the 1st payment? Is there another form I should use?
Thank you very much in advance for any help.
--Pat