Since the taxable rollover to the Roth IRA was in January, it's likely that it would be impossible to avoid an underpayment penalties for Q1 and Q2 just using estimated tax payments. Increasing tax withholding is the only way to do so.
Don't forget about state income taxes. Unlike federal treatment of withholding, some states treat tax withholding the same as estimated tax payments and it might not be possible to avoid a state underpayment penalty for Q1 and Q3. You might need to make a Q3 state estimated tax payment to make up the entire underpayment shortfall to date to avoid state underpayment penalties for Q3 and Q4.
