Answer
$34.7\;\rm psi$
Work Step by Step
Let's assume that the volume of the tire is constant and that the gas inside it obeys the ideal gas law.
Hence,
$$\dfrac{P_1 \color{red}{\bf\not} V_1}{T_1}=\dfrac{P_2 \color{red}{\bf\not} V_2}{T_2}$$
Solving for $P_2$;
$$P_2=\dfrac{P_1T_2}{T_1}\tag 1$$
Remember that we should use absolute pressure, not gauge pressure.
So, the initial pressure is given by
$$P_1=P_{\rm gauge}+P_A$$
Plugging the known;
$$P_1=30+ 14.7=\bf 44.7\;\rm psi$$
Plugging into (1);
$$P_2=\dfrac{(44.7)(45+273)}{(15+273)}=\bf 49.36\;\rm psi$$
Hence, your tires gauge pressure is given by
$$P_f=49.36-P_a=49.36-14.7$$
$$P_{f,\rm gauge}=\color{red}{\bf 34.66}\;\rm psi$$
