Dear Kehilla,
Here are two questions that have come to me regarding hlichot tefilah and rain:
1. If you are in the middle of Shemoneh
Esreh and it starts to rain, it's permitted
to quietly move to a spot where there is no rain and to continue.
2. If you cannot read the Torah during Shacharit because of rain, it's permitted to take the Torah out and read before Mincha begins.