Hi Kaz,
I would keep an eye out and make sure you see the momma stay with the babies during this storm. When it's really cold and rainy, hummingbirds go into a sleep like state called torpor to maintain body temperature.
I had a similar situation happen during a winter storm where the momma went into torpor for a couple of days. I ended up cutting the large branch that the nest was attached to and took the babies to a hummingbird rescue person in Huntington Beach so she could feed them and keep them warm. After the storm was over and the momma woke up, I picked the babies up and tied the branch in the same spot.
I know some birds will abandon their young if they've been held by humans, but hummingbirds are okay with it.
Also, the momma is expending a lot of energy looking for food in this cold. I opened up my compost tumbler so she had plenty of fruit flies, which is a main source of protein they need in addition to nectar from flowers. Hope your birds stay safe.
Janet