Fed-Ex sent us this notice. It could be applicable to you Santas out there.

"A rainy weather system that caused low flight ceilings, combined with an inoperable radar at the local airport traffic control, delayed flight and sort operations at the FedEx Express Memphis Hub overnight.  Because of the weather and radar issues, some customers could experience service delays today."
Continue to check fedex.com for service updates as well as their tracker to follow the status of your shipment.