I'm not sure there is any way to get data
directly to the NWS except for an expensive
RAWS station.
OTOH, anything sent over APRS or CWOP should get to the NWS via CWOP or MesoWest.
Respond to them and see if they can give you some clarification. I'm in the late implementation process of a product/service that would be perfect for a situation like this, if they can do it via CWOP/MesoWest. I have hardware and demo web pages running now, full service by the end of the year.