Might also check and see if other weather stations near you are sending correctly. Chances are, the problem is on Wunderground's end which knowing their track record is a very strong possibility.
BTW, I'm not sure if this is still the case, but I've noticed that shortly after putting my station online either for the first time or after a prolonged period of downtime, the data feed seems to have issues the first few days.
My guess is this problem is on Wunderground's behalf.