I've been using Weather Underground for a few years now, and by far - as a lifelong weather buff - it has been the most accurate:
I've got a Mad River trip with a bunch of 8-12yo girls and dads, and we're concerned about driving on Saturday: 2" of snow tomorrow, with 9" of snow forecast for Saturday.
Of more concern is the bottom falling out on the thermostat on Sunday and Monday. Make sure your cars have a 50/50 mix of coolant!