Is there a tool or site where I can see wind vectors overlaid on a prognostic chart?
Most pilots here in the states get their weather data from NOAA (The national weather service) you can find all of their charts on their site here. 

Localized aviation weather is usually reported out of airports and can be found via their METAR's. 

For visualization apps like Foreflight and Garmin Pilot allow certain overlaying of data onto a map (these are however paid services).