Here are numerous links that you may find useful. If you have others to share, please send.

NOAA/NCEP:

NCAR RAP: http://www.ral.ucar.edu/weather/

coolwx.com:

FSU:

PSU

Univ. at Albany: http://www.atmos.albany.edu/index.php?d=wx_data

Univ. Wisconsin: http://www.ssec.wisc.edu/data/geo/

College of DuPage: http://weather.cod.edu/

Univ. South Alabama: http://www.southalabama.edu/meteorologyclub/synoptic/

WeatherUnderGround: http://www.wunderground.com/

Kean University:

METAR sources: