For a 300 Mb Jet Stream analysis and forecast, try SFSU's Jetstream site:
What you should look for here is the jet stream flowing perpendicular to the border between California and Nevada, right where that border takes a 45 degree bend to the east (right on Lake Tahoe).
Look for wind speed and direction where the 120 degrees west longitude line intersects the 40 degrees north latitude line. The tell-tale 45 degree state boundary line is just below that point. Wind speeds over 30 Kts and directions between 210 and 310 are indicative of mountain wave conditions.
Many soaring pilots use Skew-T soundings for information on strength and height of lift, based on balloon soundings. A good Skew-T source for the Minden area (actually, from Reno) is available at from Unisys.com.