1.  An obstruction is needed...
             (Not necessarily a ridge line - see the Petersburg W.V. area)

        2.  Wind must be within about 30 degrees of perpendicular 
             to the obstruction...

        3.  Wind (at the obstruction) should be in excess of 25 kts...

        4.  Wind velocity should gradually increase with altitude...

        5.  A stable layer aloft...
 

 

June 7, 1998 / Plots prepared for 12Z and 18Z (8W2) -- New Market, Virginia Cool north-west winds over the last couple of days climaxed with a significant wave condition today.  Jim Kellett recorded winds at 8,000 msl as 310 T at 22 kts (GPS data logger).  He reached 12,400 msl over the airport - in wave.  Concerned about getting caught on top of the developing overcast he abandoned the wave and proceeded to a point some 20 miles north to get down.  Their were numerous reports of significant thermal action along the ridge and lots of lenticular clouds were observed throughout the day.  Note that good wave conditions are usually associated with a High over Kentucky and a Low in New England...

 

December 11, 1999 / Front Royal, VA

Late Friday afternoon a Cold Front crossed the area and dry Canadian air began to flow in from 
the northwest.  The wind peaked (Woodstock area) at about midnight and began to diminish 
gradually through the day.  By about 1 pm (18Z) we had two 1-26's, the K-21, Ka-7, the
Sprite (SGS1-36), and Miss Daisy (SGS 2-33) in Wave - most flights achieving altitudes of
10,000 msl.  The Sprite recorded a Silver Altitude flight to about 10,700 msl for the highest. 
These flights were scattered from the north end of the Massanutten Ridge (Strasburg) to 
Winchester, Va - west to Little North Mountain.  It appears that Great North Mountain was the 
primary source of this wave condition.

Shown below is the first forty five minutes of the flight in the Ka-7.  I released at about 12:45 pm. 

Note the rather steep climb on tow to the 5,200 msl level, shortly after release you see a quick 
"notch" then a fairly steady climb at about 1 m/s (about 200 ft/min) to about 10,300 msl.  The 
altimeter setting recorded by the NWS for Winchester was 30.18 (1 pm).  Front Royal is at 
710 ft. msl.

This Sounding Projection was generated on Friday evening (some 18 hours before the flight)... 

Note the close correlation with the Balloon sounding for Dulles (Washington D.C.) at 7 am on 
Saturday morning.  This is a classic Wave Profile, with a stable layer riding above a less stable 
lower layer.  The strong inversion apparently kept the strong winds from reaching the surface,
resulting in a strong wind gradient (lower 2,000 feet).  From the ridge level (about 950 mb) 
upward into the Jet Stream the wind does increase with a lesser gradient.

Right Click -- select "View Image" to enlarge...