Saturday, November 16, 2013

Saturday, November 16, 2013 Beautiful Soaring Day, Thermals in Mid November

Visibility: 20 miles +
Wind: 10 kts. out of the South
Altitudes: 4500 MSL
Time Aloft: 1.2 hrs.
Max Lift: 4 kts.
Temperature: 65 deg. F.
Comment: Beautiful Fall weather at Avenal once again. This time with good lift all afternoon. Everybody stayed up.
Tow pilot: Shawn Knight in his Pawnee

Another beautiful Fall day at Avenal. An upper level trough passed through bringing in some cool air aloft, resulting in a good lapse rate.  There were thermals all afternoon,  with altitudes well over 4000 MSL easily achievable.
Everybody who flew today was able to stay up. Martin Caskey is working on his commercial add on rating and was flying Big Bird from the back seat. We used the available lift to extend one of our flights to over an hour.  This allowed extra practice thermaling, flight at minimum controllable airspeed, stalls, steep turns and coordination. Note the vario,  with the lift steady at 3 to 4 kts.  We saw a few times where it briefly hit 5 kts.  You may be able to see that  we actually had a dreaded "yaw string malfunction", where the yaw string wrapped around the pitot tube and became useless.  But, having the "right stuff",  we kept our cool, did not panic, and it later untangled itself. Whew! That adventure, combined with no longer having the house thermal "Tanks" to locate thermals,  and for helping to navigate back to the airport really made this flight challenging! (Just kidding!).  

This is an image from the RASP forecast for today's  Avenal sounding in a Skew-T  diagram format.  You can see that the usual low level inversion we get at this time of year was very weak,  and the lapse rate above this weak inversion was quite steep up to about  5000ft. MSL. Even though the high temp. for the day was only about 65 deg. F., we were able to break through the low level inversion and thermals went up quite high for this time of year.

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