Saturday, July 12, 2008

Cloud streets and TVs

We've been getting some heat and tropical moisture influx for a few days, so I figured we might get some cumulus clouds to mark the lift... normally Hemet is so dry that all we get are "blue" thermals. There were big CU over the mountains, and the cloudbase there was maybe 9,000' MSL. There were CU and some lenticular-looking clouds all around the valley. My thermal forecast at trigger temperature (88F) was for lift to 6300' MSL. When I took off, the temp was 99F.

I came off tow at 4300' MSL and joined a thermal about 1000' under a 2-33. I worked that one up to 6000', and the 2-33 headed away, so I figured that was probably the top. Just a short distance away was a dark little cloud leading to a "cloud street" along the ridge north of the valley. I easily followed that over to the "S" ridge, which was pretty good because that ridge often has no lift working. I spotted a turkey vulture (TV)... and then a big flock of them, probably 15 to 20, all circling in lift. Sure enough, right under them, I found lift again. I worked that one up to 6300' MSL (and the TV's scattered).

With all this good lift, I would have liked to attack Mt. San Jacinto, but the peak was quite obscured by haze and clouds. Plus, my PDA / GPS had failed due to the heat, so I did not have glide calculations available electronically. If I was seriously planning to go to the mountain, I should have studied the distances and altitudes so I would have a good idea of my range, which I had not done.

So with plenty of altitude, I headed south across the valley, over the lowest foothills. As I mentioned, there were some lenticular-looking clouds in various places, and one was just ahead of me, so I thought I'd see if there really was any mountain wave lift working. It occasionally does work in the Hemet valley, but I have not encountered it yet. I went just adjacent to what looked like the leading edge of the lennie, but I was at least 1,000' lower than it, probably 2,000'. Either I was too low, or it really wasn't a lennie, or the wind was going the opposite direction, but I did not find either lift or sink near it. Not finding any meaningful lift there, I continued to the southeast corner of the valley, where I found yet another thermal to 6,000' MSL or higher.

Heading west along the hills north of Diamond Valley Lake, I found no lift and not much sink. I played with correlating the sink rate to the airspeed. (I really found no serious sink all day.) I went nearly to the town of Winchester, thereby completing a modified version of the "cross-country practice triangle" that we use, about a 30-mile flight path. I didn't find much more useful lift in that area, so I planned to land. The wind had picked up at ground level... AWOS said 12kt gusting to 20kt, with some really bumpy, turbulent lift at about 2,000' AGL. I did a pretty darn good crosswind landing after a 1 hour and 10 minute flight.

A very good soaring day! And guess what - I topped out at 6300' MSL, exactly what my forecast indicated (though for the 88F trigger temp, not the 99F actual temp).