Monday, August 9, 2021

Saturday, August 7, 2021

Visibility: Lousy. Optimistically, about  4.5 statute miles, due to a major smoke intrusion from big California wildfires.
Wind: Mostly light and variable.  Somewhat more of the time out of the SSE.
Altitudes: 2950 ft.,  after releasing at pattern altitude. 
Time Aloft: 30 minutes
Max Lift: 325 fpm
Temperature: Maximum about 101 deg. F. in the late afternoon.
Tow pilot: Jim Rickey

The San Joaquin Valley filled with smoke today from the recent wildfires in Northern California, presumably.  Hanford AWOS was reporting visibility of 4.5 miles in "haze".  We could just make out Tar Canyon and Tar Peak to the SW of the field, so that seemed about right. We could not make out Black Mountain to the West, which is a bit  further away at about 7.5 to 8 miles distance. Rick Ibarra and Quinn Marsh came out,  and we decided to do some training flights.  Carl Lindgren also came by but did not fly today.  Congratulations to Carl on passing his private pilot practical test last Thursday with DPE Dan Gudgel! Flight visibility was pretty poor all day. We've been pretty lucky so far this year not to have had a lot of smokey days from all the fires, but our luck ran out today.  We only did pattern tows today.  Both Quinn and Rick got quite a bit of practice at "premature termination of the tow" rope breaks, as well as "no wing runner" take offs, and take offs and landings on different runways.  In some directions, we didn't have a distinct horizon, but we could always make out references on the ground, and Tar Peak and Tar Canyon.   On one flight, Rick found a nice thermal right after releasing at 1100 ft AGL.  He was able to climb up to 2950 ft. MSL. We quit there,  because of the smoke and reduced visibility.  Both Quinn and Rick are very close to being able to solo. Rick  is a licensed power pilot with instrument and multi-engine ratings,  and  is looking over the glider  Pre-Solo test I gave him, and Quinn just finished his IACRA application for his required FAA Student License,  and is also doing the FAA required pre-solo test.   The "Skew-T" App, a free app available for the Android system, that  I have on my phone, pulls up a forecast from the "Op40"  computer model forecast.  For Avenal Airport,  it indicated thermals could go up to as high as 5500 MSL in mid afternoon. But I don't believe that model takes into account the effects of smoke on cutting down the heating, due to the reduced  amount of sunlight reaching the ground.  It also does not say anything about the effect of the smoke on flight visibility.  I'm sure the thermal we had would have gone somewhat  higher, but we quit trying,  due to the poor visibility.   I actually  don't think any of the currently popular computer based  soaring forecasts take wildfire smoke into account.  There is, however,  a newer "Experimental"  version of the HRRR (High resolution Rapid Refresh) computer  model available from the NWS that does try to take the effects of smoke into account. That new HRRR computer may become more useful. It also  forecasts a visibility parameter,   which should  be useful for  soaring, as well as other types of flying. 

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