Where the Heck is my thermals going to go???

[jteulker]

Got myself confused. When I was scouting today I thought I had it figured out in this spot. Then I came home and looked at the map and started to second guess myself on where my thermals are going to get pulled in this situation. Is my diagram correct? What do you guys think?

[stash59]

Depends on the days temperature. In warm to high temps the water in the pond will stay warmer than the air temp as the sun sets. This will heat the air above the pond and cause it to rise. This will create a vacuum and pull the cooler air to the center of the pond.

Opposite in cooler/cold temps.

I think you would actually be better off picking trees on each end of the funnel/pinch point. One for each thermal pull on each end of the funnel. So 4 trees in total. Also will help to have all of these options in case the prevailing wind of the day will have any influence on the thermals.

[jteulker]

Depends on the days temperature. In warm to high temps the water in the pond will stay warmer than the air temp as the sun sets. This will heat the air above the pond and cause it to rise. This will create a vacuum and pull the cooler air to the center of the pond.

Opposite in cooler/cold temps.

I think you would actually be better off picking trees on each end of the funnel/pinch point. One for each thermal pull on each end of the funnel. So 4 trees in total. Also will help to have all of these options in case the prevailing wind of the day will have any influence on the thermals.

So if im hunting early season (Warm) in the evening and I would want to set on the river side of the deer path?

[stash59]

Depends on the days temperature. In warm to high temps the water in the pond will stay warmer than the air temp as the sun sets. This will heat the air above the pond and cause it to rise. This will create a vacuum and pull the cooler air to the center of the pond.

Opposite in cooler/cold temps.

I think you would actually be better off picking trees on each end of the funnel/pinch point. One for each thermal pull on each end of the funnel. So 4 trees in total. Also will help to have all of these options in case the prevailing wind of the day will have any influence on the thermals.

So if im hunting early season (Warm) in the evening and I would want to set on the river side of the deer path?

Pond side!

[dan]

When the pond is warmer than the air it will pull your scent over the water when calm. Cold water on the other hand should push your scent away. The evening after a hot day thermal pulling over the pond is more reliable. At about sunset of coarse.

[stash59]

Thanx for clarifying this Dan. Didn't want to steer the OP wrong.

This is a similar occurance/concept to what alot of western back country horse pack hunters/guides use for heating water in wood stoves. They often have a small tank that holds the water. Then a copper pipe coming out off the bottom of the tank. Goes into the stove. Then back out into the top of the tank. The water in the pipe in the stove gets hot. Then rises upwards. As that happens cooler water goes into the pipe from the tank. Replacing the heated water. The heated water continues up and over, back into the tank. Once in the tank it cools and settles downward. And you get the continuous circulation of the water.

Remember, like Dan said. At sunset this starts if it's calm. Before sunset the cooler river water will pull the thermals into it, if it's calm.

[Ranger Matthews]

When the pond is warmer than the air it will pull your scent over the water when calm. Cold water on the other hand should push your scent away. The evening after a hot day thermal pulling over the pond is more reliable. At about sunset of coarse.

Dan-
I think where everyone gets confused is that it has to be pretty calm to see the affect especially on flat ground. The speed of the thermal would have to be greater than the wind speed to push the wind in the other direction. With you observations with milkweed. What wind speeds do see a lot of thermal affect and at what wind speed do you pay less attention to thermals?

[dan]

The effect of flat land thermals is mostly a concern at sundown when its dead calm. You often get a very calm period at sunset. That's when thermals are king in flat land

[jteulker]

The effect of flat land thermals is mostly a concern at sundown when its dead calm. You often get a very calm period at sunset. That's when thermals are king in flat land

Thanks for the clarity Dan. I thought I understood what was going on until I ran into this scenario.
Do you feel the flowing river has a suction effect on thermals at all?

[dan]

A little. The warm stagnant water seems to have a bigger effect.