Re: Sattahip radar range reduced since 19/11/2024

Hello,

Looking at https://weather.tmd.go.th/satLoop.php it shows that (apparently) the radar is stuck at April 22nd?

I read topics explaining they reduced the range. But on the image it says "Range: 240km".

Not having this data cuts starting Chantaburi and leaves Koh Chang, Koh Mak and Koh Kood "in the dark". Having actual weather information is important.

I also read a topic which explained that Windy had cut off the Sattahip radar because of interference with Bangkok. WHat is the situation?

Few days ago I learned on this forum, that the “weather radar” is showing me data from a radar. Should not have been a surprise, since the word contains radar... But I always thought it was satellite data.

So I located the radar responsible for my whether display on Windy to be on a 148 meter high hill in Sattahip. Looking at a photo of the building, I estimate the focal point of the radar to be at approximately 18 meters. Makes the radar 166 meter over sea level. The horizon for the radar is in 46 kilometers distance. Everything beyond that it cannot see (sure: clouds are higher up). There is nothing in the line of sight to the horizon.

Since I am 190 kilometers away, it means that the radar is “looking” at 1627 meter over me. Doesn’t that quite falsify the result the further away one is from the radar? I am pretty sure the heavy rain zones that cross my location now during monsoon season are very much lower.

At the outer edge of its range (which is 240 kilometers) it is actually “looking” almost 3 kilometers over sea level. I have the impression it is sort of guessing what it looks down on the ground from what it sees at the height? Somebody knows how this data is being analyzed?

PS: sorry to the flaterthlers reading this. I am assuming the earth is a sphere ;-)

@dodohjk Thank you for the extensive explanation.

I meanwhile "discovered" two more areas that behave the same.

I do not see any logic in why this would be like that.

I did realize we are at the edge of the range (I actually always tought it would be satellite data). But the data we see here is very accurate. When I can see rain (dark red clouds) coming it matches what Windy is showing. Just when the rain area reaches that shadow, it disappears in Windy but not in reality.

Will probably remain a mistery.

Concerning the line of sight to Sattahip: I do not know the exact radar position but I suppose it is on a 148 meter hill south of Sattahip. Mountains in the near area are not in the way. But it actually means the radar is looking (due to earth curvature) at an altitude of aproximately 3000 meter (9850 feets) over our island. That makes me wonder about how the data is collected. The dark red rainy clouds are definetly lower than 3000 meters.

Hello Community,

I noticed that the island we live on has most of the time an almost rain free area around itself.

In this example, looking at the last hour this rain free area remained in the display, even though it was pouring outside. If you look at this last hour you can see the red area approchaing Koh Mak. But when it arrives, Koh Mak stays light blue (even though it is pouring outside)

I started the web version with another username and browser and did not allow windy to locate me (since I thought that maybe it is doing that around my location). But no. Still have this rain free area.

Is there some logical explanation to this?

Our location N11°49'4",E102°29'27"