How to Hide From Drones: Cloud Ceilings

[Music] when it comes to concealing oneself from aerial surveillance one of the most crucial data points that you will need is the altitude of clouds in the sky if you would like to know why this information is important to know check out our previous video on the subject which is linked below and on screen but today what we're going to look at is how to calculate what we call the cloud base or the lowest altitude that a cloud is above ground level as one might imagine cloud layers are sometimes thousands of feet thick so we cannot reliably predict from the ground the top of the cloud layer all we can really do is predict the bottom of the cloud layer which for counter surveillance purposes is really all we need anyway now fortunately various agencies and entities in the world produce this data for us so we don't even need to calculate it for ourselves the us air force provides a product called a metar or meteorological aerodrome report which is a short product that details the weather conditions for a specific place at a certain time to include cloud levels the air force also puts out another product called a taf or terminal aerodrum forecast that is just that the forecasted weath to include cloud levels the air force also puts out another product called a taf or terminal aerodrum forecast that is just that the forecasted weather conditions usually for the next 24 hours almost every single airport in the world will have a specific metar for their location and most major airports will also have a taft which is awesome because if you ever wanted to check out your local raw weather conditions you can simply find the closest airport and download their latest metar and if you're close enough you might be able to use a ham radio to tune into the automated recordings of weather conditions that are broadcast for most busy airports but let's say that we don't have all of that high-tech weather gear that the air force has or we're located far away from an airport or even more likely we don't have internet access well in this case all we need is a pocket weather meter and a calculator to be able to estimate cloud levels and determine if it's likely that an aerial surveillance platform is flying now before we dive into the math of how to do this it must be noted that the field of weather observation and forecasting is much like the intel world in that for every rule of e math of how to do this it must be noted that the field of weather observation and forecasting is much like the intel world in that for every rule of thumb that exists there seems to be 50 exceptions to the rule or so it seems there are many different factors that can skew your results so when you're trying this at home don't be disheartened if your data is a bit off so let's get right to it the only two data points that we need are the temperature in celsius that's important and the dew point also in celsius you can get these data points using any weather sensor really but we recommend using a kestrel for those of you that don't know what these are the kestrel is a brand of handheld weather meter that is by far the industry standard for taking weather measurements in the field you don't need to get a super expensive one you can get one of the cheaper models which will still display dew point and temperature or you can use another weather meter it doesn't really matter for this process so once you have your dew point and temperature you can use this equation to find the altitude of the cloud base in altitude above sea level temperature minus the dew point all divided by 2.5 and fi you can use this equation to find the altitude of the cloud base in altitude above sea level temperature minus the dew point all divided by 2.5 and finally multiplied by 1000. now a very important final step is to take into account your present altitude above sea level this formula will get you the cloud altitude in what we call msl or mean sea level otherwise known as the altitude above sea level if you want to find out how high the clouds are over your head you need to convert this into an altitude agl or altitude above ground level so if your math works out to be a cloud level of 1800 feet but you're currently standing on a hill that is 1000 feet above sea level you have to subtract this from your result to finally determine that the cloud base is 800 feet above your head so that's how you determine the altitude of a cloud base but wait there's more there's another way to do this and here is that equation air temperature minus the dew point multiplied by 400 this will also get you a pretty close estimate to the cloud-based altitude but wait there's even more like i mentioned there are many different rules of thumb for this and one of the most common ones in the field of weather but wait there's even more like i mentioned there are many different rules of thumb for this and one of the most common ones in the field of weather is that the closer that your air temperature and dew point get the more clouds you will have this is because dew point is just a fancy way of indicating how much moisture there is in the air the higher the dew point the higher the moisture content of the air at a given temperature this means that if your dew point is 70 degrees fahrenheit and your air temperature is also 70 degrees fahrenheit it would most likely be raining or you would be standing in a cloud because the air simply cannot hold any more moisture without it falling out of the clouds as precipitation this also means that the dew point can never be higher than the temperature that's scientifically impossible so if you find that your data indicates this or this is the data you're using you know you're doing something wrong and you might want to go back and check your numbers so as your dew point rises or as your temperature falls the two numbers get closer and closer together and as they get closer together clouds will form and the chances of precipitation go up this is a alls the two numbers get closer and closer together and as they get closer together clouds will form and the chances of precipitation go up this is a neat trick if you want to be able to predict almost down to the minute when it will rain you can watch your weather meter and when the two numbers get closer and closer together or when they spike together and get really close it will probably rain this also means that the inverse is true let's say that your temperature is 80 degrees fahrenheit and your dew point is 65 degrees fahrenheit in this case there will most likely be clear skies as the two numbers get farther and farther from each other no clouds that's why i mentioned these exceptions to the rule earlier because if you did the math based on a temperature of 80 degrees fahrenheit and a dew point of 65 degrees fahrenheit the math would tell you that the cloud base is at 3 360 feet above sea level but i can guarantee you that if you had these weather conditions and you looked up there would be not a cloud in the sky so when trying to calculate the cloud-based your data will be most reliable when there is in fact an overcast sky all we are trying to do with this data is roughly to calculate the cloud-based your data will be most reliable when there is in fact an overcast sky all we are trying to do with this data is roughly estimate what level the clouds are at and in fact once you practice this a few times you'll realize that you don't even really need to do the math at all you can look at a temperature and a dew point and reliably be able to tell if the sky is overcast or not also and this is super important to understand this equation really only works at lower altitudes with lower cloud levels you will most likely not be able to tell if a cloud ceiling is at eighteen thousand feet or at twenty eight thousand feet you're really only going to be able to use this accurately at a couple of thousand feet or lower this is because this equation calculates the lowest level of clouds you might have an overcast sky at 10 000 feet but a thin nearly invisible cloud layer at 900 feet and that's the layer that you're going to be determining with this data also atmospheric and weather data changes with altitude the air gets thinner and colder which makes it harder to hold moisture so the relationship changes again one can see how complex and utterly maddening this r gets thinner and colder which makes it harder to hold moisture so the relationship changes again one can see how complex and utterly maddening this process can get especially if all you want to know is if a drone is likely to be effective so all in all you might be able to skip the math altogether and just look at the temperature and dew point if the numbers are close together and there's an overcast sky over your head chances are high-flying reconnaissance assets will probably not be flying because they won't be able to fly below the clouds but as always make sure to practice this in your local area and compare it with the actual metars from your local airport if you can most of the time weather plays a critical role based on just a few data points anybody can tell you when a thunderstorm is about to roll in but it takes a special skill to be able to determine a cloud level within a few hundred feet of accuracy or predict visibility within a just barely acceptable level weather most severely impacts operations right at that level right at the bleeding edge of what is an acceptable level of risk so understanding simple but boring things like cloud ceilings and the relationship be ight at the bleeding edge of what is an acceptable level of risk so understanding simple but boring things like cloud ceilings and the relationship between temperature and the dew point is a huge force multiplier and more often than not can mean the difference between resounding success or crushing failure [Music] you