This post is the third in a four-part series on weather observation and prediction. The first post dealt with the topics of cloud observation and identification. The second post had to do with observing the wind. These skills associated with the clouds and the wind can go a long way in giving you a great deal of information which you could use to watch and predict the weather. However, if one wanted to become more serious about weather watching, one needs to also monitor other variables of the weather as well. Factors such as temperature, rain fall, and humidity are all important measurements of weather, but to observe these things, you must add a third set of skills. I am speaking of the use of weather instruments.
Let’s start with one instrument we all should be familiar with…the thermometer.
The purpose of the thermometer is, of course, to measure the current temperature. Many already have an outdoor thermometer that they use for this purpose. Another option that some others have is known as an indoor/outdoor thermometer. These instruments give the measurements of both the indoor and outdoor temperatures simultaneously from within the comfort of their own home. (This is done by the means of a sensor located outside which is connected by either a wire or by a wireless transmitter which, in turn, sends the outdoor temperatures to an indoor display unit. That’s very convenient if you ask me!) In addition, there are even small thermometers available in a keychain form that you could clip on to your “bug out” bag. Whatever thermometer(s) you choose to use, make a point to observe the temperature at least once a day at the same time every day. If done this way, you eliminate the obvious differences that normally take place in temperatures at different times during any given day. That way you would be able to more clearly see any trends in temperatures from one day to the next. It is also suggested that you record the measurements you observe. You may even wish to record more temperature readings at different times during the day. However, you should know that if the thermometer is attached to your home on an outdoor wall, the heating or cooling of your home may affect the readings. Keep this in mind when observing the outdoor temperatures. In order to minimize any effects, the best place to keep an outdoor thermometer is away from any climate-controlled structures in a separate “weather shack” if possible. Also, if this is a true interest of yours, consider using a min-max thermometer in addition to a regular one. This type of thermometer records the minimum and the maximum temperatures reached within a specific period of time. This would give you a better overall picture of what would be happening with the temperatures from day to day because you would be aware of the lowest low temperatures and the greatest high temperatures. It should go without saying that the more information you observe and record, the better idea you would get of what was occurring with the weather.
This brings us to our second recommended instrument: the rain gauge. Many are familiar with this as a small glass or plastic tube kept in gardens to measure rainfall. There are many on the market to choose from. There are small, inexpensive, cylinder types, and there are also higher-priced, larger, fully-electronic models. In my opinion, the best rain gauge value on the market is a “CoCoRaHs approved” rain gauge. These specially designed gauges are about 14 inches in length and about 4 inches in diameter. What is unique about these gauges is that there is an inner collection tube which measures the precipitation as accurately as .01 of an inch. In comparison, small hardware-store rain gauges are not capable of that degree of accuracy. However, like small plastic rain gauges, CoCoRaHs gauges do not require any power, and they are simple to clean and maintain. In addition, the inner tubes of CoCoRaHs rain gauges can also be removed to collect and measure snowfall measurements. Whatever kind of rain gauge you choose, it is best to observe and record any amount of precipitation collected by the gauge every 24 hours, and again, it would be advisable to do this at about the same time every day. Also record whether the precipitation is rain, snow, or hail.
Speaking of snow and hail, another instrument I would recommend having on hand to observe the weather is a simple ruler. Not only should you measure the amount of snow that has fallen, but you should also use this item to measure the size of any hailstones. Trained storm spotters record and report the size of hail that they observe, and they do so by noting the size of the largest hailstones they can find.
Rain gauges, rulers, and thermometers are all inexpensive instruments which anyone can easily use to aid their skills of watching the weather. However, there are two other measurements which could greatly enhance your ability of observing and predicting the weather. These measurements monitor the air pressure and the humidity. The instruments required to do this take a bit more practice to read, and they are often quite expensive. Even so, the advantages of these instruments may be worth the investment. These instruments are barometers and hygrometers.
Barometers are used to measure air pressure. In weather, the pressure of the air can greatly affect the conditions you experience. You may have heard the weather forecasters on TV speak of “highs” and “lows” in the atmosphere. If you did not quite understand the significance, they are speaking of the differences in air pressure. For a basic explanation, any gaseous substance (including air) will flow from higher pressures to lower ones. This is what causes the wind. The greater the differences in pressure in any given area, the higher the wind speeds one would encounter. Also, in high pressure, air sinks, while in low pressure, air rises. This behavior contributes to the formation of different types of clouds and other weather phenomena. For instance, fair weather is usually associated with high pressures, while low pressures will attract air flow which could possibly form more clouds. In addition, changes in air pressure could also be signaling coming changes in the weather, and sharp changes in air pressure will also be accompanied by higher winds. As you should be able to see, knowing the current air pressure would be a useful thing to know if you are observing the weather. Again, to do this, one would use a barometer. There are different kinds of barometers. Some barometers use fluid levels to demonstrate the differences in air pressure. Other barometers have sealed vacuum capsules which expand or contract as a result of the air pressure. This expansion or contraction directs the barometers to then display the current air pressure measurements. A variation of this kind of barometer is known as an altimeter. This instrument is often used to measure elevation due to the differences of air pressure that exist at different distances above sea level. However, if one uses an altimeter while stationary, one could use this instrument just as one would use a regular barometer. While larger, more expensive barometers are usually more accurate, an altimeter is small enough to carried in a “bug out” bag. Depending on your situation, you may find this to be an advantage. In any case, a barometer is a very useful instrument in observing the weather.
Besides air pressure, there is another aspect of the air which is helpful to monitor: the humidity. Humidity measures how much water is in the air. The higher the humidity, of course, the more water is in the air. This increases the chance of cloud development and precipitation depending on other weather conditions. Because of the obvious effects that humidity has on weather, one should see that this measurement would also be beneficial to know. The instrument used to do this is called a hygrometer. These instruments measure the humidity by different means depending on the kind of hygrometer that it is. Many measure by evaporating water, and some use electricity. Some even use human hair. One kind of hygrometer that would be useful to the prepper is called a sling psychrometer. This small, hand-held device contains two thermometers. After one thermometer is dampened, the psychrometer is swung around to dry. The resulting difference in temperatures between the two thermometers could then be used to calculate the humidity. A sling psychrometer is not electronic, and it is compact, so it makes an ideal instrument for the prepper to use to monitor the weather.
As you can see, the use of weather instruments is a useful set of skills which could be combined with observing the clouds and the wind in order to help you to watch and predict the weather. Doing so would give you information you could use in order to do such things such as plan for your crops, make homestead preparations, or make arrangements to practice other valuable skills. In some cases, these skills may even help you survive life or death situations. In addition, if you desire to observe trends in the weather, and to also monitor its effects, it is best to incorporate a fourth set of skills for observing and predicting the weather. This would be record keeping. This will be the fourth and final topic in this four-part series.