One thing that is often overlooked by preppers is the ability to read the skies. There may come a day where you no longer have access to that convenient weather app or Accuweather forecasts. Understanding the basics of meteorology can help you understand what the weather forecast may be for the near future. We first need to understand some of the common terms and phenomenon before we can use that knowledge to predict the weather. There are several aspects of weather that I will get into:
- Pressure and Fronts
- Weather Instruments
- Forecasting from Observations
Please note that I am not a meteorologist and not an expert of weather. As a little kid, I wanted to grow up and be a weatherman, but that changed shortly before I entered my undergraduate studies. Still, I have always been interested in the subject.
I am drawing very heavily on Weather: A Golden Guide. I have two versions of the book – a 1965 print that was discarded from the local library, and a 1987 version. Each of these copies have been in my possession for 30 years, and are well worn. The good news is that there is a newer version from 2001! It can be found on Amazon here, and it costs $6.95 new as of this article. I highly recommend picking up a copy. Are there more detailed books out there? Sure! But I have found none that are as good as this tiny little field book, and the price point makes it well worth it.
As promised, this post will be much shorter than my last one on clouds.
Wind: An Introduction
So, what causes wind? Wind is caused by the uneven heating of the earth. As warm air rises, cold air rushes beneath it, generating wind. The constant movement of the air in this manner is called convection. This convection causes local winds and breezes because different terrain heats the air differently. A mountain will heat the air differently than dark plowed ground. Coastlines see shifting winds because of this: during the day, the land heats faster than the ocean, which typically causes the wind to come from the water to the land (onshore). Overnight, the land cools much faster than the ocean (which retains heat better) and the winds shift to an offshore breeze.
Wind is measured using an anemometer. A future post is going to go over the different tools we can use as prepared citizens, but two sample anemometers are below: a handheld, and the traditional cup. A weather vane also does some of this, but typically only gives direction of the wind instead of anemometers that give direction AND speed. As a reminder, wind is named using the direction it is COMING from, not GOING TO.
However, as we see below, we can also use the things around us to estimate the speed of the wind.
The Beaufort Scale
Admiral Beaufort of the British Royal Navy created a wind estimation scale in 1805 to estimate wind speeds from their effect on the sails of his ships. The table has since been translated to terrestrial conditions, and three version of that table exist below: one land-specific, one that has both land and sea conditions (as based on a sailboat), and one that described the water conditions. Please note the following conversion: 1 knot = 1.15 mph.
Beaufort Scale: Land Specific
Beaufort Scale: Land and Sea
Beaufort Scale: Water Conditions
As many of you know, wind is an incredibly important factor for several reasons. The most obvious one is, of course, shooting. There are others, however – for example, you may want to approach an observation site downwind of the target so that any residual scents from you are not detected. Know the wind also helps us understand and make some informed forecasts. As such, knowing how to estimate wind is a very useful skill for the toolbox.