You can tell a lot about the weather coming to a particular region simply by reading the wind direction. Be aware that when a meteorologist states the direction of the wind, she is referring to the direction the wind is blowing from, not toward. For instance, a westerly wind is blowing from the west, not into the west. There are three main wind direction indicators commonly found on weather maps. These are wind barbs, wind vectors and isobars. Each of these will tell you about wind direction, plus one other wind characteristic. Wind barbs will also give you information on wind speed. Wind vectors will give information on wind intensity. Isobars provide information on the high- or low-pressure centre a wind is associated with.
Locate a wind barb on a weather map or, on its own, on a meteorological website. A wind barb is a simple diagram made up of a "stem," or longer line, with "barbs," medium and short lines, or triangular "flags" extending from it at a slight angle on one end.
Notice which end of the wind barb stem the barbs extend from.
Picture the stem being oriented to a compass with north pointing straight up. The end of the stem with the barbs or flags extending from it points to the direction the wind is coming from. In the example below, the barbs are oriented on the east end of the stem. This represents an easterly wind or a wind blowing from the east.
Find a weather map showing wind vectors. These will look like arrows of varying size scattered about the map. These vectors or arrows may be straight or curved. There will probably be vectors of different sizes.
Notice the direction in which the vectors are pointing. Vectors point in the direction the wind is actually blowing, instead of pointing to the direction the wind is coming from. The example below depicts an easterly wind blowing toward the west.
Notice the curve of the vector to find what direction the wind is actually blowing from. Winds often do not blow in a straight line, so a wind blowing toward the east might be coming from the northwest instead of the west.
Find a weather map showing isobars with high- and low-pressure centres indicated. Isobars are lines that connect points of equal barometric pressure. The patterns that they make reveal areas of high and low pressure and usually end up curving around them. Winds basically follow the paths of isobars.
Notice the isobars curving around low-pressure areas. Winds flow counterclockwise around low-pressure areas. Therefore, the isobars around low-pressure systems will show you the general directions that winds in those areas are blowing.
Notice the isobars curving around high-pressure areas. Winds flow clockwise around high-pressure areas. Therefore, the isobars around high-pressure systems will show you the general directions that winds in those areas are blowing.
The barbs on wind barbs indicate the speed at which the wind is blowing: The short barbs represent five knots, the long barbs represent 10 knots and the triangular flags represent 50 knots. You add up the values on a wind barb to find the overall speed of the wind. The relative sizes of wind vectors on a weather map indicate wind intensity.
Tips and warnings
- The barbs on wind barbs indicate the speed at which the wind is blowing: The short barbs represent five knots, the long barbs represent 10 knots and the triangular flags represent 50 knots. You add up the values on a wind barb to find the overall speed of the wind.
- The relative sizes of wind vectors on a weather map indicate wind intensity.
- The Ultimate Weather Education Website; Wind Direction and Weather Forecasting
- University of Illinois; The Weather World 2010 Project; Observed Winds Represented by Wind Barbs
- University of Illinois; The Weather World 2010 Project; Wind Vectors
- University of Illinois; The Weather World 2010 Project; Wind Direction and Isobars
- National Center for Atmospheric Research; About Wind Barbs
- Encyclopedia.com; World Encyclopedia; Isobar