The temperature data on a weather map gives an indication of the locations of fronts, where air masses having different characteristics come together. Most severe weather occurs near fronts. The isobars are "kinked" along the line of an intense or fast-moving front. Stormy weather tends to occur near these zones. Weather fronts are plotted as lines with bumps or barbs that indicate the type of front and the direction of movement.
cooler air. In a stationary front, a warm air mass and a cold air mass meet in a boundary that moves slowly or not at all. When a cold front catches up to a warm front ahead of it, the result is called an occluded front.
The common weather map symbols are shown in Fig. 2-7, and a hypothetical weather map, similar to the type you might see in a major daily newspaper, is shown in Fig. 2-8. In the situation of Fig. 2-8, a strong midwinter low-pressure system is sweeping across the central United States, and an intense cold front is pushing eastward across Texas.
The weather maps used by meteorologists are more detailed than the one shown in Fig. 2-8. Computer-generated maps show such things as lines of equal temperature (isotherms) or weather conditions at various altitudes, but the simple
map found in the daily newspaper is sufficient for you to get a good idea of what is happening throughout the continent. You can tell with reasonable accuracy where the major weather systems are. If you know the position of the jet stream, you can forecast where the storms will pass.
In the situation shown by Fig. 2-8, where would the strongest widespread winds likely be found?
The most intense winds are likely to occur where two things happen simultaneously: (1) the isobars on the weather map are close together, and (2) the wind direction is the same as the direction in which the weather system giving rise to that wind is moving. In Fig. 2-8, this is near, and to the south of, the center of the low-pressure system over the middle part of the United States.
In the situation shown by Fig. 2-8, where would the strongest localized winds likely be found?
This question is more difficult to answer than the previous one. Localized winds are affected by mountains, canyons, the presence of tall buildings, and storms associated with weather fronts. Cold fronts are often associated with heavy thunderstorms, which can occur at any time of year in the extreme southern United States. It is even possible that there is a tornado somewhere near the cold front in the situation shown by Fig. 2-8, in which case the highest localized winds would be found there.
Was this article helpful?