Surface Weather Map Features
Looking at the weather map above we can see that we have three and four digit numbers on the map. These numbers are known as Sea Level Pressure. They are recorded in MB.
Looking at the Northern part of South Dakota we see a number at 995mb while over parts of Maine we see the number closer to 1020mb. So we would say that high pressure is over Maine, while low pressure is over the Dakota’s as our MB numbers show.
A surface pressure map can be very useful to a weather forecaster in many ways such as identifying areas of high and low pressure.
High pressure brings partly cloudy skies and low pressure brings rain and storms. High pressure in the winter can also bring colder temps while low pressure in the winter can bring warmer air to the area. High pressure and low pressure also bring different wind patterns.
All of these are important facts that a weather forecaster needs to look at before they create their weather forecast for the day. Also using the pressure map we can determine the winds and how strong they may be. For example if we look at Southeast Iowa there are three lines together representing stronger winds than compared to Florida where there is only one line which would indicate light winds.