What Is Weather Map?

The National Weather Service Forecast Map

A high pressure system is a dense air mass that is cooler and less humid than the surrounding air. A low pressure system is usually a less dense air mass that is warmer than the surrounding air. Areas that experience high atmospheric pressure are more likely to have fair weather.

Clouds and storms can be formed by low pressure systems. Air usually flows from high pressure to low pressure. A warm front is when a mass of warm air moves to replace a mass of cold air.

A warm front is usually drawn using a red line and half circles to point the way of the cold air that will be replaced. Warm fronts move from one side to the other. A warm front can bring some rain, but then clear skies and warm temperatures.

A cold front is when a mass of cold air moves in to replace warm air. A cold front is usually drawn on a weather map with a solid blue line and triangles pointing in the direction of warm air that will be replaced. Cold fronts can move from northwest to southeast.

A cold front can bring cold temperatures and heavy rains. A cold front and warm front meet up, but neither moves out of the way. A stationary front is usually drawn using alternating cold front and warm front symbols.

The southern wind

The wind in the southern hemisphere is anticlockwise. The air above a high pressure system sinks and warms as it does. The sinking air is very stable and therefore it is dry.

Lows are usually cold, wet, and windy, and are smaller systems than highs. The isobars are close together around a low, which indicates stronger winds. Cold fronts can cause a change in wind direction and sometimes a large drop in temperature.

The hot and dry conditions ahead of the front combine with strong winds and a fire danger that can be increased by cold fronts. Winter cold fronts can cause damage. They can cause snow to fall at low levels by drawing cold air up from south of Australia.

The weather

The weather describes the atmosphere. The sky can be cloudy or gray when temperatures climb and fall. The meteorology department uses the weather to predict what will happen tomorrow.

Detailed weather maps show surface weather conditions over a wide area, which gives a variety of information to meteorologists. Maps in newspapers and on television show some of the data to help keep people aware of the weather. Air temperature is recorded at official stations.

The current temperature, the high or low temperature in the past day, or the predicted temperatures are displayed on a map. Many maps use isotherms to show areas with the same temperature. The temperature maps have shades of red and blue in hot areas and violet and blue in cold areas.

The official weather stations record barometric pressure and temperature. Each station has pressure readings printed on maps. The barometric pressure is summarized into a map that has lines connecting points of equal pressure.

Readers can see pressure trends and find zones of high and low pressure with the help of isobars. The centers of high- and low-pressure cells are marked by large letters. The edges of moving air mass are called fronts.

Weather Maps and Sky Cover Symbol

If a weather map has already been analyzed, you won't find much use for the station plot data. Station plot data is the most important information you start with when analyzing a weather map. Having a map of all stations helps you decide where to draw in high- and low-pressure systems, fronts, and the like.

Sky cover symbols have been established by the National Oceanic and Atmospheric Administration. The percentage that the circle is filled is a good indicator of the amount of sky that's covered with clouds. The sky cover circle has a line that extends out.

A Public Warning on the Development of Tornadoes

It issued when the conditions are favorable for the development of tornadoes. 6 hours is the most common time for a watch to be in effect, and issued by the coastal zone. It was issued to inform the public that flash flooding is usually occurring within 6 hours after the event, and that it can happen in urban areas.

It was issued from areas small as portions of cities. The same conditions were described in the Hurricane Warning, except for the possibility of occurrence over the next 24 to 48 hours. Watches can be issued out to 60 hours or longer in cases of high confidence.

Climate Forecasting

Air pressure changes in the area are what control the weather events. The air pressure is caused by the weight of air. Skies are usually clear and blue when air pressure is high.

The high pressure causes air to flow down and fan out when it is close to the ground. When air pressure is low, air flows together and then upward, where it forms clouds. Local or regional weather forecasts are developed by meteorologyologists.

The weather events that are happening over a broad region are taken into account by the best forecasts. Knowing where storms are now can help predict where storms will be tomorrow and the next day. The process of looking over a large area is aided by the network of weather observations.

The unpredictable nature of the atmosphere means that it will be impossible to predict the weather more than two weeks in advance, but new technologies combined with more traditional methods are allowing forecasters to develop better and more complete forecasts. Climate is the average weather pattern over several decades. Different regions have different climates.

The central pressure of a high

The example shows the isobars and the surface wind at the same time. The wind arrow shows the direction. Some winds line up nicely with the isobars and others are almost at right angles to them.

A weak High has a central pressure of about 1015hPa, while a strong or intense High has a central pressure of about 1030hPa. A rising central pressure is the result of an intensifying High and a falling central pressure is the result of a weakened High. There areas of low cloud near the centre of a High.

The winds are sometimes strong. Strong winds are created when the isobars are squeezed together. Summer Highs can bring storms and hail.

The fronts that are trying to follow the bigger Highs are sometimes blocked by the slower ones. A low pressure system is like a giant funnel of wind that pushes warm air in the centre. Clouds form as air rises.

The central pressure of a shallow Low is over 1000 hPa, of a moderate Low 980-1000 hPa, and of a deep or intense Low below 980hPa. The Low is said to be complex if there are more than one centre. The low is said to be filling or weakened if the central pressure is rising.

Predicting the future of Earth's weather

The degree to which it is hot or cold, wet or dry, calm or storm, clear or cloudy, is called the weather. The troposphere is the lowest layer of the planet's atmosphere and is just below the stratosphere. Climate is the term for the average of atmospheric conditions over a longer period of time.

Studying how the weather works on other planets has helped in understanding how weather works on Earth. Jupiter's Great Red Spot is anti-cyclonic storm that has existed for at least 300 years. The weather is not limited to planets.

A star's corona is being lost to space, creating a very thin atmosphere throughout the Solar System. The solar wind is the movement of mass from the Sun. Predicting future conditions is no longer an all-human endeavor, but rather a model used to determine barometric pressure, current weather conditions, and sky condition.