Synoptic scale meteorology

The first weather maps in the 19th century were drawn well after the fact to help devise a theory on storm systems.

Use of the Norwegian cyclone model for frontal analysis began in the late 1910s across Europe, with its use finally spreading to the United States during World War II.

Surface weather analyses have special symbols which show frontal systems, cloud cover, precipitation, or other important information.

Isobars are commonly used to place surface boundaries from the horse latitudes poleward, while streamline analyses are used in the tropics.

[4] An extratropical cyclone is a synoptic scale low-pressure weather system that has neither tropical nor polar characteristics, being connected with fronts and horizontal gradients in temperature and dew point otherwise known as "baroclinic zones".

[5] The descriptor "extratropical" refers to the fact that this type of cyclone generally occurs outside of the tropics, in the middle latitudes of the planet.

[10] During the day, since no clouds are present to reflect sunlight, there is more incoming shortwave solar radiation and temperatures rise.

At night, the absence of clouds means that outgoing longwave radiation (i.e. heat energy from the surface) is not absorbed, giving cooler diurnal low temperatures in all seasons.

[13] The low, sharp inversion can lead to areas of persistent stratocumulus or stratus cloud, colloquially known as anticyclonic gloom.

For example, extensions of the Azores high pressure may bring about anticyclonic gloom during the winter, as they are warmed at the base and will trap moisture as they move over the warmer oceans.

[18] A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena.

A surface weather analysis for the United States on October 21, 2006.
A fictitious synoptic chart of an extratropical cyclone affecting the UK and Ireland. The blue arrows between isobars indicate the direction of the wind, while the "L" symbol denotes the centre of the "low". Note the occluded, cold and warm frontal boundaries .
Different air masses tend to be separated by frontal boundaries. The Arctic front separates Arctic from Polar air masses, while the Polar front separates Polar air from warm air masses. (cA is continental arctic; cP is continental polar; mP is maritime polar; cT is continental tropic; and mT is maritime tropic.)