Surface Map Symbols Explained

Fronts can bring drastic weather changes, including the temperature drop we’ll be seeing starting on Monday, but they can only be inferred through analysis of surface observations from weather stations throughout the country. Different fronts have different characteristics and associated symbols shown on surface maps like one would see on television. Understanding which symbol corresponds to what type of front can help you prepare for weather changes associated with them.

Cold Front

The star of the forecast for the next couple days- cold fronts can bring much cooler and drier weather behind it as it’s the leading edge of a drier and colder air mass. On certain occasions it can bring rainy or severe weather as it can provide lift needed for storms to develop in a warmer, more unstable, environment.

Cold fronts are illustrated by blue lines with sharp, blue triangle teeth pointing away from the colder air. You can see this in the graphic above with a cold front draped over Kansas.

Warm Front

Warm fronts are the leading edge of a boundary of advancing warm air. These are seen in particular along the left side of a low pressure system in its “warm sector.”

Cold fronts are illustrated by red lines with rounded, half-circle teeth pointing away from the warmer air. Seen on the graphic above Missouri and much of the Mid-West is within that “warm sector” region. You will see that the warm front is not alongside a low pressure system but away from it, that takes us to our final front seen in the image above.

Occluded Fronts

The most complex of the fronts, this front only occurs when the warm air becomes “occluded” or separated from the low pressure center. You can see this in the image as the occluded front, visualized by a magenta line with both triangle and semi-circle teeth, is separated from the low pressure center located in Canada.