Answer:
Warm moist air, semicircles.
Step-by-step explanation:
Warm fronts are characterized as being low pressure systems because warm air is being lifted to create precipitation events. After the passage of the warm front, the temperature increases since temperatures behind the front are warmer than temperatures ahead of the front.
On a weather map, warm fronts are labelled as curved red lines with red semicircles that point in the direction that the front is moving.