What are earth crossing asteroids and how do we monitor them

Earth-crossing asteroid, asteroid whose path around the Sun crosses Earth's orbit. Two groups of such asteroids—Aten and Apollo asteroids—are distinguished by the size of their orbits and how closely they approach the Sun.

Explanation:

weather forecasts are done by collecting data about the current state of the atmosphere mainly the temperature, humidity and wind and using meteorology, to determine the atmosphere that evolves over time. the h and l mean the high and low pressure. the red strip is a warm front. the blue strip is a cold front. the blue and red strip is a stationary front. the purple strip is a occluded front.

explanation: