how do scientists predict what the weather may be?

Answer 1

they base their ideas of weather on the temperatures and pressure. and how the wind is moving the pressure systems and where.

for example:
a low pressure system may be moving into your area, the weatherman predicts rain. this is because air rises near low pressure areas, and as the air rises, it condenses into clouds, which leads to precipitation.

the site listed below also explains the fronts, and how they tell you about storms.

scientists just know a lot about the systems and know how they manipulate weather a lot better than anyone else.

Answer 2

High and low pressures (barometer) Along with satellite pictures.