1. Weather Fronts Ms. Bireley’s 8 th Grade Science

2. What is a front? Boundary separating two masses of air of different densities and is the principal cause of weather phenomena Boundary separating two masses of air of different densities and is the principal cause of weather phenomena Depicted using various colored lines and symbols depending on the type of front Depicted using various colored lines and symbols depending on the type of front There are four types of weather fronts There are four types of weather fronts Cold Fronts Cold Fronts Warm Fronts Warm Fronts Stationary Fronts Stationary Fronts Occluded Fronts Occluded Fronts

3. Cold Fronts Characteristics Cold air mass is replacing a warmer air mass Cold air mass is replacing a warmer air mass Generally move front NW to SE Generally move front NW to SE Air behind is colder and drier than the air ahead of it Air behind is colder and drier than the air ahead of it When a cold front passes through, temps can drop more than 15 degrees within the first hour When a cold front passes through, temps can drop more than 15 degrees within the first hour

4. Warm Fronts Characteristics Warm air mass is replacing cold air mass Warm air mass is replacing cold air mass Generally move from SW to NE Generally move from SW to NE Air behind warm front is warmer and more moist than the air ahead of it Air behind warm front is warmer and more moist than the air ahead of it When it passes through, the air becomes noticeably warmer and more humid than it was before When it passes through, the air becomes noticeably warmer and more humid than it was before

5. Stationary Fronts Characteristics When a warm or cold front stops moving When a warm or cold front stops moving Once this boundary resumes forward motion, it once again becomes a warm or cold front Once this boundary resumes forward motion, it once again becomes a warm or cold front Noticeable temperature change and/or shift in wind direction is commonly observed when crossing sides of this front Noticeable temperature change and/or shift in wind direction is commonly observed when crossing sides of this front

6. Occluded Fronts Characteristics When a cold front overtakes a warm front When a cold front overtakes a warm front Occurs during the process of cyclogenesis (we will cover this tomorrow) Occurs during the process of cyclogenesis (we will cover this tomorrow)

7. Questions… What is the difference between a cold front and warm front? What is the difference between a cold front and warm front? Which front is designated by its blue line and triangles? Which front is designated by its blue line and triangles? How would you draw an occluded front? How would you draw an occluded front?