1. 1 Fog What is fog? What is fog? Warm, moist air which has been cooled Warm, moist air which has been cooled

2. 2 Fog A boiling kettle in a cold room A boiling kettle in a cold room Exhaled breath on a cold day Exhaled breath on a cold day Steam from shower in a cold bathroom Steam from shower in a cold bathroom

3. 3 Advection (Sea) Fog Warm moist air comes over cold sea/land Warm moist air comes over cold sea/land Usually from South or SSE Usually from South or SSE Usually Spring (sea still cold) Usually Spring (sea still cold) Can persist at sea for days Can persist at sea for days

4. 4 Advection (Sea) Fog How does it clear? How does it clear? Needs a change in conditions Needs a change in conditions Remove source of warm air Remove source of warm air Ie Change in wind direction Ie Change in wind direction

5. 5 Radiation (Land) Fog Warm moist air Warm moist air Cooled at night Cooled at night High pressure – no clouds High pressure – no clouds Warm day –cold night Warm day –cold night Mainly winter Mainly winter Valleys, bogs Valleys, bogs Can drift to sea Can drift to sea

6. 6 Radiation (Land) Fog How does it clear? How does it clear? Wind will blow it away Wind will blow it away Sun will burn it up during the day Sun will burn it up during the day

7. 7 Fog – what to do