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Which of the following statements is true concerning frontal fog?
  • A
    It develops rapidly and dissipates slowly
  • B
    It may be formed by day as well as by night
  • C
    It usually forms by day
  • D
    It usually forms by night

Refer to figure.

FRONTAL FOG. Occurs at a warm front or occlusion. The main cause – precipitation lowering the cloud base to the ground. Formed due to evaporation and following condensation of warm falling precipitation down in a cold moist layer ahead of a warm front. It is formed by day and night.

  • The fog can form along a belt up to 200 NM wide which then travels with the front. - unless the front is a very slow moving one, the fog is typically present for only about 2 to 3 hours.
  • Orographic lifting => increases the fog intensity
  • Dissipation of frontal fog: by passing of the front
Note: Frontal fog does not form ahead of cold fronts, because the rain and showers connected with a cold front are made up of drops that are too large, they have a high falling speed and at the same time the temperature of the drops is low.

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