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Refer to figure.
What happens to the pressure at position A on the chart as the front approaches?
  • A
    Remain unchanged.
  • B
    It will increase.
  • C
    Fluctuate up and down by about 50 feet.
  • D
    It will decrease.

Refer to figure.

The figure depicts a COLD OCCLUSION – the cold air behind the cold front undercuts the less cold air ahead of the warm front, warm front becomes a front aloft. In simple words, the cold front transits into the occlusion (and not the warm front).

As we can see in the attached figure:
A – Cold front
B – Warm sector
C – Warm front
D – Cold occlusion
F – zone ahead of warm front (cool air)
E – Zone behind cold front (cold air)

PRESSURE CHANGES IN A FRONTAL OCCLUSION:

  • Ahead of a warm front: steady decreasing
  • At the warm front: stops falling (lowest value)
  • In the warm sector: steady and drops with the arrival of cold front
  • At the cold front: starts to rise
  • Behind the cold front: increases slowly
With regards to this question, when a cold front is approaching (in this case, in the warm sector), the pressure decreases slightly. The lowest pressure value is read at the cold front. After the front passage/behind the cold front, the pressure increases.

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