Cold Front-Cross Section

  • warm air ahead of front is lifted up and over
  • can get intense showers/thunderstorms at frontal boundary
  • Cs and Ci clouds are blown ahead of the front by upper level winds
  • cloud base is generally lower behind the front.... why???
  • further behind the front, the air is quite dry, few clouds
  • steep frontal boundary, slopes backward into the cold air
  • frontal speed averages 15-25 knots
  • temperature and wind profiles on either side of cold front???
  • fronts can weaken with time - frontolysis
  • fronts can strengthen with time - frontogenesis
    • what processes can lead to frontogenesis? ANSWER
from Meteorology Today by D. Ahrens   Before Passing   While Passing   After Passing
Winds   south-southwest   gusty; shifting   west-northwest
Temperature   warm   sudden drop   steadily dropping
Pressure   falling steadily   minimum, then sharp rise   rising steadily
Clouds   increasing: Ci, Cs and Cb   Cb   Cu
Precipitation   short period of showers   heavy rains, sometimes with hail, thunder and lightning   showers then clearing
Visibility   fair to poor in haze   poor, followed by improving   good, except in showers
Dew Point   high; remains steady   sharp drop   lowering