Precipitation & Storms

Forms of Precipitation

Convectional — rising, warm air from beneath

  • needs humidity to condense (reach dew point) and form clouds
  • additional energy is provide when condensation begins
  • Sierra Nevada summers (temps and moisture increase)

Frontal — when zones or "air masses" collide

  • causes uplift and precipitation
  • common "extratropical" storms across U.S in winter

Orographic

  • air forced up by landform barriers
  • needs prevailing or other winds
  • "rainshadow" results on leeward side

Distribution of Precipitation (discussed earlier with wind belts & cells)



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