Here's why:
* Cyclone Structure: Mid-latitude cyclones are rotating weather systems with low pressure at their center. Air flows counter-clockwise around the low pressure in the Northern Hemisphere.
* Air Flow: On the eastern side of the cyclone, the air is flowing from the north towards the south.
* mP Air Mass: Maritime polar air masses originate over the cold waters of the North Atlantic and North Pacific oceans. They are characterized by:
* Cool, moist air: The air is relatively cool due to its origin over cold water.
* Stability: mP air masses are often quite stable, leading to stratiform clouds (layered clouds) and drizzle.
* Weather: This combination of cool, moist, and stable air leads to the typical weather conditions associated with the eastern side of a mid-latitude cyclone, including:
* Cloudy skies
* Precipitation (rain, snow, or sleet)
* Cooler temperatures
Important Note: While mP air masses are common on the eastern side of mid-latitude cyclones, other air masses can also be involved, depending on the specific location and time of year.
