1) Mid-latitude cyclones form at the polar front when the temperature difference between two air masses is large. These air masses blow past each other in opposite directions. Coriolis effect deflects winds to the right in the Northern Hemisphere, causing the winds to strike the polar front at an angle.
2) Mid-latitude cyclones, sometimes called extratropical cyclones, form at the polar front when the temperature difference between two air masses is large. ... Since the rising air is moist, rain or snow falls. Mid-latitude cyclones form in winter in the mid-latitudes and move eastward with the westerly winds.
3) the Gulf of Mexico, off the East Coast, and the eastern side of the Rocky Mountains
