Many eastern parts of North America are being hit by heavy downpours and a sharp temperature drop [EPA]

North America is no stranger to severe weather. It’s a continent that sees the extremes, from bitter cold to extreme heat. Currently a weather system is giving torrential rains across many eastern parts of the USA and Canada.

The current active weather is not a surprise for this time of year. It’s caused by the cold air from the north which is digging down across the continent, and interacting with the warmer air which is feeding up from the Gulf of Mexico. The result is often explosive, with torrential rain and strong winds.

In the 24 hours up to 6 GMT on 28 November 2011, Chattanooga in Tennessee was swamped with 58.5mm (2.3 inches) of rain, and in the neighbouring state of Alabama, Montgomery saw even more, reporting 62mm (2.4 ins).

As the storm sweeps across the eastern parts of North America, there is also a very dramatic drop in temperature. Ahead of the rain, the winds are being sucked up from the south, then behind the rain, the winds swing round, screaming down from Canada.

Atlanta has already experienced the sudden change. On Sunday the city enjoyed temperatures of 22C (72F), but for the next few days the temperatures will struggle to reach 14C (57F).

The drop in night time temperature is just as dramatic. Before the rain started, Atlanta’s minimum temperature wasn’t dropping below 15C (59F), but on Monday night the temperature is expected to drop to a chilly 2C (36F).

In fact, the temperatures behind the system are so low, that there could even be some snow in Georgia, Mississippi and Alabama on Monday night. However, accumulations of snow should be kept to a minimum as the ground at this time of year is still fairly warm, which should ensure that the snow melts fairly readily.

The system is eventually expected to spiral away from eastern Canada during the day on Wednesday, but it’s not the only system that’s brought severe weather to North America recently.

The weather has also been very active in the western parts of the continent as well. Heavy rain and snow has been falling in northwest USA and southwest Canada for several days. In Squamish, British Colombia, 146mm (5.75 ins) of rain fall in the 24 hours up to midnight on 28 November 2011. The temperature in Squamish hovered at 9C (48F) for much of the day, which kept the snow at bay, but further east, many parts have been covered in a thick blanket.

This system is finally releasing its hold on the region, and a high pressure is building. This should ensure the weather calms down, and the residents can enjoy a break in the weather, for a few days at least.

Source: Al Jazeera