What's causing all the record dry weather and mild winter temperatures?

By Daily Mail Reporters

Last updated at 7:50 AM on 14th January 2012

The first week in January was the driest in U.S. history with more than 95 per cent of the U.S. reporting below-average snow.

About  half of the U.S. had temperatures at least 5 degrees Fahrenheit above average during December.

Now meteorologists believe the atmospheric pressure pattern called the Arctic Oscillation is controlling the jet stream and causing records to be broken on a near daily basis.

Unusual atmospheric pressure over the Arctic has kept the jet stream far north, making way for warm, dry air from the south

The jet stream flows from west to east across the northern latitudes of America and Europe, changing temperatures and precipitation as it meanders north and south, digg.com reports.

This season we've been experiencing a strong straight jet stream which has been preventing the cold arctic air from drifting south.

Meteorologist Jeffrey Masters said: 'The cause of this warm first half of winter is the most extreme configuration of the jet stream ever recorded.'

Drought conditions still prevail in Texas after one of the driest years on record. Here a farmer checks dying Christmas trees in November 2011

The jet stream headed north in a straight path and stayed that way, allowed warm southern air to fill most of the states.

It has also prevented cold fronts from clashing with warm fronts, which leads to precipitation.

The lower edge of the Arctic Oscillation is called the North Atlantic Oscillation.

Greater variations in the NAO in recent years is another mystery scientists are trying to solve.

The frozen far north: Only parts of Alaska have seen heavy snowfall so far this winter

A study published in the January 13 issue of the journal Environmental Research Letters focuses on harsh winters in the Northern Hemisphere in recent years.

The research by the University of Massachusetts and the University of Alaska, Fairbanks, shows that increasing temperatures and melting ice in the Arctic regions are creating more snowfall in the autumn months at lower latitudes, which leads to colder winters, Livescience.com reports.

The strongest winter cooling trends were observed in the eastern United States, southern Canada and much of northern Eurasia.

The researchers' observations showed that the average snow coverage in Eurasia has increased over the past two decades.

Source : dailymail

Related Video :

ABC's World News Now celebrates 20 years on ABC-TV. We have a look back at our favorite moments. *Like us: WNNfans.com