During a severe thunderstorm event, storm chasers and meteorologists will talk about the infamous back-sheared anvil. The clouds can produce hail, mammatus clouds, and even tornadoes.

Snow is already falling in many parts of the country. Whether you are driving in the winter, or tucked safely away at home, a winter storm can strike with little warning. Cold weather can cause deaths from exposure, exertion, and traffic accidents. You can become snowed in at home or in your vehicle. It is important to make an emergency weather kit specifically designed for the winter months. Learn the essential ingredients of a winter safety kit.

Scientists and researchers agree - Climate change is happening. According to the University Corporation for Atmospheric Research (UCAR), 18 leading scientific organizations have sent a letter to members of the senate reaffirming the scientific consensus that climate change is occurring and that greenhouse gases from human activities are the primary driver. The letter, sent October 21, 2009 to the United States Senate, outlines the consensus among these leading scientific agencies. In June 2009, the U.S. House of Representatives passed a landmark, bi-partisan 1,200-page climate change bill. Read the full climate change support letter.

From December 2009 to February 2010, winter weather conditions are expected to be mild. The effects of an El Niño in the Pacific are causing temperatures to be at or above normal for much of the contiguous United States. Much of the Midwest and Northwest will likely experience higher than normal temperatures. Meanwhile, temperatures in the Southeast and in Hawaii are expected to be below normal.

Rainfall is also expected to increase along the Gulf Coast region and throughout the California coastal regions. While the increases in precipitation expected for Texas may help to alleviate the drought, tornado records suggest that there will also be an increased chance of winter tornado activity for the Gulf Coast region.