For more than 75% of the United States, the Blizzard Forecast 2011-2012 Season predictions predict extreme cold and multiple snowstorms, coupled with more ice than snow, than in many years past. The primary culprit is La Niña which is a phenomenon occurring when the temperature of the sea’s surface across the equatorial regions are below normal.
La Niñas typically produce significantly more volatile weather patterns for the Northeast and Midwest sections of the country during the wintertime because of the manner in which they affect the jet stream.
As the jet stream is positioned during the La Niña-influenced season, winter storms cover a wider range of the country than they do without this influence, and the brunt of it hits more toward the middle section of the country than the farther Northeast. Chicago will be much harder affected than New York with snowfalls predicted of upwards of 60 inches.
There are a number of parameters that weather forecasters consider in order to predict the Blizzard Forecast 2011-2012 Season, which include the following:
La Niñas – When the sea temperatures around the equatorial regions across the globe are lower than normal, they have an effect on the jet stream, pushing it further north, causing that colder air to be distributed throughout the plains of the Midwest and along to the eastern seaboard. Because of La Niña, the brunt of the storm will be significant throughout the Midwest causing larger accumulations of blizzard-like conditions and greater accumulations of snow and ice in the southern planes along Texas and Oklahoma.
Jet Stream – As the jet stream weaves its path across the United States, instead of keeping path further north, it tends to move further south bringing that colder Arctic down into the Midwest.
Moisture – Typically during these La Niñas years, there is significant more moisture in the air than during the dryer El Niño years. Greater levels of moisture coupled with the La Niña’s effect and the lower jet stream makes for greater snow and ice accumulations.
Interpreting These Parameters
Generally when weather forecasters have predicted a blizzard is on the way, it’s because several factors have come into play and these conditions have been prevalent for three hours or longer.
Temperatures that are falling consistently coupled with falling or blowing snow.
Sustained winds that have frequent gusts of up to 35 miles per hour or greater.
Visibility that is reduced to less than one-quarter of a mile.
Blizzard warnings are issued when all three of these parameters are prevalent for a minimum of three hours. It doesn’t even have to continue snowing for the blizzard to be in effect if the winds are continuing to pick up surface snow that has already accumulated and is being blown by strong winds. Generally blowing snow is accompanied by drifting snow.
Blowing Snow Advisories can also be issued when the wind is blowing accumulated snow from drifts that have piled up, which also reduces visibility to less than one-quarter of a mile.
Throughout the country, there are some areas that are affected by this La Niña effect to a much greater extent than the rest of the country. Some of the predictions include:
Midwest and Great Lakes – This region can expect to have the worst of the blizzards and cold than the rest of the country. Bitter cold arctic air from December through January with snowfall significantly above average.
Northeast – This region is not expected to have the extreme blizzards that have been seen in past years; however, snowfall is expected to be higher than normal from Virginia to Maine. Pennsylvania and western New York will still experience significant amounts of lake-effect snow and colder temperatures.
Southern States – The deep Southern states are expected to see far more ice than snow with more significant accumulations than in the past, with greater potential for flooding in the lower Mississippi valley during the Spring.
Western States – The western coast should expect great swings in weather conditions, due in part to the “Pineapple Express” that occurs when excessive moisture arrives from the Hawaiian Islands and floods great parts of the west Coast with moisture as well as providing greater potential for snow events.
Finally, the majority of the country will have heavier snowfalls, colder temperatures, and higher winds.
The Brunt of the Winter Season
With all the factors of the La Niña’s effect and the “Pineapple Express” from the Hawaiian Islands, the potential Blizzard Forecast 2011-2012 Season paints a dismal picture for much of the Midwest, Northeast, Atlantic seaboard, south, and southwest.
Since the Northwest will have the brunt of the Arctic winds brought by the jet stream, coupled with La Niña, and the “Pineapple Express” they are likely to experience great accumulations of snow and even blizzard-like effect in this region also. This season is predicted to be quite the eventful season across the country; keeping weather forecasters quite busy around the country.