NOAA Releases Their Winter Outlook... Snow and Cold The Theme
October 21, 2011 8:36 PM
As unbelievable as it sounds, we are beginning to head into another winter season, but what does that mean for South Dakotans? Well, the National Oceanic and Atmospheric Administration, also known as NOAA, released their predictions for the upcoming winter and the reasons behind them. If you are not one to appreciate the snow and cold then this probably wont be good news for you. Check out the full story below:
“For the second winter in a row, La Niña will influence weather patterns across the country, but as usual, it’s not the only climate factor at play. The “wild card” is the lesser-known and less predictable Arctic Oscillation that could produce dramatic short-term swings in temperatures this winter.
NOAA expects La Niña, which returned in August, to gradually strengthen and continue through the upcoming winter. It is associated with cooler than normal water temperatures in the tropical Pacific Ocean and influences weather throughout the world.
“The evolving La Niña will shape this winter,” said Mike Halpert, deputy director of NOAA’s Climate Prediction Center. “There is a wild card, though. The erratic Arctic Oscillation can generate strong shifts in the climate patterns that could overwhelm or amplify La Niña’s typical impacts.”
The Arctic Oscillation is always present and fluctuates between positive and negative phases. The negative phase of the Arctic Oscillation pushes cold air into the U.S. from Canada. The Arctic Oscillation went strongly negative at times the last two winters, causing outbreaks of cold and snowy conditions in the U.S. such as the “Snowmaggedon” storm of 2009. Strong Arctic Oscillation episodes typically last a few weeks and are difficult to predict more than one to two weeks in advance.
With La Niña in place Texas, Oklahoma, New Mexico and parts of surrounding states are unlikely to get enough rain to alleviate the ongoing drought. Texas, the epicenter of the drought, experienced its driest 12-month period on record from October 2010 through September 2011.
Stormy periods can occur anytime during the winter season. To improve the ability to predict and track winter storms, NOAA implemented a more accurate weather forecast model on Oct.18. Data gathered from the model will support local weather forecast office efforts to prepare for and protect the public from weather events. This service is helping the country to become a Weather-Ready Nation at a time when extreme weather is on the rise.
Highlights of the U.S. Winter Outlook (December through February) include:
· Pacific Northwest: colder and wetter than average. La Niña often results in below-average temperatures and increased mountain snow in the Pacific Northwest and western Montana during the winter months. This may set the stage for spring flooding in the Missouri River Basin;
· California: colder than average with odds favoring wetter than average conditions in northern California and drier than average conditions in southern California. All of the southern part of the nation are at risk of having above normal wildfire conditions starting this winter and lasting into the spring;
· Northern Plains: colder and wetter than average. Spring flooding could be a concern in parts of this region;
· Southern Plains and Gulf Coast States: warmer and drier than average. This will likely exacerbate drought conditions in these regions;
· Florida and south Atlantic Coast: drier than average, with an equal chance for above-, near-, or below-normal temperatures. Above normal wildfire conditions;
· Ohio and Tennessee Valleys: wetter than average with equal chances for above-, near-, or below-average temperatures. Potential for increased storminess and flooding;
· Northeast and Mid-Atlantic: equal chances for above-, near-, or below-normal temperatures and precipitation. Winter weather for these regions is often driven not by La Niña but by the Arctic Oscillation. If enough cold air and moisture are in place, areas north of the Ohio Valley and into the Northeast could see above-average snow;
· Great Lakes: tilt toward colder and wetter than average;
· Hawaii: Above-average temperatures are favored in the western islands with equal chances of above-, near-, or below average average precipitation. Statewide, the current drought is expected to continue through the winter. Drought recovery is more likely over the windward slopes of the Big Island and Maui; · Alaska: colder than average over the southern half of the state and the panhandle with below average precipitation in the interior eastern part of the state.
This seasonal outlook does not project where and when snowstorms may hit or provide total seasonal snowfall accumulations. Snow forecasts are dependent upon winter storms, which are generally not predictable more than a week in advance.
NOAA's National Weather Service is the primary source of weather data, forecasts and warnings for the United States and its territories. NOAA’s National Weather Service operates the most advanced weather and flood warning and forecast system in the world, helping to save lives and livelihoods and enhance the national economy. Working with partners, NOAA’s National Weather Service is building a Weather-Ready Nation to support community resilience in the face of increasing vulnerability to extreme weather.”
Now, we are going into another La Nina winter much like we experienced last year. But we aren’t expecting anything like we experienced. Remember that many records were broken all across the country with snow and cold rarely seen for many, so even though this year will once again be a La Nina, it will likely not compare to last year…. At least we hope. If you don’t remember just how ridiculous last year was across the United States, here is a recap thanks to NBC and The Weather Channel:
For the second consecutive winter, La Nina conditions in the equatorial Pacific Ocean will be in play. La Nina is a natural cooling of the tropical equatorial Pacific Ocean, which, in turn, exerts an influence on the overall global weather pattern. That said, La Nina is not the only factor controlling winter weather in the U.S. With that in mind, let's take a brief look back at the winter of 2010-2011.
Where do we start regarding the 2010-2011 snowstorms? Well, let's begin before winter "officially" began.
A snowstorm collapsed an NFL stadium's roof in the Twin Cities in early December. Two major snowstorms clobbered New York City, one snarling post-Christmas holiday travel. Cars were stranded in Chicago by a Pre-Groundhog's Day storm. Not to mention record snowstorms in Tulsa and Hartford, as well as snow, ice, and cold weather wreaking havoc over multiple days with the Super Bowl in Texas and in early January in Atlanta.
Interestingly enough, as you can see in the Dec-Feb. map below, the "wettest" areas, relative to average, were in the Northern Plains, setting the stage for what would be severe flooding later in the spring and summer in the Missouri River Basin. Below are some of the stunning snowfall stats from the 2010-2011 "season":
La Nina’s influence carried on well into the spring as well, leading to incredible late-season snowpack in the Rockies and heavy rain in the Ohio Valley.
Does that mean this season will be a snowy "repeat"? Frankly it's not nearly that simple.
It's true there is a tendency for snowier winters during La Nina (vs. El Nino) in Midwest cities such as Minneapolis, in the Pacific Northwest and northern Rockies. However, as we discussed earlier, La Nina is not the only "driver" of the atmospheric pattern.
Furthermore, as TWC Senior Meteorologist Stu Ostro pointed out in a 2007 blog entry, no two La Nina episodes are exactly alike! Near the bottom of that blog entry, see the season snowfall bar graphs in recent La Nina winters for New York City. Using La Nina alone doesn't provide any skill forecasting seasonal snowfall there.
The core winter months of December 2010 through February 2011 were colder than the long-term average for the U.S. as a whole. You can see the "real estate" that shivered last winter in the map below, in the blue shadings.
Normally a prime winter getaway, Florida shivered in its top 10 coldest Dec-Feb...for the second consecutive winter season! Talk about confused "snowbirds", the term for northern tourists flocking south to Florida seeking an escape from winter's cold and snow.
It wasn't just the "Sunshine State", either. Last winter was only a bit less cold in the South than the previous winter.
But aren't La Nina's typically warm and dry in the South? We return again to the point that it's not just La Nina/El Nino influencing the pattern.
In this case, persistent, stubborn blocking high pressure near Greenland, the “negative phase” of the so-called North-Atlantic Oscillation, plus the "negative phase" of the so-called Arctic Oscillation, helped lock stubborn cold air in the South for longer periods of time.