La Niña Returns!

September 8, 2011

As I stated in my 2011/2012 Winter Forecast, I expected a return to a La Niña type weather pattern by the Fall/early Winter months. The NWS officially announced today that La Niña has returned. A La Niña type weather pattern will likely lead to another active and extreme winter across the Plains, Midwest and Ohio Valley. Here is the official press release from NOAA – Brandon

La Niña, which contributed to extreme weather around the globe during the first half of 2011, has re-emerged in the tropical Pacific Ocean and is forecast to gradually strengthen and continue into winter. Today, forecasters with NOAA’s Climate Prediction Center upgraded last month’s La Niña Watch to a La Niña Advisory.

NOAA will issue its official winter outlook in mid-October, but La Niña winters often see drier than normal conditions across the southern tier of the United States and wetter than normal conditions in the Pacific Northwest and Ohio Valley.

“This means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico,” said Mike Halpert, deputy director of the Climate Prediction Center. “La Niña also often brings colder winters to the Pacific Northwest and the northern Plains, and warmer temperatures to the southern states.”

Climate forecasts from NOAA’s National Weather Service give American communities advance notice of what to expect in the coming months so they can prepare for potential impacts. This service is helping the country to become a Weather Ready Nation at a time when extreme weather is on the rise.

Seasonal hurricane forecasters factored the potential return of La Niña into NOAA’s updated 2011 Atlantic hurricane season outlook, issued in August, which called for an active hurricane season. With the development of tropical storm Nate this week, the number of tropical cyclones entered the predicted range of 14-19 named storms.

The strong 2010-11 La Niña contributed to record winter snowfall, spring flooding and drought across the United States, as well as other extreme weather events throughout the world, such as heavy rain in Australia and an extremely dry equatorial eastern Africa.

La Niña is a naturally occurring climate phenomenon located over the tropical Pacific Ocean and results from interactions between the ocean surface and the atmosphere. During La Niña, cooler-than-average Pacific Ocean temperatures influence global weather patterns. La Niña typically occurs every three-to-five years, and back-to-back episodes occur about 50 percent of the time. Current conditions reflect a re-development of the June 2010-May 2011 La Niña episode.

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 protect lives and property and enhance the national economy. Visit us online at weather.gov.

NOAA’s mission is to understand and predict changes in the Earth’s environment, from the depths of the ocean to the surface of the sun, and to conserve and manage our coastal and marine resources. Join us on Facebook , Twitter and our other social media channels.

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2011 – 2012 Winter Forecast

August 12, 2011
2011-2012 Winter Forecast
Issued by Brandon Redmond on August 12th, 2011
www.IndianaWeatherOnline.com
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Upcoming winter to rival last year’s harsh winter 
 
The 2010-2011 winter was the coldest winter in over 30 years across much of the Northeastern United States. Temperatures during the 200-2011 were well below normal in places like New York, Chicago, Indianapolis, Minneapolis and even New Orleans! Snowfall records were shattered across much of the Midwest and Northeast. With the 2010-2011 winter being so extreme, what can we expect for this upcoming winter?

 

The Winter forecast is compiled based on several factors. Analogs, Oceanic Temperatures, Climatology and Pattern Recognition are just a few of the factors used when making seasonal forecasts. Analogs in meteorology compare the current weather pattern to previous winter patterns. Oceanic temperatures refer to El Niño and La Niña which both refer to the Sea Surface Temperatures in the Equatorial Pacific. 

 

One of the main factors used in my long range and winter forecasts are the Sea Surface Temperatures in the Equatorial Pacific and whether our weather pattern is being influenced by La Niña (cooler water temperatures in the Equatorial Pacific) or an El Niño (warmer water temperatures in the Equatorial Pacific). The Sea Surface Temperatures in the Equatorial Pacific provide a regulating force for North American Weather, particularly temperatures and winter storm tracks. 

 

La Niña cools the equatorial seas of the Pacific and the 2010-2011 La Niña was one of the strongest on record. Less warm air rises during La Niña conditions with a cooling influence on the atmosphere that has significant implications on global climate and global weather patterns.
The upcoming 2011-2012 winter will likely be influenced by a weak to moderate La Niña. Oceanic temperatures in the Equatorial Pacific are already cooling and long range indications show a weak to moderate La Niña developing as early as this Fall.  

 

La Niña conditions will likely start off fairly weak and strengthen as we head towards the middle and end of the winter. It will likely take much of the winter before the United States begins feeling the full impacts of La Niña, making the forecast two months of the forecast (December and January) much more difficult. 

 

December looks to start off dry with warmer than normal temperatures as the jet stream will be displaced to the North and West. The far Northwestern United States will see above normal precipitation will the rest of the nation will see relatively quiet weather through the middle of December. With the jet stream displaced to the North, temperatures should climb to above normal values across much of the Nation through the middle of December. By the middle of December, the ridge will begin to break down as a major trough ejects south. As the trough ejects south, significant cyclogenesis (storm development) should occur across the Southern Plains and then transverse across the Central and Midwestern United States. A temporary Greenland Block by the end of December will lead to increased storminess and below normal temperatures across much of the Central and Eastern United States. 

 

 

 

As the La Nina continues to try to build and take hold on the global circulation patterns, January will likely become a transition month. The main story during the month of January will likely be the extreme cold as the Polar Vortex should be displaced significantly farther South than normal. This will lead to a major arctic outbreak across the Eastern two thirds of the United States.

 

 

 

A La Niña like pattern will ensue during February leading to near normal temperatures across most of the Central and Eastern United States. A storm track from the South Central Plains through the Tennessee Valley and into the Middle Atlantic/Northeast will cause increased storminess and potential overrunning situations during the month of February. This will create an increased chance of snow and ice across the Midwest, Ohio Valley, Great Lakes, Middle Atlantic and Northeast.  

 

 

 

With the La Niña pattern developing in February and influencing the global weather and circulation patterns, I would not be surprised to see a colder and snowier pattern continue into March. The potential for overrunning situations will continue into March with a continuing threat of snow and ice across the Midwest, Ohio Valley, Great Lakes, Middle Atlantic and Northeast.

 

Here are my ideas for the entire Winter as to who picks up above normal snowfall & ice. Obviously this is just based off of my forecast storm tracks, areas that receive above normal precipitation and either near normal or below normal temperatures.

 

  

In the end, I think the potential for record breaking cold across must of the Midwest, Great Lakes, Ohio Valley and even portions of the Northeast will be the big story this winter. Temperatures across the Plains should stay near normal with above normal temperatures across the Southern Plains and Deep South.

 

Don’t forget, you can book your 2012 Storm Chase Tour with SWATTours.com!