La Nina for Seattle 2011-2012 

It's official, the Climate Prediction Center has a La Nina Advisory in place for winter of 2011/2012.  What it means for the Pacific Northwest will be a trend towards wetter and cooler than average weather.  There has been an increasing amount of research on the atmospheric impact of changing sea surface temperatures in the equatorial Pacific in the last decade.  One thing that has become apparent: when you have two La Nina winters back to back,  the second La Nina event trends weaker.  As of October 2011, about half of the climate models show our new La Nina, the second one in a row, as strengthening in fall and winter and that it will be weak.  The Climate Prediction Center is calling for a weak to moderate La Nina.

The way to approach the upcoming season is, La Nina will be weaker but it's impact will not be lessened. 

Impacts will be:

 1. Heavier precipitation earlier in the season. (Oct-Dec).

 2. Cold weather favored later in the season.(Jan-Mar)

3. Lowland snow events more likely later in season (Dec-Mar)

4. Flooding earlier in season. (Oct-Dec)

5. Increasing mountain snow pack.

6. Windstorms (typically happen Nov-Dec) can occur throughout entire season.

Here is a video overview:

See you on KIRO7 for continuing coverage of our new La Nina season!

Rebecca Stevenson