The Sweet Spot for Good Winter Weather


Will the cooling Tropical Pacific become a La Niña? Source: NASA

Oct 31, 2016

RSS By: Evelyn Browning Garriss and James J. Garriss, Browning Media, LLC

Right now, there are a lot of scientists arguing. Their models are tied up in knots. It looks like cattle raisers and corn farmers will be the real winners of this debate.

Will the cooling Tropical Pacific become a La Niña? Source: NASA

Here’s what they are fighting about. The Tropical Pacific is cold. Will it be a La Niña, a neutral Pacific or a really weird event called a La Niña Modoki? (It’s also called a Central Pacific La Niña, but a Modoki sounds like a rather nice cocktail.)

It matters because a La Niña cools one-tenth of the Earth’s surface and alters weather all around the world. A strong La Niña causes drought in Texas and the Midwest. The temperatures in the tropics warp air pressure, which in turn shapes wind and weather. When the tropical waters turn cold, less tropical moisture flows north to the US. When they are warm, huge streams of moisture, called atmospheric rivers, flow north and bring rainfall. The ones that hit Texas and then flow north into the Midwest are called the Mayan Express. The ones that hit California are the Pineapple Express.

Atmospheric rivers from the tropics bring heavy US rainfall that can be good for crops and pastures.

So, what does this have to do with the climate model battle? Basically, the location of the warm spot in the Tropical Pacific determines where tropical moisture will fall. Right now, scientists are discussing whether we are experiencing Central Pacific La Niña (Modoki) or standard La Niña conditions. One creates a dry winter and the other lets Texas have rain. Notice how the two La Niñas are different.

Modokis are cold in the center of the Tropical Pacific but the area by South America is warm. History suggests that that make Mayan Expresses and Gulf storms more common. When scientists discuss the Modoki, they say its impact is felt more heavily in Asia and it only produces weak La Niña effects in North America.

Weak La Niña produce very different weather than moderate La Niñas.

A weak La Niña is good for Texas and bad for California while the Midwest gets to have normal weather. So, whether it is a cocktail or a weather event, let’s sit back and enjoy a Modoki.

James Garriss and Evelyn Browning Garriss are part of Browning Media which publishes the Browning World Climate Bulletin™ that has provided accurate regional climate information and forecasts for over 40 years. The information in the Browning Bulletin provides useful.....(Read More...@ AgWeb Farm Journal)