Thursday, the Climate Prediction Center issued a La Niña Watch for this coming cold weather season. The El Niño appears to be weakening rapidly and this is often a sign of a La Niña the following fall and winter.
La Niña is, in many ways, the opposite of El Niño. Instead of weakening Trade Winds, the Trades become stronger. Ocean water across the equatorial central Pacific cools instead of warms. For the Northern Plains region, statistical outcomes linked to La Niña are not as clear and obvious as with El Niño. However, it does increase the likelihood of a colder and stormier than average winter season.
Actually, for La Niña to follow El Niño is pretty standard. However, when strong El Niño turns into strong La Niña, the atmosphere has been known to react strongly and turn a little violent. If anything, it decreases the odds of another mild winter.
Meteorologist John Wheeler