La Niña Watch issued ahead of expected brief pattern change
AUSTIN (KXAN) — As we march through our hottest month of summer in Central Texas, we’re continuing to get a better idea of what to expect in the fall and upcoming winter.
The Climate Prediction Center just released their updated ENSO (El Niño-Southern Oscillation) forecast and for the first time they’re expecting a return to La Niña later this year.
And with three consecutive overlapping 3-month seasons expected to be in La Niña, a La Niña Watch has been issued.
Previous odds had either favored ENSO Neutral (neither La Niña or El Niño) or too brief a dip into La Niña conditions that wouldn’t warrant a definitive change in the climate pattern.
For the periods of September-November, October-December and November-January, La Niña is marginally favored over ENSO Neutral. This now means that fall and the beginning of winter would have sea surface temperatures in a region of the eastern Pacific Ocean that are cooler than average by at least 0.5º Celsius.
For meteorological winter as a whole (December-February), ENSO Neutral is favored over La Niña, but only slightly.
La Niña into winter
While La Niña’s impact on weather in the fall season for North America is less defined, more conclusions can be made should a weak La Niña continue into winter.
Winter La Niña periods tend to be warmer and drier than normal here in Central Texas.
Last winter was also a La Niña pattern, but it didn’t fit true to form. Sure, it was a drier than normal winter, which is typical for La Niña winters in Austin, but it ended up being cooler-than-normal too. This was despite an incredibly warm December, both January and February were below average.
Impact on the tropics?
While fall weather patterns over the continental U.S. have little connection to La Niña conditions, there are connections between La Niña and what happens in the tropical Atlantic.
Usually during La Niña Atlantic Hurricane seasons we see more hurricanes as vertical wind shear is usually weaker.
So far this hurricane season is off to a fairly average start, but we’ll see what develops as we head into the fall as La Niña begins before hurricane season officially ends.
Stay with the First Warning Weather Team as we track any changes in expectations for the phase of ENSO, especially for this winter.
