AUSTIN (KXAN) — While we’ve talked about ENSO (El Niño Southern Oscillation) at length over the past year, there’s another player in our weather that we’re watching this year…PDO.

PDO stands for Pacific Decadal Oscillation and it can influence the amount of precipitation we get in Central Texas.

Pacific Decadal Oscillation

The Pacific Decadal Oscillation is quantified by a number that represents three things:

  • The strength of the Aleutian Low;
  • Kuroshiro Current: Ocean current that changes over the course of decades; and
  • The reemergence of pre-summer water temperature anomalies.
Pacific Ocean sea surface temperature anomalies (Blue is colder than normal)
Pacific Ocean sea surface temperature anomalies (Blue is colder than normal)

Why do we care?

As we’ve told you there’s a relationship between ENSO and rain here in Central Texas. When ENSO is positive (El Niño phase) we get more rain.

Well, there’s a rain relationship with PDO too. The more positive PDO is, the wetter our weather is. The more negative PDO is, the less rain we see.

PDO/ENSO and Precipitation (NOAA/
PDO/ENSO and Precipitation (NOAA/

As you can see from the chart below, PDO is VERY negative right now (see far right).

PDO status (NOAA)
PDO status (NOAA)

That would generally favor drier than normal weather for Central Texas.

But, wouldn’t El Niño make us wetter?

El Niño has the greatest impact on our weather during the winter (December-February) in Central Texas. That’s when we’re most likely to see wetter than normal conditions. In some years a strong El Niño has made for a very wet fall, but in those years (like in 2015) PDO was positive.

This fall, El Niño and PDO may just work to balance each other out.

Official fall forecast from the Climate Prediction Center

The resulting 3-month outlook from CPC seems to come to that conclusion. September, October and November (meteorological fall) show an expectation for near normal precipitation.

Fall rainfall forecast
Fall rainfall forecast (CPC)

For completeness, here’s the temperature forecast for the meteorological fall.

Fall temperature forecast (CPC)
Fall temperature forecast (CPC)

Bottom line

The influence of El Niño should eventually bring us wetter-than-normal weather to Central Texas, but we may have to wait until the winter months for that to happen. In the mean time we’ll have dry and wet spells, but nothing the conclusively leans one way or the other.