Of factors lending themselves to predictability in weather forecasting, temperatures in the Pacific Ocean and Atlantic Ocean are proving among the most reliable, says John Nielsen-Gammon, regents professor at Texas A&M University and Texas state climatologist.

And computer simulations based on current ocean conditions point to “a slight tendency” for a continuation of below normal rainfall in Texas and across much for the Southwest for the first three months of 2013, he said at the Beltwide Cotton Conferences at San Antonio, Texas.

Indications are that the March through May period will see a continuation of the trend toward dry conditions, he says, with “probably below normal rainfall” from June through August.

For the long-term, the simulations point to slightly warmer than normal temperatures, he says.

“As long as temperatures are warmer than normal in the North Atlanta, we should continue to see drier than normal summers and hotter summers,” he says. And for the longer haul, the years ahead should bring hotter, drier summers, and “more likely record warm winters and summers than cool.”

The farther-out trend, he says, is “fairly alarming” for hotter, drier summers.

Temperatures in both the Pacific and Atlantic Oceans “have been effectively working against us since 1990,” he says. “These periods tend to last 20 years to 25 years, and we’ve been in this current cycle for about 15 years, so hopefully we’re at least halfway through it.”

Many factors can affect weather, Nielsen-Gammon says — some are fairly predictable, others such as volcanic eruptions are random.