Thu October 20, 2011
New Federal Forecast Says Drought to Worsen Over Winter
While already-sodden northern regions of the United States can expect above-average rains this winter, the worst one-year drought in Texas history looks set to persist in the coming months, federal forecasters said today.
It is "most likely that severe drought will persist through the winter" in the Southern Plains, said Mike Halpert, deputy director of NOAA's Climate Predictions Center, speaking on a press call timed with the release of the National Oceanic and Atmospheric Administration's Winter Outlook, which covers the months of December through February.
Southern parts of the United States, including Texas, are likely to be warmer and dryer than normal during the winter, Halpert said. The main reason is that La Nina — an intermittent Pacific Ocean phenomenon that was the chief cause of the drought — has returned, and while it is "weaker than what was experienced during this time last year," Halpert said, it has potential for strengthening.
La Nina does not always bring warmer and drier conditions to the South, Halpert said, but typically it does — though a climate "curveball" that would scramble the usual patterns is always possible.
David Brown, NOAA's Fort Worth-based regional climate services director for the southern region, said that while the Southern Plains (including Texas) have experienced the worst one-year drought on record from Oct. 1, 2010 to Sept. 30, 2011, the drought still has a ways to go before it is a candidate for the worst drought ever in Texas recorded history. That title belongs to the 1950s, which saw drought stretched over multiple years. However, Brown said, if the drought continues, then it will be time for a reassessment.
The rains earlier this month "really only constituted a small dent in the drought situation," Brown said. It would take "upwards of 10 or even 15 inches of rain in many regions to make an appreciable improvement in the drought situation." Some parts of Southeast Texas, he said, have accumulated rainfall deficits over the past year of more than 30 inches, Brown said.
"It's fair to say that the communities in our region that have been experiencing the exceptional drought conditions will continue to struggle," Brown said. Currently, 92 percent of Texas is experiencing drought classified as "extreme" or "exceptional," the two worst categories. So is 87 percent of Oklahoma and 63 percent of New Mexico.
For Texans watching their crops and watering holes dry up and their lake levels fall, this is all fairly bad news, although it's consistent with earlier predictions by NOAA. If there is a shred of hope, it is that while two back-to-back La Ninas (as has happened in the last few years) are relatively common, the probability for yet another La Nina occuring during the 2012-13 winter, for the third year in a row, is fairly low. Halpert estimated the chances of a third La Nina are at 10 to 15 percent.