University of Connecticut Climate Resource Exchange

Thursday, September 15, 2011

La Niña and the Droughts


Towards the end of August, speculation began that La Niña was at work again causing extended droughts in both the Southwest US and East Africa. Last week, the verdict came in from NOAA: La Niña is back.

“'This means drought is likely to continue in the drought-stricken states of Texas, Oklahoma and New Mexico,' said Mike Halpert, deputy director of the (NOAA) Climate Prediction Center. 'La Niña also often brings colder winters to the Pacific Northwest and the northern Plains, and warmer temperatures to the southern states.'"


This Voice of America article explains the consequences in regard to East Africa.

"Wassila Thiaw studies Africa for the Climate Prediction Center at the National Weather Service in the United States. With a La Niña, Mr. Thiaw says the easterly winds that are supposed to bring moisture into East Africa are reduced." 
"Starting late last year, rains that were supposed to fall over Somalia, southern Ethiopia and northern Kenya failed. That part of the Horn of Africa has a second rainy season from March through May. Mr. Thiaw says that one failed, too, but for different reasons."

Consequently, it seems that the conditions in areas being affected by extended drought, like the Southwest US and East Africa, will not improve in the near future. 
La Niña is only one phase of a climate pattern known as El Niño Southern Oscillation (ENSO). The video below, from the NOAA Environmental Visualizations Labratory, shows 22 years of sea surface temperature. The ENSO pattern can be notably seen on the west coast of South America near Peru.