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.

NOAA Accurately Predicts Irene's Path

Although there are some examples of catastrophic damage caused by Irene, the National Oceanic and Atmospheric Administration was able to accurately predict the track of the storm, thus warning millions of people days in advance. The video below shows Irene's predicted track as well as the actual storm moving up the east coast

Hopefully this accuracy can be maintained in the future, as NOAA's budget to replace an aging generation of satellites has been slashed.

July's Extreme Heat

Vegetation anomalies in North America (July 2011)

Throughout July 2011, the United States experienced extraordinarily high temperatures and many states in the Southwest felt the effects of drought conditions. The impact of this drought on vegetation growth can be seen in the photo above. The image, from the NASA Earth Observatory, displays vegetation anomalies across North America in July. To learn about the national weather pattern that caused such extreme conditions, visit this NOAA page. The progression of the heatwave can be seen in these two NOAA Environmental Visualization Laboratory animations that show how conditions changed throughout the second half of the month:

• High Dew Point Makes Heatwave Miserable
• Heat Wave Sweeps Across The U.S.

NOAA Animation Shows ENSO Transition in Pacific

A recent time-lapse (March 1, 2011 to June 7, 2011) animation created at NOAA's Environmental Visualization Laboratory shows a transition in the Pacific from La Niña to a neutral period. This warming and cooling cycle happens every few years and is called the El Niño Southern Oscillation or ENSO. While El Niño is marked by warmer than normal temperatures, La Niña is marked by cooler temperatures. For more information on what ENSO, visit this NOAA website!