Drought Conditions in Southwest US to Worsen

Through mid-July, the summer monsoon has started fairly weak and little rainfall has been observed. The monsoon typically peaks during the month of August. Official Climate Prediction Center precipitation outlooks favour below-average precipitation in these areas August through October.

"If the monsoon remains erratic during the next few weeks, then the drought development area may be expanded on the updated outlook scheduled for 5th August," said Wayne Higgins, director of the NOAA Climate Prediction Center.

Factors leading to the forecast of enhanced chances for drier-than-normal conditions in the Southwest during the above periods include coupled ocean-atmosphere global climate forecasts and historical conditions during the late summer when transitioning from El Niño to La Niña.

"Beyond this time period, expected dryness associated with established La Niña conditions may bring further expansion of drought conditions in the Southwest during the 2010-11 winter season," Higgins said. La Niña may also provide wetter-than-normal conditions in the Pacific Northwest during fall 2010 and winter 2010-2011.

Other important areas highlighted in this outlook include continued severe to exceptional drought conditions across many areas of Hawaii and forecasts for improvement across moderate drought areas in the mid-Atlantic and severe/extreme drought areas of the upper Great Lakes and lower Mississippi Valley respectively.