Southwest Climate Outlook July 2011

Date issued

July 2011 Climate Summary

Drought– A spotty and slow start to the monsoon has caused drought conditions to deepen across much of New Mexico. Most of Arizona also remains gripped in drought, with little relief so far.

Temperature–Most of New Mexico was 2–6 degrees Fahrenheit warmer than average in the past month, while temperatures in most of Arizona ranged between 0–2 degrees F warmer than average.

Precipitation– The monsoon has brought relief to the higher elevations of Arizona, but rainfall in New Mexico generally has been scant, particularly in the southeast and southwest corners of the state.

ENSO– Neutral conditions were present again across the equatorial Pacific Ocean in the past 30 days. Neutral conditions are expected to persist through the remainder of 2011, but there is some indication that La Niña could reemerge later this fall.

Climate Forecasts– Precipitation forecasts spanning the monsoon are historically difficult to make, and the NOAA-Climate Prediction Center calls for equal chances of above-, below-, or near-average rainfall. Temperature forecasts call for increased chances for above-average temperatures through the winter.

The Bottom Line–Exceptional drought, which is defined as a drought that occurs once in every 50 years, remains entrenched in New Mexico and southeast Arizona. Since the monsoon officially began on June 15, little rain has fallen in New Mexico. On the other hand, a gulf surge from Tropical Storm Arlene provided Arizona with much needed precipitation around July 4, and spotty thunderstorms have moistened the parched landscape, especially at higher elevations. Another gulf surge beginning on July 23—which is not reflected in this issue—dumped copious rains in southeast Arizona and southwest New Mexico and will help alleviate drought in those areas. Forecasts call for improving drought conditions in parts of both states. However, even if the monsoon delivers average or above-average rain, the dry conditions brought on by this past winter’s La Niña event will not be completely erased. While a high probability exists that ENSO-neutral conditions will persist into at least early next year, a pool of cold water below the sea surface in the tropical Pacific Ocean hints at a return to La Niña conditions in the fall. The state of ENSO this winter will become clearer in upcoming months.

Published by the Climate Assessment for the Southwest (CLIMAS), with support from University of Arizona Cooperative Extension, the Arizona State Climate Office, and the New Mexico State Climate office.

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