Southwest Climate Outlook April 2008

April Climate Summary
Drought – Wet winter conditions helped keep short-term drought at bay across
most of Arizona even with very dry conditions over the past thirty days. New Mexico
has not faired as well with deepening drought conditions due to many months of
below-average precipitation.
Temperature – Temperatures were above-average across much of Arizona and New
Mexico over the past thirty days. Many locations across the Southwest observed
temperatures at least 1–2 degrees F above-average.
Precipitation – Much of Arizona and New Mexico observed below-average precipitation
again this past thirty days. Almost no measurable precipitation fell across
Arizona and southern New Mexico during this period.
ENSO – The current La Niña event weakened considerably this past month with
warming sea surface temperatures in the eastern and central Pacific as well as a
weakening influence on atmospheric circulations. Most forecast models indicate a
steady slide towards ENSO-neutral conditions by mid-summer 2008.
Climate Forecasts – Seasonal climate forecasts project above-average temperatures
and an equal chances precipitation forecast as La Niña impacts on precipitation patterns
across the Southwest wane into the spring.
The Bottom Line – The transition from wet and cool winter conditions to more
typical warm and dry springtime conditions appears to be complete with storm
tracks retreating north. La Niña continues to become less of a player in Southwest
weather. Long-term temperature trends dominate the expectation of above-average
temperatures through the summer.