Rain, rain…
by John Weckerle
Yesterday, I used the last of my harvested rainwater. Even though I have a 3,600 gallon capacity, the dry winter, followed by a dry spring, left me with far less than half of that to get through the season. With the second-year trees and shrubs associated with our ecological enhancement activities and the new vegetable gardens, plus the fountains/wildlife bubblers, that much only goes so far.
Why so dry? Part of the answer lies in the state of the El Nino РSouthern Oscillation (ENSO), which is a coupled ocean-atmosphere phenomenon that affects weather on a global scale. It involves temperature anomalies in the surface waters of the central tropical Pacific Ocean. El Ni̱o represents a period when surface waters are 0.5o or more warmer than normal, and La Ni̱a represents a time during which temperatures are 0.5o or more cooler than normal. ENSO neutral conditions exist when surface water temperatures are within 0.5o of normal. During the El Ni̱o part of the cycle, our area tends to get more rain, while dryer conditions persist during La Ni̱a. During ENSO neutral conditions, there is an equal chance of having normal, above average, or below average conditions. We are currently experiencing the La Ni̱a effect, which is currently weakening.
The causes and mechanisms associated with this phenomenon are still under investigation, so long-term predictions are elusive. According to the National Weather Service Climate Prediction Center, La Niña continued to weaken in May, and ENSO neutral conditions are expected within the June-July time frame. Most models indicate ENSO neutral conditions during the second half of the year, although NWS points out that there is considerable uncertainty, as some models predict the emergence of El Niño while others suggest a reemergence of La Niña conditions.
What does this mean for Central New Mexico? Unfortunately, it is similarly hard to tell. Under our “normal” conditions, weather is variable and, as previously stated, everything is equally probable under ENSO neutral conditions. The upside, however, is that the conditions that nearly guarantee dry weather are abating, so at least there is some chance that we will receive a little more moisture in the not-too-distant future.
To check the status of the ENSO, visit the NWS Climate Prediction Center’s El Niño/La Niña Diagnostic Discussion page.