Oceanic and atmospheric conditions over the last month remained generally consistent with a La Niña event (Figs. 1-2), but given the rapid decline of these conditions and the imminent seasonal transition, it is only a matter of time before ENSO-neutral conditions return. The current ENSO forecasts reflect this steady weakening, with most indicating a likely transition to ENSO-neutral conditions over the spring, and others having already declared an end to this La Niña event. On April 10, the Japanese Meteorological Agency (JMA) identified ongoing La Niña conditions but called for a 90-percent chance that this event will end in spring. On April 10, the Australian Bureau of Meteorology maintained their ENSO Outlook at “inactive,” stating “there is little sign of El Niño or La Niña developing in the coming months.” On April 12, the NOAA Climate Prediction Center (CPC) continued its La Niña advisory but expected a transition to ENSO-neutral conditions by May and forecast a greater-than-50-percent chance of ENSO-neutral lasting through summer. On April 19, the International Research Institute (IRI) issued its ENSO Quick Look, which still identified weak La Niña conditions present but called for a rapid transition to ENSO-neutral conditions over spring (Fig. 3). The North American Multi-Model Ensemble (NMME) is consistently indicative of a return to ENSO-neutral conditions, but with greater uncertainty over what the latter half of 2018 might hold (Fig. 4). (read more)

Precipitation and Temperature: Precipitation varied across the Southwest in March, but temperatures remained warm throughout the region. Precipitation amounts ranged from record driest to above average (Fig. 1a). Temperatures ranged from average to above average in Arizona, and from above average to much-above average in New Mexico (Fig. 1b). 2018 year-to-date (Jan-Mar) precipitation ranged from near average to much-below average (Fig. 2a), while temperatures for the same period were above average to much-above average (Fig. 2b). (read more)

Precipitation & Temperature: Precipitation varied considerably across the Southwest in February, but temperatures remained warm throughout the region. Precipitation amounts ranged from below average to much-above average, with the wetter areas concentrated in southern Arizona and southwestern New Mexico and the driest areas occurring in the Four Corners region and northeastern New Mexico (Fig. 1a). Temperatures ranged from average to above average in Arizona, and from above average to much-above average in New Mexico (Fig. 1b). (read more)

Winter precipitation (Dec-Feb (DJF)), during most weak La Niña events (ENSO Index Value between -0.5 and -1.0) has been below average, although a few years (1968, 1985) were notable outliers (Figs. 5-6). The monthly breakdown of weak, moderate, and strong La Niña events reveals that while the DJF totals for Tucson, AZ and Las Cruces, NM have been mostly below average, there have been individual months that recorded precipitation above the monthly average (represented by black lines on the plots). The most likely outcome for the Southwest this year is below-average precipitation totals for the winter season, but the way that these events unfold will have an impact on how residents perceive and experience this La Niña event (see the following page for examples from Arizona and New Mexico during La Niña events). (read more)

La Niña conditions continued for another month, with both atmospheric and oceanic conditions demonstrating a La Niña pattern (Figs. 1-2). Forecasts continue to suggest a weak-to-moderate La Niña event that has likely peaked and will gradually weaken this spring. (read more)

Precipitation & Temperature: January was warm and dry across the Southwest. Precipitation was average to below average in most of Arizona, and below average to much-below average in New Mexico (Fig. 1a). Temperatures were much-above average to record warmest in Arizona, and ranged from near average to much-above average in New Mexico (Fig. 1b). (read more)

The year 2017 was record warm across most of Arizona and New Mexico, in no small part thanks to the exceptionally warm conditions during the final three months of the year (and November in particular). (read more)

La Niña conditions have continued for another month at weak-to-moderate strength, with both atmospheric and oceanic conditions, including sea-surface temperatures (SSTs), demonstrating a consistent La Niña pattern (Figs. 1-2). Forecasts continue to suggest that a weak-to-moderate La Niña event will last through the winter before weakening this spring. (read more)

December Precipitation & Temperature: December precipitation ranged from average to much-below average across most of Arizona and New Mexico, with record-dry conditions along the western edge of Arizona and in pockets of central and eastern New Mexico (Fig. 1a). December temperatures were above average to record warmest in both states (Fig. 1b), continuing the pattern observed during fall 2017. (read more)

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