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Similar to last month, oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) are in the range of neutral (Figs. 1-2), and these conditions are forecast to last through the spring and summer. Most forecasts and outlooks indicate that El Niño conditions could return in mid-to-late 2017, but these assessments come with the annual caveat of increased uncertainty associated with the “spring predictability barrier”, during which time the specifics regarding the possibility, timing, and intensity of an El Niño event are elusive. At any rate, the models and forecasts indicate a near-zero probability of La Niña in 2017, leaving forecasters to decide between the probability of neutral or El Niño conditions in later 2017. (read more)

Precipitation & Temperature: March precipitation totals were average to below average in most of the Southwest except for the northeastern corner of New Mexico (Fig. 1a). March temperatures were much-above average across the entire Southwest, with record warm temperatures in the southeast corner of Arizona and most of New Mexico (Fig. 1b). April precipitation to date has been below average for much of southern Arizona and New Mexico (Fig. 2), while April temperatures have been between 0 and 6 degrees above normal for most of the region. Water year precipitation has been normal to above normal for most of Arizona and New Mexico, aside from a dry region along much of the Arizona-Mexico border (Fig. 3). (read more)

Precipitación Y Temperatura: En febrero, Arizona experimentó precipitación media a precipitación por arriba del promedio, mientras Nuevo México experimento precipitación que osciló entre media a por arriba de la media (Fig. 1ª). Temperaturas muy por arriba del promedio se observaron en la mayor parte de la región; el este de Nuevo México experimento las temperaturas mas altas registradas (Fig. 1b).  Las primeras dos semanas de marzo fueron secos para el Suroeste, una inversión de las condiciones mojadas del inicio del invierno (Fig. 2ª). Temperaturas por arriba del promedio se observan en marzo también (Fig. 2b) y incluyen un serie de temperaturas casi record en el mediados de marzo. Para el año pluviométrico, el Suroeste ha experimentado precipitación y temperaturas por encima del promedio (Fig. 3). (Resumen completo)

This event began in fall 2016, ended in early February 2017, and throughout the period oceanic and atmospheric indicators generally hovered near the boundary between weak La Niña and ENSO-neutral conditions. According to CPC criteria, this was a weak La Niña event (but just barely); other agencies use slightly different criteria (see last month's ENSO tracker for details), highlighting the difficulty in categorizing these borderline events. This weak strength also affects how precipitation and temperature patterns are interpreted. In the Southwest, a La Niña event is more likely than not to bring warmer- and drier-than-average conditions over the cool season, but a weak La Niña event might not even stand out from the normal seasonal variation of typically dry southwestern winters (Fig. 5).

So how did this La Niña event stack up compared to expectations? (read more)

Oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) are currently neutral (Figs. 1-2), and most forecast agencies predict they will remain so through spring 2017. These agencies also forecast that El Niño conditions could return in mid-to-late 2017, but given the uncertainty of ENSO forecasts associated with the “spring predictability barrier,” we can get only a general sense now of the range of outcomes likely later this year (i.e. La Niña is basically off the table). More detailed information about the timing or intensity of a possible El Niño will start to become available in late spring or early summer. (read more)

Precipitation & Temperature: February precipitation totals were average to above average in Arizona and ranged from below to above average in New Mexico (Fig. 1a). February temperatures were much-above average across most of region, including record warmest temperatures in eastern New Mexico (Fig. 1b). March precipitation to date has been dry across the Southwest, reversing the wet trends of early winter (Fig. 2a). March temperatures have also been above average across the Southwest (Fig. 2b), including a run of near-record temperatures at the time of this writing. Water-year precipitation and temperature are both above average across much of the Southwest (Fig. 3). (read more)

Originally published in the Feb 2017 CLIMAS Southwest Climate Outlook

The La Niña event of 2016-2017 is officially over, with oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) having returned to neutral conditions (Figs. 1-2). Neutral conditions are expected to remain in place for the next few months, but the usual difficulty in accurate forecasting that occurs in the spring means the current ENSO forecast includes a wide range of timing and uncertain outcomes. Most forecast agencies are predicting that ENSO-neutral conditions will remain in place through at least spring 2017, with a possible return of El Niño conditions sometime in mid-to-late 2017. (read more)

Originally published in the Feb 2017 CLIMAS Southwest Climate Outlook

Precipitation & Temperature: January precipitation totals were above average in Arizona, and in New Mexico they ranged from much-above average to record wettest (Fig. 1a). January temperatures were average to above average in Arizona, and above average in New Mexico (Fig. 1b). February precipitation to date has been variable across the West. In Arizona, it has been mostly below average; in New Mexico, a few large pockets have received impressive precipitation; and widespread activity has occurred across Northern California and the upper Great Basin (Fig. 2a). February temperatures have been well-above average across the southern two-thirds of the western U.S., with particularly warm temperatures in parts of Utah and Colorado (Fig. 2b). Water-year precipitation is average to above average across most of the Southwest except for southern Arizona and much of southeastern New Mexico (Fig. 3). (read more)

Oceanic and atmospheric indicators of the El Niño-Southern Oscillation (ENSO) continue to indicate weak La Niña conditions that are in rapid decline. Most forecast agencies identified a likely end to La Niña conditions (and by extension, this La Niña event) by February. This is not surprising given many of the oceanic and atmospheric indicators of La Niña have been weak to borderline neutral for much of the last few months (Figs. 1-2). (read more)

Precipitation & Temperature: December precipitation totals for the past 30 days were above average to much above average in Arizona’s climate divisions and were mostly above average in New Mexico’s climate divisions (Fig. 1a). December temperatures were much above average across most of southern Arizona and southwestern New Mexico, with mostly above-average temperatures across the remainder of the two states (Fig. 1b). A number of storm systems in so far 2017 have brought well above-average moisture to the region, although portions of Arizona have missed out on this precipitation (Fig. 2). January temperatures have been warmer than average across the Southwest and colder than average across the Northwest. (read more)