Oceanic and atmospheric conditions remained ENSO-neutral over the last month (Figs. 1-2) and most ENSO forecasts and outlooks reflect that. On July 10, the Japanese Meteorological Agency (JMA) identified neutral conditions in oceanic and atmospheric indicators, but with indications of warming oceanic temperatures in the coming months. The agency forecast equal chances (50 percent) of either ENSO-neutral or El Niño by fall 2018. (read more)

Precipitation and Temperature: Precipitation in June ranged from record driest to much-above average (Fig. 1a); the wetter-than-average areas were those impacted by the remnants of Hurricane Bud in mid-June. June is typically dry, barring an early onset of monsoon activity, so any pre-monsoon precipitation will boost percentile rankings. June temperatures were warmer than average across all of Arizona and New Mexico (Fig. 1b), including record-warm conditions in eastern Arizona and central New Mexico. (read more)

Was our mid-June precipitation the monsoon? In 2008, the National Weather Service (NWS) changed the definition of the start of the Southwest monsoon from a variable date based on locally measured conditions to a fixed date of June 15 (and a fixed end date of Sept 30). This allowed for a clear delineation of the period of monsoon activity (108 days) and focused NWS’s messaging strategy as it pertains to the expected hazards during that period, which include extreme heat, strong winds, dust storms, flash flooding, lightning, and wildfires (see NWS Tucson monsoon information hub). Prior to 2008, the flexible start date reflected the seasonal progression of the monsoon, with a considerable temporal gradient across the region (Fig. 1). (read more)

Oceanic and atmospheric conditions remained ENSO-neutral over the last month (Figs. 1-2), and most ENSO forecasts and outlooks reflect these conditions. (read more)

Precipitation and Temperature: The Southwest was characterized by below-average precipitation in May, ranging locally from record driest to near average (Fig. 1a). Temperatures were above average to much-above average across most of the Southwest, with small pockets of record-warm conditions in the northwest corner of New Mexico and along the eastern edge of the state (Fig. 1b). The March through May period exhibited similar patterns of mostly drier-than-average to record-dry precipitation (Fig. 2a) and much-above-average to record-warm temperatures (Fig. 2b). (read more)

**Disclaimer: This blog post was adapted from a term paper for Dr. Christopher Scott's, Adaptation and Resilience in Water Resources Systems seminar GEOG 6960. **

The U.S. Southwest is rapidly becoming an urbanized region that is characterized by an intense urban heat island and summertime heat waves. At the city scale, high levels of urbanization in addition to local rising surface temperatures can affect the quality of life for several areas across residential communities, public and commercial spaces, etc. Heat within cities arises from different ways in which the built environment impacts energy exchange between the surface and atmosphere. This relationship causes unevenly distributed heat patterns across urban areas and some places tend to be hotter than others. Implementing green infrastructure shows promise to enhance the resiliency of urban areas (Benedict and McMahon, 2012). However, in several situations, the lack and disproportionality of green spaces withinin low-income, marginalized communities may further increase the vulnerability to heat and augment stress to communities that are already considered to be at a greater risk to heat (Read More).

Oceanic and atmospheric conditions returned to ENSO-neutral over the last month (Figs. 1-2) and most ENSO forecasts and outlooks reflect this transition. On May 8, the Australian Bureau of Meteorology maintained its ENSO Outlook at “inactive,” with indications of neutral conditions persisting through at least this summer. (read more)

After a warm and dry winter (detailed in past issues of the SW Climate Outlook), drought, fire, and poor air quality (dust and pollen) are growing concerns as spring turns to summer. In May, warm temperatures (Fig.1), including triple-digit highs (Fig. 2), are increasingly common, while average precipitation is among the lowest monthly totals for the region (Fig. 3), and additional precipitation is unlikely. At the same time, the winds are picking up due to seasonal transitional conditions (Fig. 4), further increasing fire risk (Figs. 6a-b) and impacting air quality and public safety (e.g. dust storms). (read more)

Precipitation and Temperature: The Southwest was characterized by below-average precipitation in April, ranging locally from record driest to near average (Fig. 1a). Temperatures were mostly above average for yet another month, with record-warm conditions along the eastern third of Arizona and the edge of western New Mexico, but also with a band of average to below-average temperatures on the eastern edge of New Mexico (Fig. 1b). (read more)

Monthly and cool-season (Oct-Mar) precipitation totals demonstrate how this La Niña year compares to previous years, and helps characterize the influence of ENSO on cool-season precipitation. Figures 5a-8a describe monthly and cool season precipitation totals at four weather stations (Flagstaff, AZ; Tucson, AZ, Albuquerque, NM, and El Paso, TX), where each dot corresponds to observed monthly and cool-season precipitation for each year since 1950, color coded by the ENSO status of that year, and the horizontal black lines correspond to 2017-2018 precipitation. Figures 5b-8b are scatterplots of ENSO index vs. precipitation totals for the regional climate division that contains each weather station. (read more)