Heat Watch
Temperatures reached record levels along the Rio Grande-Bravo during July. Figure 13 shows the daily temperature anomalies for Albuquerque, NM and El Paso, TX, as well as several other Southwest U.S. cities. The histograms (on the right) show the number of days when temperatures reached levels above or below average. For example, in El Paso there were 7 days where temperatures were 7-8 °F above average.
Figure 13 (above): Daily temperature anomalies from July 1 – August 14, 2018 (left) and frequency of temperature anomalies (right). Figure adapted from August Southwest Climate Outlook.
One heat wave in particular (July 18-24) broke numerous records across the basin. In Santa Fe, NM, the temperature reached 98 °F (36.7 °C) on July 21, and 99 °F (37.2 °C) on July 22, both of which set a new record high. In El Paso, TX, the temperature ranged from 103 °F (39.4 °C) to 107 °F (41.7 °C) from July 19-23, breaking the previous record on 4 of the 5 days. Del Rio, TX and Laredo, TX broke the record on almost every day from July 18-24, with temperatures ranging from 106 °F (41.1 °C) to 110 °F (43.3 °C). And in Brownsville, TX, the temperature reached 101 °F (38.3 °C) and 102 °F (38.9 °C) on July 23 and 24, respectively, both of which broke the previous record.
A heat wave in late May and early June set new maximum temperature records in some localities in Mexico, such as 117.5 °F (47.5 °C) on May 31, in Urique, Chihuahua, and 113.9 °F (45.5 °C) at Coyote Dam in Torreon, Coahuila. On May 26, 109.4 °F (43.0 °C) was recorded in San Antonio, Baja California Sur, which exceeded a previous record of 107.6 °F (42.0 °C) from 2011. On June 1, Urique, Chihuahua set a new record at 122 °F (50 °C), and in San Bernardo, Sonora, the temperature reached 118.4 °F (48 °C). At the same time, there were five other records that were tied in stations at Durango and Zacatecas. In July, only one record was broken in northern Mexico, with a temperature of 116.6 °F (47 °C) in Linares, Nuevo León.
Looking ahead, forecasts indicate that temperatures will be above average over the next month for both New Mexico and Texas (Figure 5). A new heat forecasting tool produced by the U.S. National Weather Service provides additional insight into near future temperatures. HeatRisk is an experimental forecasting tool for visualizing heat risk potential one-week in advance (Figure 14). It is designed to provide guidance to decision makers and heat-sensitive populations (such as outdoor workers and those with young children) on when to take action to prepare for a heat event. Each color category shown in the map represents different levels of risk and specifies the population that is at risk. For example, yellow is a low-level of risk and means that those who are extremely sensitive to heat should take action to prevent illness. When the highest level (magenta) is forecasted, the entire population is at risk, due to long-duration heat with little to no relief overnight. HeatRisk can be accessed from the National Weather Service page for most cities (https://www.wrh.noaa.gov/wrh/heatrisk/?wfo=epz).
Figure 14 (above): Screenshot of NWS HeatRisk on Friday, August 31. The table (right) describes the meaning of each color.
Extreme heat causes the most deaths in the U.S. of any weather-related disaster, according to the National Center for Environmental Information, and it is particularly important to be prepared for the unrelenting heat. Populations typically at increased risk of heat-related illness include children, pregnant women, elderly, those taking medications, those working outdoors, those with disabilities, those without adequate cooling, and the socially isolated. Be sure to check on loved ones and neighbors and call 911 if anyone is experiencing symptoms of heat stroke (e.g., headache, fast pulse, confusion, nausea, loss of consciousness). For more information on vulnerable populations, the symptoms of heat-related illness, and what to do to prepare, visit the CDC extreme heat webpage (en Espanol: https://www.cdc.gov/es/disasters/extremeheat/index.html).