Regional Climate Overview - December 2017 - February 2018
Temperatures over the past three months (December-February) were 2–5 °F (1.1–2.8 °C) above average for most of New Mexico and parts of North and West Texas (Figure 1; left). For the remainder of Texas, temperatures over the past three months were 0–3 °F (0–1.7 °C) below average. Precipitation over the same time period was 0-70% of average for most of New Mexico and Northwest Texas, and 110-150% of average for Northeast Texas (Figure 1; right).
Figure 1 (above): Departure from average temperature in degrees F (left) and percent of average precipitation (right), compared to the 1981–2010 climate average, for 12/1/2017–2/28/2018. Maps from HPRCC.
Temperatures from March 1-19 were 4–8 °F (2.2–4.4 °C) above average throughout most of southern Texas and 0–2 °F (0-1.1 °C) below average for several areas along northwestern New Mexico (figure not shown). Precipitation over the same time period was 0–5% below average for almost all of Texas and 25-90% below average for New Mexico and East Texas.
The winter was especially warm in Northwest Mexico for the period from December 2017 to February 2018. Only the lower basin of the Rio Bravo had colder than normal temperatures. Departures ranged from more than 9 °F (5.0 °C) in Southwest Durango to less than 3.8 °F (-1.0 °C) in northern Coahuila, Nuevo León and Tamaulipas (Figure 2, left). There were between 50 and 70 days with minimum temperature at or less than 32 °F (0 °C) that occurred in the Chihuahua-Durango border; however, the footprint between 1 and 5 days at or below 32°F also extended toward the Northeast (Figure 2, right).
Figure 2 (above): Temperature anomalies in °C (left) and number of days with minimum temperatures at or below 0 °C (32 °F) (right) for December-February. Maps from SMN.
This winter, in addition to being warm was also dry for the Northwest part of Mexico, despite seasonal accumulated precipitation between 3.9 -7.8 inches (100-200mm) in Sonora (Figure 3, left). This situation contrasted with Central and northern areas where winter systems provided enough moisture, although dryness continued toward the Northeast. Main highlights include rains that fell in northern Sonora and southern Chihuahua that helped reduce some drought conditions (Figure 3, right).
Figure 3 (above): Accumulated precipitation in mm (left) and percent of normal (right) for December-February. Maps from SMN.
Drought
Dry conditions in the past month have expanded drought conditions in New Mexico and North Texas, according to the North American Drought Monitor (NADM) (Figure 4). Extreme drought conditions have developed in northern New Mexico and spread towards northern Texas. Severe drought conditions remained in most of New Mexico, and moderate conditions developed in South and West Texas. Mexican states bordering the Rio Bravo remain mostly drought-free. However, abnormally dry conditions continued in parts of Chihuahua and moderate to severe drought conditions developed in southern Tamaulipas. Conditions are predicted to persist through June in New Mexico and the West half of Texas, according to the U.S. Seasonal Drought Outlook, and drought is predicted to develop throughout South and West Texas.
Figure 4 (above): North American Drought Monitor, released March 12, 2018.