The Southwest was characterized by below-average precepitation. Temperatures were mostly above average. Drought designated areas continue to expand, and above normal wildland fire risk has been identified in specific areas. The La Niña event is officially over, and conditions have returned to normal. The three month outlook for June through August calls for equal chances of above or below average precepitation in certain areas.
Studies show that snowpack has been declining throughout the Western U.S. for decades. And climate change is expected to worsen the problem in the coming years. "When you have snowpack disappearing really early, the soil will dry out faster and the plants, also," said Donald Falk, an ecologist and wildfire expert at the UA.
In recent days, the temperature at the North Pole has soared to the melting point of ice. Eliot Herman, a biologist and a professor in the School of Plant Sciences at the UA, recently returned from the North Pole and said that the 2017-2018 winter season was the shortest ever for visitors, due to the thin ice.
Forest fires, climate change and the wrath of non-native fish are threatening the survival of the Apache trout, a species found only in Arizona. "Climate change, the drying out of the forests (in the White Mountains), increases chances that there'll be forest fires, and the general increasing of the temperatures," said Scott Bonar, the leader of a research cooperative at the UA who has been studying desert fish since 2000.
After a slow start in June and a record-wet July, precipitation in much of the Southwest has been mostly absent since early August. The high-pressure ridge that helped hold Hurricane Harvey in place over Houston kept moisture from circulating into the Southwest. This year, the late-season monsoon has been particularly dry, with very few storms and limited tropical storm activity that might otherwise help boost seasonal totals
The 2017 monsoon started a bit later than average but more than made up that with numerous storms throughout much of July and early August. Tucson recorded its wettest July on record and second-wettest month on record, and it and many other stations across the region have already surpassed their normal cumulative values, with some even exceeding their seasonal (June 15 – Sept. 30) average.
July was the wettest July on record in Tucson, with the airport receiving 6.80 inches of rainfall, more than triple the average.
Forecasts favor above-average precipitation for all of the Rio Grande/Bravo Basin through October.
The official start of the monsoon was June 15, but widespread activity started relatively late this year, especially in southern Arizona. There, numerous storms in mid-July brought widespread and frequent precipitation activity, boosting the percent normal monsoon precipitation in several locations. New Mexico had a comparatively earlier start to monsoon activity, which is expected given the typical spatiotemporal progression of the monsoon, and has seen more steady and widespread monsoon activity, as evidenced by the percent of days with rain.
In this edition of the CLIMAS Southwest Climate Podcast - Mike Crimmins and Zack Guido sit down to discuss Southwestern weather & climate, including:
- The extended heat wave of June 2017 (and the near record heat for the first half of 2017 (Jan-Jun)) (1:00 - 15:00),
- The wildfires in the Southwest , and the role that a monsoon late arrival might have played (15:00-19:00)
- The Southwestern Monsoon - the components of the system, comparisons to other years, and what we might expect going forward (19:00-38:00)