October was not only dry this year, but also warm. Tucson’s remaining fall and winter might not be any different, with consequences for the spring wildflower bloom.
Last month had 25 days with highs above 90 degrees, making it the second-hottest October here on record with an average temperature of 77.3 degrees. Tucson hit 99 degrees on Oct. 4-5, according to the National Weather Service in Tucson. The average high temperature for the month was 92.5 degrees, about 8 degrees above normal.
The hottest October recorded in Tucson was in 2016 with an average temperature of 77.5 degrees.
These warmer than normal temperatures are expected to continue this month, according to the NWS Tucson Climate Prediction Center forecasts.
“Precipitation-wise, the forecast is flip-of-the-coin,” said John Glueck, meteorologist at the NWS Tucson. “It could go the other way.”
This is gearing up to be a La Niña winter however, according to a presentation prepared by Glenn Lader, meteorologist at the NWS Tucson, meaning that cooler-than-normal ocean temperatures in the Pacific will drive the jet stream north.
This pattern will usher in a warmer than normal — and possibly drier than normal — winter.
Recorded temperatures between January and mid-October show that 2017 is the hottest year on record and is tracking to be one of the warmest years on record in Tucson.
This does not bode well for annual spring wildflowers which are dependent on at least an inch of rain before freezing temperatures set in December.
The forecasted fall conditions “would pretty well squelch it,” said Mark Dimmitt, wildflower expert and retired director of natural history at the Arizona-Sonora Desert Museum.
“We flower-watchers don’t get excited until one good soaking in the fall,” he said. “Pray for rain!”
As for short-term forecast it appears that highs in the 90s have ended with Tucson temperatures expected to remain in the 80s through the weekend.