TUCSON, Ariz. (KGUN) — Just because fall is here and we’re almost to the end of September, it doesn’t mean monsoon is going to just give up. In fact, monsoon will be quite active for our first weekend of fall!
A low pressure system will settle over northern Baja and swing a good amount of moisture over southern Arizona. This pattern will be slow to change and will bring a chance of showers and thunderstorms to the region all the way into Monday.
This additional moisture will help fuel showers and thunderstorms on Saturday and Sunday. A few of the thunderstorms could be quite strong and produce some heavy rain as they move slowly to the north and northeast.
Most of us will see relatively light rainfall amounts with the heaviest rain likely to fall on Sunday. Some rainfall forecast models are indicating a few locations could receive over 1” of rain from Saturday into Monday. As is usually the case, the heaviest rain will likely fall over and near the mountains of southeastern Arizona.
We could use some rain because after a record-setting July and a productive August, September failed to keep the active monsoon trend in motion. As of this writing, we’re running three-quarters of an inch below average for the month of September. Even so, we’re still in good shape for the year as we continue to run over 5” above average.
Many of us have been hoping to break the record for the all-time wettest monsoon ever recorded in Tucson. The wettest monsoon ever recorded produced 13.84” of rain in 1964. So far, at the Tucson International Airport, we’ve received 12.48” of rain since monsoon began on June 15th.
We only need 1.37” to break the old record. To see that much rain before monsoon ends is going to be a real stretch, but it’s not totally out of the question. One or two good thunderstorms may do the trick!
Another reason it would be nice to get some rain is because the 2021 monsoon has allowed us to chip away at the critical drought conditions that have existed for the past year. Since most of September remained dry, some wet weather to end the month and bring monsoon to a close would be a welcome change.
The first weekend of fall looks to be quite interesting thanks to monsoon making one final attempt at breaking the all-time record for the wettest monsoon ever recorded in Tucson. Enjoy what is likely to be monsoon’s last big act of the year and enjoy the cooler temperatures that will accompany the clouds and rain!