A thunderstorm rare in its intensity formed over Fresno Yosemite International Airport on Thursday and dropped nearly 2 inches of rain in one hour.
Fresno’s downtown stayed largely dry despite the ominous gray-and-black clouds to the east. But Cindy Bean, a meteorologist with the National Weather Service’s Hanford office, said the airport sustained a drenching when the thunderstorm parked over it.
“We don’t see that very often here where we see that heavy a rainfall, especially something sitting over the airport that long,” said Bean.
The storm began forming after 3 p.m. and really got going by 3:30. She said the thunderstorm was “pulsing” in its behavior: It would drop heavy rain, then ease back, gather new strength, then dump some more.
From 4 p.m. to 4:53 p.m., the airport measured 1.75 inches of rain.
Two United Airlines flights were delayed, said Vikkie Calderon of Fresno Yosemite International airport. One of them was departing for San Francisco, and it had to wait for an hour. The other was an arrival from San Francisco, and it was delayed 35 minutes.
Street flooding occurred around the airport, but there was no airfield flooding or any damage to the terminal, Calderon said.
There was one other impact of the thunderstorm: Fresno’s official rainfall measurement is taken at the airport. As of 5 p.m. Thursday, Fresno had received 16.74 inches for the 2016-17 season – way above the average of 10.20 inches. But nearly 2 inches of that came from the unusual storm, and was precipitation that did not fall anywhere else in Fresno.
Bean said conditions were good Thursday for thunderstorms to form: Cold air in the wake of the main storm system having moved through. That meant lots of instability in the atmosphere.
A warning was issued at 5 p.m. for east Fresno and Clovis as the thunderstorm finally began heading that way. “Heavy rain and small hail will be possible with this storm,” the NWS said in its advisory.
Bean said showers happened all over the central San Joaquin Valley on Thursday afternoon – from Tranquillity to the west to Clovis and Visalia to the east. Rain also fell at Yosemite National Park, and snow was forecast at the higher elevations of the Sierra. China Peak Mountain Resort near Huntington Lake reported 2 to 4 inches of fresh snow as of early Thursday afternoon.
The forecast calls for the storm system to keep heading east through the evening. The overnight low will fall into the 40s, but Friday should be sunny in Fresno with a high near 70.