National Weather Service forecasters blamed a sub-tropical air mass from Mexico for the light rain that dampened San Diego County Sunday night, shutting down the outdoor performance of a Starlight musical.
Weather forecasters predicted a chance of rain through today, but a wind shift is expected to push the moist air mass out of the county on Wednesday.
Forecaster Wilbur Shigehara said .02 of an inch of rain was measured at the Miramar Naval Air Station. Only traces were recorded at Lindbergh Field.
"There could have been other areas where there was measurable rainfall but we don't have rain gauges there," Shigehara said. He said the weather service received reports of rain from most communities and cities in the county.
The Starlight production of "A Student Prince" at the Starlight Bowl in Balboa Park was canceled 20 minutes into the performance Sunday night when the rain continued to drip onto the stage from an awning.
"We were hoping that it would be dampish and go away but it didn't. The moisture collects on the awnings. It was wet enough that it was dripping on the stage and people were sliding around," Starlight spokesman Danny Martin said.
He said the play would be staged Monday night for viewers who were sent home.
"The audience certainly understood--they were sitting in the rain," Martin said.
Although the July rain surprised San Diegans, forecaster Shigehara said precipitation is not that rare this time of year.
"It was enough to produce some excitement in San Diego. But it does rain here in July," he said. No rain was recorded at Lindbergh Field last July, but small amounts were recorded in 1984 and 1983.
"August is our thunderstorm month and as we approach, we do get upper-level winds that shift and bring up the sub-tropical air mass," he said.
Forecasters had predicted rain in the mountains for Sunday, but they did not expect it to come close to the shore.
Monday's high at Lindbergh Field was 79 degrees at about noon. The norm is 74. Relative humidity was 67% at 2 p.m., slightly above normal. Shigehara said the combination of the temperature and humidity, however, made the air uncomfortable.
More muggy weather was predicted for today, but the air is expected to dry out Wednesday. Late-night and early-morning clouds with sunny days were forecast through this week.
But Shigehara predicted more muggy weather next week.
"We are getting to that time of year," he said. "I expect the warm and humid weather to return again next week."