UNDATED -- A record-setting heat wave threatened Friday to trigger delays on the Bay Area's massive BART transit system for a second day after the strain of triple-digit temperatures was proving to be too much for the aging system's equipment.

BART spokesman Linton Johnson said the system knew it was going to have problems when the heat wave was forecast and had extra personnel on duty when the delays began on Thursday.

"We knew the heat was going to cause problems," Johnson said. "We have old equipment. So we staffed up, we put everybody on maximum staffing and overtime to pounce on the problems. But the equipment is old. We are trying to replace things but we don't have the funds to do it. "

Johnson likened the situation to putting an answering machine instead a microwave. But passengers were critical not of the delays, but a lack of communication to passenger by the transit line.

"It was very confusing," said Terry Wynn. "There were very few announcements. That added to the confusion."

Delays grew to about 45 minutes by the evening rush hour and did not clear up until around 9 p.m. as the evening breeze cooled the temperatures.

Around the Bay Area, temperatures soared to record levels. Among the new highs set for the date were 103 in Gilroy, 100 in both Santa Rosa and Napa, 99 in San Jose, 98 in Oakland and 97 in San Francisco.

Santa Rosa was expected to reach 100 degrees Friyday, breaking its record of 96 degrees. On Thursday, Santa Rosa was around 100 degrees as well, topping the record of 97, weather service meteorologist Steve Anderson said.

"There will be a few broken records today, but not as many as yesterday," he said.

Residents along the coast can expect cooler weather Saturday, Anderson said. Inland temperatures will begin to drop Sunday when the heat wave ends.

Next week the Bay Area was expected be cooler but still warm.

"Temperatures will be above normal but not hot," Anderson said.

Beginning Monday, San Francisco was expected to be around 70 degrees. Inland areas should reach 90 degrees and along the coast temperatures are expected to be in the upper 60s to around 70, according to Anderson.

The weather service issued a heat advisory for the Bay Area at 3 a.m. Thursday, which is expected to remain in effect until 8 p.m.

The heat, easterly Diablo winds and tinder-dry conditions combined to create a challenging day for Northern California firefighters. A handful of fires erupted in Sonoma, Napa and Contra Costa counties and in the Sierra near Pollock Pines.

Most of the blazes were contained by early Friday but there would be no time for relaxation forecasting temperatures in the upper 70s to lower 90s on the coast to the lower 100s inland.