The Bay Area geared up for another day of searing heat on Wednesday, as all the conditions that have contributed to a sizzling start of October remained in place, according to the National Weather Service.

And just as telling as the figures on the ground surface — which again will surpass 100 degrees and break records throughout the region — were the figures above it, meteorologist Dylan Flynn said. The air 5,000 feet above the surface is the hottest it’s ever been in October, he said, and that affected the sunrise temperatures in upper elevations such as the Santa Cruz Mountains.

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“What’s really incredible is what’s happening above 1,500 feet,” NWS meteorologist Dylan Flynn said. He said that as the sun rose, air mass at that elevation showed temperatures in the 80s and in some cases 90s that far above the surface.

Mixed with what tiny amount of marine air remained, the ground temperatures in elevations above 2,000 feet were in the 80s at sunrise, Flynn said.

“So there’s absolutely no relief there,” he said.

It also means a delay in the relief that was expected to start Thursday but now does not appear to be likely until Friday, according to the weather service. That will extend the possibility of new temperatures records. The overnight warmth wasn’t left just to the highest elevations; San Francisco — coming off a day that saw the mercury reach 96 degrees downtown — was already at 67 degrees at 6 a.m.

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As far as high temperature records, more are likely to fall, Flynn said. The weather service has forecast highs for Livermore (Alameda County) of 106, Kentfield (Marin County) at 104 and San Jose (Santa Clara County) at 102, all of which would at least match high marks for the day. The Livermore mark would tie its previous record set in 1980, while the San Jose and Kentfield marks would break marks set in 2012.

Even where records don’t fall, it will be excessively hot, Flynn said. Brentwood is expected to reach 107, Concord 106, Walnut Creek 105, and Lafayette 101 in Contra Costa County. Pleasanton is expected to bake at 105, and Oakland and Berkeley at 92 in Alameda County. Morgan Hill (Santa Clara County) is forecast to peak at 104, while Redwood City (San Mateo County) is supposed to get to 97.

San Francisco is not expected to reach 90 again but will get into the upper 80s, according to the weather service.

As Flynn put it, that will make it a “nearly carbon copy” of Tuesday, when records fell in San Rafael (105, breaking the the mark of 104 set in 1980), Kentfield (104, breaking 2012’s mark of 100) and San Jose (102, breaking 2012’s mark of 96).

The weather service extended an excessive heat warning for the interior parts of region through 11 p.m. Thursday and also extended a heat advisory for the coast through the same time. The Bay Area Air Management District also had a third straight Spare the Air Alert in place for Wednesday.

“One thing that’s different now though is that the duration of this thing has been extended,” Flynn said. “The cooldown that we’re expecting is going to take a lot more time.”

That has to do with the intensity of the heat above the ground surface, Flynn said. The weather service said it launches balloons twice a day near the San Francisco Bay Oakland International Airport to measure weather conditions high in the air. Flynn said recent data has been unprecedented.

“The balloon we launched (Wednesday morning) showed it was 90 degrees at 2,000 feet,” he said. “The one we launched (Tuesday) showed the highest temperatures at 5,000 feet that we’ve ever recorded in October. The air is incredibly hot.”

So it is that the cooldown likely won’t be felt significantly until Friday along the coast, Flynn said. Inland, there may be a day of slight relief on Friday before another jump into the high 90s and possibly 100s through the weekend.

“We have a tiny disturbance that may move through on Friday,” he said. “Once that happens, you’re going to see a rebound in those temperatures for a couple of more days. Eventually, the high pressure will erode but that’s going to take several days.”

Cooling centers were set to remain open throughout the region again on Wednesday.

Santa Clara County opened libraries in Cupertino, Gilroy, Los Altos, Milpitas, Morgan Hill and Saratoga and Sunnyvale as cooling centers, as well as other sites in Campbell, Milpitas and Mountain View.

Alameda County had cooling centers at six sites in Union City, two in Newark and one each in Dublin, Fremont and San Lorenzo. In San Mateo County, cooling centers were at libraries in San Mateo, Atherton, Belmont, Brisbane, Burlingame, East Palo Alto, Foster City, Half Moon Bay, Menlo Park, Millbrae, Redwood City, Portola Valley, San Bruno, San Carlos, South San Francisco and Woodside.

In Contra Costa County, the city of Concord said its Senior Center would be available as a cooling center Tuesday and Wednesday. In Martinez, the public library and the senior center will be open as cooling centers.

This is a developing report. Please check back for updates.