Battered by severe storms that killed at least two people and left thousands without electricity, Oklahoma faced more relentless heat and severe storms on Wednesday as crews worked furiously to restore power in the hard-hit northeast part of the state.

Ambulance crews in the Tulsa region were struggling to keep up with calls related to the storm and power disruptions, according to Adam Paluka, a spokesman for the Emergency Medical Services Authority in Tulsa.

“We had our highest-volume day ever, in our history,” Mr. Paluka said. “This chaos is our reality right now.” He said the authority’s crews responded to 487 calls, compared with the average of 335 for a Tuesday in June. Many of the calls were related to heat exhaustion or to people falling ill because they had no power for medical equipment in their homes.

Storms, possibly with hail, were expected to continue battering Tulsa and others parts of the state on Wednesday and the next few days. But officials were more worried about the relentless heat, which is expected to reach triple digits by the weekend.

Highway and utility crews were racing to restore power lines and repair the substantial damage done by storms last weekend, whose hurricane-force winds knocked down trees and scattered debris that made some roads unusable. One tornado was recorded in the Oologah area.

More than 100,000 customers in Oklahoma were still without power Wednesday morning, mostly near Tulsa, and many of them would not have service restored for several days yet, officials said.

At least two people died as a result of the storms, in Creek County and McCurtain County, according to medical examiners’ records.

The National Weather Service in Oklahoma said on Wednesday that more perilous storms and possible hail were on the way as a line of storms moved in from Kansas. “As this line moves through northern and central Oklahoma,” the agency said on Twitter, “large hail and 60-80 m.p.h. winds could accompany the strongest storms.”

Extreme heat eased slightly in Tulsa on Wednesday, to a more normal high of 90 degrees, with nighttime lows in the 70s. A heat advisory remained in effect for the region because the combination of heat and humidity was expected to create dangerous conditions for people without electricity, Weather Service forecasters in Tulsa warned on Wednesday morning.

The worst of the heat was shifting on Wednesday and Thursday to western and southern Texas, as well as to portions of New Mexico, where high temperatures were expected to spike into the triple digits, threatening to break daily records in places like Abilene, Austin, Odessa and San Angelo in Texas.

Weather forecasters were also watching the Oklahoma and Texas panhandles for the possibility of more severe thunderstorms. “Those storms could produce hail the size of baseballs,” said Forrest Mitchell, a forecaster with the service.

Over the next few days, temperatures could surpass the 100-degree mark, especially in southern Oklahoma, Mr. Mitchell said. On Sunday, Wichita Falls, Texas, could reach 107 degrees.

The chaotic weather was unusual for this time of year, with summer only just beginning on Wednesday.

In Central Oklahoma, which includes Oklahoma City, the 30-year normal for high average temperatures has hovered in the high 80s. “We’re already seeing readings in the mid 90s,” Mr. Mitchell said. “It’s not common, but it also has happened in years past.”

The prolonged heat wave is a result of a high-pressure ridge in the atmosphere, the kind of condition that is typically responsible for long-duration heat waves.

“In terms of temperatures, there is really no end in sight for the excessive heat that has plagued particularly south and western Texas/southeastern New Mexico,” forecasters with the Weather Prediction Center said.

The long-term forecasts did not look any better. The current weather pattern could stay locked in through the first week of July, with above-average daytime heat and little recovery at night, the center said.