Dangerous heat wave continues baking Texas, expanding in U.S. South

HOUSTON, June 27 (Xinhua) -- Triple-digit heat wave is sweeping south central U.S. state of Texas, pushing the state's power grid to new limits while expanding to other parts of the U.S. South.

More than 55 million people in the United States were under some form of heat advisory, watch or warning on Tuesday, according to New York Times estimates using National Weather Service (NWS) advisories and LandScan population data.

"The Gulf Coast and areas immediately inland most likely will see no breaks in the oppressive heat and humidity as we look forward to the Fourth of July holiday," the National Oceanic and Atmospheric Administration's Weather Prediction Center forecast on Tuesday.

Around 90 afternoon high-temperature records could be broken across the U.S. South, from Texas to the Mississippi Valley and parts of Florida, said a CNN report. Parts of Florida could get 110-degree heat early next week.

Forecasters said Tuesday was expected to be the warmest day of the week in parts of Texas, where a heat dome, which occurs when the atmosphere traps hot air over a certain area for days or weeks, remained stalled over.

Dallas in northern Texas is set to go six consecutive days without seeing temperatures drop below 80 degrees Fahrenheit overnight, a June record for the city.

Houston, the fourth largest U.S. city in southeastern Texas, has had nine days for this month that haven't dropped below 80 degrees Fahrenheit, nearly double what's typical for June.

San Antonio and Austin, also major cities in Texas, already broke daily temperature records last week as the heat reached 105 and 106 degrees Fahrenheit respectively and were forecast to get triple-digit heat again Tuesday, according to the NWS.

At least three hikers died in Texas last week after suffering heat-related fatigue, including a teenage boy and his stepfather in Big Bend National Park where temperatures rose to 119 degrees Fahrenheit, the second-highest mark ever recorded in the state.

According to data provided by the Electric Reliability Council of Texas (ERCOT), total grid demand hit 80,144 megawatts around 5 p.m. Monday evening. ERCOT published a fact sheet earlier this month listing 80,148 MW as the all-time record.

This week's heat wave "may be more danger than a typical heat event, due to the longevity of near-record or record high nighttime lows and elevated heat index readings," forecasters at the Weather Prediction Center have warned.

Triple-digit temperatures and extreme humidity together make it feel hotter than 110 degrees Fahrenheit in some of the region's most populous cities.

Meanwhile, overnight temperatures will also stay abnormally high, with potentially 180 nighttime records broken over the coming days, according to the NWS.

Climate change is widely blamed for causing heat waves to be more intense, longer-lasting and more frequent.