by Wen Tsui
LOS ANGELES, July 28 (Xinhua) -- Rapid City in the U.S. state of South Dakota recorded a record high of 44.4 degrees Celsius last weekend as a large-scale heat wave kept parts of the central and southern United States under extreme heat warnings, according to the National Weather Service (NWS).
The temperature surpassed the previous record of 43.9 degrees Celsius set at Rapid City Regional Airport on July 15, 2006. Records at the site date back to 1942, the NWS said.
The agency's Weather Prediction Center said the high-pressure system would shift westward later this week, bringing renewed heat risks to California, the Southwest and the Great Basin, an inland region between the Rocky Mountains and the Sierra Nevada.
Extreme heat warnings remained in effect Sunday for Phoenix, Las Vegas and the lower Colorado River valley, where afternoon temperatures were forecast to reach 42 to 46 degrees Celsius across desert areas and exceed 46 degrees Celsius in some locations.
Regional NWS offices warned Sunday that high humidity would push heat-index values, which combine air temperature and humidity, above 43 degrees Celsius across parts of Nebraska, Iowa, Missouri, Kansas and Arkansas.
In Arkansas, heat advisories and extreme heat warnings were expected to remain in place through Tuesday evening. The NWS office in Little Rock warned that overnight temperatures in some areas could stay near or above 27 degrees Celsius, offering little relief from daytime heat.
The U.S. Centers for Disease Control and Prevention warned that extreme heat can cause or worsen heat exhaustion, heat stroke and other serious health problems. Older adults, children, pregnant people, outdoor workers, people without reliable air conditioning and those with chronic medical conditions face increased risks, the agency said.
Houston Mayor John Whitmire announced at a city council meeting last Wednesday that about 112 cooling sites would open at libraries, community centers and other public facilities. City officials advised residents who depend on refrigerated medicine or on medical equipment demanding electricity to make backup plans.
The heat has also raised concerns over agriculture. A U.S. Department of Agriculture report showed worsening pasture and rangeland conditions in Minnesota, Iowa, Nebraska, the Dakotas and Montana. The Climate Prediction Center said existing dryness, above-normal temperatures and expected below-normal rainfall could increase the risk of rapid-onset drought across parts of the Great Plains and the Corn Belt, a major U.S. agricultural region.
The NWS said the most dangerous heat in parts of the central United States could ease after Monday as a cold front moves through the northern Plains and Upper Midwest. However, a broader high-pressure pattern was expected to strengthen over the West later in the week, potentially extending extreme heat into early August.
The Climate Prediction Center has warned of a high risk of extreme heat in parts of California, the Southwest and the Great Basin for the week beginning Aug.2. Forecasters also warned of increased wildfire risks in parts of the Intermountain West, while severe thunderstorms and flash flooding could occur along the edges of the high-pressure system.
Although some central states may see temporary relief, federal forecasts indicated that much of the western and southern United States will remain hotter than normal into early August.■
