A huge heat wave that has set dozens of temperature records from Texas to California is swell in the eastern United States. More than 100 million Americans from the Gulf Coast to the Great Lakes are on high heat by mid-week as temperatures soar to triple digits. Suppressive humidity levels will make it feel 5 to 15 degrees warmer, producing heat index values of 100 to 115 degrees in a large area of central and eastern Lower 48. “Vomiting. Loss of strength: Southwest heat causes health fears Heat warnings or clocks and overheat warnings cover all of Arkansas, Mississippi, Kentucky, Missouri, Iowa, Illinois and Indiana and parts of more than a dozen other states. The National Weather Service predicts temperatures could break records in more than 100 cities by Wednesday, from Denver to Charleston, SC The heat is forecast to be more prolonged and intense in the middle of the country. Unstoppable heat is forecast in St. Louis, where the mercury is forecast to reach at least 100 each of these days – with heat index values up to 113. It is warning of extreme heat for “dangerous heat waves”, according to the Meteorological Service. The suffocating wind simultaneously feeds the risk of strong thunderstorms along the northern periphery of the heat wave. The Meteorological Agency is closely monitoring the development of a violent storm that could sweep across the Upper Midwest in the Ohio Valley and the Mid-Atlantic on Monday afternoon until early Tuesday. Forecasts for next week call for the punitive heat wave to continue in the central states. Such heat waves are typically key elements of summer, but their effects become more pronounced and prolonged by man-made climate change.
Where is the heat now, where is it headed and how long could it last? Excess heat is the result of an intense and extensive high-pressure zone, sometimes referred to as a heat dome. The dome, centered on the southwest on Saturday, has shifted east. On Monday, it hovered over the lower Mississippi Valley, targeting much of the eastern half of the country except the northeast. By Wednesday, it will be heading to Nashville before spilling west again. The Science of Heat Domes and How Drought and Climate Change Make Them Worse On Monday, prices are forecast above 100 degrees for most of Texas, with the 1990s from the Corn Belt to the East to the Carolina. Challenges close to 100 are set in Denver, Dallas, Omaha, Memphis and Charlotte, among many other locations. Temperatures in the 1990s to near 100 could reach as far north as Minneapolis on Tuesday, with 98 degrees in Atlanta, 97 in Chicago and 101 degrees in Raleigh, NC Columbia, SC, could reach 102 degrees. The combination of heat and humidity in Charlotte on Tuesday and Wednesday – producing heat index values close to 110 – may be the strongest since 2010. On Wednesday, temperatures in the 1990s will be ubiquitous from the central plains and Texas through the eastern Great Lakes, the Midwest and the interior of the Mid-Atlantic and Appalachian, as well as the southeastern. The disks could threaten the area from about Flint, Michigan, to Columbus, Ohio, and Knoxville, Tenn., To Atlanta. The heat will not go anywhere soon. It may shift slightly west and consolidate in the central states late this week until the weekend. The Meteorological Agency’s Climate Prediction Center predicts temperatures will continue to rise above normal in the central states for the next two weeks. Along the northern periphery of the heat dome, where the thunderstorm meets the coldest air, the resulting temperature contrast is expected to cause intense thunderstorms. Thunderstorms were already evident Monday afternoon in the Upper Midwest and Great Lakes. There was growing concern that a bow echo, or curved mute line capable of producing harmful straight winds, would be organized and spread south and east Monday afternoon and evening through the Upper Midwest and Ohio Valley. The Meteorological Agency’s Storm Forecast Center put the area from Wisconsin to North West Virginia at greater risk than this potential thunderstorm or intermediate transmission system (MCS). “It seems likely that a long-term MCS bow could lead to a significant lane of wind damage along this runway,” wrote the Storm Forecast Center, which also warned of heavy hail and some tornadoes. Cities on the high-risk corridor include Chicago, Milwaukee, Detroit, Indianapolis, Columbus, Cleveland and Pittsburgh. There is an external possibility that MCS will meet the criteria of a derecho, which is a rapidly moving, extensive, long-lived and violent storm complex. Derecho era: Why you should be aware of these potentially devastating windstorms It is unclear if the storm will survive its journey over the Appalachians on Monday night and what the consequences will be for Washington and Baltimore, but it is worth watching the area late into the night until early Tuesday morning. Then another such complex could develop over the Upper Midwest or the Great Lakes and move inland northeast late Wednesday through Thursday. As the heat spread to the area from Texas to Central California late last week until the weekend, it set a record high. Phoenix set a trio of daily high temperature records in the series – 113 degrees on Friday, 114 on Saturday and 112 on Sunday. The average high there at this time of year is about 105 degrees. On Friday, the morning low in Phoenix did not fall below 87 degrees, which means that, taking into account the afternoon high of 113, the average temperature of the day was 100 degrees. This is the first three-digit average daily temperature recorded in Phoenix. Las Vegas reached 109 on Friday and Saturday, tying or breaking records, and Salt Lake City reached 102 on Saturday and 103 on Sunday. And these broke records. Denver jumped to 100 on Saturday, a draw for its first record to reach the turn of the century. In Texas, rainy days and stuffy nights set dozens of records. Dallas saw the morning low of 80 degrees on Sunday, a record minimum temperature. Rising overnight temperatures often play an even greater role than high daily temperatures in boosting heat stress in the body and contributing to heat-related illnesses and deaths in vulnerable populations. Dallas then hit a record high of 103 points on Sunday afternoon. Abilene, Texas, saw three consecutive daily records – 102 on Friday, 108 on Saturday and 109 on Sunday. San Antonio also tied or broke records in those days, at 101, 104 and 105 points, respectively, as did Austin, with 101 on Thursday, 103 on Friday, 104 on Saturday and 105 on Sunday. In Houston and Galveston, Texas, the heat overlaps with the oppressive humidity, contributing to temperatures in the area of 105 to 110 degrees. It could have been worse, though – southeastern Oklahoma saw heat index values in the incredible 120-degree range on Saturday. It was due to air temperatures around 105 in combination with dew points, a meter of humidity, in the upper 70s and close to 80.
