A heatwave that has been ravaging Southern California for almost two weeks is now moving eastwards, bringing some relief in temperatures to Los Angeles and certain cities along the west coast. However, San Bernardino County and Riverside County in Eastern Southern California, as well as Phoenix in Arizona and Las Vegas in Nevada, are still under the grip of scorching heat.
Meteorologist Gregg Gallina stated that this weather condition is expected to persist until the middle of next week, possibly easing up as April approaches. According to meteorological records, this heat dome effect has brought the hottest March on record to 14 states in the western and southern United States, including California, Nevada, Arizona, Texas, New Mexico, Utah, Kansas, Nebraska, South Dakota, Missouri, Iowa, Wyoming, Minnesota, and Idaho, breaking high temperature records for March in nearly 180 cities.
KTAR radio in Phoenix reported that the city is experiencing its hottest March on record, with temperatures exceeding 100 degrees Fahrenheit (about 37.8 degrees Celsius) for the sixth consecutive day. Normally, temperatures would hover around 80 degrees (about 26.7 degrees Celsius) at this time of year, with triple-digit temperatures in March occurring only once before in 1988.
Local media reported that around 400 spectators at an air show in Glendale, Arizona, required treatment for heat-related illnesses due to the scorching weather.
Similar to Phoenix, the southern part of Nevada is also facing a heatwave, with temperatures being 15 to 20 degrees Fahrenheit above normal. Las Vegas has broken daily high temperature records for six consecutive days and this trend may continue until Friday. With the eastward movement of the high-pressure ridge, temperatures in the gambling city are expected to drop to around 90 degrees Fahrenheit by Friday and Sunday.
According to the National Weather Service’s Weather Channel forecast, Las Vegas will experience a significant temperature drop next Monday and Tuesday, with a surge of cold air from the Pacific bringing temperatures down to 70-80 degrees Fahrenheit.
Analysis indicates that this heatwave in the U.S. West is primarily caused by a high-pressure system trapping the warmth of the abnormally warm Pacific Ocean waters. AccuWeather senior meteorologists explain that the heat dome acts like a balloon, expanding and contracting over time. It can prevent the formation of clouds, leading to ample sunlight exposure and subsequently raising temperatures.
The U.S. weather website Weather.com describes how the high-pressure system causing the “heat dome” can extend up to 1,000 miles, bringing sinking air currents to the affected areas. As the air sinks near the surface and compresses, temperatures rise, creating a warm, dry air mass above the ground and nearly still air directly beneath the high-pressure ridge.
On a positive note, as the high-pressure ridge continues to move eastward, the sky in the Los Angeles area is expected to become cloudy starting from Friday, with temperatures decreasing accordingly. A significant drop in temperatures is anticipated next Monday, with the possibility of rainfall by Tuesday.