44 Million Under Heat Warnings or Advisories in U.S.

Roughly 44 million people are under either heat warnings or advisories in the United States as the National Weather Service (NWS) identifies extreme heat as the “number one weather-related killer.”

Heat advisories are expanding the U.S. on Monday, including the Southeast, mid-South, “much” of the Great Plains, even including Southern California as well as Texas. The heat advisories are going as north as Aberdeen, South Dakota and south as North Florida.

Per the NWS:

An ongoing heat wave will continue today and Tuesday from much of the Great Plains to the lower Mississippi River Valley and into northern Florida. Dangerous heat is also expected in southern California and Puerto Rico. Scattered severe thunderstorms will be possible over parts of the Upper Midwest today with destructive wind gusts possible for parts of Minnesota into Wisconsin.

Temperatures are expected to soar into the 90s and 100s, and the heat index could reach as high as 110 degrees in some of these areas, including New Orleans.

As an upper-level trough moves over the northeastern U.S., bringing relief from the heat over the weekend, a broad upper-level ridge will build over the central/western U.S., shifting the focus for the ongoing heat wave to the Southeast, Mid-South, and central/southern Plains early this week. Forecast high temperatures will continue to soar into the upper 90s over the region, with low 100s possible over the central Plains. When combined with the humidity, heat index values may reach as high as 110, prompting widespread Heat Advisories. Meanwhile, low temperatures will mostly remain in the mid- to upper 70s, bringing little relief from the heat overnight. The arrival of this more intense heat early in the Summer season leads to a higher level of heat-related stress, especially for those outdoors and without reliable air conditioning available.

The New York Times noted that the heat index reached 104 in Philadelphia on Sunday, breaking a record made in 1888. Trenton, New Jersey saw a heat index of 103 that same day. However, the heat index in both areas is expected to remain in the 80s on Monday.

The heat index in Jacksonville, Florida area is expect to range from 102 to 110 degrees on Monday. As a result of the extreme heat, the City of Jacksonville is giving a tour of its cooling center.

Further, Salina, Kansas is expected to hit a heat index of 108 degrees, and Missouri will see heat indexes exceed 100 across the entirety of the state:

NWS has identified extreme heat as the number one weather-related killer and advises those under the warnings to drink plenty of water, reduce outdoor activities, wear light-colored clothing, and spend time indoors during the hottest part of the day.