( CNN ) -- The dangerous heat wave blamed for as many as 22 deaths spread into the eastern United States on Wednesday , extending its reach across nearly half the U.S. population , officials said . About 141 million people in a 1 million-square-mile area were under heat advisories and warnings , Justin Kenney , spokesman for the National Oceanic and Atmospheric Administration , tweeted . The National Weather Service said , `` These triple-digit temperatures are forecast to remain in place across the eastern U.S. through Saturday before cooling off slightly to the mid-90s by Sunday . '' `` After several days of deadly heat and humidity as many as 22 people have died , '' the National Weather Service reported Wednesday afternoon . In Oklahoma , four heat-related deaths have been confirmed since May , said Cherokee Ballard , spokesperson for the state medical examiner . Three of those occurred in the past 30 days , including the deaths of a 3-year-old boy in a car in Norman and a 69-year-old man from Blackwell , she said . Another eight Oklahoma deaths may potentially be related to the heat , Ballard told CNN , with most occurring in July . For parts of the country that have already been scorched , some relief was forecast to arrive later Wednesday , the weather service said . A cold front moving across Montana Wednesday `` will significantly drop temperatures across the north central U.S. for the rest of the week , though locations across the central and southern Plains and parts of the Midwest will not see much change from the extended period of heat . '' But in the East , some of the worst temperatures were just setting in . Excessive-heat watches , warnings and heat advisories were in effect in more than 30 states Wednesday , in what the weather service described as `` a large portion of the central U.S. and Ohio River Valley , as well as portions of the mid-Atlantic and northeastern states . Temperatures will feel like 100 to 110 degrees or higher during the afternoon hours . '' The heat wave in recent days has brought heat index values -- which measure how hot it feels -- to as high as 131 , the weather service said . Heat indices on Tuesday reached 129 in Newton , Iowa ; 121 in Taylorville , Illinois ; 122 in Gwinner , North Dakota ; and 123 in Hutchinson , Minnesota . Minneapolis recorded its highest dew point ever , 82 degrees , on Tuesday . The dew point temperature is a measure of atmospheric moisture . Part of what makes the heat wave so dangerous is that it offers no break , even at night . Chicago on Tuesday tied its record for the warmest low temperature of 78 degrees . In Rockford , Illinois , temperatures dropped down only to 76 degrees -- the warmest on record . The Centers for Disease Control and Prevention said people in areas affected by extreme heat should drink more water than usual -- and not wait until they feel thirsty . `` Avoid alcohol or liquids containing high amounts of sugar , '' the CDC says . The CDC also recommends taking cool showers or baths and avoiding direct sunlight . `` Check on those most at-risk twice a day , '' the CDC said . CNN 's Sean Morris , Jacqui Jeras , Dave Alsup and Phil Gast contributed to this report .
NEW : This means the product will ship as received by the manufacturer, sealed, with all advertised components, and with the manufacturer warranty. 141 million people are under advisories or warnings , NOAA spokesman tweets . Watches , warnings , and advisories cover more than 30 states .