earliest ever presidential debate. what we know about how the current president and the former president are preparing. first, to that severe weather threat in the northeast. powerful thunderstorms, damaging winds, even possible tornadoes as 100 million americans across 27 states remain under heat alerts. in the heartland, the national guard is assisting residents in flood-ravaged northwest iowa. rivers are expected to crest over record levels. ike ejiochi reports from washington, d.c. somara theodore has the forecast. as americans seek relief, beachgoers beware. officials warn of a high risk of rip currents along the eastern seaboard and gulf coast. several recent drownings reported from florida to new york. what experts say you should do if you're cut in a rip current. the death toll rises in the deadly mass shooting in arkansas as authorities share details of how the incident unfolded in the parking lot of that supermarket. and what we are learning about the victims, including the nurse being hailed as a hero. four days until the first presidential debate of 2024. president biden hunkering down at camp david. former president trump on the campaign trail, teasing his possible vice-presidential pick. what we know about the very different ways the two men are getting ready. overseas, and the war between israel and hamas. prime minister netanyahu doubles down on his claims that arms shipments from the u.s. are decreasing. what the white house is saying as deadly idf strikes level more buildings in northern gaza, and israel's defense minister prepares for meetings with officials here in the u.s. tom soufi burridge tonight from tel aviv. details just coming in of several deadly attacks in the southern russian republic of dagestan. a synagogue and two churches targeted. what we're learning. fishermen to the rescue, saving dozens of dogs from a mississippi lake. and "america strong" tonight. they aren't just saving lives, they're making them. the baby boom at one california fire department. >> announcer: from abc news world headquarters in new york, this is "world news tonight." >> linsey: good evening, everyone. thanks so much for joining us on this sunday. i'm linsey davis. we begin with the brutal heat suffocating much of the nation. more than 100 million americans are under heat alerts across 27 states. scorches temperatures along the i-95 corridor and triple digits in the nation's capital and baltimore over the weekend. the extreme heat is triggering severe thunderstorms in the midwest. iowa's governor declaring a disaster with parts of the state overwhelmed by catastrophic flooding. and severe storms are now threatening much of the northeast. a tornado watch is in effect for parts of new york and new england, but those storms could bring some relief from all the heat. we have team coverage tonight. abc's meteorologist somara theodore is standing by with the forecast. but abc's ike ejiochi leads us off tonight from washington, d.c. >> reporter: tonight, relentless heat continuing to scorch the country. more than 100 million americans under alerts across 27 states from coast to coast. >> the heat is just unimaginable. >> it's very hot. >> reporter: most of the i-95 corridor under extreme heat risk, hitting record-setting temperatures after already enduring nearly a week long heat wave. >> i feel like the sun is just beating today. it's very -- it's very hot. >> reporter: washington, d.c. today tying its daily record high of 98 degrees. baltimore reaching 101 degrees saturday, the hottest june day there in 12 years. >> how are you staying cool? >> right here in the shade. i'm not walking to the steps. >> reporter: here in the nation's capital, galen clark telling me she's visiting from las vegas and that the two areas don't compare. >> it's not like las vegas. it is so oppressive. it's so hot. it's so wet that you can't breathe, and everything is sticking to you. >> reporter: the blistering heat now expanding to the southern and western u.s. near triple-digit temperatures forecast for huge swaths of the country. the sweltering temperatures in part fueling torrential rainstorms in the midwest. iowa governor kim reynolds declaring a disaster after floodwaters inundated northern parts of the state, forcing evacuations. >> the devastation is severe, and it's widespread. in almost every community impacted, the rivers crested several feet above record levels. >> reporter: linsey, the oppressive heat here in d.c. is finally starting to break. but tomorrow, more seasonal temperatures are expected, but it's still going to be hot with much of the northeast corridor experiencing highs in the 80s and low 90s for the week. linsey. >> linsey: at least the end is in sight. ike, we'll take it. thanks so much. let's get right to abc's meteorologist, somara theodore. somara, give us a timeline for this severe weather threat. >> reporter: well, it's happening right now. we actually have a tornado watch in effect for new england, not something you see every day, until 8:00 p.m. there's already been multiple tornado warnings issued for many states. there's also a severe thunderstorm watch issued for places like pennsylvania, nushlg, parts of ohio through tonight. these storms are fueled by the heat. the heat dome continued to expand part west. blisses like sioux city could reach triple digits. as hot as 93 degrees in new orleans with a heat advisory issued. excessive heat warnings for places like salt lake city. this heat also impacting the west. triple-digit temperatures anticipated with temperatures reaching 108 degrees for the start of the workweek in phoenix. linsey. >> linsey: all right, somara. thank you. now to those deadly wildfires in southern new mexico. the fbi is working with multiple law enforcement agencies to try to determine the cause of the south fork and salt fires. they're offering up to $10,000 for information leading to an arrest and conviction. at least two people have died in the blazes, and hundreds of homes have been destroyed. and now to the life-threatening rip currents along the eastern seaboard. since thursday, at least eight people have drowned, and the search for two teens who went missing in rough beach waters in new york on friday has now been suspended. tonight the warnings and safety tips for swimmers as beach season heats up. here's abc's morgan norwood. >> reporter: tonight, the national weather service warning of life-threatening rip currents up and down the atlantic and gulf coasts, where several people have drowned in recent days, dragged out to sea by powerful waters. beaches on long island and new jersey all the way down to north carolina and florida at high risk, meaning everyone, even strong swimmers, should stay out of the water. the heightened alerts coming as authorities called off the search for two teenage boys, ages 16 and 17, who went missing near jacob riis park in queens, new york on friday. >> i just want them back. >> reporter: emergency responders combing through 600 square miles of rough chop, but still no sign of the boys. the coast guard saying in a statement, the decision to suspend a search is always difficult and weighs heavily on all involved. our crews have conducted an exhaustive search, and our thoughts remain with the families during this difficult time. and in florida, rip currents claiming the lives of five people in just two days, including this pennsylvania couple who were carried away while swimming with their two children. tonight, swimmers urged to stay near lifeguards and heed safety advice from beach patrol and flag warning systems. >> breaking into the summer season and the timing of the stronger rips this week, i think that may be causing the, quote, unquote, perfect storm in terms of people not being acclimated for beach rip current season. >> reporter: linsey, experts say that if you find yourself caught in a rip current, remember, do not panic and try to swim directly back to shore. instead relax, float, and then swim parallel to the shore until you're free of that rip current. >> linsey: morgan, thank you. now to the new details coming in tonight about the deadly mass shooting in an arkansas grocery store near little rock. the death toll has climbed to four, and moments ago authorities said it appears to be a random act of violence. what we're now learning about the victims, including a nurse and the baby she left behind. here's abc's jacqueline lee. >> reporter: tonight, as the death toll rises to four, police in arkansas say that grocery store mass shooting appears to be a random act of violence. >> we believe he immediately began engaging victims in the parking lot after exiting his truck, and then proceeded into the store. once inside, he was firing indiscriminately at both customers and employees. >> reporter: arkansas state police revealing new details about the shooting on friday in fordyce, about an hour south of little rock. >> and there is a shooting going on. >> reporter: the suspect was armed with a 12-gauge shotgun, a pistol, and a bandolier with dozens of extra shotgun rounds, authorities say. for the first time tonight, authorities identifying the fatalities, ellen ha rum, shirley taylor, roy sturgis, and callie weems. >> instead of fleeing from the obvious danger, callie weems used her training as a nurse to render aid to a gunshot victim and unfortunately became a victim herself as a result of her selfless actions. >> reporter: weems' mother, helen, says her defaaughter die hero and is survived by her child, ivy may, just 10 months old. >> she loved god. she loved her daughter. she loved her family. >> reporter: police say the 44-year-old suspect, who is facing four counts of capital murder, shot 11 others, including two police officers. >> these officers literally and intentionally put themselves between the suspects and defenseless citizens. their actions were nothing short of heroic. >> reporter: linsey, police say four people are in the hospital. a woman is still in critical condition. arkansas state police are investigating the motive of the shooter. linsey. >> thinking of baby ivy may tonight. thank you. next tonight, the first presidential debate of 2024 between president joe biden and former president donald trump now just four days away. this is the earliest presidential debate in american history, and any stumbles or fumbles could linger for weeks, even months, more now from correspondent maryalice parks. >> reporter: with the presidential debate just four days away, tonight the biden campaign says it will be a critical moment to contrast his record with donald trump's. >> joe biden wakes up everyday thinking about the american people. donald trump wakes up every day pretty much thinking about himself. >> reporter: in a new memo, the campaign saying viewers will see two different visions, biden's one where freedoms are protected and all americans have a fair shot, and donald trump's dark vision where he will serve as a dictator on day one and give tax cuts to the ultra wealthy. >> he is a convicted felon. i think that stands in sharp contrast to president biden's defense of the rule of law. >> reporter: their debate preparations couldn't be more divergent. biden holding mock debates at camp david with more than a dozen aides. >> you know, when you say prep, i think this is prepping. >> reporter: former president donald trump on the campaign trail. overnight slamming the debate's no audience format which the biden team requested and he agreed to. >> it's like death. this could be the most boring or it could be quite exciting. who knows? >> reporter: and asking his crowd in philadelphia for strategy advice. >> should i be tough and nasty and just say you're the worst president in history, or should i be nice and calm and let him speak? >> reporter: trump now saying that his v.p. pick will most likely be at the debate. north dakota governor doug burgum, one of his top contenders, dodging questions today about why he should be the top choice. >> president trump can win this race regardless of who is vice president. he's got the luxury of not having to pick someone. >> reporter: biden's campaign surrogates were on offense today, talking about trump's criminal conviction, his role in january 6th. it will be interesting to see if the president, himself, continues that tack. on the othernd ha, we are told trump and his allies have been strategizing about how he should respond to questions he might get about his promise to pardon january 6th rioters. linsey. thursday night on abc, watch the cnn presidential debate simulcast. it starts at 8:00 p.m. with the race for the white house. i'll join david muir and the political team thursday night right here on abc. overseas now and a deadly weekend in gaza as israeli forces launch multiple strikes in northern gaza. all this comes as israel's defense chief arrives in washington, d.c. to discuss the next phase of the war and escalating hostilities on the border with lebanon. abc's tom soufi burridge is in tel aviv with more. >> reporter: tonight, benjamin netanyahu doubling down on claims that u.s. arms supplies to israel are being delayed. the israeli prime minister saying in the past four months, there's been a, quote, dramatic drop in the amount of american weaponry arriving. >> i said it's inconceivable. >> reporter: u.s. officials quoting netanyahu's initial claim on the issue in this video message released tuesday inaccurate and out of line. but israel's defense minister today stressing the importance of u.s. support just before he flew to washington for key talks with u.s. officials. it comes as israel increases attacks in gaza this weekend. young children rescued from the rubble. 60 people killed in the past 24 hours according to palestinian officials. today the idf saying it struck hamas infrastructure in central gaza. but abdulazeez saying there are massacres every day. we spoke to dr. ahmed radi, who is treating the injured in northern gaza. >> how many people have you seen killed in the last two days? >> i have seen a lot. we tried our best just to save lives, but some people lost their lives. >> reporter: and tonight, the idf investigating after this video showed an injured palestinian suspect in the west bank tied to the front of an israeli armored vehicle. the idf saying its forces violated standards. linsey, israel's defense minister saying he'll be discussing the transition to the next phase of the war in gaza when he meets face to face with u.s. officials in washington tomorrow. linsey. >> linsey: ztom, thank you. now to breaking news. nine people, including seven police officers, were killed in what appears to be a coordinated attack by gunmen in russia. let's bring in abc's patrick reevell in london tonight. patrick, what can you tell us? >> reporter: hi, linsey. yeah, this was a serious, coordinated terror attack in dagestan, in southern russia. multiple heavily armed gunmen appear to have simultaneously attacked two churches and two synagogues in the regional capital and in another city. videos show street battles between the gunmen and a synagogue also in flames. authorities say at least nine people were killed, seven of them police officers as well as an orthodox priest and another dozen police officers or so injured. police say they have now killed at least six attackers and in just a little while, their main operation is now over. dagestan has long suffered from an extreme insurgency, but this is one of the biggest attacks in years, and it will be raising questions whether russia's security forces are overstretched by the war in ukraine. linsey. >> linsey: patrick, thank you. now to heartbreak and the deadly tragedy in saudi arabia. more than 1,300 people died during this year's haaj pilgrimage. worshippers facing scorching heat with temperatures soaring above 125 degrees. some americans are among the dead but most are egyptians. officials fear that death toll will only rise as hundreds are still missing. and there's still much more ahead on "world news tonight" this sunday. the search for suspects responsible for a mass shooting in columbus, ohio. and later, what sha'carri richardson did on the track that no one else in the world has done this year on her way to paris. and when you can breathe better, what isn't better? this is better. this is better. that's better. and that. even this. dupixent is an add-on treatment for specific types of moderate-to-severe asthma. it works with your asthma medicine to help improve lung function. that's pretty good! dupixent is not for sudden breathing problems. it's proven to help prevent asthma attacks. it can reduce or even eliminate oral steroids. and doesn't that make things better? dupixent can cause allergic reactions that can be severe. tell your doctor right away if you have rash, chest pain, worsening shortness of breath, tingling or numbness in your 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