on the broadcast tonight, terror alert. the british government raises the threat level to severe and says isis is more dangerous than al qaeda. as the white house tries to clarify what some see as mixed signals on u.s. policy. return to racing. nascar champion tony stewart re-emerges t three weeks after s car struck and killed another driver. tonight, what stewart had to say about the tragedy. retail medicine. it's inexpensive, it's basic and it's a growing trend as big chains turn to health care. dr. nancy snyderman tonight on the pros and cons. and the bond. where the older brother goes the younger one is never left behind. their unforgettable story of

challenge and triumph. "nightly news" begins now. from nbc news world headquarters in new york, this is "nbc nightly news" with brian williams. good evening. i'm lester holt in for brian. tonight, as millions of americans begin a long holiday weekend, homeland security officials say they are not aware of any specific domestic threat from islamic militants. that question came into sharp focus today when great britain abruptly raised its domestic terror threat from substantial to severe. britain's prime minister, david cameron, today declaring there is no doubt that isis is targeting western europe. though uk officials also say there is no specific threat. this latest development comes as the obama white house spent much of the day on damage control trying to clarify the president's remarks yesterday about battling isis. the isis threat is one of two major foreign policy crises the president is juggling this weekend.

we have full coverage starting with nbc's keir simmons in london. keir. >> reporter: good evening, lester. raising the threat level to severe means officials believe an attack is "highly likely" though they insist there's no intelligence to indicate an imminent or specific attack. but as prime minister cameron spelled out today, it underscores the concern on both sides of the atlantic about the isis threat. kurdish fighters captured by isis militants, one later beheaded in a new video posted by isis. the latest in a wave of the latest in a wave of violent, extremist propaganda flooding the internet, some from british jihadists. james foley's apparent executioner had a british accent. >> this is james foley.

>> reporter: that set off alarm bells. tonight, security here has been heightened as prime minister david cameron issued a blunt warning. >> what we're facing in iraq now with isil is a greater and deeper threat to our security than we have known before. >> reporter: cameron made clear this is not just a distant war. >> the ambition to create an extremist caliphate in the heart of iraq and syria is a threat to our own security here in the uk. >> reporter: isis has struck in europe killing four last may at a jewish center in brussels. and british extremists have passports that could allow easy travel to america. here in london this week we met with men who justified the murder of james foley. >> does have a duty to protect themselves and, you know, defend against america. >> killing a journalist isn't protecting yourself. >> -- really to blame for the death of james foley i believe is the foreign policy of -- >> someone to put that knife in his neck surely. >> reporter: hatred in the west and willingness of isis to resort to almost medieval violence and brutality. cameron says it adds up to a

long and difficult fight. >> we are in the middle of a generational struggle amidst a poisonous and extremist ideology. we cannot appease this ideology. we have to confront it at home and abroad. >> reporter: prime minister cameron was clear that he considers isis a very real threat. but it's important to note that he did not suggest going further than president obama militarily in attacking isis. lester. >> keir simmons in london, thanks. as we said at the top, the obama administration found itself scrambling today to clarify its position on dealing with the isis threat and other foreign policy challenges including russia's intervention in ukraine. we get more tonight from nbc's kristen welker at the white house. kristen. >> reporter: lester, good evening. the white house is in close contact with british allies today as senior administration officials tried to reassure americans there are no known specific threats to the u.s. and no plans to raise the threat level here.

this as the white house plays defense after president obama's recent remarks about isis. as president obama travels to fundraisers today, his administration is in damage control mode after the president made strikingly candid comments about taking on isis militants in syria yesterday. >> i don't want to put the cart before the horse. we don't have a strategy yet. >> reporter: the remarks played directly into the hands of critics including the chair of the house intelligence committee. >> to have a press conference to say we don't have a strategy was really shocking given the severity of the threat. that's what's so concerning to me. >> the president has laid out a comprehensive plan -- >> reporter: white house press secretary josh earnest was quick to clarify on tv and in his daily briefing today. >> the pentagon is developing plans, or military options, for the president to consider if he decides that it's necessary to do so. but at this point the president hasn't made any decisions. >> reporter: the president has tried to tamp down expectations that air strikes are imminent in

syria, a suggestion left by some of his top military advisors who warned of the global threat isis poses. >> this is beyond anything that we've seen. so we must prepare for everything. >> reporter: the president's foreign policy is being tested on multiple fronts as isis militants are boosting their recruits. nadal hasan, who killed 13 people at ft. hood, reportedly wrote a letter to isis from prison requesting to join. while in ukraine, russian troops continue to build up. nato released new satellite images showing what it says are russian troops and artillery vehicles in the eastern part of the country. today speaking to a pro-kremlin youth camp, russian president vladimir putin said crimea is "indispensable to russia." it's best not to mess with us, he warned, russia is one of the leading nuclear powers. experts say president obama has a steep hill to climb. >> the president has always been very strong rhetorically on issues of foreign policy. but what people are looking for

now is the action to follow that. >> reporter: now, the president changed his schedule today to overnight in washington instead of new york. he plans to travel back to new york tomorrow to attend a private event in the evening. the white house didn't give a specific reason, but with so many crises abroad, it is possible optics played a role in that decision. lester. >> kristen, thank you. for more on all of this let's bring in our chief foreign affairs correspondent andrea mitchell. andrea, does the president have military plans to deal with either of these crises? >> reporter: they always have plans, but he's not ready to use those options now. the president is clearly not ready to attack isis in syria. and has said there's no military option for the u.s. to stop russia's moves into the ukraine. tonight mr. obama also told political supporters at a fundraiser that russia is reasserting the notion that might means right. he'll be heading to a nato meeting next week in wales where the british are expected to propose a european rapid deployment force to bolster nato's eastern defenses.

in his comments tonight the president also sounded a bit frustrated. he said if you watch the nightly news it feels like the world is falling apart. he cited the barbaric of isis saying young people are attracted to it. told nbc news tonight that foreign fighters continue to flow into syria at a steady rate and many of these are joining isis. still, homeland security said today there's no immediate threat to the homeland and no need to raise the security level here in the u.s. ahead of the labor day weekend as the british did today, lester. >> andrea, thanks. we know you'll have a lot more on this sunday when we see you on "meet the press". one of nascar's biggest stars is back behind the wheel three weeks after a deadly crash that killed a fellow driver. today, tony stewart spoke publicly for the first time about the incident that stunned the racing world. our report tonight from nbc's

gabe gutierrez. >> reporter: on the track he's been passionate and vocal. but today nascar legend tony stewart struggled for words. >> this is been one of the toughest tragedies i've ever had to deal with both professionally and personally. and this is something that will definitely affect my life forever. >> reporter: one of the sports biggest stars seen here taking practice laps will compete sunday at atlanta motor speedway. first race in three weeks since a deadly crash on a dirt track in upstate new york. this video posted on youtube showed how kevin ward, jr.'s car and stewart's car appear to bump. ward spun out and climbed out of his car and walked on to the track. he was hit by stewart's car and killed. >> tony stewart just hit that guy! >> reporter: the crash led nascar to prohibit drivers from exiting a disabled vehicle until safety crews arrive unless it's on fire. stewart's teammate, danica patrick, says it's been a long few weeks. >> you know, i'm happy that he's back. and he can start to do something more normal that he's used to. >> reporter: while many fans are standing by him. >> it was just a horrible

accident. >> reporter: some say he's getting back behind the wheel too soon. >> i feel there's going to be a lot of people that's going to boo him. and there's a lot of people that's going to think, well, his temper might have got the best of him. >> reporter: today, no reaction from ward's family and the sheriff said the crash investigation would take at least another two weeks. >> i think being back in the car this week with my racing family will help me get through this difficult time. >> reporter: a weekend that may be the toughest of his career. gabe gutierrez, nbc news, hampton, georgia. for tens of millions of us this is getaway day as the labor day weekend begins. here's a live picture of i-4 in orlando. aaa says nearly 35 million people will travel 50 miles or more this weekend, that will be the highest number in six years with 86% of them driving. one reason for the increase is a big decrease in gasoline prices. aaa says the national average for a gallon of regular was $3.44 today. that's down 12 cents from a year ago.

as for the weather, we've been telling you about those big storms offshore that have brought dangerous conditions this week to both the east and west coasts. as we begin the holiday weekend, let's get an update on conditions now and beyond from nbc meteorologist dylan dryer in rockaway beach, new york. hi, dylan. >> reporter: good evening, lester. for the past week the danger has been the rough currents on both coasts. here red flags are up and lifeguards are still warning about the dangerous rip currents. let's first take you though out into the pacific. and what was hurricane marie continues to pull away, we are still seeing seas as high as five to eight feet across southern california. but we should see those diminish, especially as we go into later in the day on saturday. now, over into the east coast with post tropical cyclone cristobal, as that continues to pull away, the threat of rough surf and dangerous rip currents should diminish as early as tonight.

looks okay heading into the weekend. want to quickly point out an area of low pressure down in the gulf of mexico. it's not tropical, but it is producing some heavier thunderstorms. and there has just been issued a high risk of rip currents down through the gulf of mexico and the gulf coast especially tonight. but that should diminish by tomorrow. now, elsewhere across the country on saturday we could see some stronger storms of wind and hail especially across the northern plains and into the dakotas. we'll see some scattered showers and storms through the great lakes down into the gulf of mexico. on sunday i just want to point out from minnesota to kansas we could see some strong storms that do produce tornadoes, especially late in the afternoon and into the evening. so that will be a huge area we have to focus on. beyond that, lester, we will unofficially say good-bye to summer and hello to fall. >> all right, thanks. we'll see you tomorrow morning on "today." comedienne joan rivers remains in a new york hospital tonight one day after she went into cardiac arrest during a procedure on her vocal cords.

in a statement her daughter said her mother's condition is serious and is touched by the tributes and prayers that have come in from around the world and asked for prayers for her recovery. still ahead as we continue tonight, retail medicine. how more and more stores are hoping to put medical care on your shopping list. but is this always the best medicine? and later, no sibling rivalry here. a lesson you won't forget, how to treat a brother.

we're back with a sign of

the times in medicine. as the country deals with a big shortage of primary care doctors and the high costs of care, more of us are turning to those quick care clinics. and now the nation's biggest retailer, walmart, is joining the mix saying it wants to be a primary health care provider. we get more on this tonight from our chief medical editor dr. nancy snyderman. >> reporter: in this hectic world, you may feel you're on-call 24/7, but your doctor is not. >> i work in the health department. and i see people every day that don't have access to medical care. >> reporter: it's that frustration retailers are banking on as more are opening low cost in-store medical clinics. and today america's biggest retailer, walmart, opened two new clinics in georgia, making a move to deliver primary care through its 5,000 u.s. stores. >> you have to have an appointment?

>> reporter: walmart's focused on opening these clinics in rural areas where there isn't as much access to care. with walk-in visits costing patients and their insurance companies just $40, analysts say these clinics could be a game changer. this could have ripple effects and also challenge hospitals and doctors to reconsider their pricing as well. there are nearly 2,000 retail clinics in stores like targets, walgreens and cvs. they're staffed by nurse practitioners or physician assistants. most are open seven days a week and some have evening hours. they're commonly used for treating colds and flu, infections, minor sprains and for getting some vaccinations. but experts caution retail clinics should not be the primary source for primary care, especially for children. >> we don't recommend that parents take children under the age of 18 months to a retail clinic. >> reporter: when you do go to a retail clinic, here's a list of

things to know. bring a list of medications and get a complete record of your visit and ask your clinic to send your doctor a report. clinics like these may well be the face of what health care looks like in the united states where a doctor isn't necessarily the first person you seement lester? >> doctor nancy snyderman, thanks. back with the news of a comedy classic who gave us the phrase, who you gonna call.

it was on this day nine years ago that hurricane katrina slammed into the gulf coast. and we want to show you some remarkable images of new orleans then and now after nearly a decade of recovery and rebuilding. photographer ted jackson found photos taken just after katrina, like this one of the industrial

canal. then recently went back to the same locations. the comparisons as you can see are dramatic. this was broad street back then as people struggled against the rising floodwaters. today, no sign of what it was like during those desperate days. among the many signature images, the misery at the convention center as 30,000 waited for help. today, the front of the building is mostly empty. but those scenes from nine years ago are impossible to forget. and from the devastated lower ninth ward this image of four women and three children holding on for their lives. today, that same house still in ruins. nine years later new orleans still a work in progress. some impressive scenes from iceland as a volcano came to life this week. that prompted authorities to raise the aviation warning code to red for a brief time and close air space at lower altitudes right around the eruption. but commercial aircraft overflying iceland are not affected and so far the volcano shows no signs of being as disruptive as the one that caused aviation chaos four years ago. here in the new york area it's not something you see every day, this photo of a humpback

whale feeding in the atlantic was taken this week only about six miles off new york city. the waters serve as a feeding ground for many kinds of marine life including whales and dolphins. a revival this weekend for the movie that gave us that unforgettable line "who ya gonna call?" on the 30th anniversary a restored and remastered version of the comedy classic has been released in 700 theaters around the country. back in the summer of '84 "ghostbusters" was the top film at the box office for nine weeks. when we come back, the story of two young brothers and their remarkable bond.

finally tonight, if you need a definition of brotherly love, it can be summed up perfectly by two young boys in idaho. their strong connection can't be captured in words but rather in actions. and what they do is touching people across the country. we get their story tonight from nbc's joe fryer. >> reporter: inside their idaho play room, lucas aldridge and his big brother, noah, share a love for "star wars" --

>> where's my light saber? >> reporter: -- and each other. >> well, just makes me happy. >> reporter: their special bond can be seen in baby photos back when lucas was diagnosed with a rare disorder that affects brain development. now 6 years old, lucas can't walk or talk or feed himself, but he sure can smile. his biggest grins reserved for noah. >> i love him. he's perfect. >> i start to well up, almost cry every time i hear him and his passion for his brother. >> reporter: so as noah trains for a kids' triathlon, he knows lucas won't settle for the sidelines. when the big race day arrives, these brothers tackle the triathlon in tandem. never mind that a few months ago noah couldn't swim at all. today, this inspired 8-year-old is paddling for two.

after four back-breaking laps in the pool, they hit the road for one and a half miles on a bike. >> you can tell how much lucas is loving this, right? >> yeah. absolutely. >> he's having a blast. just playing like brothers should. >> reporter: the final leg is a three-quarter mile run. and by now noah's a pro. >> all right, noah! >> people are making a pretty big deal about it. do you think it's a big deal? >> not really. i'm just doing something with lucas. i didn't really want to be famous. >> reporter: all he wants is to make sure every single moment with lucas counts. between these two brothers the force is strong. joe fryer, nbc news, idaho. and that's our broadcast for this friday night. thank you for being with us. i'm lester holt in for brian. i'll see you later for "dateline" and then tomorrow on "today." have a good weekend everybody. good night.

nbc bay area news starts now. right now at 6:00, it's a new idea to cut crime in the south bay, but this one would bring back some familiar faces. we've just learned where san jose plans to get new cops. good friday evening. thanks for joining us. i'm janelle wang. >> and i'm jessica aguirre. we begin with an exclusive story. the city of san jose will soon be considering a program aimed at boosting its understaffed police department by enticing officers to stay on the force after retirement.

but there's a very controversial catch. robert honda is live. it's already drawing lots of fire behind the scenes. >> reporter: they are getting ready to reveal what they call an officer retention program. but critics are already saying it's a bad version of an old idea that not only won't solve the staffing crisis but may create new problems. san jose is getting ready to roll out a program to keep officers from leaving after retirement. as we've been reporting, hundreds have quit over the pension reform efforts. to stem the tide, the police department with support from the mayor and city officials plan to offer retiring cops what is called a drop program. in essence, the officer retires and their pension is put in a trust fund so they can work two or three more years without paying into the retirement system. then when they actually leave they get that pension money in full. they say regardless of rank most officers would be putn