is "nbc nightly news" with brian williams. good evening. the evidence is now unmistakable. aspects of the u.s. economy after a long and difficult period of darkness appear to be getting more robust. and while there are lots of numbers out to prove the point of an improving economy, problem is, of course, it's hardly being felt by all americans. but first, the good news, and it's substantial. here are the stock indexes at closing time today. all three closed up. stocks, by the way, are nearing an all-time high on wall street. on the housing front, u.s. builders started work on new homes last month at the fastest rate since the summer of '08. and finally, the number of americans seeking unemployment has fallen to a five-year low. we start off by getting more on all of it tonight from nbc's john yang in chicago. john, good evening. >> reporter: good evening, brian. the signs are small, and they're far from conclusive. and we have had had false starts before. but economists are pointing to data that suggests that maybe, just maybe, we could be in for stronger economic growth this year, which has already started off with a bang. today, the stock market winning streak marked its fourth straight week. and this week, encouraging signs on jobs and higher home prices. today, the government reported that sales of new homes shot up nearly 20% in 2012, and home prices went up almost 14%. >> this is the new pricing power. >> reporter: diana olick covers real estate for cnbc. >> home building definitely improved in 2012, but nowhere near where we need it to be. we're still running half the housing starts as we would be in a normal year. >> reporter: 2012 home sales were only a third of the record set in 2005. any improvement is good news for truberry custom homes outside columbus, ohio. they haven't been this busy since the housing bubble burst in 2006. >> we are very excited. last year was good. we're expecting this year to be great. >> reporter: on wall street, the dows finished each week of the new year higher than it began. up 112% since its recession low in march, 2009, and poised to set a new record high, perhaps as soon as next week. that's encouraging for americans who have an estimated $6.5 trillion of their retirement savings tied up in stocks. analysts say the rally began after washington policymakers avoided the fiscal cliff and has continued as investors chase higher stock prices. >> and that light bulb goes off, and people say, hey, wait a minute, the market really is getting better. maybe the economy is getting better. that train is leaving the station. i better not let it leave without me. >> reporter: is the economy about to gain momentum? there's still potential pitfalls. rising mortgage rates and tight lending could threaten housing and unforeseen political or economic events could topple stock prices. but some analysts say the stage is set. >> we have made a lot of adjustments, and now the economy really has some breathing space to really improve. >> reporter: another potential speed bump to economic growth is the increase in payroll taxes, which is just beginning to show up. but some analysts say they hope it will be offset by new jobs and the new wages that come with them. brian? >> john yang starting us off in chicago tonight. john, thanks. these gains in the stock market have come despite a big-ticket name having a rough time. apple announced some rough earnings numbers earlier this week. their stock has now taken a punishing blow. in fact, today apple lost its spot as the world's most valuable company. title goes back to exxon now. since apple has lost 37% of its value from its high point of more than $700 a share back in september. across the country, as if thislu season wasn't bad enough already, it's now widespread in 47 out of the 50 states, remember. the cdc confirms what a lot of us already know from the workplace and the world around us. this other virus, the stomach bug that is making victims really miserable and they're dropping fast. more from our chief medical editor, dr. nancy snyderman. >> tonight, the cdc is warning about a new outbreak, norovirus, which causes nausea, vomiting, diarrhea and abdominal pain. what has health officials so alarmed, the strength of the virus and how quickly it spreads. norovirus is transmitted by people who don't wash their hands after using the bathroom. it lives on surfaces or on food people touch. the current strain hitting the united states is from australia. it's highly infectious and particularly vicious. >> it can stay alive for long periods of time. and can be transmitted easily to anybody. so it's a small environment with lots of people, and it can get transmitted very quickly. >> reporter: unlike influenza, there is no vaccine, so the best way to get rid of it, disinfecting surfaces with bleach and keeping hands clean. meanwhile, influenza continues to hit people from coast to coast. at the medical center in new york, the staff is working overtime to keep up with flu cases. >> our emergency room has been packed. we are stretched right now. 25% of our daily visits are flu patients. >> reporter: it's a snapshot of what's happening in emergency departments and doctors' offices across the country. flu is in the headlines a lot these days. it started with local outbreaks in october and then became widespread throughout the u.s. and today the centers for disease control is reporting 37 children have died from the flu this season. young children and the elderly are most vulnerable. in duncan, oklahoma, this elementary school is closed until at least monday. more than 10% of the students are out sick. so staff is spending the day cleaning everything. >> one morning at school -- >> reporter: and while california had a slow start, it's now catching up. at this preschool near san diego, the staff is focusing on prevention by wiping down all the surfaces and teaching kids the best ways to stay well. >> this year, this season, this last two weeks, has been very, very overwhelming, almost. because of how many people are sick. >> it's almost a perfect storm for viruses. norovirus, influenza, and of course, the pesky common cold. a basic bottom line reminder, the simplest way to avoid getting sick, wash your hands. get your vaccine, but watch your hands. >> it's rough out there. >> it's rough out there, brian. and it's not even february. thank you, as always. our cameras overseas are back in a familiar spot tonight. tahrir square in cairo. that's because it's been two years now since we were there to witness the fall of mubarak. tonight egyptians have filled the square once again to express their continuing anger and frustration. nbc's ayman mohyeldin has been in the thick of it. including the tear gas used to disperse the crowds. and while we have a shaky satellite signal tonight from our cairo bureau, he is there, nonetheless. ayman, good evening. eamon, good evening. >> reporter: good evening, brian. the temperatures have dropped. it's nighttime here, and so have the number of protesters in tahrir square where it is calming this evening after a very intense day of clashes, not too far away from the iconic birthplace of the egyptian revolution. where we are here in cairo, and in other cities, police have been clashing with protesters. many of them angry at the slow pace of transition to democracy under the leadership of mohamed morsi and his muslim brotherhood party. they say they have taken over the country and divided it. you were here two years ago. you saw the unity egyptians had during those 18 days that toppled the former dictator who hosni mubarak. many demand the revolution continue. they say it has been thwarted by the islamists and that's why they're taking back to the streets. the clashes have been intense. seven people have been killed. more than 250 injured in clashes across the country. the police using that tear gas and rubber bullets to try to keep the protesters at bay. they have been firing back with petrol bombs and stones. it's a very intense and volatile situation marking this second anniversary of the revolution. brian? >> a yman mohyeldin after a rough night in cairo. thanks. back in this country in washington today, thousands of anti-abortion demonstrators marched to the steps of the supreme court, protesting the landmark decision that legalized abortion. annual march for life as it's called, this year coincides with the 40th anniversary of the roe vs. wade decision. a federal appeals court has dealt president obama a big legal setback tonight and given republicans who charged that he acted improperly when he made some job appointments a huge victory. this is about what presidents get to do when congress is out of town, and this could affect all future presidents. our justice correspondent, pete williams, is with us from our newsroom with the details tonight. pete, good evening. >> reporter: brian, if this ruling stands, it will virtually eliminate a power that presidents of both parties have used for over a century. the constitution gives the president power, quote, to fill up all vacancies that may happen during the recess of the senate. president obama invoked that recess appointment power a year ago to fill vacancies that senate republicans refused to act on. three spots on the national labor relations board and richard cordray to run the new consumer financial protection bureau. but today a three-judge panel of the federal appeals court in washington said that power can only be used between the end of one session of congress and the beginning of another, not during any congressional break. and the court said it can be used only to fill spots that become vacant during those recesses. presidents of both parties have made more than 300 recess appointments. thurgood marshall, earl warren and william brennan got on the supreme court that way before being confirmed. it's how john bolten was made u.n. ambassador. and larry eagleburger, secretary of state. so the obama administration seems certain to appeal this to the supreme court, brian. >> huge decision today. pete williams from our d.c. newsroom tonight. pete, thanks. president filled a big job today that does not require congressional approval. he named a veteran of his own staff, his new chief of staff in the white house. denis mcdonough comes from the foreign policy shop. he has been deputy national security director. his was one of the faces around the table in the situation room during the bin laden raid. he goes back to the senate days with obama. he replaces jack lew, nominated to run the treasury department. mitt romney, who has disappeared from public life since the election, was spotted today having surfaced in washington. he and his wife were saluted by the marriott corporation. his staff did not allow any media at the event. he will also attend the annual bipartisan alfalfa club dinner saturday night. with the president now six days into his second term, a whole lot of republicans across this country are thinking about how things might have turned out differently. especially if the rules for electing presidents were different. the argument goes this way. the way the electoral college works is outdated, and it's about time those rules were changed. our report tonight from nbc's andrea mitchell. >> reporter: if republican proposals in key states to change the way we elect the president are approved and applied nationwide, this week's inaugural would have looked like this. mitt romney would be president. despite losing the popular vote to barack obama by a healthy 4%. not a bad idea, said republican chairman reince priebus today. >> i thought it was an intriguing idea that some states are looking at, which they are. and i think it will be up to them to decide what they want to do about it. >> reporter: the idea, to award electoral votes by congressional district. instead of winner take all to the candidate who carries the state. advantage republicans who control more congressional districts than democrats. and the electoral map? >> let's take a look at the new, as of 9:00 in the east, 6:00 on the west coast. the new electoral map. >> reporter: maine and nebraska already award electoral votes by congressional district. but that's never changed the election outcome. but if the whole country adopted plans now being considered in virginia, michigan, ohio, pennsylvania and wisconsin, instead of obama winning 332-206, the electoral map would have gone from blue to red. romney over obama. 273-262, by one estimate. some leading republicans oppose the change. >> i am a traditionalist myself. i really am a conservative. i'm a little bit skeptical of this. >> reporter: and tonight, virginia's governor, bob mcdonald came out against it. in fact, potential candidates are warning the party as a bigger problem. >> we've got to stop being the stupid party. and i'm serious. it's time for a new republican party that talks like adults. we had a number of republicans that damaged this year with offensive and bizarre comments. >> a warning that changing what candidates say could be more important than changing how they count votes. andrea mitchell, nbc news, washington. and still ahead here on a friday night, a public health emergency sweeping through a big american city. a danger that's in the air that has doctors sounding the alarm. and later, it's been around longer than an entire generation has been alive, and it is still going strong. of special interest to our viewers in the west tonight, right now, the problem is dirty air. while this happens every year, this year is the worst anybody can remember, making life anywhere outside the home down right dangerous. nbc's miguel almaguer has our report tonight from salt lake city. >> reporter: this is the nation's dirtiest air. >> we have i think a real health crisis on our hands. >> reporter: it's what more than a million in the salt lake city area are breathing. >> it gets pretty nasty and this is the nastiest i've ever seen it. >> can't breathe. >> reporter: the smog is choking. pregnant women and the elderly told stay inside. >> i open that door and it hits me and it gets hard to breathe. >> reporter: there was hope a winter storm would clear the air, but it made matters worse. hundreds of pile-ups, the airport shut down for hours. ksl meteorologist grant weyman blames it on the inversion. >> in the winter, you get the area above that acts as a trap and keeps everything where it's at. pollution and haze builds up in the valleys. >> reporter: what people are breathe in the valley is a combination of carbon monoxide and soot. the air so bad here, it's up to four times more toxic than what's considered safe. >> have you had a fever? >> reporter: for a region already battling the flu, ers are seeing a dramatic rise in patients with breathing problems. doctors warn, bad air could lead to heart attacks and strokes. >> what we are exposed to now is comparable to forcing all men's of the community to become active smokers. >> reporter: to fight pollution, authorities could lower the speed limit and are considering free mass transit to get cars off the road. now they could even restrict the sale of aerosols. typically known for its great outdoors, residents and visitors alike have had enough. >> it's like a utopian city. we just love it. and this is a huge, huge drawback. almost enough to consider relocating. >> we're visiting from new york city. the air quality here is just disgusting. it's nothing like i've ever seen in new york. so it's kind of shocking. >> blue skies will return. but for now, the view from here isn't what anyone wants to see. miguel almaguer, nbc news, salt lake city. we're back in a moment with the news about hillary clinton today that a lot of people have been wondering about. weather in the news tonight heading into the weekend, especially in the eastern half of the country, a big storm has left snow from the midwest through the mid atlantic and as it churns north and east tonight, it's leaving significant icing, upwards of 5 inches of snow in some places. at one point today, precip from this one storm was falling from detroit to south carolina, where 70 highway wrecks were reported. air travel is already being affected up and down the east coast tonight. those watching any of secretary hillary clinton's testimony this week noticed, she's been wearing glasses, which, of course, she has from time to time all her life. but when photographers peered in even closer, they noticed a sectional fresnel lens over her left eye. they are used to prevent double vision. her spokesman said she'll be wearing them for a while, due to lingering issues from her concussion. as you recall, she took a terrible fall at home while weakened by a stomach virus. we talked earlier tonight about the rampant winter illnesses out there and how many people have fallen victim. there are reports tonight from florida, burt reynolds has been admitted to intensive carefter catching the flu, becoming severely dehydrated. a spokesman says the 76-year-old veteran actor is improving. we're back in a moment with a big night for one of the all-time greats. finally tonight, you see the curtains behind us, it means it's a big weekend for the longest-running show ever on broadway. tomorrow night, "phantom of the opera" marks 25 years on broadway. and while hundreds of other shows have come and gone in that time, "phantom" has been strong eight times a week since january 26th, 1988. we get the story tonight from nbc's kristen dahlgren. >> reporter: the biggest blockbuster in history isn't "avatar," not "titanic" -- >> this is bad. >> reporter: or even the entire "star wars" franchise. ♪ >> reporter: it turns out, a phantom has all of them beat. ♪ >> reporter: the phantom of the opera has grossed more than $5.6 billion worldwide. 130 million people have seen it, and on saturday, it will celebrate 25 years on broadway. >> i thought everybody in the world had seen it. >> reporter: 87-year-old sylvia bailey has been an usher since the show first opened back in 1988. >> they still love it. they go, ooh. >> reporter: the appeal is universal. ♪ >> reporter: phantom has been performed in 28 countries. >> it really is like "downton abbey." it's just as mellow dramatic as that. it's got sex, it's got love. it's got everything you want in a really good story. ♪ >> reporter: she was only 5 when phantom opened on broadway. >> i had the cassette tape and i used to listen and sing along with it. >> reporter: the production is massive. >> there's nothing like sitting underneath it. it's still thrilling. still thrilling when people come in. >> reporter: the actors who play the phantom have to endure 90 minutes of makeup. and even though the show has gone through more than a ton of makeup recover over the years -- >> i wake up stuck to my pillow sometimes. you find it like in your knee. it's like, where did that come from? ♪ >> reporter: but he says it's well worth it, for a role that seems to stick so much with audiences. >> it's timeless. i think that's why we're still doing it. ♪ >> reporter: and there's no end in sight. which is good, because nobody has plans to leave. >> i'm going to be here as long as the phantom is here. when the phantom leaves, i'm leaving. >> reporter: kristen dahlgren, nbc news, new york. great show. and that is ours on a friday night and for this week. thank you for being here with us. i'm brian williams. lester holt will be here with you this weekend. we, of course, hope to see you right back here on monday night. in the meantime, have a good weekend. good night. right now at 6:00, did they go too far? the shocking hazing allegations at a local high school. fweng. i'm jess swres. we'll have more on that story in just a moment. >> and i'm janelle wang in for raj mathai. good news for michael crabtree. nbc bay area news has just learned san fran spran county district attorney will not file charges against him in connection to allegations that he sexually assaulted a woman in a hotel room a