Federal officials and leaders of the nation’s largest wireless telephone companies are set to announce Tuesday that they’re launching a new mobile telephone emergency alert system by the end of the year in Washington and New York.

The Personal Localized Alerting Network, or PLAN, won’t be available across the rest of the country until April, but top executives from AT&T, Sprint, T-Mobile and Verizon are scheduled to join Federal Communications Commission Commissioner Julius Genachowski, Federal Emergency Management Agency Administrator W. Craig Fugate and New York City Mayor Michael Bloomberg in New York on Tuesday to announce its availability in the two cities.

A separate announcement will be held in Washington at a later date, according to an FCC spokesman.

“The goal is to make sure that in times of real crisis, real emergency, life-saving information can get to people where they are quickly,” Genachowski said in an interview Monday.

While authorities plan to continue broadcasting messages across the Emergency Alert System on radio and television, Genachowski said PLAN “is a major step in recognizing that more and more people are using their mobile devices to communicate, and that it’s often the fastest way to get information to someone.”

Mobile users who currently own or plan to buy newer smart phones and cell phones sold by the four wireless companies would be able to receive the free, text-like messages that would flash across a telephone’s screen and trigger a special vibration, Genachowski said. Once operational, participating federal, state and local agencies would be able to send information regarding only the most serious alerts — including warnings about natural disasters, terrorist attacks or AMBER Alerts.

Fugate, who has spent most of the last two weeks touring deadly tornado damage in southern states, said the technology would have allowed a Washington resident visiting Alabama who owns a mobile phone with a D.C.-based area code to receive warnings about the impending tornadoes.

“What this allows us to do is have the phone know where it is at that moment, and if a broadcast goes off in that area, it’ll go to all the phones in that area,” Fugate said.

Congress in 2006 ordered the FCC to develop requirements for wireless companies to comply with the new alert system, but provided no funding to state and local agencies to use the system.

The announcement is the latest example of government agencies partnering with cellular companies to adopt consumer technology for public safety uses. Hundreds of local governments and local law enforcement across the country offer text and e-mail alerts for residents wanting up-to-date information about emergency situations, weather and traffic.

Millicent West, director of the D.C. Homeland Security and Emergency Management Agency, said the information in the new FEMA alerts would likely be an add-on to the already existing DC Alert system. That uses information from more than a dozen entities for text and e-mail alerts about weather, traffic, emergency situations and some crimes.

“Including another partner is something we welcome, provided that the information is critical,” West said. “This will enhance, not replace, our current system.”

How quickly jurisdictions adopt to new technology depends on their budgets and the current state of their infrastructure. For example, many jurisdictions are looking to upgrade 911 services to digital technology — across the country the cost of that upgrade over the next 20 years could be $9.1 billion, according to a 2009 Department of Transportation study.