The best source would be to have a battery-powered weather radio that gets advisories direct from the National Weather Service.
Berwyn, PA can get tornadoes and thus tornado warnings. Answers.com cannot provide real-time information on tornado warnings. For that information you should go to the official website of the National Weather Service. For potential weather emergencies you should purchase a battery-powered weather radio.
Yes. Tornado warnings are now a common part of severe weather alerts.
Most tornado warnings are usually based on data from Doppler radar, which can indicate a strong mesocyclone or even the signature of a tornado itself, and on reports from spotters, who may report if a tornado is forming or already on the ground.
no
Yes. The National Weather service issues tornado warnings if a tornado has been spotted or may develop very soon.
In the U.S. tornado warnings are issued by local offices of the National Weather Service.
Probably not. As of my writing this, there are no active tornado warnings in the United States, but that could change by the time you read this. For actual up-to-date information check out the website of the National Weather Service for current weather watches and warnings in the US.
Last year in 2011, there were over 1800 tornado reports (of which about 1700 were confirmed), but the number of tornado warnings was higher as not all warnings correspond to a formal report. So the number of warnings issued in 2011 was likely well over 2000. However, 2011 was an extremely active tornado season. An average tornado season sees about 1200 tornadoes in the U.S., which would likely work out to about 1800-2000 warnings.
Yes. Information on tornado warnings is broadcast through TV, radio, and smartphone apps. In some areas, sirens will sound.
The National Weather Service issues Tornado Warnings as well as Watches. This is also true for Severe Thunderstorm Warnings and Watches.
Tornado weather warnings in Canada can be found from a number of reliable sources. Local news and weather will give up to date weather and weather warnings for the area you are in or are visiting. Yon can also find this information from Canadian weather sites on the internet or buy world news and weather sites.
The National Weather Service issues warnings to alert people, telling them that a tornado is heading their way. These warnings contain information telling people to get underground or to the lowest floor of their house, and other survival information. This information is given out through TV and radio stations. In some places sirens may sound. Warnings such as these have saved thousands of lives.